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Java AWT Reference by John Zukowski

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19

java.awt Reference

19.1 AWTError

images

Description

An AWTError; thrown to indicate a serious runtime error.

Class Definition

public class java.awt.AWTError
    extends java.lang.Error {

  // Constructors
  public AWTError (String message);
}

Constructors

AWTError

public AWTError (String message)
Parameters message Detail message

See Also

Error, String

19.2 AWTEvent images

images

Description

The root class of all AWT events. Subclasses of this class are the replacement for java.awt.Event, which is only used for the Java 1.0.2 event model. In Java 1.1, event objects are passed from event source components to objects implementing a corresponding listener interface. Some event sources have a corresponding interface, too. For example, AdjustmentEvents are passed from Adjustable objects to AdjustmentListeners. Some event types do not have corresponding interfaces; for example, ActionEvents are passed from Buttons to ActionListeners, but there is no “Actionable” interface that Button implements.

Class Definition

public abstract class java.awt.AWTEvent
    extends java.util.EventObject {

  // Constants
  public final static long ACTION_EVENT_MASK;
  public final static long ADJUSTMENT_EVENT_MASK;
  public final static long COMPONENT_EVENT_MASK;
public final static long CONTAINER_EVENT_MASK;
  public final static long FOCUS_EVENT_MASK;
  public final static long ITEM_EVENT_MASK;
  public final static long KEY_EVENT_MASK;
  public final static long MOUSE_EVENT_MASK;
  public final static long MOUSE_MOTION_EVENT_MASK;
  public final static long RESERVED_ID_MAX;
  public final static long TEXT_EVENT_MASK;
  public final static long WINDOW_EVENT_MASK;

  // Variables
  protected boolean consumed;
  protected int id;

  // Constructors
  public AWTEvent (Event event);
  public AWTEvent (Object source, int id);

  // Instance Methods
  public int getID();
  public String paramString();
  public String toString();

  // Protected Instance Methods
  protected void consume();
  protected boolean isConsumed();
}

Constants

ACTION_EVENT_MASK

public static final long ACTION_EVENT_MASK

The mask for action events.

ADJUSTMENT_EVENT_MASK

public static final long ADJUSTMENT_EVENT_MASK

The mask for adjustment events.

COMPONENT_EVENT_MASK

public static final long COMPONENT_EVENT_MASK

The mask for component events.

CONTAINER_EVENT_MASK

public static final long CONTAINER_EVENT_MASK

The mask for container events.

FOCUS_EVENT_MASK

public static final long FOCUS_EVENT_MASK

The mask for focus events.

ITEM_EVENT_MASK

public static final long ITEM_EVENT_MASK

The mask for item events.

KEY_EVENT_MASK

public static final long KEY_EVENT_MASK

The mask for key events.

MOUSE_EVENT_MASK

public static final long MOUSE_EVENT_MASK

The mask for mouse events.

MOUSE_MOTION_EVENT_MASK

public static final long MOUSE_MOTION_EVENT_MASK

The mask for mouse motion events.

RESERVED_ID_MAX

public static final int

The maximum reserved event id.

TEXT_EVENT_MASK

public static final long TEXT_EVENT_MASK

The mask for text events.

WINDOW_EVENT_MASK

public static final long WINDOW_EVENT_MASK

The mask for window events.

Variables

consumed

protected boolean consumed

If consumed is true, the event will not be sent back to the peer. Semantic events will never be sent back to a peer; thus consumed is always true for semantic events.

id

protected int id

The type ID of this event.

Constructors

AWTEvent

public AWTEvent (Event event)
Parameters event A version 1.0.2 java.awt.Event object.
Description Constructs a 1.1 java.awt.AWTEvent derived from a 1.0.2 java.awt.Event object.
public AWTEvent (Object source, int id)
Parameters source The object that the event originated from.
id An event type ID.
Description Constructs an AWTEvent object.

Instance Methods

getID

public int getID()
Returns The type ID of the event.

paramString

public String paramString()
Returns A string with the current settings of AWTEvent.
Description Helper method for toString() that generates a string of current settings.

toString

public String toString()
Returns A string representation of the AWTEvent object.
Overrides Object.toString()

Protected Instance Methods

consume

protected void consume()
Description Consumes the event so it is not sent back to its source.

isConsumed

public boolean isConsumed()
Returns A flag indicating whether this event has been consumed.

See Also

ActionEvent, AdjustmentEvent, ComponentEvent, Event, EventObject, FocusEvent, ItemEvent, KeyEvent, MouseEvent, WindowEvent

19.3 AWTEventMulticaster images

Description

This class multicasts events to event listeners. Each multicaster has two listeners, cunningly named a and b. When an event source calls one of the listener methods of the multicaster, the multicaster calls the same listener method on both a and b. Multicasters are built into trees using the static add() and remove() methods. In this way a single event can be sent to many listeners.

Static methods make it easy to implement event multicasting in component subclasses. Each time an add<type>Listener() function is called in the component subclass, call the corresponding AWTEventMulticaster.add() method to chain together (or “tree up”) listeners. Similarly, when a remove<type>Listener() function is called, AWTEventMulticaster.remove() can be called to remove a chained listener.

Class Definition

public class java.awt.AWTEventMulticaster
  extends java.lang.Object
  implements java.awt.event.ActionListener, java.awt.event.AdjustmentListener,
             java.awt.event.ComponentListener, java.awt.event.ContainerListener,
             java.awt.event.FocusListener, java.awt.event.ItemListener,
             java.awt.event.KeyListener, java.awt.event.MouseListener,
java.awt.event.MouseMotionListener, java.awt.event.TextListener,
             java.awt.event.WindowListener {

  // Variables
  protected EventListener a;
  protected EventListener b;

  // Constructors
  protected AWTEventMulticaster(EventListener a, EventListener b);

  // Class Methods
  public static ActionListener add(ActionListener a, ActionListener b);
  public static AdjustmentListener add(AdjustmentListener a,
      AdjustmentListener b);
  public static ComponentListener add(ComponentListener a,
      ComponentListener b);
  public static ContainerListener add(ContainerListener a,
      ContainerListener b);
  public static FocusListener add(FocusListener a, FocusListener b);
  public static ItemListener add(ItemListener a, ItemListener b);
  public static KeyListener add(KeyListener a, KeyListener b);
  public static MouseListener add(MouseListener a, MouseListener b);
  public static MouseMotionListener add(MouseMotionListener a,
      MouseMotionListener b);
public static TextListener add(TextListener a, TextListener b);
  public static WindowListener add(WindowListener a, WindowListener b);
  protected static EventListener addInternal(EventListener a, EventListener b);
  public static ActionListener remove(ActionListener l, ActionListener oldl);
  public static AdjustmentListener remove(AdjustmentListener l,
      AdjustmentListener oldl);
  public static ComponentListener remove(ComponentListener l,
      ComponentListener oldl);
  public static ContainerListener remove(ContainerListener l,
      ContainerListener oldl);
  public static FocusListener remove(FocusListener l, FocusListener oldl);
  public static ItemListener remove(ItemListener l, ItemListener oldl);
  public static KeyListener remove(KeyListener l, KeyListener oldl);
  public static MouseListener remove(MouseListener l, MouseListener oldl);
  public static MouseMotionListener remove(MouseMotionListener l,
      MouseMotionListener oldl);
  public static TextListener remove(TextListener l, TextListener oldl);
  public static WindowListener remove(WindowListener l, WindowListener;
  protected static EventListener removeInternal(EventListener l,
      EventListener oldl);

  // Instance Methods
  public void actionPerformed(ActionEvent e);
  public void adjustmentValueChanged(AdjustmentEvent e);
  public void componentAdded(ContainerEvent e);
  public void componentHidden(ComponentEvent e);
  public void componentMoved(ComponentEvent e);
  public void componentRemoved(ContainerEvent e);
  public void componentResized(ComponentEvent e);
  public void componentShown(ComponentEvent e);
  public void focusGained(FocusEvent e);
  public void focusLost(FocusEvent e);
  public void itemStateChanged(ItemEvent e);
  public void keyPressed(KeyEvent e);
  public void keyReleased(KeyEvent e);
  public void keyTyped(KeyEvent e);
  public void mouseClicked(MouseEvent e);
  public void mouseDragged(MouseEvent e);
  public void mouseEntered(MouseEvent e);
  public void mouseExited(MouseEvent e);
  public void mouseMoved(MouseEvent e);
  public void mousePressed(MouseEvent e);
  public void mouseReleased(MouseEvent e);
  public void textValueChanged(TextEvent e);
  public void windowActivated(WindowEvent e);
  public void windowClosed(WindowEvent e);
  public void windowClosing(WindowEvent e);
  public void windowDeactivated(WindowEvent e);
  public void windowDeiconified(WindowEvent e);
public void windowIconified(WindowEvent e);
  public void windowOpened(WindowEvent e);
  // Protected Instance Methods
  protected EventListener remove(EventListener oldl);
  protected void saveInternal(ObjectOutputStream s, String k) throws IOException;
}

images

Variables

a

protected EventListener a

One of the EventListeners this AWTEventMulticaster sends events to.

b

protected EventListener b

One of the EventListeners this AWTEventMulticaster sends events to.

Constructors

AWTEventMulticaster

protected AWTEventMulticaster (EventListener a,
EventListener b)
Parameters a A listener that receives events.
b A listener that receives events.
Description Constructs an AWTEventMulticaster that sends events it receives to the supplied listeners. The constructor is protected because it is only the class methods of AWTEventMulticaster that ever instantiate this class.

Class Methods

add

public static ActionListener add (ActionListener a,
ActionListener b)
Parameters a An event listener.
b An event listener.
Returns A listener object that passes events to a and b.
public static AdjustmentListener add (AdjustmentListener a, AdjustmentListener b)
Parameters a An event listener.
b An event listener.
Returns A listener object that passes events to a and b.
public static ComponentListener add (ComponentListener a, ComponentListener b)
Parameters a An event listener.
b An event listener.
Returns A listener object that passes events to a and b.
public static ContainerListener add (ContainerListener a, ContainerListener b)
Parameters a An event listener.
b An event listener.
Returns A listener object that passes events to a and b.
public static FocusListener add (FocusListener a, FocusListener b)
Parameters a An event listener.
b An event listener.
Returns A listener object that passes events to a and b.
public static ItemListener add (ItemListener a, ItemListener b)
Parameters a An event listener.
b An event listener.
Returns A listener object that passes events to a and b.
public static KeyListener add (KeyListener a, KeyListener b)
Parameters a An event listener.
b An event listener.
Returns A listener object that passes events to a and b.
public static MouseListener add (MouseListener a, MouseListener b)
Parameters a An event listener.
b An event listener.
Returns A listener object that passes events to a and b.
public static MouseMotionListener add (MouseMotionListener a, MouseMotionListener b)
Parameters a An event listener.
b An event listener.
Returns A listener object that passes events to a and b.
public static TextListener add (TextListener a, TextListener b)
Parameters a An event listener.
b An event listener.
Returns A listener object that passes events to a and b.
public static WindowListener add (WindowListener a, WindowListener b)
Parameters a An event listener.
b An event listener.
Returns A listener object that passes events to a and b.

addInternal

public static EventListener addInternal (EventListener a,
EventListener b)
Parameters a An event listener.
b An event listener.
Returns A listener object that passes events to a and b.
Description This method is a helper for the add() methods.

remove

public static ActionListener remove (ActionListener l,
ActionListener oldl)
Parameters l An event listener.
oldl An event listener.
Returns A listener object that multicasts to l but not oldl.
public static AdjustmentListener remove (AdjustmentListener l, AdjustmentListener oldl)
Parameters l An event listener.
oldl An event listener.
Returns A listener object that multicasts to l but not oldl.
public static ComponentListener remove (ComponentListener l, ComponentListener oldl)
Parameters l An event listener.
oldl An event listener.
Returns A listener object that multicasts to l but not oldl.
public static ContainerListener remove (ContainerListener l, ContainerListener oldl)
Parameters l An event listener.
oldl An event listener.
Returns A listener object that multicasts to l but not oldl.
public static FocusListener remove (FocusListener l, FocusListener oldl)
Parameters l An event listener.
oldl An event listener.
Returns A listener object that multicasts to l but not oldl.
public static ItemListener remove (ItemListener l, ItemListener oldl)
Parameters l An event listener.
oldl An event listener.
Returns A listener object that multicasts to l but not oldl.
public static KeyListener remove (KeyListener l, KeyListener oldl)
Parameters l An event listener.
oldl An event listener.
Returns A listener object that multicasts to l but not oldl.
public static MouseListener remove (MouseListener l, MouseListener oldl)
Parameters l An event listener.
oldl An event listener.
Returns A listener object that multicasts to l but not oldl.
public static MouseMotionListener remove (MouseMotionListener l, MouseMotionListener oldl)
Parameters l An event listener.
oldl An event listener.
Returns A listener object that multicasts to l but not oldl.
public static TextListener remove (TextListener l, TextListener oldl)
Parameters l An event listener.
oldl An event listener.
Returns A listener object that multicasts to l but not oldl.
public static WindowListener remove (WindowListener l, WindowListener oldl)
Parameters l An event listener.
oldl An event listener.
Returns A listener object that multicasts to l but not oldl.
public static WindowListener remove (WindowListener l, WindowListener oldl)
Parameters l An event listener.
oldl An event listener.
Returns A listener object that multicasts to l but not oldl.

removeInternal

public static EventListener removeInternal (EventListener
l, EventListener oldl)
Parameters l An event listener.
oldl An event listener.
Returns A listener object that multicasts to l but not oldl.
Description This method is a helper for the remove() methods.

Instance Methods

actionPerformed

public void actionPerformed (ActionEvent e)
Parameters e The action event that occurred.
Description Handles the event by passing it on to listeners a and b.

adjustmentValueChanged

public void adjustmentValueChanged (AdjustmentEvent e)
Parameters e The adjustment event that occurred.
Description Handles the event by passing it on to listeners a and b.

componentAdded

public void componentAdded (ContainerEvent e)
Parameters e The container event that occurred.
Description Handles the event by passing it on to listeners a and b.

componentHidden

public void componentHidden (ComponentEvent e)
Parameters e The component event that occurred.
Description Handles the event by passing it on to listeners a and b.

componentMoved

public void componentMoved (ComponentEvent e)
Parameters e The component event that occurred.
Description Handles the event by passing it on to listeners a and b.

componentRemoved

public void componentRemoved (ContainerEvent e)
Parameters e The container event that occurred.
Description Handles the event by passing it on to listeners a and b.

componentResized

public void componentResized (ComponentEvent e)
Parameters e The component event that occurred.
Description Handles the event by passing it on to listeners a and b.

componentShown

public void componentShown (ComponentEvent e)
Parameters e The component event that occurred.
Description Handles the event by passing it on to listeners a and b.

focusGained

public void focusGained (FocusEvent e)
Parameters e The focus event that occurred.
Description Handles the event by passing it on to listeners a and b.

focusLost

public void focusLost (FocusEvent e)
Parameters e The focus event that occurred.
Description Handles the event by passing it on to listeners a and b.

itemStateChanged

public void itemStateChanged (ItemEvent e)
Parameters e The item event that occurred.
Description Handles the event by passing it on to listeners a and b.

keyPressed

public void keyPressed (KeyEvent e)
Parameters e The key event that occurred.
Description Handles the event by passing it on to listeners a and b.

keyReleased

public void keyReleased (KeyEvent e)
Parameters e The key event that occurred.
Description Handles the event by passing it on to listeners a and b.

keyTyped

public void keyTyped (KeyEvent e)
Parameters e The key event that occurred.
Description Handles the event by passing it on to listeners a and b.

mouseClicked

public void mouseClicked (MouseEvent e)
Parameters e The mouse event that occurred.
Description Handles the event by passing it on to listeners a and b.

mouseDragged

public void mouseDragged (MouseEvent e)
Parameters e The mouse event that occurred.
Description Handles the event by passing it on to listeners a and b.

mouseEntered

public void mouseEntered (MouseEvent e)
Parameters e The mouse event that occurred.
Description Handles the event by passing it on to listeners a and b.

mouseExited

public void mouseExited (MouseEvent e)
Parameters e The mouse event that occurred.
Description Handles the event by passing it on to listeners a and b.

mouseMoved

public void mouseMoved (MouseEvent e)
Parameters e The mouse event that occurred.
Description Handles the event by passing it on to listeners a and b.

mousePressed

public void mousePressed (MouseEvent e)
Parameters e The mouse event that occurred.
Description Handles the event by passing it on to listeners a and b.

mouseReleased

public void mouseReleased (MouseEvent e)
Parameters e The mouse event that occurred.
Description Handles the event by passing it on to listeners a and b.

textValueChanged

public void textValueChanged (TextEvent e)
Parameters e The text event that occurred.
Description Handles the event by passing it on to listeners a and b.

windowActivated

public void windowActivated (WindowEvent e)
Parameters e The window event that occurred.
Description Handles the event by passing it on to listeners a and b.

windowClosed

public void windowClosed (WindowEvent e)
Parameters e The window event that occurred.
Description Handles the event by passing it on to listeners a and b.

windowClosing

public void windowClosing (WindowEvent e)
Parameters e The window event that occurred.
Description Handles the event by passing it on to listeners a and b.

windowDeactivated

public void windowDeactivated (WindowEvent e)
Parameters e The window event that occurred.
Description Handles the event by passing it on to listeners a and b.

windowDeiconified

public void windowDeiconified (WindowEvent e)
Parameters e The window event that occurred.
Description Handles the event by passing it on to listeners a and b.

windowIconified

public void windowIconified (WindowEvent e)
Parameters e The window event that occurred.
Description Handles the event by passing it on to listeners a and b.

windowOpened

public void windowOpened (WindowEvent e)
Parameters e The window event that occurred.
Description Handles the event by passing it on to listeners a and b.

Protected Instance Methods

remove

protected EventListener remove(EventListener oldl)
Parameters oldl The listener to remove.
Returns The resulting EventListener.
Description This method removes oldl from the AWTEventMulticaster and returns the resulting listener.

See Also

ActionEvent, AdjustmentEvent, ComponentEvent, Event, EventListener, EventObject, FocusEvent, ItemEvent, KeyEvent, MouseEvent, WindowEvent

19.4 AWTException

images

Description

An AWTException; thrown to indicate an exceptional condition; must be caught or declared in a throws clause.

Class Definition

public class java.awt.AWTException
    extends java.lang.Exception {

  // Constructors
  public AWTException (String message);
}

Constructors

AWTException

public AWTException (String message)
Parameters message Detailed message.

See Also

Exception, String

19.5 Adjustable images

images

Description

The Adjustable interface is useful for scrollbars, sliders, dials, and other components that have an adjustable numeric value. Classes that implement the Adjustable interface should send AdjustmentEvent objects to listeners that have registered via addAdjustmentListener(AdjustmentListener).

Interface Definition

public abstract interface java.awt.Adjustable {

  // Constants
  public final static int HORIZONTAL = 0;
  public final static int VERTICAL = 1;

  // Interface Methods
  public abstract void addAdjustmentListener (AdjustmentListener l);
  public abstract int getBlockIncrement();
  public abstract int getMaximum();
  public abstract int getMinimum();
  public abstract int getOrientation();
  public abstract int getUnitIncrement();
  public abstract int getValue();
  public abstract int getVisibleAmount();
  public abstract void removeAdjustmentListener (AdjustmentListener l);
  public abstract void setBlockIncrement (int b);
  public abstract void setMaximum (int max);
  public abstract void setMinimum (int min);
  public abstract void setUnitIncrement (int u);
  public abstract void setValue (int v);
  public abstract void setVisibleAmount (int v);
}

Constants

HORIZONTAL

public static final int HORIZONTAL

A constant representing horizontal orientation.

VERTICAL

public static final int VERTICAL

A constant representing vertical orientation.

Interface Methods

addAdjustmentListener

public abstract void addAdjustmentListener (ActionListener
l)
Parameters l An object that implements the AdjustmentListener interface.
Description Add a listener for adjustment event.

getBlockIncrement

public abstract int getBlockIncrement()
Returns The amount to scroll when a paging area is selected.

getMaximum

public abstract int getMaximum()
Returns The maximum value that the Adjustable object can take.

getMinimum

public abstract int getMinimum()
Returns The minimum value that the Adjustable object can take.

getOrientation

public abstract int getOrientation()
Returns A value representing the direction of the Adjustable object.

getUnitIncrement

public abstract int getUnitIncrement()
Returns The unit amount to scroll.

getValue

public abstract int getValue()
Returns The current setting for the Adjustable object.

getVisibleAmount

public abstract int getVisibleAmount()
Returns The current visible setting (i.e., size) for the Adjustable object.

removeAdjustmentListener

public abstract void removeAdjustmentListener
(AdjustmentListener l)
Parameters l One of the object's AdjustmentListeners.
Description Remove an adjustment event listener.

setBlockIncrement

public abstract void setBlockIncrement (int b)
Parameters b New block increment amount.
Description Changes the block increment amount for the Adjustable object.

setMaximum

public abstract void setMaximum (int max)
Parameters max New maximum value.
Description Changes the maximum value for the Adjustable object.

setMinimum

public abstract void setMinimum (int min)
Parameters min New minimum value.
Description Changes the minimum value for the Adjustable object.

setUnitIncrement

public abstract void setUnitIncrement (int u)
Parameters u New unit increment amount.
Description Changes the unit increment amount for the Adjustable object.

setValue

public abstract void setValue (int v)
Parameters v New value.
Description Changes the current value of the Adjustable object.

setVisibleAmount

public abstract void setVisibleAmount (int v)
Parameters v New amount visible.
Description Changes the current visible amount of the Adjustable object.

See Also

AdjustmentEvent, AdjustmentListener, Scrollbar

19.6 BorderLayout

images

Description

BorderLayout is a LayoutManager that provides the means to lay out components along the edges of a container. It divides the container into five regions, named North, East, South, West, and Center. Normally you won't call the LayoutManager's methods yourself. When you add() a Component to a Container, the Container calls the addLayoutComponent() method of its LayoutManager.

Class Definition

public class java.awt.BorderLayout extends java.lang.Object implements java.awt.LayoutManager2, java.io.Serializable { // Constants public final static String CENTER; images public final static String EAST; images public final static String NORTH; images public final static String SOUTH; images public final static String WEST; images

// Constructors public BorderLayout(); public BorderLayout (int hgap, int vgap); // Instance Methods public void addLayoutComponent (Component comp, Object constraints); images public void addLayoutComponent (String name, Component component); images public int getHgap(); images public abstract float getLayoutAlignmentX(Container target); images public abstract float getLayoutAlignmentY(Container target); images public int getVgap(); images public abstract void invalidateLayout(Container target); images public void layoutContainer (Container target); public abstract Dimension maximumLayoutSize(Container target); images public Dimension minimumLayoutSize (Container target); public Dimension preferredLayoutSize (Container target); public void removeLayoutComponent (Component component); public void setHgap (int hgap); images public void setVgap (int vgap); images public String toString(); }

Constants

CENTER

public final static String CENTER

A constant representing center orientation.

EAST

public final static String EAST

A constant representing east orientation.

NORTH

public final static String NORTH

A constant representing north orientation.

SOUTH

public final static String SOUTH

A constant representing south orientation.

WEST

public final static String WEST

A constant representing west orientation.

Constructors

BorderLayout

public BorderLayout()
Description Constructs a BorderLayout object.
public BorderLayout (int hgap, int vgap)
Parameters hgap Horizontal space between each component in the container.
vgap Vertical space between each component in the container.
Description Constructs a BorderLayout object with the values specified as the gaps between each component in the container managed by this instance of BorderLayout.

Instance Methods

addLayoutComponent

public void addLayoutComponent (Component comp, Object constraints) images

Parameters comp The component being added.
constraints An object describing the constraints on this component.
Implements LayoutManager2.addLayoutComponent()
Description Adds the component comp to a container subject to the given constraints. This is a more general version of addLayoutComponent(String, Component) method. It corresponds to java.awt.Container's add(Component, Object) method. In practice, it is used the same in version 1.1 as in Java 1.0.2, except with the parameters swapped:
Panel p = new Panel(new BorderLayout());
p.add(new Button("OK"), BorderLayout.SOUTH);

addLayoutComponent

public void addLayoutComponent (String name, Component component) images

Parameters name Name of region to add component to.
component Actual component being added.
Implements LayoutManager.addLayoutComponent()
Description Adds a component to a container in region name. This has been replaced in version 1.1 with the more general addLayoutComponent(Component, Object).

getHgap

public int getHgap() images

Returns The horizontal gap for this BorderLayout instance.

getLayoutAlignmentX

public abstract float getLayoutAlignmentX (Container target) images

Parameters target The container to inspect.
Returns The value .5 for all containers.
Description This method returns the preferred alignment of the given container target. A return value of 0 is left aligned, .5 is centered, and 1 is right aligned.

getLayoutAlignmentY

public abstract float getLayoutAlignmentY (Container target) images

Parameters target The container to inspect.
Returns The value .5 for all containers.
Description This method returns the preferred alignment of the given container target. A return value of 0 is top aligned, .5 is centered, and 1 is bottom aligned.

getVgap

public int getVgap() images

Returns The vertical gap for this BorderLayout instance.

invalidateLayout

public abstract void invalidateLayout (Container target) images

Parameters target The container to invalidate.
Description Does nothing.

layoutContainer

public void layoutContainer (Container target)
Parameters target The container that needs to be redrawn.
Implements LayoutManager.layoutContainer()
Description Draws components contained within target.

maximumLayoutSize

public abstract Dimension maximumLayoutSize (Container target) images

Parameters target The container to inspect.
Returns A Dimension whose horizontal and vertical components are Integer.MAX_VALUE.
Description For BorderLayout, a maximal Dimension is always returned.

minimumLayoutSize

public Dimension minimumLayoutSize (Container target)
Parameters target The container whose size needs to be calculated.
Returns Minimum Dimension of the container target.
Implements LayoutManager.minimumLayoutSize()
Description Calculates minimum size of target. container.

preferredLayoutSize

public Dimension preferredLayoutSize (Container target)
Parameters target The container whose size needs to be calculated.
Returns Preferred Dimension of the container target.
Implements LayoutManager.preferredLayoutSize()
Description Calculates preferred size of target container.

removeLayoutComponent

public void removeLayoutComponent (Component component)
Parameters component Component to stop tracking.
Implements LayoutManager.removeLayoutComponent()
Description Removes component from any internal tracking systems.

setHgap

public void setHgap (int hgap) images

Parameters hgap The horizontal gap value.
Description Sets the horizontal gap between components.

setVgap

public void setVgap (int vgap) images

Parameters vgap The vertical gap value.
Description Sets the vertical gap between components.

toString

public String toString()
Returns A string representation of the BorderLayout object.
Overrides Object.toString()

See Also

Component, Container, Dimension, LayoutManager, LayoutManager2, Object, String

19.7 Button

images

Description

The Button is the familiar labeled button object. It inherits most of its functionality from Component. For example, to change the font of the Button, you would use Component's setFont() method. The Button sends java.awt.event.ActionEvent objects to its listeners when it is pressed.

Class Definition

public class java.awt.Button extends java.awt.Component { // Constructors public Button(); public Button (String label); // Instance Methods public void addActionListener (ActionListener l); images public void addNotify(); public String getActionCommand(); images public String getLabel(); public void removeActionListener (ActionListener l); images public void setActionCommand (String command); images public synchronized void setLabel (String label); // Protected Instance Methods protected String paramString(); protected void processActionEvent (ActionEvent e); images protected void processEvent (AWTEvent e); images }

Constructors

Button

public Button()
Description Constructs a Button object with no label.
public Button (String label)
Parameters label The text for the label on the button
Description Constructs a Button object with text of label.

Instance Methods

addActionListener

public void addActionListener (ActionListener l) images

Parameters l An object that implements the ActionListener interface.
Description Add a listener for the action event.

addNotify

public void addNotify()
Overrides Component.addNotify()
Description Creates Button's peer.

getActionCommand

public String getActionCommand() images

Returns Current action command string.
Description Returns the string used for the action command.

getLabel

public String getLabel()
Returns Text of the Button's label.

removeActionListener

public void removeActionListener (ActionListener l) images

Parameters l One of this Button's ActionListeners.
Description Remove an action event listener.

setActionCommand

public void setActionCommand (String command) images

Parameters command New action command string.
Description Specify the string used for the action command.

setLabel

public synchronized void setLabel (String label)
Parameters label New text for label of Button.
Description Changes the Button's label to label.

Protected Instance Methods

paramString

protected String paramString()
Returns String with current settings of Button.
Overrides Component.paramString()
Description Helper method for toString() used to generate a string of current settings.

processActionEvent

protected void processActionEvent (ActionEvent e) images

Parameters e The action event to process.
Description Action events are passed to this method for processing. Normally, this method is called by processEvent().

processEvent

protected void processEvent (AWTEvent e) images

Parameters e The event to process.
Description Low level AWTEvents are passed to this method for processing.

See Also

ActionListener, Component, String

19.8 Canvas

images

Description

Canvas is a Component that provides a drawing area and is often used as a base class for new components.

Class Definition

public class java.awt.Canvas
    extends java.awt.Component {

  // Constructors
  public Canvas();

  // Instance Methods
  public void addNotify();
  public void paint (Graphics g);
}

Constructors

Canvas

public Canvas()
Description Constructs a Canvas object.

Instance Methods

addNotify

public void addNotify()
Overrides Component.addNotify()
Description Creates Canvas's peer.

paint

public void paint (Graphics g)
Parameters g Graphics context of component.
Description Empty method to be overridden in order to draw something in graphics context.

See Also

Component, Graphics

19.9 CardLayout

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Description

The CardLayout LayoutManager provides the means to manage multiple components, displaying one at a time. Components are displayed in the order in which they are added to the layout, or in an arbitrary order by using an assignable name.

Class Definition

public class java.awt.CardLayout extends java.lang.Object implements java.awt.LayoutManager2, java.io.Serializable { // Constructors public CardLayout(); public CardLayout (int hgap, int vgap); // Instance Methods public void addLayoutComponent (Component comp, Object constraints); images public void addLayoutComponent (String name, Component component); images public void first (Container parent); public int getHgap(); images public abstract float getLayoutAlignmentX(Container target); images public abstract float getLayoutAlignmentY(Container target); images public int getVgap(); images public abstract void invalidateLayout(Container target); images public void last (Container parent); public void layoutContainer (Container target); public abstract Dimension maximumLayoutSize(Container target); images public Dimension minimumLayoutSize (Container target); public void next (Container parent); public Dimension preferredLayoutSize (Container target); public void previous (Container parent); public void removeLayoutComponent (Component component); public void setHgap (int hgap); images public void setVgap (int vgap); images

public void show (Container parent, String name);
  public String toString();
}

Constructors

CardLayout

public CardLayout()
Description Constructs a CardLayout object.
public CardLayout (int hgap, int vgap)
Parameters hgap Horizontal space around left and right of container
vgap Vertical space around top and bottom of container
Description Constructs a CardLayout object with the values specified as the gaps around the container managed by this instance of CardLayout.

Instance Methods

addLayoutComponent

public void addLayoutComponent (Component comp, Object constraints) images

Parameters comp The component being added.
constraints An object describing the constraints on this component.
Implements LayoutManager2.addLayoutComponent()
Description Adds the component comp to a container subject to the given constraints. This is a more generalized version of addLayoutComponent(String, Component). It corresponds to java.awt.Container's add(Component, Object). In practice, it is used the same in Java 1.1 as in Java 1.0.2, except with the parameters swapped:
Panel p = new Panel();
p.setLayoutManager(new CardLayout());
p.add(new Button("OK"), "Don Julio");

addLayoutComponent

public void addLayoutComponent (String name, Component component) images

Parameters name Name of the component to add.
component The actual component being added.
Implements LayoutManager.addLayoutComponent()
Description Places component under the layout's management, assigning it the given name. This has been replaced in version 1.1 with the more general addLayoutComponent(Component, Object).

first

public void first (Container parent)
Parameters parent The container whose displayed component is changing.
Throws IllegalArgumentException
If the LayoutManager of parent is not CardLayout.
Description Sets the container to display the first component in parent.

getHgap

public int getHgap() images

Returns The horizontal gap for this CardLayout instance.

getLayoutAlignmentX

public abstract float getLayoutAlignmentX (Container target) images

Parameters target The container to inspect.
Returns The value .5 for all containers.
Description This method returns the preferred alignment of the given container target. A return value of 0 is left aligned, .5 is centered, and 1 is right aligned.

getLayoutAlignmentY

public abstract float getLayoutAlignmentY (Container target) images

Parameters target The container to inspect.
Returns The value .5 for all containers.
Description This method returns the preferred alignment of the given container target. A return value of 0 is top aligned, .5 is centered, and 1 is bottom aligned.

getVgap

public int getVgap() images

Returns The vertical gap for this CardLayout instance.

invalidateLayout

public abstract void invalidateLayout (Container target) images

Parameters target The container to invalidate.
Description Does nothing.

last

public void last (Container parent)
Parameters parent The container whose displayed component is changing.
Throws IllegalArgumentException
If the LayoutManager of parent is not CardLayout.
Description Sets the container to display the final component in parent.

layoutContainer

public void layoutContainer (Container target)
Parameters target The container that needs to be redrawn.
Implements LayoutManager.layoutContainer()
Description Displays the currently selected component contained within target.

maximumLayoutSize

public abstract Dimension maximumLayoutSize .hw Container (Container target) images

Parameters target The container to inspect.
Returns A Dimension whose horizontal and vertical components are Integer.MAX_VALUE.
Description For CardLayout, a maximal Dimension is always returned.

minimumLayoutSize

public Dimension minimumLayoutSize (Container target)
Parameters target The container whose size needs to be calculated.
Returns Minimum Dimension of the container target.
Implements LayoutManager.minimumLayoutSize()
Description Calculates minimum size of the target container.

next

public void next (Container parent)
Parameters parent The container whose displayed component is changing.
Throws IllegalArgumentException
If the LayoutManager of parent is not CardLayout.
Description Sets the container to display the following component in the parent.

preferredLayoutSize

public Dimension preferredLayoutSize (Container target)
Parameters target The container whose size needs to be calculated.
Returns Preferred Dimension of the container target.
Implements LayoutManager.preferredLayoutSize()
Description Calculates preferred size of the target container.

previous

public void previous (Container parent)
Parameters parent The container whose displayed component is changing.
Throws IllegalArgumentException
If the LayoutManager of parent is not CardLayout.
Description Sets the container to display the prior component in parent.

removeLayoutComponent

public void removeLayoutComponent (Component component)
Parameters component Component to stop tracking.
Implements LayoutManager.removeLayoutComponent()
Description Removes component from the layout manager's internal tables.

setHgap

public void setHgap (int hgap) images

Parameters hgap The horizontal gap value.
Description Sets the horizontal gap for the left and right of the container.

setVgap

public void setVgap (int vgap) images

Parameters vgap The vertical gap value.
Description Sets the vertical gap for the top and bottom of the container.

show

public void show (Container parent, String name)
Parameters parent The container whose displayed component is changing.
name Name of component to display.
Throws IllegalArgumentException
If LayoutManager of parent is not CardLayout.
Description Sets the container to display the component name in parent.

toString

public String toString()
Returns A string representation of the CardLayout object.
Overrides Object.toString()

See Also

Component, Container, Dimension, LayoutManager, LayoutManager2, Object, String

19.10 Checkbox

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Description

The Checkbox is a Component that provides a true or false toggle switch for user input.

Class Definition

public class java.awt.Checkbox extends java.awt.Component implements java.awt.ItemSelectable { // Constructors public Checkbox(); public Checkbox (String label); public Checkbox (String label, boolean state); images public Checkbox (String label, boolean state, CheckboxGroup group); images public Checkbox (String label, CheckboxGroup group, boolean state); // Instance Methods public void addItemListener (ItemListener l); images public void addNotify(); public CheckboxGroup getCheckboxGroup(); public String getLabel(); public Object[] getSelectedObjects(); images public boolean getState(); public void removeItemListener (ItemListener l); images public void setCheckboxGroup (CheckboxGroup group); public synchronized void setLabel (String label); public void setState (boolean state); // Protected Instance Methods protected String paramString(); protected void processEvent (AWTEvent e); images protected void processItemEvent (ItemEvent e); images }

Constructors

Checkbox

public Checkbox()
Description Constructs a Checkbox object with no label that is initially false.
public Checkbox (String label)
Parameters label Text to display with the Checkbox.
Description Constructs a Checkbox object with the given label that is initially false.
public Checkbox (String label, boolean state) images
Parameters label Text to display with the Checkbox.
state Intial value of the Checkbox.
Description Constructs a Checkbox with the given label, initialized to the given state.
public Checkbox (String label, boolean state, CheckboxGroup group) images
Parameters label Text to display with the Checkbox.
state Intial value of the Checkbox.
group The CheckboxGroup this Checkbox should belong to.
Description Constructs a Checkbox with the given label, initialized to the given state and belonging to group.
public Checkbox (String label, CheckboxGroup group, boolean state)
Parameters label Text to display with the Checkbox.
group The CheckboxGroup this Checkbox should belong to.
state Intial value of the Checkbox.
Description Constructs a Checkbox object with the given settings.

Instance Methods

addItemListener

public void addItemListener (ItemListener l) images

Parameters l The listener to be added.
Implements ItemSelectable.addItemListener(ItemListener l)
Description Adds a listener for the ItemEvent objects this Checkbox generates.

addNotify

public void addNotify()
Overrides Component.addNotify()
Description Creates Checkbox peer.

getCheckboxGroup

public CheckboxGroup getCheckboxGroup()
Returns The current CheckboxGroup associated with the Checkbox, if any.

getLabel

public String getLabel()
Returns The text associated with the Checkbox.

getSelectedObjects

public Object[] getSelectedObjects() images

Implements ItemSelectable.getSelectedObjects()
Description If the Checkbox is checked, returns an array with length 1 containing the label of the Checkbox; otherwise returns null.

getState

public boolean getState()
Returns The current state of the Checkbox.

removeItemListener

public void removeItemListener (ItemListener l) images

Parameters l The listener to be removed.
Implements ItemSelectable.removeItemListener (ItemListener l)
Description Removes the specified ItemListener so it will not receive ItemEvent objects from this Checkbox.

setCheckboxGroup

public void setCheckboxGroup (CheckboxGroup group)
Parameters group New group in which to place the Checkbox.
Description Associates the Checkbox with a different CheckboxGroup.

setLabel

public synchronized void setLabel (String label)
Parameters label New text to associate with Checkbox.
Description Changes the text associated with the Checkbox.

setState

public void setState (boolean state)
Parameters state New state for the Checkbox.
Description Changes the state of the Checkbox.

Protected Instance Methods

paramString

protected String paramString()
Returns String with current settings of Checkbox.
Overrides Component.paramString()
Description Helper method for toString() to generate string of current settings.

processEvent

protected void processEvent(AWTEvent e) images

Parameters e The event to process.
Description Low level AWTEvents are passed to this method for processing.

processItemEvent

protected void processItemEvent(ItemEvent e) images

Parameters e The item event to process.
Description Item events are passed to this method for processing. Normally, this method is called by processEvent().

See Also

CheckboxGroup, Component, ItemEvent, ItemSelectable, String

19.11 CheckboxGroup

images

Description

The CheckboxGroup class provides the means to group multiple Checkbox items into a mutual exclusion set, so that only one checkbox in the set has the value true at any time. The checkbox with the value true is the currently selected checkbox. Mutually exclusive checkboxes usually have a different appearance from regular checkboxes and are also called “radio buttons.”

Class Definition

public class java.awt.CheckboxGroup extends java.lang.Object implements java.io.Serializable { // Constructors public CheckboxGroup(); // Instance Methods public Checkbox getCurrent(); images public Checkbox getSelectedCheckbox() images public synchronized void setCurrent (Checkbox checkbox); images public synchronized void setSelectedCheckbox (Checkbox checkbox); images public String toString(); }

Constructors

CheckboxGroup

public CheckboxGroup()
Description Constructs a CheckboxGroup object.

Instance Methods

getCurrent

public Checkbox getCurrent() images

Returns The currently selected Checkbox within the CheckboxGroup.
Description Replaced by the more aptly named getSelectedCheckbox().

getSelectedCheckbox

public Checkbox getSelectedCheckbox() images

Returns The currently selected Checkbox within the CheckboxGroup.

setCurrent

public synchronized void setCurrent (Checkbox checkbox) images

Parameters checkbox The Checkbox to select.
Description Changes the currently selected Checkbox within the CheckboxGroup.
Description Replaced by setSelectedCheckbox(Checkbox).

setSelectedCheckbox

public synchronized void setSelectedCheckbox (Checkbox checkbox) images

Parameters checkbox The Checkbox to select.
Description Changes the currently selected Checkbox within the CheckboxGroup.

toString

public String toString()
Returns A string representation of the CheckboxGroup object.
Overrides Object.toString()

See Also

Checkbox, Object, String

19.12 CheckboxMenuItem

images

Description

The CheckboxMenuItem class represents a menu item with a boolean state.

Class Definition

public class java.awt.CheckboxMenuItem extends java.awt.MenuItem implements java.awt.ItemSelectable { // Constructors public CheckboxMenuItem(); images public CheckboxMenuItem (String label); public CheckboxMenuItem (String label, boolean state); images // Instance Methods public void addItemListener (ItemListener l); images public void addNotify(); public Object[] getSelectedObjects(); images public boolean getState(); public String paramString(); public void removeItemListener (ItemListener l); images public synchronized void setState (boolean condition); // Protected Instance Methods protected void processEvent (AWTEvent e); images protected void processItemEvent (ItemEvent e); images }

Constructors

CheckboxMenuItem

public CheckboxMenuItem() images

Description Constructs a CheckboxMenuItem object with no label.
public CheckboxMenuItem (String label)
Parameters label Text that appears on CheckboxMenuItem.
Description Constructs a CheckboxMenuItem object whose value is initially false.
public CheckboxMenuItem (String label, boolean state) images
Parameters label Text that appears on CheckboxMenuItem.
state The initial state of the menu item.
Description Constructs a CheckboxMenuItem object with the specified label and state.

Instance Methods

addItemListener

public void addItemListener (ItemListener l) images

Parameters l The listener to be added.
Implements ItemSelectable.addItemListener(ItemListener l)
Description Adds a listener for the ItemEvent objects this CheckboxMenuItem fires off.

addNotify

public void addNotify()
Overrides MenuItem.addNotify()
Description Creates CheckboxMenuItem's peer.

getSelectedObjects

public Object[] getSelectedObjects() images

Implements ItemSelectable.getSelectedObjects()
Description If the CheckboxMenuItem is checked, returns an array with length 1 containing the label of the CheckboxMenuItem; otherwise returns null.

getState

public boolean getState()
Returns The current state of the CheckboxMenuItem.

paramString

public String paramString()
Returns A string with current settings of CheckboxMenuItem.
Overrides MenuItem.paramString()
Description Helper method for toString() to generate string of current settings.

removeItemListener

public void removeItemListener (ItemListener l) images

Parameters l The listener to be removed.
Implements ItemSelectable.removeItemListener (ItemListener l)
Description Removes the specified ItemListener so it will not receive ItemEvent objects from this CheckboxMenuItem.

setState

public synchronized void setState (boolean condition)
Parameters condition New state for the CheckboxMenuItem.
Description Changes the state of the CheckboxMenuItem.

Protected Instance Methods

processEvent

protected void processEvent(AWTEvent e) images

Parameters e The event to process.
Overrides MenuItem.processEvent(AWTEvent)
Description Low level AWTEvents are passed to this method for processing.

processItemEvent

protected void processItemEvent(ItemEvent e) images

Parameters e The item event to process.
Description Item events are passed to this method for processing. Normally, this method is called by processEvent().

See Also

ItemEvent, ItemSelectable, MenuItem, String

19.13 Choice

images

Description

The Choice is a Component that provides a drop-down list of choices to choose from.

Class Definition

public class java.awt.Choice extends java.awt.Component implements java.awt.ItemSelectable {

// Constructors public Choice(); // Instance Methods public synchronized void add (String item); images public synchronized void addItem (String item); images public void addItemListener (ItemListener l); images public void addNotify(); public int countItems(); images public String getItem (int index); public int getItemCount(); images public int getSelectedIndex(); public synchronized String getSelectedItem(); public synchronized Object[] getSelectedObjects(); images public synchronized void insert (String item, int index); images public synchronized void remove (int position); images public synchronized void remove (String item); images public synchronized void removeAll(); images public void removeItemListener (ItemListener l); images public synchronized void select (int pos); public synchronized void select (String str); // Protected Instance Methods protected String paramString(); protected void processEvent (AWTEvent e); images protected void processItemEvent (ItemEvent e); images }

Constructors

Choice

public Choice()
Description Constructs a Choice object.

Instance Methods

add

public synchronized void add (String item) images

Parameters item Text for new entry.
Throws NullPointerException
If item is null.
Description Adds a new entry to the available choices.

addItem

public synchronized void addItem (String item) images

Parameters item Text for new entry.
Throws NullPointerException
If item is null.
Description Replaced by add(String).

addItemListener

public void addItemListener (ItemListener l) images

Parameters l The listener to be added.
Implements ItemSelectable.addItemListener(ItemListener l)
Description Adds a listener for the ItemEvent objects this Choice generates.

addNotify

public void addNotify()
Overrides Component.addNotify()
Description Creates Choice's peer.

countItems

public int countItems() images

Returns Number of items in the Choice.
Description Replaced by getItemCount().

getItem

public String getItem (int index)
Parameters index Position of entry.
Returns A string for an entry at a given position.
Throws ArrayIndexOutOfBoundsException
If index is invalid; indices start at zero.

getItemCount

public int getItemCount() images

Returns Number of items in the Choice.

getSelectedIndex

public int getSelectedIndex()
Returns Position of currently selected entry.

getSelectedItem

public synchronized String getSelectedItem()
Returns Currently selected entry as a String.

getSelectedObjects

public synchronized Object[] getSelectedObjects() images

Implements ItemSelectable.getSelectedObjects()
Description A single-item array containing the current selection.

insert

public synchronized void insert (String item, int index) images

Parameters item The string to add.
index The position for the new string.
Throws IllegalArgumentException
If index is less than zero.
Description Inserts item in the given position.

remove

public synchronized void remove (int position) images

Parameters position The index of an entry in the Choice component.
Description Removes the entry in the given position.
public synchronized void remove (String string) images
Parameters string Text of an entry within the Choice component.
Throws IllegalArgumentException
If string is not in the Choice.
Description Makes the first entry that matches string the selected item.

removeAll

public synchronized void removeAll() images

Description Removes all the entries from the Choice.

removeItemListener

public void removeItemListener (ItemListener l) images

Parameters l The listener to be removed.
Implements ItemSelectable.removeItemListener (ItemListener l)
Description Removes the specified ItemListener so it will not receive ItemEvent objects from this Choice.

select

public synchronized void select (int pos)
Parameters pos The index of an entry in the Choice component.
Throws IllegalArgumentException
If the position is not valid.
Description Makes the entry in the given position.
public synchronized void select (String str)
Parameters str Text of an entry within the Choice component.
Description Makes the first entry that matches str the selected item for the Choice.

Protected Instance Methods

paramString

protected String paramString()
Returns A string with current settings of Choice.
Overrides Component.paramString()
Description Helper method for toString() to generate string of current settings.

processEvent

protected void processEvent (AWTEvent e) images

Parameters e The event to process.
Description Low level AWTEvents are passed to this method for processing.

processItemEvent

protected void processItemEvent (ItemEvent e) images

Parameters e The item event to process.
Description Item events are passed to this method for processing. Normally, this method is called by processEvent().

See Also

Component, ItemSelectable, String

19.14 Color

images

Description

The Color class represents a specific color to the system.

Class Definition

public final class java.awt.Color extends java.lang.Object implements java.io.Serializable { // Constants public static final Color black; public static final Color blue; public static final Color cyan; public static final Color darkGray; public static final Color gray; public static final Color green; public static final Color lightGray; public static final Color magenta; public static final Color orange; public static final Color pink; public static final Color red; public static final Color white; public static final Color yellow; // Constructors public Color (int rgb); public Color (int red, int green, int blue); public Color (float red, float green, float blue);

// Class Methods public static Color decode (String name); images public static Color getColor (String name); public static Color getColor (String name, Color defaultColor); public static Color getColor (String name, int defaultColor); public static Color getHSBColor (float hue, float saturation, float brightness); public static int HSBtoRGB (float hue, float saturation, float brightness); public static float[] RGBtoHSB (int red, int green, int blue, float hsbvalues[]); // Instance Methods public Color brighter(); public Color darker(); public boolean equals (Object object); public int getBlue(); public int getGreen(); public int getRed(); public int getRGB(); public int hashCode(); public String toString(); }

Constants

black

public static final Color black

The color black.

blue

public static final Color blue

The color blue.

cyan

public static final Color cyan

The color cyan.

darkGray

public static final Color darkGray

The color dark gray.

gray

public static final Color gray

The color gray.

green

public static final Color green

The color green.

lightGray

public static final Color lightGray

The color light gray.

magenta

public static final Color magenta

The color magenta.

orange

public static final Color orange

The color orange.

pink

public static final Color pink

The color pink.

red

public static final Color red

The color red.

white

public static final Color white

The color white.

yellow

public static final Color yellow

The color yellow.

Constructors

Color

public Color (int rgb)
Parameters rgb Composite color value
Description Constructs a Color object with the given rgb value.
public Color (int red, int green, int blue)
Parameters red Red component of color in the range[0, 255]
green Green component of color in the range[0, 255]
blue Blue component of color in the range[0, 255]
Description Constructs a Color object with the given red, green, and blue values.
public Color (float red, float green, float blue)
Parameters red Red component of color in the range[0.0, 1.0]
green Green component of color in the range[0.0, 1.0]
blue Blue component of color in the range[0.0, 1.0]
Description Constructs a Color object with the given red, green, and blue values.

Class Methods

decode

public static Color decode (String nm) images

Parameters nm A String representing a color as a 24-bit integer.
Returns The color requested.
Throws NumberFormatException
If nm cannot be converted to a number.
Description Gets color specified by the given string.

getColor

public static Color getColor (String name)
Parameters name The name of a system property indicating which color to fetch.
Returns Color instance of name requested, or null if the name is invalid.
Description Gets color specified by the system property name.
public static Color getColor (String name, Color defaultColor)
Parameters name The name of a system property indicating which color to fetch.
defaultColor Color to return if name is not found in properties, or invalid.
Returns Color instance of name requested, or defaultColor if the name is invalid.
Description Gets color specified by the system property name.
public static Color getColor (String name, int defaultColor)
Parameters name The name of a system property indicating which color to fetch.
defaultColor Color to return if name is not found in properties, or invalid.
Returns Color instance of name requested, or defaultColor if the name is invalid.
Description Gets color specified by the system property name. The default color is specified as a 32-bit RGB value.

getHSBColor

public static Color getHSBColor (float hue, float
saturation, float brightness)
Parameters hue Hue component of Color to create, in the range[0.0, 1.0].
saturation Saturation component of Color to create, in the range[0.0, 1.0].
brightness Brightness component of Color to create, in the range[0.0, 1.0].
Returns Color instance for values provided.
Description Create an instance of Color by using hue, saturation, and brightness instead of red, green, and blue values.

HSBtoRGB

public static int HSBtoRGB (float hue, float saturation,
float brightness)
Parameters hue Hue component of Color to convert, in the range[0.0, 1.0].
saturation Saturation component of Color to convert, in the range[0.0, 1.0].
brightness Brightness component of Color to convert, in the range[0.0, 1.0].
Returns Color value for hue, saturation, and brightness provided.
Description Converts a specific hue, saturation, and brightness to a Color and returns the red, green, and blue values in a composite integer value.

RGBtoHSB

public static float[] RGBtoHSB (int red, int green, int
blue, float[] hsbvalues)
Parameters red Red component of Color to convert, in the range[0, 255].
green Green component of Color to convert, in the range[0, 255].
blue Blue component of Color to convert, in the range[0, 255].
hsbvalues Three element array in which to put the result.
This array is used as the method's return object.
If null, a new array is allocated.
Returns Hue, saturation, and brightness values for Color provided, in elements 0, 1, and 2 (respectively) of the returned array.
Description Allows you to convert specific red, green, blue value to the hue, saturation, and brightness equivalent.

Instance Methods

brighter

public Color brighter()
Returns Brighter version of current color.
Description Creates new Color that is somewhat brighter than current.

darker

public Color darker()
Returns Darker version of current color.
Description Creates new Color that is somewhat darker than current.

equals

public boolean equals (Object object)
Parameters object The object to compare.
Returns true if object represents the same color, false otherwise.
Overrides Object.equals(Object)
Description Compares two different Color instances for equivalence.

getBlue

public int getBlue()
Returns Blue component of current color.

getGreen

public int getGreen()
Returns Green component of current color.

getRed

public int getRed()
Returns Red component of current color.

getRGB

public int getRGB()
Returns Current color as a composite value.
Description Gets integer value of current color.

hashCode

public int hashCode()
Returns A hashcode to use when storing Color in a Hashtable.
Overrides Object.hashCode()
Description Generates a hashcode for the Color.

toString

public String toString()
Returns A string representation of the Color object.
Overrides Object.toString()

See Also

Object, Properties, Serializable, String

19.15 Component

images

Description

The Component class is the parent of all non-menu GUI components.

Class Definition

public abstract class java.awt.Component extends java.lang.Object implements java.awt.image.ImageObserver implements java.awt.MenuContainer implements java.io.Serializable { // Constants public final static float BOTTOM_ALIGNMENT; images public final static float CENTER_ALIGNMENT; images public final static float LEFT_ALIGNMENT; images public final static float RIGHT_ALIGNMENT; images public final static float TOP_ALIGNMENT; images // Variables protected Locale locale; images

// Constructors protected Component(); images // Instance Methods public boolean action (Event e, Object o); images public synchronized void add (PopupMenu popup); images public synchronized void addComponentListener (ComponentListener l); images public synchronized void addFocusListener (FocusListener l); images public synchronized void addKeyListener (KeyListener l); images public synchronized void addMouseListener (MouseListener l); images public synchronized void addMouseMotionListener (MouseMotionListener l); images public void addNotify(); public Rectangle bounds(); images public int checkImage (Image image, ImageObserver observer); public int checkImage (Image image, int width, int height, ImageObserver observer); public boolean contains (int x, int y); images public boolean contains (Point p); images public Image createImage (ImageProducer producer); public Image createImage (int width, int height); public void deliverEvent (Event e); images public void disable(); images public final void dispatchEvent (AWTEvent e) images public void doLayout(); images public void enable(); images public void enable (boolean condition); images public float getAlignmentX(); images public float getAlignmentY(); images public Color getBackground(); public Rectangle getBounds(); images public synchronized ColorModel getColorModel(); public Component getComponentAt (int x, int y); images public Component getComponentAt (Point p); images public Cursor getCursor(); images public Font getFont(); public FontMetrics getFontMetrics (Font f); public Color getForeground(); public Graphics getGraphics(); public Locale getLocale(); images public Point getLocation(); images public Point getLocationOnScreen(); images public Dimension getMaximumSize(); images public Dimension getMinimumSize(); images public String getName(); images public Container getParent(); public ComponentPeer getPeer(); images public Dimension getPreferredSize(); images

public Dimension getSize(); images public Toolkit getToolkit(); public final Object getTreeLock(); images public boolean gotFocus (Event e, Object o); images public boolean handleEvent (Event e); images public void hide(); images public boolean imageUpdate (Image image, int infoflags, int x, int y, int width, int height); public boolean inside (int x, int y); images public void invalidate(); public boolean isEnabled(); public boolean isFocusTraversable(); images public boolean isShowing(); public boolean isValid(); public boolean isVisible(); public boolean keyDown (Event e, int key); images public boolean keyUp (Event e, int key); images public void layout(); images public void list(); public void list (PrintStream out); public void list (PrintStream out, int indentation); public void list (PrintWriter out); images public void list (PrintWriter out, int indentation); images public Component locate (int x, int y); images public Point location(); images public boolean lostFocus (Event e, Object o); images public Dimension minimumSize(); images public boolean mouseDown (Event e, int x, int y); images public boolean mouseDrag (Event e, int x, int y); images public boolean mouseEnter (Event e, int x, int y); images public boolean mouseExit (Event e, int x, int y); images public boolean mouseMove (Event e, int x, int y); images public boolean mouseUp (Event e, int x, int y); images public void move (int x, int y); images public void nextFocus(); images public void paint (Graphics g); public void paintAll (Graphics g); public boolean postEvent (Event e); images public Dimension preferredSize(); images public boolean prepareImage (Image image, ImageObserver observer); public boolean prepareImage (Image image, int width, int height, ImageObserver observer); public void print (Graphics g); public void printAll (Graphics g); public synchronized void remove (MenuComponent popup); images public synchronized void removeComponentListener (ComponentListener l); images public synchronized void removeFocusListener (FocusListener l); images public synchronized void removeKeyListener (KeyListener l); images

public synchronized void removeMouseListener (MouseListener l); images public synchronized void removeMouseMotionListener (MouseMotionListener l); images public void removeNotify(); public void repaint(); public void repaint (long tm); public void repaint (int x, int y, int width, int height); public void repaint (long tm, int x, int y, int width, int height); public void requestFocus(); public void reshape (int x, int y, int width, int height); images public void resize (Dimension d); images public void resize (int width, int height); images public void setBackground (Color c); public void setBounds (int x, int y, int width, int height); images public void setBounds (Rectangle r); images public synchronized void setCursor (Cursor cursor); images public void setEnabled (boolean b); images public synchronized void setFont (Font f); public void setForeground (Color c); public void setLocale (Locale l); images public void setLocation (int x, int y); images public void setLocation (Point p); images public void setName (String name); images public void setSize (int width, int height); images public void setSize (Dimension d); images public void setVisible (boolean b); images public void show(); images public void show (boolean condition); images public Dimension size(); images public String toString(); public void transferFocus(); images public void update (Graphics g); public void validate(); // Protected Instance Methods protected final void disableEvents (long eventsToDisable); images protected final void enableEvents (long eventsToEnable); images protected String paramString(); protected void processComponentEvent (ComponentEvent e); images protected void processEvent (AWTEvent e); images protected void processFocusEvent (FocusEvent e); images protected void processKeyEvent (KeyEvent e); images protected void processMouseEvent (MouseEvent e); images protected void processMouseMotionEvent (MouseEvent e); images }

Constants

BOTTOM_ALIGNMENT

public final static float BOTTOM_ALIGNMENT images

Constant representing bottom alignment in getAlignmentY().

CENTER_ALIGNMENT

public final static float CENTER_ALIGNMENT images

Constant representing center alignment in getAlignmentX() and getAlignmentY().

LEFT_ALIGNMENT

public final static float LEFT_ALIGNMENT images

Constant representing left alignment in getAlignmentX().

RIGHT_ALIGNMENT

public final static float RIGHT_ALIGNMENT images

Constant representing right alignment in getAlignmentX().

TOP_ALIGNMENT

public final static float TOP_ALIGNMENT images

Constant representing top alignment in getAlignmentY().

Variables

locale

protected Locale locale images

Description The locale for the component. Used for internationalization support.

Constructors

Component

protected Component() images

Description This constructor creates a “lightweight” component. This constructor allows Component to be directly subclassed using code written entirely in Java.

Instance Methods

action

public boolean action (Event e, Object o) images

Parameters e Event instance identifying what triggered the call to this method.
o Argument specific to the component subclass that generated the event.
Returns true if event handled, false to propagate it to parent container.
Description Method called when user performs some action in Component. This method is a relic of the old 1.0.2 event model and is replaced by the process . . . Event() methods.

add

public synchronized void add (PopupMenu popup) images

Parameters popup The menu to add.
Description After the PopupMenu is added to a component, it can be shown in the component's coordinate space.

addComponentListener

public void addComponentListener (ComponentListener l) images

Description Adds a listener for the ComponentEvent objects this Component generates.

addFocusListener

public void addFocusListener (FocusListener l) images

Description Adds a listener for the FocusEvent objects this Component generates.

addKeyListener

public void addKeyListener (KeyListener l) images

Description Adds a listener for the KeyEvent objects this Component generates.

addMouseListener

public void addMouseListener (MouseListener l) images

Description Adds a listener for the MouseEvent objects this Component generates.

addMouseMotionListener

public void addMouseMotionListener (MouseMotionListener l) images

Description Adds a listener for the motion MouseEvent objects this Component generates.

addNotify

public void addNotify()
Description Creates peer of Component's subclass.

bounds

public Rectangle bounds() images

Returns Gets bounding rectangle of Component.
Description A Rectangle that returns the outer limits of the Component. Replaced by getBounds() in 1.1.

checkImage

public int checkImage (Image image, ImageObserver
observer)
Parameters image Image to check.
observer The object an image will be rendered onto.
Returns ImageObserver Flags ORed together indicating the image's status.
Description Checks status of image construction.
public int checkImage (Image image, int width, int height, ImageObserver observer)
Parameters image Image to check.
width Horizontal size image will be scaled to.
height Vertical size image will be scaled to.
observer Object image will be rendered onto.
Returns ImageObserver flags ORed together indicating the image's status.
Description Checks status of image construction.

contains

public boolean contains (int x, int y) images

Parameters x The x coordinate, in this Component's coordinate system.
y The y coordinate, in this Component's coordinate system.
Returns true if the Component contains the point; false otherwise.
public boolean contains (Point p) images
Parameters p The point to be tested, in this Component's coordinate system.
Returns true if the Component contains the point; false otherwise.

createImage

public Image createImage (ImageProducer producer)
Parameters producer Class that implements ImageProducer interface to create the new image.
Returns Newly created image instance.
Description Creates an Image based upon an ImageProducer.
public Image createImage (int width, int height)
Parameters width Horizontal size for in-memory Image.
height Vertical size for in-memory Image.
Returns Newly created image instance.
Description Creates an empty in-memory Image for double buffering; to draw on the image, use its graphics context.

deliverEvent

public void deliverEvent (Event e) images

Parameters e Event instance to deliver.
Description Delivers event to the component for processing.

disable

public void disable() images

Description Disables component so that it is unresponsive to user interactions. Replaced by setEnabled(false).

dispatchEvent

public final void dispatchEvent (AWTEvent e) images

Parameters e The AWTEvent to process.
Description Tells the component to deal with the AWTEvent e.

doLayout

public void doLayout() images

Description Lays out component. This method is a replacement for layout().

enable

public void enable() images

Description Enables component so that it is responsive to user interactions. Use setEnabled(true) instead.
public void enable (boolean condition) images
Parameters condition true to enable the component; false to disable it.
Description Enables or disables the component based upon condition. Use setEnabled(boolean) instead.

getAlignmentX

public float getAlignmentX() images

Returns A number between 0 and 1 representing the horizontal alignment of this component.
Description One of the constants LEFT_ALIGNMENT, CENTER_ALIGNMENT, or RIGHT_ALIGNMENT may be returned. CENTER_ALIGNMENT is returned by default.

getAlignmentY

public float getAlignmentY() images

Returns A number between 0 and 1 representing the vertical alignment of this component.
Description One of the constants TOP_ALIGNMENT, CENTER_ALIGNMENT, or BOTTOM_ALIGNMENT may be returned. CENTER_ALIGNMENT is returned by default.

getBackground

public Color getBackground()
Returns Background color of the component.

getBounds

public Rectangle getBounds() images

Returns Gets bounding rectangle of Component.
Description Returns a Rectangle that returns the outer limits of the Component.

getColorModel

public synchronized ColorModel getColorModel()
Returns ColorModel used to display the current component.

getComponentAt

public Component getComponentAt (int x, int y) images

Parameters x The x coordinate, in this Component's coordinate system.
y The y coordinate, in this Component's coordinate system.
Returns Returns the Component containing the given point.
public Component getComponentAt (Point p) images
Parameters p The point to be tested, in this Component's coordinate system.
Returns Returns the Component containing the given point.

getCursor

public Cursor getCursor() images

Returns Current cursor of the component.

getFont

public Font getFont()
Returns Current font of the component.

getFontMetrics

public FontMetrics getFontMetrics (Font f)
Parameters f A Font object, whose platform specific information is desired.
Returns Size information for the given Font.

getForeground

public Color getForeground()
Returns Foreground color of component.

getGraphics

public Graphics getGraphics()
Throws InternalException
If acquiring graphics context is unsupported.
Returns Component's graphics context.

getLocale

public Locale getLocale() images

Throws IllegalComponentStateException
If the component does not have a locale or it has not been added to a hierarchy that does.
Returns Component's locale.

getLocation

public Point getLocation() images

Returns Position of component.
Description Gets the current position of this Component in its parent's coordinate space.

getLocationOnScreen

public Point getLocationOnScreen() images

Returns Position of component.
Description Gets the current position of this Component in the screen's coordinate space.

getMaximumSize

public Dimension getMaximumSize() images

Returns The maximum dimensions of the component.
Description By default, a maximal Dimension is returned.

getMinimumSize

public Dimension getMinimumSize() images

Returns The minimum dimensions of the component.

getName

public String getName() images

Returns This component's name.

getParent

public Container getParent()
Returns Parent Container of Component.
Description Gets container that this Component is held in.

getPeer

public ComponentPeer getPeer() images

Returns Peer of Component.

getPreferredSize

public Dimension getPreferredSize() images

Returns The preferred dimensions of the component.

getSize

public Dimension getSize() images

Returns Dimensions of component.
Description Gets width and height of component.

getToolkit

public Toolkit getToolkit()
Returns Toolkit of Component.

getTreeLock

public final Object getTreeLock() images

Returns The AWT tree locking object.
Description Returns the object used for tree locking and layout operations.

gotFocus

public boolean gotFocus (Event e, Object o) images

Parameters e Event instance identifying what triggered the call to this method.
o Argument specific to the component subclass that generated the event.
Returns true if event handled, false to propagate it to parent container.
Description Called when Component gets input focus. This method is not used in the 1.1 event model.

handleEvent

public boolean handleEvent (Event e) images

Parameters e Event instance identifying what triggered the call to this method.
Returns true if event handled, false to propagate it to parent container.
Description High-level event handling routine that calls helper routines. Replaced by processEvent(AWTEvent).

hide

public void hide() images

Description Hides component from view. Replaced by setVisible(false).

imageUpdate

public boolean imageUpdate (Image image, int infoflags,
int x,
int y, int width, int height)
Parameters image Image being loaded.
infoflags ImageObserver flags ORed together of available information.
x x coordinate of upper-left corner of Image.
y y coordinate of upper-left corner of Image.
width Horizontal dimension of Image.
height Vertical dimension of Image.
Returns true if Image fully loaded, false otherwise.
Implements ImageObserver.imageUpdate()
Description An asynchronous update interface for receiving notifications about Image information as it is loaded. Meaning of parameters changes with values of flags.

inside

public boolean inside (int x, int y) images

Parameters x Horizontal position.
y Vertical position.
Returns true if the point (x, y) falls within the component's bounds, false otherwise.
Description Checks if coordinates are within bounding box of Component. Replaced by contains(int, int).

invalidate

public void invalidate()
Description Sets the component's valid state to false.

isEnabled

public boolean isEnabled()
Returns true if enabled, false otherwise.
Description Checks to see if the Component is currently enabled.

isFocusTraversable

public boolean isFocusTraversable() images

Returns true if this Component can be traversed using Tab and Shift Tab, false otherwise.
Description Checks to see if the Component is navigable using the keyboard.

isShowing

public boolean isShowing()
Returns true if showing, false otherwise.
Description Checks to see if the Component is currently showing.

isValid

public boolean isValid()
Returns true if valid, false otherwise.
Description Checks to see if the Component is currently valid.

isVisible

public boolean isVisible()
Returns true if visible, false otherwise.
Description Checks to see if the Component is currently visible.

keyDown

public boolean keyDown (Event e, int key) images

Parameters e Event instance identifying what triggered the call to this method.
key Integer representation of key pressed.
Returns true if event handled, false to propagate it to parent container.
Description Method called whenever the user presses a key. Replaced by processKeyEvent(KeyEvent).

keyUp

public boolean keyUp (Event e, int key) images

Parameters e Event instance identifying what triggered the call to this method.
key Integer representation of key released.
Returns true if event handled, false to propagate it to parent container.
Description Method called whenever the user releases a key. Replaced by processKeyEvent(KeyEvent).

layout

public void layout() images

Description Lays out component. Replaced by doLayout().

list

public void list()
Description Prints the contents of the Component to System.out.
public void list (PrintStream out)
Parameters out Output stream to send results to.
Description Prints the contents of the Component to a PrintStream.
public void list (PrintStream out, int indentation)
Parameters out Output stream to send results to.
indentation Indentation to use when printing.
Description Prints the contents of the Component indented to a PrintStream.
public void list (PrintWriter out)
Parameters out Output stream to send results to.
Description Prints the contents of the Component to a PrintWriter.
public void list (PrintWriter out, int indentation)
Parameters out Output stream to send results to.
indentation Indentation to use when printing.
Description Prints the contents of the Component indented to a PrintWriter.

locate

public Component locate (int x, int y) images

Parameters x Horizontal position.
y Vertical position.
Returns Component if the point (x, y) falls within the component, null otherwise.
Description Replaced by getComponentAt(int, int).

location

public Point location() images

Returns Position of component.
Description Gets the current position of this Component in its parent's coordinate space. Replaced by getLocation().

lostFocus

public boolean lostFocus (Event e, Object o) images

Parameters e Event instance identifying what triggered the call to this method.
o Argument specific to the component subclass that generated the event.
Returns true if event handled, false to propagate it to parent container.
Description Method called when Component loses input focus. Replaced by processFocusEvent(FocusEvent).

minimizeSize

public Dimension minimumSize() images

Returns The minimum dimensions of the component. Replaced by getMinimumSize().

mouseDown

public boolean mouseDown (Event e, int x, int y) images

Parameters e Event instance identifying what triggered the call to this method.
x Horizontal position of the mouse within Component when Event initiated
y Vertical position of the mouse within Component when Event initiated
Returns true if event handled, false to propagate it to parent container.
Description Method called when the user presses a mouse button over Component. Replaced by processMouseEvent(MouseEvent).

mouseDrag

public boolean mouseDrag (Event e, int x, int y) images

Parameters e Event instance identifying what triggered the call to this method.
x Horizontal position of the mouse within Component when Event initiated
y Vertical position of the mouse within Component when Event initiated
Returns true if event handled, false to propagate it to parent container.
Description Method called when the user is pressing a mouse button and moves the mouse. Replaced by processMouseMotionEvent(MouseEvent).

mouseEnter

public boolean mouseEnter (Event e, int x, int y) images

Parameters e Event instance identifying what triggered the call to this method.
x Horizontal position of the mouse within Component when Event initiated
y Vertical position of the mouse within Component when Event initiated
Returns true if event handled, false to propagate it to parent container.
Description Method called when the mouse enters Component. Replaced by processMouseEvent(MouseEvent).

mouseExit

public boolean mouseExit (Event e, int x, int y) images

Parameters e Event instance identifying what triggered the call to this method.
x Horizontal position of the mouse within Component when Event initiated
y Vertical position of the mouse within Component when Event initiated
Returns true if event handled, false to propagate it to parent container.
Description Method called when the mouse exits Component. Replaced by processMouseEvent(MouseEvent).

mouseMove

public boolean mouseMove (Event e, int x, int y) images

Parameters e Event instance identifying what triggered the call to this method.
x Horizontal position of the mouse within Component when Event initiated
y Vertical position of the mouse within Component when Event initiated
Returns true if event handled, false to propagate it to parent container.
Description Method called when the user is not pressing a mouse button and moves the mouse. Replaced by processMouseMotionEvent(MouseEvent).

mouseUp

public boolean mouseUp (Event e, int x, int y) images

Parameters e Event instance identifying what triggered the call to this method.
x Horizontal position of the mouse within Component when Event initiated
y Vertical position of the mouse within Component when Event initiated
Returns true if event is handled, false to propagate it to the parent container.
Description Method called when user releases mouse button over Component. Replaced by processMouseEvent(MouseEvent).

move

public void move (int x, int y) images

Parameters x New horizontal position for component.
y New vertical position for component.
Description Relocates component. Replaced by setLocation(int, int).

nextFocus

public void nextFocus() images

Description Moves focus from current component to next one in parent container. Replaced by transferFocus().

paint

public void paint (Graphics g)
Parameters g Graphics context of component.
Description Empty method to be overridden to draw something in the graphics context.

paintAll

public void paintAll (Graphics g)
Parameters g Graphics context of component.
Description Method to validate component and paint its peer if it is visible.

postEvent

public boolean postEvent (Event e) images

Parameters e Event instance to post to component
Returns If Event is handled, true is returned. Otherwise, false is returned.
Description Tells Component to deal with Event.

preferredSize

public Dimension preferredSize() images

Returns The preferred dimensions of the component. Replaced by getPreferredSize().

prepareImage

public boolean prepareImage (Image image, ImageObserver
observer)
Parameters image Image to start loading.
observer Component on which image will be rendered.
Returns true if Image is fully loaded, false otherwise.
Description Forces Image to start loading.
public boolean prepareImage (Image image, int width, int height, ImageObserver observer)
Parameters image Image to start loading.
width Horizontal size of the Image after scaling.
height Vertical size of the Image after scaling.
observer Component on which image will be rendered.
Returns true if Image is fully loaded, false otherwise.
Description Forces Image to start loading.

print

public void print (Graphics g)
Parameters g Graphics context.
Description Empty method to be overridden to print something into the graphics context.

printAll

public void printAll (Graphics g)
Parameters g Graphics context.
Description Method to print this component and its children.

remove

public void remove (MenuComponent popup) images

Parameters popup The menu to remove.
Description After adding a PopupMenu, you can use this method to remove it.

removeComponentListener

public void removeComponentListener (ComponentListener l) images

Description Removes the specified ComponentListener from this Component.

removeFocusListener

public void removeFocusListener (FocusListener l) images

Description Removes the specified FocusListener from this Component.

removeKeyListener

public void removeKeyListener (KeyListener l) images

Description Removes the specified KeyListener from this Component.

removeMouseListener

public void removeMouseListener (MouseListener l) images

Description Removes the specified MouseListener from this Component.

removeMouseMotionListener

public void removeMouseMotionListener (MouseMotionListener l) images

Description Removes the specified MouseMotionListener from this Component.

removeNotify

public void removeNotify()
Description Removes peer of Component's subclass.

repaint

public void repaint()
Description Requests scheduler to redraw the component as soon as possible.
public void repaint (long tm)
Parameters tm Millisecond delay allowed before repaint.
Description Requests scheduler to redraw the component within a time period.
public void repaint (int x, int y, int width, int height)
Parameters x Horizontal origin of bounding box to redraw.
y Vertical origin of bounding box to redraw.
width Width of bounding box to redraw.
height Height of bounding box to redraw.
Description Requests scheduler to redraw a portion of component as soon as possible.
public void repaint (long tm, int x, int y, int width, int height)
Parameters tm Millisecond delay allowed before repaint.
x Horizontal origin of bounding box to redraw.
y Vertical origin of bounding box to redraw.
width Width of bounding box to redraw.
height Height of bounding box to redraw.
Description Requests scheduler to redraw a portion of component within a time period.

requestFocus

public void requestFocus()
Description Requests the input focus for this Component.

reshape

public void reshape (int x, int y, int width, int height) images

Parameters x New horizontal position for component.
y New vertical position for component.
width New width for component.
height New height for component.
Description Relocates and resizes component. Replaced by setBounds(int, int, int, int).

resize

public void resize (Dimension d) images

Parameters d New dimensions for the component.
Description Resizes component. Replaced by setSize(Dimension).
public void resize (int width, int height) images
Parameters width New width for component.
height New height for component.
Description Resizes component. Replaced by setSize(int, int).

setBackground

public void setBackground (Color c)
Parameters c New background color.
Description Changes the component's background color.

setBounds

public void setBounds (int x, int y, int width, int height) images

Parameters x New horizontal position for component.
y New vertical position for component.
width New width for component.
height New height for component.
Description Relocates and resizes the component.
public void setBounds (Rectangle r) images
Parameters r New coordinates for component.
Description Relocates and resizes component.

setCursor

public synchronized void setCursor (Cursor cursor) images

Parameters cursor The new cursor for the component.
Description Changes the component's cursor.

setEnabled

public void setEnabled (boolean b) images

Parameters b true to enable the component, false to disable it.
Description Enables or disables the component. Replaces enable(), enable(boolean), and disable().

setFont

public synchronized void setFont (Font f)
Parameters f Font to change component to.
Description Changes the font of the component.

setForeground

public void setForeground (Color c)
Parameters c New foreground color.
Description Changes the foreground color of component's area.

setLocale

public void setLocale (Locale l) images

Parameters l The locale object for the component.
Description Sets the Component's locale.

setLocation

public void setLocation (int x, int y) images

Parameters x New horizontal position for component.
y New vertical position for component.
Description Relocates the component.
public void setLocation (Point p) images
Parameters p New position for component.
Description Relocates the component.

setName

public void setName (String name) images

Parameters name New name for component.
Description Sets the component's name.

setSize

public void setSize (int width, int height) images

Parameters width New width for component.
height New height for component.
Description Resizes the component.
public void setSize (Dimension d) images
Parameters d New dimensions for the component.
Description Resizes the component.

setVisible

public void setVisible (boolean b) images

Parameters b true to show component, false to hide it.
Description Shows or hides the component based on the b parameter.

show

public void show() images

Description Replaced by setVisible(true).
public void show (boolean condition) images
Parameters condition true to show the component, false to hide it.
Description Replaced by setVisible(boolean).

size

public Dimension size() images

Returns Dimensions of the component.
Description Gets width and height of the component. Replaced by getSize().

toString

public String toString()
Returns A string representation of the Component object.
Overrides Object.toString()

transferFocus

public void transferFocus() images

Description Transfers focus to the next component in the container hierarchy.

update

public void update (Graphics g)
Parameters g Graphics context of component.
Description Called to update the component's display area.

validate

public void validate()
Description Sets the component's valid state to true.

Protected Instance Methods

disableEvents

protected final void disableEvents (long eventsToDisable) images

Parameters eventsToDisable
A value representing certain kinds of events. This can be constructed by ORing the event mask constants defined in java.awt.AWTEvent.
Description By default, a component receives events corresponding to the event listeners that have registered. If a component should not receive events of a certain type, even if there is a listener registered for that type of event, this method can be used to disable that event type.

enableEvents

protected final void enableEvents (long eventsToEnable) images

Parameters eventsToEnable A value representing certain kinds of events. This can be constructed by ORing the event mask constants defined in java.awt.AWTEvent.
Description By default, a component receives events corresponding to the event listeners that have registered. If a component should receive other types of events as well, this method can be used to request them.

paramString

protected String paramString()
Returns A String with the current settings of the Component.
Description Helper method for toString() to generate a string of current settings.

processComponentEvent

protected void processComponentEvent(ComponentEvent e) images

Parameters e The event to process.
Description Component events are passed to this method for processing. Normally, this method is called by processEvent().

processEvent

protected void processEvent(AWTEvent e) images

Parameters e The event to process.
Description Low level AWTEvents are passed to this method for processing.

processFocusEvent

protected void processFocusEvent(FocusEvent e) images

Parameters e The event to process.
Description Focus events are passed to this method for processing. Normally, this method is called by processEvent().

processKeyEvent

protected void processKeyEvent(KeyEvent e) images

Parameters e The event to process.
Description Key events are passed to this method for processing. Normally, this method is called by processEvent().

processMouseEvent

protected void processMouseEvent(MouseEvent e) images

Parameters e The event to process.
Description Mouse events are passed to this method for processing. Normally, this method is called by processEvent().

processMouseMotionEvent

protected void processMouseMotionEvent(MouseEvent e) images

Parameters e The event to process.
Description Mouse motion events are passed to this method for processing. Normally, this method is called by processEvent().

See Also

Button, Canvas, Checkbox, Choice, Color, ColorModel, ComponentPeer, Container, Dimension, Event, Font, FontMetrics, Graphics, ImageObserver, ImageProducer, Label, List, MenuContainer, Object, Point, PrintStream, Rectangle, Scrollbar, Serializable, String, TextComponent, Toolkit

19.16 Container

Description

The Container class serves as a general purpose holder of other Component objects.

Class Definition

public abstract class java.awt.Container extends java.awt.Component { // Constructors protected Container(); images // Instance Methods public Component add (Component component); public Component add (Component component, int position);

public void add (Component comp, Object constraints); images public void add (Component comp, Object constraints, int position); images public Component add (String name, Component component); images public synchronized void addContainerListener (ContainerListener l); images public void addNotify(); public int countComponents(); public void deliverEvent (Event e); images public void doLayout(); images public float getAlignmentX(); images public float getAlignmentY(); images public Component getComponent (int n); public Component getComponentAt (int x, int y); images public Component getComponentAt (Point p); images public int getComponentCount(); images public Component[] getComponents(); public Insets getInsets(); images public LayoutManager getLayout(); public Dimension getMaximumSize(); images public Dimension getMinimumSize(); images public Dimension getPreferredSize(); images public Insets insets(); public void invalidate(); images public boolean isAncestorOf (Component c); images public void layout(); images public void list (PrintStream out, int indentation); public void list (PrintWriter out, int indentation); images public Component locate (int x, int y); images public Dimension minimumSize(); images public void paint (Graphics g); images public void paintComponents (Graphics g); public Dimension preferredSize(); images public void print (Graphics g); images public void printComponents (Graphics g); public void remove (int index); images public void remove (Component component); public void removeAll(); public void removeContainerListener (ContainerListener l); images

public void removeNotify(); public void setLayout (LayoutManager manager); public void validate(); // Protected Instance Methods protected void addImpl (Component comp, Object constraints, int index); images protected String paramString(); protected void processContainerEvent (ContainerEvent e); images protected void processEvent (AWTEvent e); images protected void validateTree(); images }

images

Constructors

Container

protected Container() images

Description This constructor creates a “lightweight” container. This constructor allows Container to be subclassed using code written entirely in Java.

Instance Methods

add

public Component add (Component component)
Parameters component Component to add to container.
Returns Component just added.
Throws IllegalArgumentException if you add component to itself.
Description Adds component as the last component in the container.
public Component add (Component component, int position)
Parameters component Component to add to container.
position Position of component; -1 adds the component as the last in the container.
Returns Component just added.
Throws ArrayIndexOutOfBoundsException
If position invalid.
IllegalArgumentException
If you add Component to itself.
Description Adds component to container at a certain position.
public void add (Component component, Object constraints) images
Parameters component Component to add to container.
constraints An object describing constraints on the component being added.
Description Adds component to container subject to contraints.
public void add (Component component, Object constraints, int index) images
Parameters component Component to add to container.
constraints An object describing constraints on the component being added.
index The position of the component in the container's list.
Description Adds component to container subject to contraints at position index.
public Component add (String name, Component component) images
Parameters name Name of component being added. This parameter is often significant to the layout manager of the container (e.g “North”, “Center”).
component Component to add to container.
Returns Component just added.
Throws IllegalArgumentException
If you add component to itself.
Description Adds the component to the container with the given name. Replaced by the more general add(Component, Object).

addContainerListener

public synchronized void addContainerListener (ContainerListener l) images

Parameters l An object that implements the ContainerListener interface.
Description Add a listener for the container events.

addNotify

public void addNotify()
Overrides Component.addNotify()
Description Creates Container's peer and peers of contained components.

countComponents

public int countComponents()
Returns Number of components within Container.

deliverEvent

public void deliverEvent (Event e) images

Parameters e Event instance to deliver.
Overrides Component.deliverEvent(Event)
Description Tries to locate the component contained in the container that should receive the event.

doLayout

public void doLayout() images

Description Lays out the container. This method is a replacement for layout().

getAlignmentX

public float getAlignmentX() images

Returns A number between 0 and 1 representing the horizontal alignment of this component.
Overrides Component.getAlignmentX()
Description If the container's layout manager implements LayoutManager2, this method returns the getLayoutAlignmentX() value of the layout manager. Other wise the getAlignmentX() value of Component is returned.

getAlignmentY

public float getAlignmentY() images

Returns A number between 0 and 1 representing the vertical alignment of this component.
Overrides Component.getAlignmentY()
Description If the container's layout manager implements LayoutManager2, this method returns the getLayoutAlignmentY() value of the layout manager. Other wise the getAlignmentY() value of Component is returned.

getComponent

public synchronized Component getComponent (int position)
Parameters position Position of component to get.
Throws ArrayIndexOutOfBoundsException
If position is invalid.
Returns Component at designated position within Container.

getComponentAt

public Component getComponentAt (int x, int y) images

Parameters x The x coordinate, in this Container's coordinate system.
y The y coordinate, in this Container's coordinate system.
Returns Returns the Component containing the give point.
public Component getComponentAt (Point p) images
Parameters p The point to be tested, in this Container's coordinate system.
Returns Returns the Component containing the give point.

getComponentCount

public int getComponentCount() images

Returns Returns the number of components in the container.

getComponents

public Component[] getComponents()
Returns Array of components within the container.

getInsets

public Insets getInsets()
Returns The insets of the container.

getLayout

public LayoutManager getLayout()
Returns LayoutManager of Container.

getMaximumSize

public Dimension getMaximumSize() images

Overrides Component.getMaximumSize()
Returns The maximum dimensions of the component.

getMinimumSize

public Dimension getMinimumSize() images

Overrides Component.getMinimumSize()
Returns The minimum dimensions of the component.

getPreferredSize

public Dimension getPreferredSize() images

Returns The preferred dimensions of the component.

insets

public Insets insets() images

Returns Current Insets of Container. Replaced by getInsets().

invalidate

public void invalidate()
Overrides Component.invalidate()
Description Sets the container's valid state to false.

isAncestorOf

public boolean isAncestorOf (Component c) images

Parameters c The component in question.
Returns If c is contained in the container's hierarchy, returns true; otherwise false.

layout

public void layout() images

Overrides Component.layout()
Description Replaced by doLayout().

list

public void list (PrintStream out, int indentation)
Parameters out Output Stream to send results to.
indentation Indentation to use when printing.
Overrides Component.list(PrintStream, int)
Description Recursively lists all components in Container.
public void list (PrintWriter out, int indentation)
Parameters out Output Writer to send results to.
indentation Indentation to use when printing.
Overrides Component.list(PrintWriter, int)
Description Recursively lists all components in Container.

locate

public Component locate (int x, int y) images

Parameters x Horizontal position to check.
y Vertical position to check.
Returns Component within Container at given coordinates, or Container.
Overrides Component.locate(int, int)
Description Replaced by getComponentAt(int, int).

minimizeSize

public Dimension minimumSize() images

Returns Minimum dimensions of contained objects.
Overrides Component.minimumSize()
Description Replaced by getMinimumSize().

paint

public void paint (Graphics g)
Parameters g Graphics context of container.
Overrides Component.paint()
Description This method tells any lightweight components that are children of this container to paint themselves.

paintComponents

public void paintComponents (Graphics g)
Parameters g Graphics context of Container.
Description Paints the different components in Container.

preferredSize

public Dimension preferredSize() images

Returns Preferred dimensions of contained objects.
Overrides Component.preferredSize()
Description Replaced by getPreferredSize().

print

public void print (Graphics g)
Parameters g Graphics context of container.
Overrides Component.print()
Description This method tells any lightweight components that are children of this container to print themselves.

printComponents

public void printComponents (Graphics g)
Parameters g Graphics context of Container.
Description Prints the different components in Container.

remove

public void remove (int index) images

Parameters index Index of the component to remove.
Description Removes the component in position index from Container.
public void remove (Component component)
Parameters component Component to remove.
Description Removes component from Container.

removeAll

public void removeAll()
Description Removes all components from Container.

removeContainerListener

public void removeContainerListener (ContainerListener l) images

Parameters l One of this Container's ContainerListeners.
Description Remove a container event listener.

removeNotify

public void removeNotify()
Overrides Component.removeNotify()
Description Removes Container's peer and peers of contained components.

setLayout

public void setLayout (LayoutManager manager)
Parameters manager New LayoutManager for Container.
Description Changes LayoutManager of Container.

validate

public void validate()
Overrides Component.validate()
Description Sets Container's valid state to true and recursively validates its children.

Protected Instance Methods

addImpl

protected void addImpl (Component comp, Object constraints, int index) images

Parameters comp The component to add.
constraints Constraints on the component.
index Position at which to add this component. Pass -1 to add the component at the end.
Description This method adds a component subject to the given constraints at a specific position in the container's list of components. It is a helper method for the various overrides of add().

paramString

protected String paramString()
Returns String with current settings of Container.
Overrides Component.paramString()
Description Helper method for toString() to generate string of current settings.

processContainerEvent

protected void processContainerEvent (ContainerEvent e) images

Parameters e The event to process.
Description Container events are passed to this method for processing. Normally, this method is called by processEvent().

processEvent

protected void processEvent (AWTEvent e) images

Parameters e The event to process.
Overrides Component.processEvent()
Description Low level AWTEvents are passed to this method for processing.

validateTree

protected void validateTree() images

Description Descends recursively into the Container's components and recalculates layout for any subtrees that are marked invalid.

See Also

Component, Dimension, Event, Graphics, Insets, LayoutManager, Panel, PrintStream, String, Window

19.17 Cursor images

images

Description

The Cursor class represents the mouse pointer. It encapsulates information that used to be in java.awt.Frame in the 1.0.2 release.

Class Definition

public class java.awt.Cursor
    extends java.lang.Object
    implements java.io.Serializable {

  // Constants
  public final static int CROSSHAIR_CURSOR;
  public final static int DEFAULT_CURSOR;
  public final static int E_RESIZE_CURSOR;
  public final static int HAND_CURSOR;
  public final static int MOVE_CURSOR;
  public final static int N_RESIZE_CURSOR;
  public final static int NE_RESIZE_CURSOR;
  public final static int NW_RESIZE_CURSOR;
  public final static int S_RESIZE_CURSOR;
  public final static int SE_RESIZE_CURSOR;
  public final static int SW_RESIZE_CURSOR;
  public final static int TEXT_CURSOR;
  public final static int W_RESIZE_CURSOR;
  public final static int WAIT_CURSOR;

  // Class Variables
  protected static Cursor[] predefined;

  // Class Methods
  public static Cursor getDefaultCursor();
  public static Cursor getPredefinedCursor (int type);

  // Constructors
  public Cursor (int type);

  // Instance Methods
  public int getType();
}

Constants

CROSSHAIR_CURSOR

public final static int CROSSHAIR_CURSOR

Constant representing a cursor that looks like a crosshair.

DEFAULT_CURSOR

public final static int DEFAULT_CURSOR

Constant representing the platform's default cursor.

E_RESIZE_CURSOR

public final static int E_RESIZE_CURSOR

Constant representing the cursor for resizing an object on the left.

HAND_CURSOR

public final static int HAND_CURSOR

Constant representing a cursor that looks like a hand.

MOVE_CURSOR

public final static int MOVE_CURSOR

Constant representing a cursor used to move an object.

N_RESIZE_CURSOR

public final static int N_RESIZE_CURSOR

Constant representing a cursor for resizing an object on the top.

NE_RESIZE_CURSOR

public final static int NE_RESIZE_CURSOR

Constant representing a cursor for resizing an object on the top left corner.

NW_RESIZE_CURSOR

public final static int NW_RESIZE_CURSOR

Constant representing a cursor for resizing an object on the top right corner.

S_RESIZE_CURSOR

public final static int S_RESIZE_CURSOR

Constant representing a cursor for resizing an object on the bottom.

SE_RESIZE_CURSOR

public final static int SE_RESIZE_CURSOR

Constant representing a cursor for resizing an object on the bottom left corner.

SW_RESIZE_CURSOR

public final static int SW_RESIZE_CURSOR

Constant representing a cursor for resizing an object on the bottom right corner.

TEXT_CURSOR

public final static int TEXT_CURSOR

Constant representing a cursor used within text.

W_RESIZE_CURSOR

public final static int W_RESIZE_CURSOR

Constant representing a cursor for resizing an object on the right side.

WAIT_CURSOR

public final static int WAIT_CURSOR

Constant representing a cursor that indicates the program is busy.

Class Variables

predefined

protected static Cursor[] predefined

An array of cursor instances corresponding to the predefined cursor types.

Class Methods

getDefaultCursor

public static Cursor getDefaultCursor()
Returns The default system cursor.

getPredefinedCursor

public static Cursor getPredefinedCursor (int type)
Parameters type One of the type constants defined in this class.
Returns A Cursor object with the specified type.

Constructors

Cursor

public Cursor (int type)
Parameters type One of the type constants defined in this class.
Description Constructs a Cursor object with the specified type.

Instance Methods

getType

public int getType()
Returns The type of cursor.

See Also

Frame

19.18 Dialog

images

Description

The Dialog class provides a special type of display window that is used for pop-up messages and acquiring input from the user. Unlike most other components, dialogs are hidden by default; you must call show() to display them. Dialogs are always associated with a parent Frame. A Dialog may be either modal or nonmodal; a modal dialog attracts all input typed by the user. The default layout for a Dialog is BorderLayout.

Class Definition

public class java.awt.Dialog extends java.awt.Window { // Constructors public Dialog (Frame parent); images public Dialog (Frame parent, boolean modal); public Dialog (Frame parent, String title); images public Dialog (Frame parent, String title, boolean modal); // Instance Methods public void addNotify(); public String getTitle(); public boolean isModal(); public boolean isResizable(); public void setModal (boolean b); images public synchronized void setResizable (boolean resizable); public synchronized void setTitle (String title); public void show(); images // Protected Instance Methods protected String paramString(); }

Constructors

Dialog

public Dialog (Frame parent) images

Parameters parent Frame that is to act as the parent of Dialog.
Throws IllegalArgumentException
If parent is null.
Description Constructs a Dialog object.
public Dialog (Frame parent, boolean modal)
Parameters parent Frame that is to act as the parent of Dialog.
modal true if the Dialog is modal; false otherwise.
Throws IllegalArgumentException
If parent is null.
Description Replaced with Dialog(Frame, String, boolean).
public Dialog (Frame parent, String title) images
Parameters parent Frame that is to act as parent of Dialog.
title Initial title to use for Dialog.
Throws IllegalArgumentException
If parent is null.
Description Constructs a Dialog object with given characteristics.
public Dialog (Frame parent, String title, boolean modal)
Parameters parent Frame that is to act as parent of Dialog.
title Initial title to use for Dialog.
modal true if the Dialog is modal; false otherwise.
Throws IllegalArgumentException
If parent is null.
Description Constructs a Dialog object with given characteristics.

Instance Methods

addNotify

public void addNotify()
Overrides Window.addNotify()
Description Creates Dialog's peer and peers of contained components.

getTitle

public String getTitle()
Returns The current title for the Dialog.

isModal

public boolean isModal()
Returns true if modal, false otherwise.

isResizable

public boolean isResizable()
Returns true if resizable, false otherwise.

setModal

public void setModal (boolean b) images

Parameters b true makes the Dialog modal; false if the Dialog should be modeless.
Description Changes the modal state of the Dialog.

setResizable

public synchronized void setResizable (boolean resizable)
Parameters resizable true makes the Dialog resizable; false if the Dialog cannot be resized.
Description Changes the resize state of the Dialog.

setTitle

public synchronized void setTitle (String title)
Parameters title New title for the Dialog.
Description Changes the title of the Dialog.

show

public void show() images

Overrides Window.show()
Description If the dialog is hidden, this method shows it. If the dialog is already visible, this method brings it to the front.

Protected Instance Methods

paramString

protected String paramString()
Returns String with current settings of Dialog.
Overrides Container.paramString()
Description Helper method for toString() to generate string of current settings.

See Also

FileDialog, Frame, String, Window, WindowEvent, WindowListener

19.19 Dimension

images

Description

The Dimension class encapsulates width and height in a single object.

Class Definition

public class java.awt.Dimension extends java.lang.Object implements java.io.Serializable { // Variables public int height; public int width; // Constructors public Dimension(); public Dimension (int width, int height); public Dimension (Dimension d); // Instance Methods public boolean equals (Object obj); images public Dimension getSize(); images public void setSize (Dimension d); images public void setSize (int width, int height); images public String toString(); }

Variables

height

public int height

The height of the Dimension.

width

public int width

The width of the Dimension.

Constructors

Dimension

public Dimension()
Description Constructs an empty Dimension object.
public Dimension (int width, int height)
Parameters width Initial width of the object
height Initial height of the object
Description Constructs a Dimension object with an initial dimension of width x height.
public Dimension (Dimension d)
Parameters d Initial dimensions of the object
Description Constructs a Dimension object that is a clone of d.

Instance Methods

equals

public boolean equals (Object obj) images

Parameters obj The object to compare.
Returns true if this Dimension is equivalent to obj; false otherwise.
Overrides Object.equals(Object)
Description Compares two Dimension instances.

getSize

public Dimension getSize() images

Returns The size of the Dimension.

setSize

public void setSize (Dimension d) images

Parameters d The new size.
Description Changes the size of the Dimension.
public void setSize (int width, int height) images
Parameters width The new width.
height The new height.
Description Changes the size of the Dimension.

toString

public String toString()
Returns A string representation of the Dimension object.
Overrides Object.toString()

See Also

Object, String, Serializable

19.20 Event

images

Description

The Event class represents events that happen within the Java environment in a platform independent way. Events typically represent user actions, like typing a key or clicking the mouse. Although this class has been updated for the 1.1 release, it is only used for the 1.0 event model. When using the 1.1 event model, all events are represented by subclasses of java.awt.AWTEvent.

Class Definition

public class java.awt.Event extends java.lang.Object implements java.io.Serializable { // Constants public static final int ACTION_EVENT; public static final int ALT_MASK; public static final int BACK_SPACE; images public static final int CAPS_LOCK; images public static final int CTRL_MASK; public static final int DELETE; images public static final int DOWN; public static final int END; public static final int ENTER; images public static final int ESCAPE; images public static final int F1; public static final int F2; public static final int F3; public static final int F4; public static final int F5; public static final int F6; public static final int F7; public static final int F8; public static final int F9; public static final int F10; public static final int F11; public static final int F12;

public static final int GOT_FOCUS; public static final int HOME; public static final int INSERT; images public static final int KEY_ACTION; public static final int KEY_ACTION_RELEASE; public static final int KEY_PRESS; public static final int KEY_RELEASE; public static final int LEFT; public static final int LIST_DESELECT; public static final int LIST_SELECT; public static final int LOAD_FILE; public static final int LOST_FOCUS; public static final int META_MASK; public static final int MOUSE_DOWN; public static final int MOUSE_DRAG; public static final int MOUSE_ENTER; public static final int MOUSE_EXIT; public static final int MOUSE_MOVE; public static final int MOUSE_UP; public static final int NUM_LOCK; images public static final int PAUSE; images public static final int PGDN; public static final int PGUP; public static final int PRINT_SCREEN; images public static final int RIGHT; public static final int SAVE_FILE; public static final int SCROLL_ABSOLUTE; public static final int SCROLL_BEGIN; images public static final int SCROLL_END; images public static final int SCROLL_LINE_DOWN; public static final int SCROLL_LINE_UP; public static final int SCROLL_LOCK; images public static final int SCROLL_PAGE_DOWN; public static final int SCROLL_PAGE_UP; public static final int SHIFT_MASK; public static final int TAB; images public static final int UP; public static final int WINDOW_DEICONIFY; public static final int WINDOW_DESTROY; public static final int WINDOW_EXPOSE; public static final int WINDOW_ICONIFY; public static final int WINDOW_MOVED; // Variables public Object arg; public int clickCount; public Event evt; public int id; public int key;

public int modifiers; public Object target; public long when; public int x; public int y; // Constructors public Event (Object target, int id, Object arg); public Event (Object target, long when, int id, int x, int y, int key, int modifiers); public Event (Object target, long when, int id, int x, int y, int key, int modifiers, Object arg); // Instance Methods public boolean controlDown(); public boolean metaDown(); public boolean shiftDown(); public String toString(); public void translate (int x, int y); // Protected Instance Methods protected String paramString(); }

Constants

ACTION_EVENT

public static final int ACTION_EVENT

ID constant for Action Event.

ALT_MASK

public static final int ALT_MASK

Mask for ALT key.

BACK_SPACE

public static final int BACK_SPACE images

ID constant for Backspace.

CAPS_LOCK

public static final int CAPS_LOCK images

ID constant for Caps Lock key.

CTRL_MASK

public static final int CTRL_MASK

Mask for Control key.

DELETE

public static final int DELETE images

ID constant for Delete.

DOWN

public static final int DOWN

ID constant for the down arrow key.

END

public static final int END

ID constant for End key.

ENTER

public static final int ENTER images

ID constant for Enter key.

ESCAPE

public static final int ESCAPE images

ID constant for Escape key.

F1

public static final int F1

ID constant for F1 key.

F2

public static final int F2

ID constant for F2 key.

F3

public static final int F3

ID constant for F3 key.

F4

public static final int F4

ID constant for F4 key.

F5

public static final int F5

ID constant for F5 key.

F6

public static final int F6

ID constant for F6 key.

F7

public static final int F7

ID constant for F7 key.

F8

public static final int F8

ID constant for F8 key.

F9

public static final int F9

ID constant for F9 key.

F10

public static final int F10

ID constant for F10 key.

F11

public static final int F11

ID constant for F11 key.

F12

public static final int F12

ID constant for F12 key.

GOT_FOCUS

public static final int GOT_FOCUS

ID constant for getting input focus Event.

HOME

public static final int HOME

ID constant for Home key.

INSERT

public static final int INSERT images

ID constant for Insert key.

KEY_ACTION

public static final int KEY_ACTION

ID constant for Special Key Down Event.

KEY_ACTION_RELEASE

public static final int KEY_ACTION_RELEASE

ID constant for Special Key Up Event.

KEY_PRESS

public static final int KEY_PRESS

ID constant for Key Down Event.

KEY_RELEASE

public static final int KEY_RELEASE

ID constant for Key Up Event.

LEFT

public static final int LEFT

ID constant for the left arrow key.

LIST_DESELECT

public static final int LIST_DESELECT

ID constant for List DeSelect Event.

LIST_SELECT

public static final int LIST_SELECT

ID constant for List Select Event.

LOAD_FILE

public static final int LOAD_FILE

ID constant for File Load Event.

LOST_FOCUS

public static final int LOST_FOCUS

ID constant for losing input focus Event.

META_MASK

public static final int META_MASK

Mask for ALT key.

MOUSE_DOWN

public static final int MOUSE_DOWN

ID constant for Mouse Down Event.

MOUSE_DRAG

public static final int MOUSE_DRAG

ID constant for Mouse Drag Event.

MOUSE_ENTER

public static final int MOUSE_ENTER

ID constant for Mouse Enter Event.

MOUSE_EXIT

public static final int MOUSE_EXIT

ID constant for Mouse Exit Event.

MOUSE_MOVE

public static final int MOUSE_MOVE

ID constant for Mouse Move Event.

MOUSE_UP

public static final int MOUSE_UP

ID constant for Mouse Up Event.

NUM_LOCK

public static final int NUM_LOCK images

ID constant for Num Lock key.

PAUSE

public static final int PAUSE images

ID constant for Pause key.

PGDN

public static final int PGDN

ID constant for PageDown key.

PGUP

public static final int PGUP

ID constant for PageUp key.

PRINT_SCREEN

public static final int PRINT_SCREEN images

ID constant for Print Screen key.

RIGHT

public static final int RIGHT

ID constant for the right arrow key.

SAVE_FILE

public static final int SAVE_FILE

ID constant for File Save Event.

SCROLL_ABSOLUTE

public static final int SCROLL_ABSOLUTE

ID constant for Absolute Scroll Event.

SCROLL_BEGIN

public static final int SCROLL_ BEGIN images

ID constant for Begin Scroll Event.

SCROLL_END

public static final int SCROLL_ END images

ID constant for End Scroll Event.

SCROLL_LINE_DOWN

public static final int SCROLL_LINE_DOWN

ID constant for Line Down Scroll Event.

SCROLL_LINE_UP

public static final int SCROLL_LINE_UP

ID constant for Line Up Scroll Event.

SCROLL_LOCK

public static final int SCROLL_LOCK images

Mask for Scroll Lock key.

SCROLL_PAGE_DOWN

public static final int SCROLL_PAGE_DOWN

ID constant for Page Down Scroll Event.

SCROLL_PAGE_UP

public static final int SCROLL_PAGE_UP

ID constant for Page Up Scroll Event.

SHIFT_MASK

public static final int SHIFT_MASK

Mask for SHIFT key.

TAB

public static final int TAB images

ID constant for Tab key.

UP

public static final int UP

ID constant for the up arrow key.

WINDOW_DEICONIFY

public static final int WINDOW_DEICONIFY

ID constant for Window DeIconify Event.

WINDOW_DESTROY

public static final int WINDOW_DESTROY

ID constant for Window Destroy Event.

WINDOW_EXPOSE

public static final int WINDOW_EXPOSE

ID constant for Window Expose Event.

WINDOW_ICONIFY

public static final int WINDOW_ICONIFY

ID constant for Window Iconify Event.

WINDOW_MOVED

public static final int WINDOW_MOVED

ID constant for Window Move Event.

Variables

arg

public Object arg

A variable argument that is specific to the event type.

clickCount

public int clickCount

The number of consecutive MOUSE_DOWN events.

evt

public Event evt

A means of passing a linked list of events as one.

id

public int id

The ID constant that identifies the Event type.

key

public int key

Integer value of key pressed, or ID constant identifying a special key.

modifiers

public int modifiers

The state of the shift/alt/control/meta keys, formed by ORing the masks for the appropriate keys.

target

public Object target

The Object that generated the event.

when

public long when

The time the event happened.

x

public int x

The x position at which the event happened.

y

public int y

The y position at which the event happened.

Constructors

Event

public Event (Object target, int id, Object arg)
Parameters target The component to which the Event should be delivered
id The identifier of Event
arg The Object that is the cause of the event
Description Constructs an Event object with the given values.
public Event (Object target, long when, int id, int x, int y, int key, int modifiers)
Parameters target The component to which the Event should be delivered
when The time the event happened
id The identifier of Event
x The x position at which the event happened
y The y position at which the event happened
key Integer value of key pressed, or a constant identifying a special key
modifiers The state of the shift/alt/control/meta keys
Description Constructs an Event object with the given values.
public Event (Object target, long when, int id, int x, int y, int key, int modifiers, Object arg)
Parameters target The component to which the Event should be delivered
when The time the event happened
id The identifier of Event
x The x position at which the event happened
y The y position at which the event happened
key Integer value of key pressed, or a constant identifying a special key
modifiers The state of the shift/alt/control/meta keys
arg The Object that is the cause of the event
Description Constructs an Event object with the given values.

Instance Methods

controlDown

public boolean controlDown()
Returns true if the control key was down when the event was triggered, false otherwise.
Description Checks current settings for modifiers of the Event.

metaDown

public boolean metaDown()
Returns true if the meta key was down when the event was triggered, false otherwise.
Description Checks current settings for modifiers of the Event.

shiftDown

public boolean shiftDown()
Returns true if the shift key was down when the event was triggered, false otherwise.
Description Checks current settings for modifiers of the Event.

toString

public String toString()
Returns A string representation of the Event object.
Overrides Object.toString()

translate

public void translate (int x, int y)
Parameters x Amount to move Event in horizontal direction.
y Amount to move Event in vertical direction.
Description Translates x and y coordinates of Event instance by x and y.

Protected Instance Methods

paramString

protected String paramString()
Returns String with current settings of Event.
Description Helper method for toString() to generate string of current settings.

See Also

AWTEvent, Component, Object, String

19.21 EventQueue images

images

Description

The EventQueue class is a facility for queuing Java 1.1 AWT events, either for the system or for some other purpose. You rarely need to create your own event queue; for most purposes, you will want to work with the system's event queue, which you acquire using the Toolkit.

Class Definition

public class EventQueue extends Object {

  // Constructor
  public EventQueue();

  // Instance Methods
  public synchronized AWTEvent getNextEvent() throws InterruptedException;
  public synchronized AWTEvent peekEvent();
  public synchronized AWTEvent peekEvent (int id);
  public synchronized void postEvent (AWTEvent theEvent);
}

Constructor

EventQueue

public EventQueue()
Description Creates an EventQueue for your own use.

Instance Methods

getNextEvent

public synchronized AWTEvent getNextEvent() throws
InterruptedException
Throws InterruptedException
If the thread is interrupted before an event is posted to the queue.
Returns AWTEvent taken from the event queue.
Description Removes the next event from the event queue and returns it. If there are no events in the queue, this method will block until another thread posts one.

peekEvent

public synchronized AWTEvent peekEvent()
Returns Next AWTEvent on the event queue.
Description Returns a reference to the next event on the queue without removing it from the queue.
public synchronized AWTEvent peekEvent (int id)
Parameters id Type of event to find.
Returns AWTEvent with the given type id; null if no event with the given type is currently in the queue.
Description Returns an event with the given type if one exists, but doesn't remove the event from the queue.

See Also

AWTEvent, Event

19.22 FileDialog

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Description

The FileDialog class provides file selection capabilities for opening or saving files. Because FileDialog is a subclass of Dialog, a FileDialog is always associated with a Frame and is hidden by default. FileDialogs are always modal (i.e., they always attract all user input). In addition, FileDialogs have a load/save mode; the LOAD mode is for selecting files for an application to load, SAVE is for selecting a filename to save.

Class Definition

public class java.awt.FileDialog extends java.awt.Dialog { // Constants public final static int LOAD; public final static int SAVE; // Constructors public FileDialog (Frame parent); images public FileDialog (Frame parent, String title); public FileDialog (Frame parent, String title, int mode); // Instance Methods public void addNotify(); public String getDirectory(); public String getFile(); public FilenameFilter getFilenameFilter(); public int getMode(); public synchronized void setDirectory (String directory); public synchronized void setFile (String file); public synchronized void setFilenameFilter (FilenameFilter filter); public void setMode(int mode); images // Protected Instance Methods protected String paramString(); }

Constants

LOAD

public final static int LOAD

Constant to specify the FileDialog's load mode.

SAVE

public final static int SAVE

Constant to specify the FileDialog's save mode.

Constructors

FileDialog

public FileDialog (Frame parent) images

Parameters parent Frame that is to act as parent of FileDialog.
Description Constructs a FileDialog object in LOAD mode.
public FileDialog (Frame parent, String title)
Parameters parent Frame that is to act as parent of FileDialog.
title Title to use for FileDialog.
Description Constructs a FileDialog object in LOAD mode.
public FileDialog (Frame parent, String title, int mode)
Parameters parent Frame that is to act as parent of Dialog.
title Title to use for FileDialog.
mode The constant LOAD or SAVE, specifying the dialog's mode.
Description Constructs a FileDialog object in the given mode.

Instance Methods

addNotify

public void addNotify()
Overrides Dialog.addNotify()
Description Creates FileDialog's peer for the native platform.

getDirectory

public String getDirectory()
Returns The current directory for the FileDialog.

getFile

public String getFile()
Returns The current file selected by the FileDialog.

getFilenameFilter

public FilenameFilter getFilenameFilter()
Returns The current filename filter for the FileDialog.

getMode

public int getMode()
Returns The current mode of the FileDialog.

setDirectory

public synchronized void setDirectory (String directory)
Parameters directory Directory to be displayed by the FileDialog.
Description Changes the directory displayed in the FileDialog.

setFile

public synchronized void setFile (String file)
Parameters file Initial file string for FileDialog.
Description Change the default file selected by the FileDialog.

setFilenameFilter

public synchronized void setFilenameFilter (FilenameFilter
filter)
Parameters filter Initial filter for FileDialog.
Description Changes the current filename filter of the FileDialog.

setMode

public void setMode (int mode) images

Parameters mode The constant LOAD or SAVE, specifying the dialog's mode.
Description Change the mode of the file dialog.

Protected Instance Methods

paramString

protected String paramString()
Returns String with current settings of FileDialog.
Overrides Dialog.paramString()
Description Helper method for toString() to generate string of current settings.

See Also

Dialog, FilenameFilter, String

19.23 FlowLayout

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Description

The FlowLayout LayoutManager provides the means to lay out components in a row by row fashion. As each row fills up, the components continue on the next row.

Class Definition

public class java.awt.FlowLayout extends java.lang.Object implements java.awt.LayoutManager, java.io.Serializable { // Constants public static final int CENTER; public static final int LEFT; public static final int RIGHT; // Constructors public FlowLayout(); public FlowLayout (int alignment); public FlowLayout (int alignment, int hgap, int vgap); // Instance Methods public void addLayoutComponent (String name, Component component); public int getAlignment(); images public int getHgap(); images public int getVgap(); images public void layoutContainer (Container target); public Dimension minimumLayoutSize (Container target); public Dimension preferredLayoutSize (Container target); public void removeLayoutComponent (Component component); public void setAlignment (int align); images public void setHgap (int hgap); images public void setVgap (int vgap); images public String toString(); }

Constants

CENTER

public static final int CENTER

The default alignment for a FlowLayout object; rows of components are centered within the container.

LEFT

public static final int LEFT

An alignment for a FlowLayout object; rows of components start on the left side of the container.

RIGHT

public static final int RIGHT

An alignment for a FlowLayout object; rows of components start on the right side of the container.

Constructors

FlowLayout

public FlowLayout()
Description Constructs a FlowLayout object with CENTER alignment.
public FlowLayout (int alignment)
Parameters alignment Alignment of components within the container.
Description Constructs a FlowLayout object with the given alignment.
public FlowLayout (int alignment, int hgap, int vgap)
Parameters alignment Alignment of components within container
hgap Horizontal space between each component in a row
vgap Vertical space between each row
Description Constructs a FlowLayout object with the given alignment and the values specified as the gaps between each component in the container managed by this instance of FlowLayout.

Instance Methods

addLayoutComponent

public void addLayoutComponent (String name, Component
component)
Parameters name Name of component to add.
component Actual component being added.
Implements LayoutManager.addLayoutComponent()
Description Does nothing.

getAlignment

public int getAlignment() images

Returns The alignment constant for this FlowLayout.

getHgap

public int getHgap() images

Returns The horizontal gap between components.

getVgap

public int getVgap() images

Returns The vertical gap between components.

layoutContainer

public void layoutContainer (Container target)
Parameters target The container that needs to be redrawn.
Implements LayoutManager.layoutContainer()
Description Draws the components contained within the target container.

minimumLayoutSize

public Dimension minimumLayoutSize (Container target)
Parameters target The container whose size needs to be calculated.
Returns Minimum Dimension of container target
Implements LayoutManager.minimumLayoutSize()
Description Calculates minimum size of target container.

preferredLayoutSize

public Dimension preferredLayoutSize (Container target)
Parameters target The container whose size needs to be calculated.
Returns Preferred Dimension of container target
Implements LayoutManager.preferredLayoutSize()
Description Calculates preferred size of target container.

removeLayoutComponent

public void removeLayoutComponent (Component component)
Parameters component Component to stop tracking.
Implements LayoutManager.removeLayoutComponent()
Description Does nothing.

setAlignment

public void setAlignment(int align) images

Parameters alignment Alignment of components within container
Description Sets the alignment for the FlowLayout.

setHgap

public void setHgap(int hgap) images

Parameters hgap The horizontal gap value.
Description Sets the horizontal gap between components.

setVgap

public void setVgap(int vgap) images

Parameters vgap The vertical gap value.
Description Sets the vertical gap between components.

toString

public String toString()
Returns A string representation of the FlowLayout object.
Overrides Object.toString()

See Also

Component, Container, Dimension, LayoutManager, Object, Serializable, String

19.24 Font

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Description

The Font class represents a specific font to the system.

Class Definition

public class java.awt.Font extends java.lang.Object implements java.io.Serializable { // Constants public static final int BOLD; public static final int ITALIC; public static final int PLAIN; // Variables protected String name; protected int size; protected int style; // Constructors public Font (String name, int style, int size); // Class Methods public static Font decode (String str); images public static Font getFont (String name) public static Font getFont (String name, Font defaultFont) // Instance Methods public boolean equals (Object object); public String getFamily(); public String getName(); public FontPeer getPeer(); images public int getSize(); public int getStyle(); public int hashCode(); public boolean isBold(); public boolean isItalic(); public boolean isPlain(); public String toString(); }

Constants

BOLD

public static final int BOLD

Constant for specifying bold fonts.

ITALIC

public static final int ITALIC

Constant for specifying fonts.

PLAIN

public static final int PLAIN

Constant for specifying plain fonts.

Variables

name

protected String name

The font's logical name.

size

protected int size

The font size; allegedly in points, though probably not true typographer's points.

style

protected int style

The font style, e.g., bold or italic or a combination thereof.

Constructors

Font

public Font (String name, int style, int size)
Parameters name The name of the desired font.
style One of the style flags (PLAIN, BOLD, or ITALIC) or a combination.
size The size of the font to create.
Description Constructs a Font object with the given characteristics.

Class Methods

decode

public static Font decode (String str) images

Parameters str The string describing the font.
Returns Font instance requested, or default if str is invalid.
Description Gets font specified by str.

getFont

public static Font getFont (String name)
Parameters name The name of a system property specifying a font to fetch.
Returns Font instance for name requested, or null if name is invalid.
Description Gets font specified by the system property name.
public static Font getFont (String name, Font defaultFont)
Parameters name The name of a system property specifying a font to fetch.
defaultFont Font to return if name not found in properties.
Returns Font instance of name requested, or defaultFont if name is invalid
Description Gets font specified by the system property name.

Instance Methods

equals

public boolean equals (Object object)
Parameters object The object to compare.
Returns true if the objects are equivalent fonts (same name, style, and point size), false otherwise.
Overrides Object.equals(Object)
Description Compares two different Font instances for equivalence.

getFamily

public String getFamily()
Returns Retrieves the actual name of the font.

getName

public String getName()
Returns Retrieves the logical name of the font.

getPeer

public FontPeer getPeer() images

Returns The font's peer.

getSize

public int getSize()
Returns Retrieves the size parameter from creation

getStyle

public int getStyle()
Returns Retrieves the style parameter from creation.

hashCode

public int hashCode()
Returns A hashcode to use when using the Font as a key in a Hashtable.
Overrides Object.hashCode()
Description Generates a hashcode for the Font.

isBold

public boolean isBold()
Returns true if Font style is bold, false otherwise.

isItalic

public boolean isItalic()
Returns true if Font style is italic, false otherwise.

isPlain

public boolean isPlain()
Returns true if Font style is neither bold nor italic, false otherwise.

toString

public String toString()
Returns A string representation of the Font object.
Overrides Object.toString()

See Also

FontMetrics, Object, Properties, String

19.25 FontMetrics

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Description

The FontMetrics class provides the means to calculate actual width and height of text if drawn on the screen.

Class Definition

public abstract class java.awt.FontMetrics
    extends java.lang.Object
    implements java.io.Serializable {

  // Variables
  protected Font font;

  // Constructors
  protected FontMetrics (Font font);

  // Instance Methods
  public int bytesWidth (byte data[], int offset, int length);
  public int charsWidth (char data[], int offset, int length);
  public int charWidth (char character);
  public int charWidth (int character);
  public int getAscent();
  public int getDescent();
  public Font getFont();
  public int getHeight();
  public int getLeading();
  public int getMaxAdvance();
  public int getMaxAscent();
  public int getMaxDecent();
  public int getMaxDescent();
public int[] getWidths();
  public int stringWidth (String string);
  public String toString();
}

Variables

font

protected Font font

The Font object whose metrics are represented by this object.

Constructors

FontMetrics

protected FontMetrics (Font font)
Parameters font The Font object whose metrics you want.
Description Constructs a platform specific FontMetrics object for the given font.

Instance Methods

bytesWidth

public int bytesWidth (byte data[], int offset, int
length)
Parameters data[] Array of characters to lookup.
offset Initial character position.
length Number of characters to lookup.
Returns Advance width of characters in the array, starting with offset and ending with offset+length, in pixels.
Throws ArrayIndexOutOfBoundsException
If offset or length is invalid.

charsWidth

public int charsWidth (char data[], int offset, int
length)
Parameters data[] Array of characters to lookup.
offset Initial character position.
length Number of characters to lookup.
Returns Advance width of characters in the array, starting with offset and ending with offset+length-1, in pixels.
Throws ArrayIndexOutOfBoundsException
If offset or length is invalid.

charWidth

public int charWidth (char character)
Parameters character character to lookup
Returns Advanced pixel width of character.
public int charWidth (int character)
Parameters character int value of character to lookup
Returns Advanced pixel width of character.

getAscent

public int getAscent()
Returns Amount of space above the baseline required for the tallest character in the font.

getDescent

public int getDescent()
Returns Amount of space below the baseline required for the lowest descender (e.g., the tail on “p”) in the font.

getFont

public Font getFont()
Returns The Font whose metrics are represented by this object.

getHeight

public int getHeight()
Returns The sum of getDescent(), getAscent(), and getLeading(); recommended total space between baselines.

getLeading

public int getLeading()
Returns Retrieves recommended amount of space between lines of text.

getMaxAdvance

public int getMaxAdvance()
Returns Retrieves advance pixel width of widest character in the font.

getMaxAscent

public int getMaxAscent()
Returns Retrieves maximum amount of space above the baseline required for the tallest character within the font's FontMetrics. May differ from getAscent() for characters with diacritical marks.

getMaxDecent

public int getMaxDecent()
Returns Retrieves the maximum amount of space below the baseline required for the deepest character for the font.
Description A misspelling of getMaxDescent().

getMaxDescent

public int getMaxDescent()
Returns Retrieves the maximum amount of space below the baseline required for the deepest character for the font.

getWidths

public int[] getWidths()
Returns 255 element array of character widths.
Description Retrieves an integer array of the advance widths of the first 255 characters in the FontMetrics' font.

stringWidth

public int stringWidth (String string)
Parameters string Character string to lookup.
Returns Advance pixel width of string.

toString

public String toString()
Returns A string representation of the FontMetrics object.
Overrides Object.toString()

See Also

Font, Object, String

19.26 Frame

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Description

The Frame class is a special type of Window that will appear like other high-level programs in your windowing environment. It adds a MenuBar, window title, and window gadgets (like resize, maximize, minimize, window menu) to the basic Window object. Frames are initially invisible; call show() to display them. Frames may also be associated with an Image to be used as an icon. The Frame class includes many constants to represent different cursor styles. All styles aren't necessarily available on any platform. In 1.1, these constants are defined in java.awt.Cursor.

Class Definition

public class java.awt.Frame extends java.awt.Window implements java.awt.MenuContainer { // Constants public final static int CROSSHAIR_CURSOR; public final static int DEFAULT_CURSOR; public final static int E_RESIZE_CURSOR; public final static int HAND_CURSOR; public final static int MOVE_CURSOR; public final static int N_RESIZE_CURSOR; public final static int NE_RESIZE_CURSOR; public final static int NW_RESIZE_CURSOR; public final static int S_RESIZE_CURSOR; public final static int SE_RESIZE_CURSOR; public final static int SW_RESIZE_CURSOR;

public final static int TEXT_CURSOR; public final static int W_RESIZE_CURSOR; public final static int WAIT_CURSOR; // Constructors public Frame(); public Frame (String title); // Instance Methods public void addNotify(); public synchronized void dispose(); public int getCursorType(); images public Image getIconImage(); public MenuBar getMenuBar(); public String getTitle(); public boolean isResizable(); public synchronized void remove (MenuComponent component); public synchronized void setCursor (int cursorType); images public synchronized void setIconImage (Image image); public synchronized void setMenuBar (MenuBar bar); public synchronized void setResizable (boolean resizable); public synchronized void setTitle (String title); // Protected Instance Methods protected String paramString(); }

Constants

CROSSHAIR_CURSOR

public final static int CROSSHAIR_CURSOR

Constant representing a cursor that looks like a crosshair.

DEFAULT_CURSOR

public final static int DEFAULT_CURSOR

Constant representing the platform's default cursor.

E_RESIZE_CURSOR

public final static int E_RESIZE_CURSOR

Constant representing the cursor for resizing an object on the left.

HAND_CURSOR

public final static int HAND_CURSOR

Constant representing a cursor that looks like a hand.

MOVE_CURSOR

public final static int MOVE_CURSOR

Constant representing a cursor used to move an object.

N_RESIZE_CURSOR

public final static int N_RESIZE_CURSOR

Constant representing a cursor for resizing an object on the top.

NE_RESIZE_CURSOR

public final static int NE_RESIZE_CURSOR

Constant representing a cursor for resizing an object on the top left corner.

NW_RESIZE_CURSOR

public final static int NW_RESIZE_CURSOR

Constant representing a cursor for resizing an object on the top right corner.

S_RESIZE_CURSOR

public final static int S_RESIZE_CURSOR

Constant representing a cursor for resizing an object on the bottom.

SE_RESIZE_CURSOR

public final static int SE_RESIZE_CURSOR

Constant representing a cursor for resizing an object on the bottom left corner.

SW_RESIZE_CURSOR

public final static int SW_RESIZE_CURSOR

Constant representing a cursor for resizing an object on the bottom right corner.

TEXT_CURSOR

public final static int TEXT_CURSOR

Constant representing a cursor used within text.

W_RESIZE_CURSOR

public final static int W_RESIZE_CURSOR

Constant representing a cursor for resizing an object on the right side.

WAIT_CURSOR

public final static int WAIT_CURSOR

Constant representing a cursor that indicates the program is busy.

Constructors

Frame

public Frame()
Description Constructs a Frame object, with no title.
public Frame (String title)
Parameters title Initial title to use for Frame.
Description Constructs a Frame object, with the given title.

Instance Methods

addNotify

public void addNotify()
Overrides Window.addNotify()
Description Creates Frame's peer and peers of contained components.

dispose

public synchronized void dispose()
Overrides Window.dispose()
Description Releases the resources of the Frame.

getCursorType

public int getCursorType() images

Returns The constant for the current cursor. Replaced by Component. getCursor()

getIconImage

public Image getIconImage()
Returns The image used as the icon, or null if there is no icon for this frame.

getMenuBar

public MenuBar getMenuBar()
Returns The Frame's current menu bar, or null if there is no menu bar for this frame.

getTitle

public String getTitle()
Returns The current title for the Frame, or null if there is no title for this frame.

isResizable

public boolean isResizable()
Returns true if resizable, false otherwise.

remove

public synchronized void remove (MenuComponent component)
Parameters component MenuBar to remove from Frame.
Implements MenuContainer.remove()
Description Removes component from Frame if component is the Frame's menu bar.

setCursor

public synchronized void setCursor (int cursorType) images

Parameters cursorType One of Frame's cursor constants.
Throws IllegalArgumentException
If cursorType invalid.
Description Changes the cursor of the Frame. Replaced by Component. setCursor(Cursor).

setIconImage

public synchronized void setIconImage (Image image)
Parameters image New image to use for the Frame's icon.
Description Changes the icon's image for the Frame.

setMenuBar

public synchronized void setMenuBar (MenuBar bar)
Parameters bar New MenuBar to use for the Frame.
Description Changes the menu bar of the Frame.

setResizable

public synchronized void setResizable (boolean resizable)
Parameters resizable true to make the frame resizable, false to prevent resizing.
Description Changes the resize state of the Frame.

setTitle

public synchronized void setTitle (String title)
Parameters title New title to use for the Frame.
Description Changes the title of the Frame.

Protected Instance Methods

paramString

protected String paramString()
Returns String with current settings of Frame.
Overrides Container.paramString()
Description Helper method for toString() to generate a string of current settings.

See Also

Container, Image, MenuBar, MenuContainer, String, Window

19.27 Graphics

images

Description

The Graphics class is an abstract class that represents an object on which you can draw. The concrete classes that are actually used to represent graphics objects are platform dependent, but because they extend the Graphics class, must implement the methods here.

Class Definition

public abstract class java.awt.Graphics extends java.lang.Object { // Constructors protected Graphics(); // Instance Methods public abstract void clearRect (int x, int y, int width, int height); public abstract void clipRect (int x, int y, int width, int height); public abstract void copyArea (int x, int y, int width, int height, int deltax, int deltay); public abstract Graphics create(); public Graphics create (int x, int y, int width, int height); public abstract void dispose(); public void draw3DRect (int x, int y, int width, int height, boolean raised); public abstract void drawArc (int x, int y, int width, int height, int startAngle, int arcAngle); public void drawBytes (byte text[], int offset, int length, int x, int y); public void drawChars (char text[], int offset, int length, int x, int y); public abstract boolean drawImage (Image image, int x, int y, ImageObserver observer); public abstract boolean drawImage (Image image, int x, int y, int width, int height, ImageObserver observer); public abstract boolean drawImage (Image image, int x, int y, Color backgroundColor, ImageObserver observer); public abstract boolean drawImage (Image image, int x, int y, int width, int height, Color backgroundColor, ImageObserver observer); public abstract boolean drawImage(Image img, int dx1, int dy1, int dx2, int dy2, int sx1, int sy1, int sx2, int sy2, ImageObserver observer); images

public abstract boolean drawImage(Image img, int dx1, int dy1, int dx2, int dy2, int sx1, int sy1, int sx2, int sy2, Color bgcolor, ImageObserver observer); images public abstract void drawLine (int x1, int y1, int x2, int y2); public abstract void drawOval (int x, int y, int width, int height); public abstract void drawPolygon (int xPoints[], int yPoints[], int numPoints); public void drawPolygon (Polygon p); public abstract void drawPolyline(int[ ] xPoints, int[ ] yPoints, int nPoints); images public void drawRect (int x, int y, int width, int height); public abstract void drawRoundRect (int x, int y, int width, int height, int arcWidth, int arcHeight); public abstract void drawString (String text, int x, int y); public void fill3DRect (int x, int y, int width, int height, boolean raised); public abstract void fillArc (int x, int y, int width, int height, int startAngle, int arcAngle); public abstract void fillOval (int x, int y, int width, int height); public abstract void fillPolygon (int xPoints[], int yPoints[], int numPoints); public void fillPolygon (Polygon p); public abstract void fillRect (int x, int y, int width, int height); public abstract void fillRoundRect (int x, int y, int width, int height, int arcWidth, int arcHeight); public void finalize(); public abstract Shape getClip(); images public abstract Rectangle getClipBounds(); images public abstract Rectangle getClipRect(); public abstract Color getColor(); public abstract Font getFont(); public FontMetrics getFontMetrics(); public abstract FontMetrics getFontMetrics (Font font); public abstract void setClip (int x, int y, int width, int height); images public abstract void setClip (Shape clip); images public abstract void setColor (Color color); public abstract void setFont (Font font); public abstract void setPaintMode(); public abstract void setXORMode (Color xorColor); public String toString(); public abstract void translate (int x, int y); }

Constructors

Graphics

protected Graphics()
Description Called by constructors of platform specific subclasses.

Instance Methods

clearRect

public abstract void clearRect (int x, int y, int width,
int height)
Parameters x x coordinate of origin of area to clear.
y y coordinate of origin of area to clear.
width size in horizontal direction to clear.
height size in vertical direction to clear.
Description Resets a rectangular area to the background color.

clipRect

public abstract void clipRect (int x, int y, int width,
int height)
Parameters x x coordinate of origin of clipped area.
y y coordinate of origin of clipped area.
width size in horizontal direction to clip.
height size in vertical direction to clip.
Description Reduces the drawing area to the intersection of the current drawing area and the rectangular area defined by x, y, width, and height.

copyArea

public abstract void copyArea (int x, int y, int width,
int height, int deltax, int deltay)
Parameters x x coordinate of origin of area to copy.
y y coordinate of origin of area to copy.
width size in horizontal direction to copy.
height size in vertical direction to copy.
deltax offset in horizontal direction to copy area to.
deltay offset in vertical direction to copy area to.
Description Copies a rectangular area to a new area, whose top left corner is (x+deltax, y+deltay).

create

public abstract Graphics create()
Returns New graphics context.
Description Creates a second reference to the same graphics context.
public Graphics create (int x, int y, int width, int height)
Parameters x x coordinate of origin of new graphics context.
y y coordinate of origin of new graphics context.
width size in horizontal direction.
height size in vertical direction.
Returns New graphics context
Description Creates a second reference to a subset of the same graphics context.

dispose

public abstract void dispose()
Description Frees system resources used by graphics context.

draw3DRect

public void draw3DRect (int x, int y, int width, int
height, boolean raised)
Parameters x x coordinate of the rectangle origin.
y y coordinate of the rectangle origin
width Width of the rectangle to draw.
height Height of the rectangle to draw.
raised Determines if rectangle drawn is raised or not; true for a raised rectangle.
Description Draws an unfilled 3-D rectangle from (x, y) of size width x height.

drawArc

public abstract void drawArc (int x, int y, int width, int
height, int startAngle, int arcAngle)
Parameters x x coordinate of the bounding rectangle's origin.
y y coordinate of the bounding rectangle's origin
width Width of the bounding rectangle for the arc.
height Height of the bounding rectangle for the arc.
startAngle Angle at which arc begins, in degrees
arcAngle length of arc, in degrees
Description Draws an unfilled arc from startAngle to arcAngle within bounding rectangle from (x, y) of size width x height. Zero degrees is at three o'clock; positive angles are counter clockwise.

drawBytes

public void drawBytes (byte text[], int offset, int
length, int x, int y)
Parameters text Text to draw, as a byte array.
offset Starting position within text to draw.
length Number of bytes to draw.
x x coordinate of baseline origin.
y y coordinate of baseline origin.
Throws ArrayIndexOutOfBoundsException
If offset or length is invalid.
Description Draws text on screen, starting with text[offset] and ending with text[offset+length-1].

drawChars

public void drawChars (char text[], int offset, int
length, int x, int y)
Parameters text Text to draw, as a char array.
offset Starting position within text to draw.
length Number of bytes to draw.
x x coordinate of baseline origin.
y y coordinate of baseline origin.
Throws ArrayIndexOutOfBoundsException
If offset or length is invalid.
Description Draws text on screen, starting with text[offset] and ending with text[offset+length-1].

drawImage

public abstract boolean drawImage (Image image, int x, int
y, ImageObserver observer)
Parameters image Image to draw.
x x coordinate of image origin.
y y coordinate of image origin.
observer Object that watches for image information; almost always this.
Returns true if the image has fully loaded when the method returns, false otherwise.
Description Draws image to screen at (x, y), at its original size. Drawing may be asynchronous. If image is not fully loaded when the method returns, observer is notified when additional information made available.
public abstract boolean drawImage (Image image, int x, int y, int width, int height, ImageObserver observer)
Parameters image Image to draw.
x x coordinate of image origin.
y y coordinate of image origin.
width New image size in horizontal direction.
height New image size in vertical direction.
observer Object that watches for image information; almost always this.
Returns true if the image has fully loaded when the method returns, false otherwise.
Description Draws image to screen at (x, y), scaled to width x height. Drawing may be asynchronous. If image is not fully loaded when the method returns, observer is notified when additional information made available.
public abstract boolean drawImage (Image image, int x, int y, Color backgroundColor, ImageObserver observer)
Parameters image Image to draw.
x x coordinate of image origin.
y y coordinate of image origin.
backgroundColor Color to show through image where transparent.
observer Object that watches for image information; almost always this.
Returns true if the image has fully loaded when the method returns, false otherwise.
Description Draws image to screen at (x, y), at its original size. Drawing may be asynchronous. If image is not fully loaded when the method returns, observer is notified when additional information made available. The background color is visible through any transparent pixels.
public abstract boolean drawImage (Image image, int x, int y, int width, int height, Color backgroundColor, ImageObserver observer)
Parameters image Image to draw.
x x coordinate of image origin.
y y coordinate of image origin.
width New image size in horizontal direction.
height New image size in vertical direction.
backgroundColor Color to show through image where transparent.
observer Object that watches for image information; almost always this.
Returns true if the image has fully loaded when the method returns, false otherwise.
Description Draws image to screen at (x, y), scaled to width x height. Drawing may be asynchronous. If image is not fully loaded when the method returns, observer is notified when additional information made available. The background color is visible through any transparent pixels.
public abstract boolean drawImage (Image image, int dx1, int dy1, int dx2, int dy2, int sx1, int sy1, int sx2, int sy2, ImageObserver observer) images
Parameters image Image to draw.
dx1 x coordinate of one corner of destination (device) rectangle.
dy1 y coordinate of one corner of destination (device) rectangle.
dx2 x coordinate of the opposite corner of destination (device) rectangle.
dy2 y coordinate of the opposite corner of destination (device) rectangle.
sx1 x coordinate of one corner of source (image) rectangle.
sy1 y coordinate of one corner of source (image) rectangle.
sx2 x coordinate of the opposite corner of source (image) rectangle.
sy2 y coordinate of the opposite corner of source (image) rectangle.
observer Object that watches for image information; almost always this.
Returns true if the image has fully loaded when the method returns, false otherwise.
Description Draws the part of image described by dx1, dy1, dx2, and dy2 to the screen into the rectangle described by sx1, sy1, sx2, and sy2. Drawing may be asynchronous. If image is not fully loaded when the method returns, observer is notified when additional information is made available.
public abstract boolean drawImage (Image image, int dx1, int dy1, int dx2, int dy2, int sx1, int sy1, int sx2, int sy2, Color backgroundColor, ImageObserver observer) images
Parameters image Image to draw.
dx1 x coordinate of one corner of destination (device) rectangle.
dy1 y coordinate of one corner of destination (device) rectangle.
dx2 x coordinate of the opposite corner of destination (device) rectangle.
dy2 y coordinate of the opposite corner of destination (device) rectangle.
sx1 x coordinate of one corner of source (image) rectangle.
sy1 y coordinate of one corner of source (image) rectangle.
sx2 x coordinate of the opposite corner of source (image) rectangle.
sy2 y coordinate of the opposite corner of source (image) rectangle.
backgroundColor Color to show through image where transparent.
observer Object that watches for image information; almost always this.
Returns true if the image has fully loaded when the method returns, false otherwise.
Description Draws the part of image described by dx1, dy1, dx2, and dy2 to the screen into the rectangle described by sx1, sy1, sx2, and sy2. Drawing may be asynchronous. If image is not fully loaded when the method returns, observer is notified when additional information made available. The background color is visible through any transparent pixels.

drawLine

public abstract void drawLine (int x1, int y1, int x2, int
y2)
Parameters x1 x coordinate of one point on line.
y1 y coordinate of one point on line.
x2 x coordinate of the opposite point on line.
y2 y coordinate of the opposite point on line.
Description Draws a line connecting (x1, y1) and (x2, y2).

drawOval

public abstract void drawOval (int x, int y, int width,
int height)
Parameters x x coordinate of bounding rectangle origin.
y y coordinate of bounding rectangle origin
width Width of bounding rectangle to draw in.
height Height of bounding rectangle to draw in.
Description Draws an unfilled oval within bounding rectangle from (x, y) of size width x height.

drawPolygon

public abstract void drawPolygon (int xPoints[], int
yPoints[], int numPoints)
Parameters xPoints[] The array of x coordinates for each point.
yPoints[] The array of y coordinates for each point.
numPoints The number of elements in both xPoints and yPoints arrays to use.
Description Draws an unfilled polygon based on first numPoints elements in xPoints and yPoints.
public void drawPolygon (Polygon p)
Parameters p Points of object to draw.
Description Draws an unfilled polygon based on points within the Polygon p.

drawPolyline

public abstract void drawPolyline (int xPoints[], int yPoints[], int nPoints) images

Parameters xPoints[] The array of x coordinates for each point.
yPoints[] The array of y coordinates for each point.
nPoints The number of elements in both xPoints and yPoints arrays to use.
Description Draws a series of line segments based on first numPoints elements in xPoints and yPoints.

drawRect

public void drawRect (int x, int y, int width, int height)
Parameters x x coordinate of rectangle origin.
y y coordinate of rectangle origin
width Width of rectangle to draw.
height Height of rectangle to draw.
Description Draws an unfilled rectangle from (x, y) of size width x height.

drawRoundRect

public abstract void drawRoundRect (int x, int y, int
width, int height, int arcWidth, int arcHeight)
Parameters x x coordinate of bounding rectangle origin.
y y coordinate of bounding rectangle origin
width Width of rectangle to draw.
height Height of rectangle to draw.
arcWidth Width of arc of rectangle corner.
arcHeight Height of arc of rectangle corner.
Description Draws an unfilled rectangle from (x, y) of size width x height with rounded corners.

drawString

public abstract void drawString (String text, int x, int
y)
Parameters text Text to draw.
x x coordinate of baseline origin.
y y coordinate of baseline origin.
Description Draws text on screen.

fill3DRect

public void fill3DRect (int x, int y, int width, int
height, boolean raised)
Parameters x x coordinate of rectangle origin.
y y coordinate of rectangle origin
width Width of rectangle to draw.
height Height of rectangle to draw.
raised true to draw a rectangle that appears raised; false to draw a rectangle that appears depressed.
Description Draws a filled 3-D rectangle from (x, y) of size width x height.

fillArc

public abstract void fillArc (int x, int y, int width, int
height, int startAngle, int arcAngle)
Parameters x x coordinate of bounding rectangle origin.
y y coordinate of bounding rectangle origin
width Width of bounding rectangle to draw in.
height Height of bounding rectangle to draw in.
startAngle Starting angle of arc.
arcAngle The extent of the arc, measured from startAngle
Description Draws a filled arc from startAngle to arcAngle within bounding rectangle from (x, y) of size width x height. Zero degrees is at three o'clock; positive angles are counter clockwise.

fillOval

public abstract void fillOval (int x, int y, int width,
int height)
Parameters x x coordinate of bounding rectangle origin.
y y coordinate of bounding rectangle origin
width Width of bounding rectangle to draw in.
height Height of bounding rectangle to draw in.
Description Draws filled oval within bounding rectangle from (x, y) of size width x height.

fillPolygon

public abstract void fillPolygon (int xPoints[], int
yPoints[], int numPoints)
Parameters xPoints[] The array of x coordinates for each point.
yPoints[] The array of y coordinates for each point.
numPoints The number of elements in both xPoints and yPoints arrays to use.
Throws ArrayIndexOutOfBoundsException
If numPoints > xPoints.length or numPoints > yPoints.length.
Description Draws filled polygon based on first numPoints elements in xPoints and yPoints.
public void fillPolygon (Polygon p)
Parameters p Points of object to draw.
Description Draws filled polygon based on points within the Polygon p.

fillRect

public abstract void fillRect (int x, int y, int width,
int height)
Parameters x x coordinate of rectangle origin.
y y coordinate of rectangle origin
width Width of rectangle to draw.
height Height of rectangle to draw.
Description Draws filled rectangle from (x, y) of size width x height.

fillRoundRect

public abstract void fillRoundRect (int x, int y, int
width, int height, int arcWidth, int arcHeight)
Parameters x x coordinate of bounding rectangle origin.
y y coordinate of bounding rectangle origin
width Width of rectangle to draw.
height Height of rectangle to draw.
arcWidth Width of arc of rectangle corner.
arcHeight Height of arc of rectangle corner.
Description Draws a filled rectangle from (x, y) of size width x height with rounded corners.

finalize

public void finalize()
Overrides Object.finalize()
Description Tells the garbage collector to dispose of graphics context.

getClip

public abstract Shape getClip () images

Returns Shape describing the clipping are of the graphics context.

getClipBounds

public abstract Rectangle getClipBounds() images

Returns Rectangle describing the clipping area of the graphics context.

getClipRect

public abstract Rectangle getClipRect() images

Returns Replaced by getClipBounds().

getColor

public abstract Color getColor()
Returns The current drawing Color of the graphics context.

getFont

public abstract Font getFont()
Returns The current Font of the graphics context.

getFontMetrics

public FontMetrics getFontMetrics()
Returns The FontMetrics of the current font of the graphics context.
public abstract FontMetrics getFontMetrics (Font font)
Parameters font Font to get metrics for.
Returns The FontMetrics of the given font for the graphics context.

setClip

public abstract void setClip (int x, int y, int width, int height) images

Parameters x x coordinate of rectangle
y y coordinate of rectangle
width width of rectangle
height height of rectangle
Description Changes current clipping region to the specified rectangle.
public abstract void setClip (Shape clip) images
Parameters clip The new clipping shape.
Description Changes current clipping region to the specified shape.

setColor

public abstract void setColor (Color color)
Parameters color New color.
Description Changes current drawing color of graphics context.

setFont

public abstract void setFont (Font font)
Parameters font New font.
Description Changes current font of graphics context.

setPaintMode

public abstract void setPaintMode()
Description Changes painting mode to normal mode.

setXORMode

public abstract void setXORMode (Color xorColor)
Parameters xorColor XOR mode drawing color.
Description Changes painting mode to XOR mode; in this mode, drawing the same object in the same color at the same location twice has no net effect.

toString

public String toString()
Returns A string representation of the Graphics object.
Overrides Object.toString()

translate

public void translate (int x, int y)
Parameters x x coordinate of new drawing origin.
y y coordinate of new drawing origin.
Description Moves the origin of drawing operations to (x, y).

See Also

Color, Font, FontMetrics, Image, ImageObserver, Object, Polygon, Rectangle, Shape, String

19.28 GridBagConstraints

images

Description

The GridBagConstraints class provides the means to control the layout of components within a Container whose LayoutManager is GridBagLayout.

Class Definition

public class java.awt.GridBagConstraints
    extends java.lang.Object
    implements java.lang.Cloneable, java.io.Serializable {

  // Constants
  public final static int BOTH;
  public final static int CENTER;
  public final static int EAST;
  public final static int HORIZONTAL;
  public final static int NONE;
  public final static int NORTH;
  public final static int NORTHEAST;
  public final static int NORTHWEST;
  public final static int RELATIVE;
  public final static int REMAINDER;
  public final static int SOUTH;
  public final static int SOUTHEAST;
  public final static int SOUTHWEST;
  public final static int VERTICAL;
  public final static int WEST;
// Variables
  public int anchor;
  public int fill;
  public int gridheight;
  public int gridwidth;
  public int gridx;
  public int gridy;
  public Insets insets;
  public int ipadx;
  public int ipady;
  public double weightx
  public double weighty

  // Constructors
  public GridBagConstraints();

  // Instance Methods
  public Object clone();
}

Constants

BOTH

public final static int BOTH

Constant for possible fill value.

CENTER

public final static int CENTER

Constant for possible anchor value.

EAST

public final static int EAST

Constant for possible anchor value.

HORIZONTAL

public final static int HORIZONTAL

Constant for possible fill value.

NONE

public final static int NONE

Constant for possible fill value.

NORTH

public final static int NORTH

Constant for possible anchor value.

NORTHEAST

public final static int NORTHEAST

Constant for possible anchor value.

NORTHWEST

public final static int NORTHWEST

Constant for possible anchor value.

RELATIVE

public final static int RELATIVE

Constant for possible gridx, gridy, gridwidth, or gridheight value.

REMAINDER

public final static int REMAINDER

Constant for possible gridwidth or gridheight value.

SOUTH

public final static int SOUTH

Constant for possible anchor value.

SOUTHEAST

public final static int SOUTHEAST

Constant for possible anchor value.

SOUTHWEST

public final static int SOUTHWEST

Constant for possible anchor value.

VERTICAL

public final static int VERTICAL

Constant for possible fill value.

WEST

public final static int WEST

Constant for possible anchor value.

Variables

anchor

public int anchor

Specifies the alignment of the component in the event that it is smaller than the space allotted for it by the layout manager; e.g., CENTER centers the object within the region.

fill

public int fill

The component's resize policy if additional space available.

gridheight

public int gridheight

Number of columns a component occupies.

gridwidth

public int gridwidth

Number of rows a component occupies.

gridx

public int gridx

Horizontal grid position at which to add component.

gridy

public int gridy

Vertical grid position at which to add component.

insets

public Insets insets

Specifies the outer padding around the component.

ipadx

public int ipadx

Serves as the internal padding within the component in both the right and left directions.

ipady

public int ipady

Serves as the internal padding within the component in both the top and bottom directions.

weightx

public double weightx

Represents the percentage of extra horizontal space that will be given to this component if there is additional space available within the container.

weighty

public double weighty

Represents the percentage of extra vertical space that will be given to this component if there is additional space available within the container.

Constructors

GridBagConstraints

public GridBagConstraints()
Description Constructs a GridBagConstraints object.

Instance Methods

clone

public Object clone()
Returns A new instance of GridBagConstraints with same values for constraints.
Overrides Object.clone()

See Also

Cloneable, GridBagLayout, Insets, Object, Serializable

19.29 GridBagLayout

images

Description

The GridBagLayout LayoutManager provides the means to layout components in a flexible grid-based display model.

Class Definition

public class java.awt.GridBagLayout extends java.lang.Object implements java.awt.LayoutManager2, java.io.Serializable { // Protected Constants protected static final MAXGRIDSIZE; protected static final MINSIZE; protected static final PREFERREDSIZE; // Variables public double columnWeights[]; public int columnWidths[]; public int rowHeights[]; public double rowWeights[]; // Protected Variables protected Hashtable comptable; protected GridBagConstraints defaultConstraints; protected GridBagLayoutInfo layoutInfo; // Constructors public GridBagLayout(); // Instance Methods public void addLayoutComponent (Component comp, Object constraints); images public void addLayoutComponent (String name, Component component); public GridBagConstraints getConstraints (Component component);

public abstract float getLayoutAlignmentX(Container target); images public abstract float getLayoutAlignmentY(Container target); images public int[][] getLayoutDimensions(); public Point getLayoutOrigin(); public double[][] getLayoutWeights(); public abstract void invalidateLayout(Container target); images public void layoutContainer (Container target); public Point location (int x, int y); public abstract Dimension maximumLayoutSize(Container target); images public Dimension minimumLayoutSize (Container target); public Dimension preferredLayoutSize (Container target); public void removeLayoutComponent (Component component); public void setConstraints (Component component, GridBagConstraints constraints); public String toString(); // Protected Instance Methods protected void AdjustForGravity (GridBagConstraints constraints, Rectangle r); protected void ArrangeGrid (Container target); protected GridBagLayoutInfo GetLayoutInfo (Container target, int sizeFlag); protected Dimension GetMinSize (Container target, GridBagLayoutInfo info); protected GridBagConstraints lookupConstraints (Component comp); }

Protected Constants

MAXGRIDSIZE

protected static final MAXGRIDSIZE

Maximum number of rows and columns within container managed by GridBagLayout.

MINSIZE

protected static final MINSIZE

Used for internal sizing purposes.

PREFERREDSIZE

protected static final PREFERREDSIZE

Used for internal sizing purposes.

Variables

columnWeights

public double[] columnWeights

The weightx values of the components in the row with the most elements.

columnWidths

public int[] columnWidths

The width values of the components in the row with the most elements.

rowHeights

public int[] rowHeights

The height values of the components in the column with the most elements.

rowWeights

public double[] rowWeights

The weighty values of the components in the column with the most elements.

Protected Variables

comptable

protected Hashtable comptable

Internal table to manage components.

defaultConstraints

protected GridBagConstraints defaultConstraints

Constraints to use for Components that have none.

layoutInfo

protected GridBagLayoutInfo layoutInfo

Internal information about the GridBagLayout.

Constructors

GridBagLayout

public GridBagLayout()
Description Constructs a GridBagLayout object.

Instance Methods

addLayoutComponent

public void addLayoutComponent (Component comp, Object constraints) images

Parameters comp The component being added.
constraints An object describing the constraints on this component.
Implements LayoutManager2.addLayoutComponent()
Description Adds the component comp to container subject to the given constraints. This is a more generalized version of addLayoutComponent(String, Component). It corresponds to java.awt.Container's add(Component, Object).
public void addLayoutComponent (String name, Component component)
Parameters name Name of component to add.
component Actual component being added.
Implements LayoutManager.addLayoutComponent()
Description Does nothing.

getConstraints

public GridBagConstraints getConstraints (Component
component)
Parameters component Component whose constraints are desired
Returns GridBagConstraints for component requested.

getLayoutAlignmentX

public abstract float getLayoutAlignmentX (Container target) images

Parameters target The container to inspect.
Returns The value .5 for all containers.
Description This method returns the preferred alignment of the given container target. A return value of 0 is left aligned, .5 is centered, and 1 is right aligned.

getLayoutAlignmentY

public abstract float getLayoutAlignmentY (Container target) images

Parameters target The container to inspect.
Returns The value .5 for all containers.
Description This method returns the preferred alignment of the given container target. A return value of 0 is top aligned, .5 is centered, and 1 is bottom aligned.

getLayoutDimensions

public int[][] getLayoutDimensions()
Returns Returns two single dimension arrays as a multi-dimensional array. Index 0 is an array of widths (columnWidths instance variable), while index 1 is an array of heights (rowHeights instance variable).

getLayoutOrigin

public Point getLayoutOrigin()
Returns Returns the origin of the components within the Container whose LayoutManager is GridBagLayout.

getLayoutWeights

public double[][] getLayoutWeights()
Returns Returns two single dimension arrays as a multi-dimensional array. Index 0 is an array of columns weights (columnWeights instance variable), while index 1 is an array of row weights (rowWeights instance variable).

invalidateLayout

public abstract void invalidateLayout (Container target) images

Parameters target The container to invalidate.
Description Does nothing.

layoutContainer

public void layoutContainer (Container target)
Parameters target The container that needs to be redrawn.
Implements LayoutManager.layoutContainer()
Description Draws components contained within target.

location

public Point location (int x, int y)
Parameters x The x coordinate of the grid position to find.
y The y coordinate of the grid position to find.
Returns Returns the grid element under the location provided at position (x, y) in pixels. Note that the returned Point uses the GridBagLayout's grid for its coordinate space.
Description Locates the grid position in the Container under the given location.

maximumLayoutSize

public abstract Dimension maximumLayoutSize (Container target) images

Parameters target The container to inspect.
Returns A Dimension whose horizontal and vertical components are Integer.MAX_VALUE.
Description For GridBagLayout, a maximal Dimension is always returned.

minimumLayoutSize

public Dimension minimumLayoutSize (Container target)
Parameters target The container whose size needs to be calculated.
Returns Minimum Dimension of container target.
Implements LayoutManager.minimumLayoutSize()
Description Calculates minimum size of target container.

preferredLayoutSize

public Dimension preferredLayoutSize (Container target)
Parameters target The container whose size needs to be calculated.
Returns Preferred Dimension of container target
Implements LayoutManager.preferredLayoutSize()
Description Calculates preferred size of target container.

removeLayoutComponent

public void removeLayoutComponent (Component component)
Parameters component Component to stop tracking.
Implements LayoutManager.removeLayoutComponent()
Description Does nothing.

setConstraints

public void setConstraints (Component component,
GridBagConstraints constraints)
Parameters component Component to set constraints for
constraints Constraints for component
Description Changes the GridBagConstraints on component to those provided.

toString

public String toString()
Returns A string representation of the GridBagLayout object.
Overrides Object.toString()

Protected Instance Methods

AdjustForGravity

protected void AdjustForGravity (GridBagConstraints
constraints, Rectangle r)
Parameters constraints Constraints to use for adjustment of Rectangle.
r Rectangular area that needs to be adjusted.
Description Helper routine for laying out a cell of the grid. The routine adjusts the values for r based upon the constraints.

ArrangeGrid

protected void ArrangeGrid (Container target)
Parameters target Container to layout.
Description Helper routine that does the actual arrangement of components in target.

GetLayoutInfo

protected GridBagLayoutInfo GetLayoutInfo (Container
target, int sizeFlag)
Parameters target Container to get information about.
sizeFlag One of the constants MINSIZE or PREFERREDSIZE.
Returns Returns an internal class used to help size the container.

GetMinSize

protected Dimension GetMinSize (Container target,
GridBagLayoutInfo info)
Parameters target Container to calculate size.
info Specifics about the container's constraints.
Returns Minimum Dimension of container target based on info.
Description Helper routine for calculating size of container.

lookupConstraints

protected GridBagConstraints lookupConstraints (Component
comp)
Parameters comp Component in question.
Returns A reference to the GridBagConstraints object for this component.
Description Helper routine for calculating size of container.

See Also

Component, Container, Dimension, GridBagConstraints, Hashtable, LayoutManager, LayoutManager2, Object, Point, Rectangle, String

19.30 GridLayout

images

Description

The GridLayout LayoutManager provides the means to layout components in a grid of rows and columns.

Class Definition

public class java.awt.GridLayout extends java.lang.Object implements java.awt.LayoutManager, java.io.Serializable { // Constructors public GridLayout(); images public GridLayout (int rows, int cols); public GridLayout (int rows, int cols, int hgap, int vgap); // Instance Methods public void addLayoutComponent (String name, Component component); public int getColumns(); images public int getHgap(); images public int getRows(); images public int getVgap(); images public void layoutContainer (Container target); public Dimension minimumLayoutSize (Container target); public Dimension preferredLayoutSize (Container target); public void removeLayoutComponent (Component component); public int setColumns(int cols); images public int setHgap(int hgap); images public int setRows(int rows); images public int setVgap(int vgap); images public String toString(); }

Constructors

GridLayout

public GridLayout() images

Description Constructs a GridLayout object with a default single row and one column per component.
public GridLayout (int rows, int cols)
Parameters rows Requested number of rows in container.
cols Requested number of columns in container.
Description Constructs a GridLayout object with the requested number of rows and columns. Note that the actual number of rows and columns depends on the number of objects in the layout, not the constructor's parameters.
public GridLayout (int rows, int cols, int hgap, int vgap)
Parameters rows Requested number of rows in container.
cols Requested number of columns in container.
hgap Horizontal space between each component in a row.
vgap Vertical space between each row.
Description Constructs a GridLayout object with the requested number of rows and columns and the values specified as the gaps between each component. Note that the actual number of rows and columns depends on the number of objects in the layout, not the constructor's parameters.

Instance Methods

addLayoutComponent

public void addLayoutComponent (String name, Component
component)
Parameters name Name of component to add.
component Actual component being added.
Implements LayoutManager.addLayoutComponent()
Description Does nothing.

getColumns

public int getColumns() images

Returns The number of columns.

getHgap

public int getHgap() images

Returns The horizontal gap for this GridLayout instance.

getRows

public int getRows() images

Returns The number of rows.

getVgap

public int getVgap() images

Returns The vertical gap for this GridLayout instance.

layoutContainer

public void layoutContainer (Container target)
Parameters target The container that needs to be redrawn.
Implements LayoutManager.layoutContainer()
Description Draws the components contained within the target.

minimumLayoutSize

public Dimension minimumLayoutSize (Container target)
Parameters target The container whose size needs to be calculated.
Returns Minimum Dimension of the container target.
Implements LayoutManager.minimumLayoutSize()
Description Calculates the minimum size of the target container.

preferredLayoutSize

public Dimension preferredLayoutSize (Container target)
Parameters target The container whose size needs to be calculated.
Returns Preferred Dimension of the container target.
Implements LayoutManager.preferredLayoutSize()
Description Calculates the preferred size of the target container.

removeLayoutComponent

public void removeLayoutComponent (Component component)
Parameters component Component to stop tracking.
Implements LayoutManager.removeLayoutComponent()
Description Does nothing.

setColumns

public void setColumns(int cols) images

Parameters cols The new number of columns.
Description Sets the number of columns.

setHgap

public void setHgap(int hgap) images

Parameters hgap The horizontal gap value.
Description Sets the horizontal gap between components.

setRows

public void setRows(int rows) images

Parameters rows The new number of rows.
Description Sets the number of rows.

setVgap

public void setVgap(int vgap) images

Parameters vgap The vertical gap value.
Description Sets the vertical gap between components.

toString

public String toString()
Returns A string representation of the GridLayout object.
Overrides Object.toString()

See Also

Component, Container, Dimension, LayoutManager, Object, String

19.31 IllegalComponentStateException images

images

Description

An Exception indicating that a Component was not in an appropriate state to perform a requested action.

Class Definition

public class java.awt.IllegalComponentStateException
    extends java.lang.IllegalStateException {

  // Constructors
  public IllegalComponentStateException();
  public IllegalComponentStateException (String s);
}

Constructors

IllegalComponentStateException

public IllegalComponentStateException()
Description Constructs the exception object with no detail message.
public IllegalComponentStateException (String s)
Parameters s Detail message
Description Constructs the exception object with the given detail message.

See Also

Exception, String

19.32 Image

images

Description

The Image class represents a displayable object maintained in memory. Because

Image is an abstract class, you never work with the Image class itself, but with a platform specific subclass. However, you should never need to know what that subclass is. To draw on an Image, get its graphics context.

Class Definition

public abstract class java.awt.Image extends java.lang.Object implements java.io.Serializable { // Constants public final static int SCALE_AREA_AVERAGING; images public final static int SCALE_DEFAULT; images public final static int SCALE_FAST; images

public final static int SCALE_REPLICATE; images public final static int SCALE_SMOOTH; images public final static Object UndefinedProperty; // Instance Methods public abstract void flush(); public abstract Graphics getGraphics(); public abstract int getHeight (ImageObserver observer); public abstract Object getProperty (String name, ImageObserver observer); public Image getScaledInstance (int width, int height, int hints); images public abstract ImageProducer getSource(); public abstract int getWidth (ImageObserver observer); }

Constants

SCALE_AREA_AVERAGING

public final static int SCALE_AREA_AVERAGING images

Flag that requests use of AreaAveragingScaleFilter.

SCALE_DEFAULT

public final static int SCALE_DEFAULT images

Flag that requests use of the default image scaling algorithm.

SCALE_FAST

public final static int SCALE_FAST images

Flag that requests use of an image scaling algorithm that is faster rather than smoother.

SCALE_REPLICATE

public final static int SCALE_REPLICATE images

Flag that requests use of ReplicateScaleFilter.

SCALE_SMOOTH

public final static int SCALE_SMOOTH images

Flag that requests use of an image scaling algorithm that is smoother rather than faster.

UndefinedProperty

public final static Object UndefinedProperty

Possible return object from getProperty().

Instance Methods

flush

public abstract void flush()
Description Resets image to initial state.

getGraphics

public abstract Graphics getGraphics()
Throws ClassCastException
If image created from file or URL.
Returns The graphics context of the image.
Description Gets the graphics context of the image for drawing.

getHeight

public abstract int getHeight (ImageObserver observer)
Parameters observer An image observer; usually the Component on which the image is rendered.
Returns Image height, or -1 if the height is not yet available.

getProperty

public abstract Object getProperty (String name,
ImageObserver observer)
Parameters name Name of the property to fetch.
observer An image observer; usually the Component on which the image is rendered.
Returns Object representing the requested property, null, or UndefinedProperty.
Throws ArrayIndexOutOfBoundsException
If offset or length is invalid.
Description Retrieves a property from the image's private property list.

getScaledInstance

public Image getScaledInstance (int width, int height, int hints) images

Parameters width The width for the scaled image. Use -1 to preserve the aspect ratio with reference to height.
height The height for the scaled image. Use -1 to preserve the aspect ratio with reference to width.
hints One or more of the SCALE_ constants.
Returns The scaled image. It may be loaded asynchronously, even if the original image was fully loaded.
Description Creates a copy of an image, scaled to width x height and using an algorithm chosen based on the hints given.

getSource

public abstract ImageProducer getSource()
Returns The ImageProducer of the image.

getWidth

public abstract int getWidth (ImageObserver observer)
Parameters observer An image observer; usually the Component on which the image is rendered.
Returns Image width, or -1 if the width is not yet available.

See Also

Graphics, ImageObserver, ImageProducer, Object, Properties, String

19.33 Insets

images

Description

The Insets class provides a way to encapsulate the layout margins of the four different sides of a Container.

Class Definition

public class java.awt.Insets
    extends java.lang.Object
    implements java.io.Serializable, java.lang.Cloneable {

  // Variables

public int bottom; public int left; public int right; public int top; // Constructors public Insets (int top, int left, int bottom, int right); // Instance Methods public Object clone(); public boolean equals (Object obj); images public String toString(); }

Variables

bottom

public int bottom

The border width for the bottom of a Container.

left

public int left

The border width for the left side of a Container.

right

public int right

The border width for the right side of a Container.

top

public int top

The border width for the top of a Container.

Constructors

Insets

public Insets (int top, int left, int bottom, int right)
Parameters top The border width for the top of a Container.
left The border width for the left side of a Container.
bottom The border width for the bottom of a Container.
right The border width for the right side of a Container.
Description Constructs an Insets object with the appropriate border settings.

Instance Methods

clone

public Object clone()
Returns Clone of original object.
Overrides Object.clone()
Description Creates a copy of the original instance of an object.

equals

public boolean equals (Object obj) images

Parameters obj The object to be tested.
Returns true if the objects are equal; false otherwise.
Overrides Object.equals(Object)
Description Tests two Insets objects for equality.

toString

public String toString()
Returns A string representation of the Insets object.
Overrides Object.toString()

See Also

Cloneable, Container, Object, Serializable, String

19.34 ItemSelectable images

Description

An interface that describes an object that has one or more items that can be selected.

Interface Definition

public abstract interface ItemSelectable {

  // Instance Methods
  public abstract void addItemListener (ItemListener l);
  public abstract Object[] getSelectedObjects();
  public abstract void removeItemListener (ItemListener l);
}

images

Interface Methods

addItemListener

public abstract void addItemListener (ItemListener l)
Parameters l The listener to be added.
Description Adds a listener for ItemEvent objects.

getSelectedObjects

public abstract Object[] getSelectedObjects()
Description This method returns an array containing Objects representing the items that are currently selected. If no items are selected, null is returned.

removeItemListener

public abstract void removeItemListener (ItemListener l)
Parameters l The listener to be removed.
Description Removes the specified ItemListener so it will not receive ItemEvent objects.

See Also

Checkbox, CheckboxMenuItem, Choice, ItemEvent, ItemListener, List

19.35 Label

Description

The Label is a Component that displays a single line of static text.

images

Class Definition

public class java.awt.Label
    extends java.awt.Component {

  // Constants
  public static final int CENTER;
  public static final int LEFT;
  public static final int RIGHT;

  // Constructors
  public Label();
  public Label (String label);
  public Label (String label, int alignment);

  // Instance Methods
  public void addNotify();
  public int getAlignment();
  public String getText();
  public synchronized void setAlignment (int alignment);
  public synchronized void setText (String label);

  // Protected Instance Methods
  protected String paramString();
}

Constants

CENTER

public static final int CENTER
Description Constant to center text within the label.

LEFT

public static final int LEFT
Description Constant to left justify text within the label.

RIGHT

public static final int RIGHT
Description Constant to right justify text within the label.

Constructors

Label

public Label()
Description Constructs a Label object with the text centered within the label.
public Label (String label)
Parameters label The text for the label
Description Constructs a Label object with the text label centered within the label.
public Label (String label, int alignment)
Parameters label The text for the label
alignment The alignment for the label; one of the constants CENTER, LEFT, or RIGHT.
Throws IllegalArgumentException
If alignment is not one of CENTER, LEFT, or RIGHT.
Description Constructs a Label object, with a given alignment and text of label.

Instance Methods

addNotify

public void addNotify()
Overrides Component.addNotify()
Description Creates Label's peer.

getAlignment

public int getAlignment()
Returns Current alignment.

getText

public String getText()
Returns Current text of Label.

setAlignment

public synchronized void setAlignment (int alignment)
Parameters alignment New alignment for Label; CENTER, LEFT, or RIGHT.
Throws IllegalArgumentException
If alignment is not one of CENTER, LEFT, or RIGHT.
Description Changes the current alignment of Label.

setText

public synchronized void setText (String label)
Parameters label New text for Label.
Description Changes the current text of Label.

Protected Instance Methods

paramString

protected String paramString()
Returns String with current settings of Label.
Overrides Component.paramString()
Description Helper method for toString() to generate string of current settings.

See Also

Component, String

19.36 LayoutManager

Description

LayoutManager is an interface that defines the responsibilities of an object that wants to lay out Components to the display in a Container.

Interface Definition

public abstract interface java.awt.LayoutManager {

  // Interface Methods
  public abstract void addLayoutComponent (String name,
      Component component);
public abstract void layoutContainer (Container target);
  public abstract Dimension minimumLayoutSize (Container target);
  public abstract Dimension preferredLayoutSize (Container target);
  public abstract void removeLayoutComponent (Component component);
}

images

Interface Methods

addLayoutComponent

public abstract void addLayoutComponent (String name,
Component component)
Parameters name Name of component to add.
component Actual component being added.
Description Called when you call Container.add(String, Component) to add an object to a container.

layoutContainer

public abstract void layoutContainer (Container target)
Parameters target The container who needs to be redrawn.
Description Called when target needs to be redrawn.

minimumLayoutSize

public abstract Dimension minimumLayoutSize (Container
target)
Parameters target The container whose size needs to be calculated.
Returns Minimum Dimension of the container target
Description Called when the minimum size of the target container needs to be calculated.

preferredLayoutSize

public abstract Dimension preferredLayoutSize (Container
target)
Parameters target The container whose size needs to be calculated.
Returns Preferred Dimension of the container target
Description Called when the preferred size of the target container needs to be calculated.

removeLayoutComponent

public abstract void removeLayoutComponent (Component
component)
Parameters component Component to no longer track.
Description Called when you call Container.remove(Component) to remove a component from the layout.

See Also

Component, Container, FlowLayout, GridLayout, Object, String

19.37 LayoutManager2 images

images

Description

LayoutManager2 is an extension of LayoutManager. It provides a more generalized way to add components to a container, as well as more sizing and alignment methods.

Interface Definition

public abstract interface java.awt.LayoutManager2
    extends java.awt.LayoutManager {

  // Interface Methods
  public abstract void addLayoutComponent (Component comp,
      Object constraints);
  public abstract float getLayoutAlignmentX(Container target);
  public abstract float getLayoutAlignmentY(Container target);
  public abstract void invalidateLayout(Container target);
  public abstract Dimension maximumLayoutSize(Container target);
}

Interface Methods

addLayoutComponent

public abstract void addLayoutComponent (Component comp,
Object constraints)
Parameters comp Component to add.
constraints Constraints on the component.
Description Called to add an object to a container. This is slightly more generic than LayoutManager's addLayoutComponent(String, Component).

getLayoutAlignmentX

public abstract float getLayoutAlignmentX (Container
target)
Parameters target The container to inspect.
Returns A value between 0 and 1.
Description This method returns the preferred alignment of the given container target. A return value of 0 is left aligned, .5 is centered, and 1 is right aligned.

getLayoutAlignmentY

public abstract float getLayoutAlignmentY (Container
target)
Parameters target The container to inspect.
Returns A value between 0 and 1.
Description This method returns the preferred alignment of the given container target. A return value of 0 is top aligned, .5 is centered, and 1 is bottom aligned.

invalidateLayout

public abstract void invalidateLayout (Container target)
Parameters target The container to invalidate.
Description Sophisticated layout managers may cache information to improve performance. This method can be used to signal the manager to discard any cached information and start fresh.

maximumLayoutSize

public abstract Dimension maximumLayoutSize (Container
target)
Returns The maximum size of target.
Parameters target The container to inspect.
Description This method returns the maximum size of target using this layout manager.

See Also

BorderLayout, CardLayout, Component, Container, GridBagLayout, Object, String

19.38 List

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Description

The List is a Component that provides a scrollable list of choices to select from. A List can be in one of two modes: single selection mode, in which only one item may be selected at a time; and multiple selection mode, in which several items may be selected at one time. A list does not necessarily display all of the choices at one time; one of the constructors lets you specify the number of choices to display simultaneously. Although the changes in 1.1 are extensive, almost all of them can be boiled down to (1) using the 1.1 event model, and (2) standardizing method names (e.g. set/get pairs).

Class Definition

public class java.awt.List extends java.awt.Component implements java.awt.ItemSelectable { // Constructors public List(); public List (int rows); images public List (int rows, boolean multipleSelections); // Instance Methods public void add (String item); images public synchronized void add (String item, int index); images public void addActionListener (ActionListener l); images public void addItem (String item);

public synchronized void addItem (String item, int index); images public void addItemListener (ItemListener l); images public void addNotify(); public boolean allowsMultipleSelections(); images public synchronized void clear(); images public int countItems(); images public synchronized void delItem (int position); public synchronized void delItems (int start, int end); images public synchronized void deselect (int index); public String getItem (int index); public int getItemCount(); images public synchronized String[] getItems(); images public Dimension getMinimumSize(); images public Dimension getMinimumSize (int rows); images public Dimension getPreferredSize(); images public Dimension getPreferredSize (int rows); images public int getRows(); public synchronized int getSelectedIndex(); public synchronized int[] getSelectedIndexes(); public synchronized String getSelectedItem(); public synchronized String[] getSelectedItems(); public Object[] getSelectedObjects(); images public int getVisibleIndex(); public boolean isIndexSelected(int index); images public boolean isMultipleMode(); images public boolean isSelected (int index); images public synchronized void makeVisible (int index); public Dimension minimumSize(); images public Dimension minimumSize (int rows); images public Dimension preferredSize(); images public Dimension preferredSize (int rows); images public synchronized void remove (int position); images public synchronized void remove (String item); images public void removeActionListener (ActionListener l); images public synchronized void removeAll(); images public void removeItemListener (ItemListener l); images public void removeNotify(); public synchronized void replaceItem (String newItem, int index); public synchronized void select (int position); public synchronized void setMultipleMode (boolean b); images public synchronized void setMultipleSelections (boolean value); images // Protected Instance Methods protected String paramString(); protected void processActionEvent (ActionEvent e); images protected void processEvent (AWTEvent e); images protected void processItemEvent (ItemEvent e); images }

Constructors

List

public List()
Description Constructs a List object in single-selection mode.
public List (int rows) images
Parameters rows Requested number of rows to display.
Description Constructs a List object with the specified number of rows, in single-selection mode.
public List (int rows, boolean multipleSelections)
Parameters rows Requested number of rows to display.
multipleSelections true to allow multiple selections; false to select one item at a time.
Description Constructs a List object.

Instance Methods

add

public void add (String item) images

Parameters item Text for entry to add.
Description Adds a new entry to the available choices.
public synchronized void add (String item, int index) images
Parameters item Text for entry to add.
index Position at which to add entry; the first entry has an index of zero.
Description Adds a new entry to the available choices at the designated position.

addActionListener

public void addActionListener (ActionListener l) images

Parameters l An object that implements the ActionListener interface.
Description Add a listener for the action event.

addItem

public void addItem (String item)
Parameters item Text for entry to add.
Description Replaced by add(String).
public synchronized void addItem (String item, int index) images
Parameters item Text for entry to add.
index Position at which to add entry; the first entry has an index of zero.
Description Replaced by add(String, int).

addItemListener

public void addItemListener (ItemListener l) images

Parameters l The listener to be added.
Implements ItemSelectable.addItemListener(ItemListener l)
Description Adds a listener for the ItemEvent objects this List fires off.

addNotify

public void addNotify()
Overrides Component.addNotify()
Description Creates List's peer.

allowsMultipleSelections

public boolean allowsMultipleSelections() images

Returns true if multi-selection active, false otherwise. Replaced by isMultipleMode().

clear

public synchronized void clear() images

Description Clears all the entries out of the List. Replaced by removeAll().

countItems

public int countItems() images

Returns Number of items in the List. Replaced by getItemCount().

delItem

public synchronized void delItem (int position)
Parameters position Position of item to delete.
Description Removes a single entry from the List. Replaced by remove(int) and remove(String).

delItems

public synchronized void delItems (int start, int end) images

Parameters start Starting position of entries to delete.
end Ending position of entries to delete.
Description Removes a set of entries from the List.

deselect

public synchronized void deselect (int index)
Parameters index Position to deselect.
Description Deselects the entry at the designated position, if selected.

getItem

public String getItem (int index)
Parameters index Position of entry to get.
Throws ArrayIndexOutOfBoundsException
If index is invalid.
Returns String for entry at given position.

getItemCount

public int getItemCount() images

Returns Number of items in the List.

getItems

public String[] getItems() images

Returns The string items in the List.

getMinimumSize

public Dimension getMinimumSize() images

Returns The minimum dimensions of the List.
public Dimension getMinimumSize (int rows) images
Parameters rows Number of rows within List to size.
Returns The minimum dimensions of a List of the given size.

getPreferredSize

public Dimension getPreferredSize() images

Returns The preferred dimensions of the List.
public Dimension getPreferredSize (int rows) images
Parameters rows Number of rows within List to size.
Returns The preferred dimensions of a List of the given size.

getRows

public int getRows()
Returns Returns number of rows requested to be displayed in List.

getSelectedIndex

public synchronized int getSelectedIndex()
Returns Position of currently selected entry, or -1 if nothing is selected, or if multiple entries are selected.

getSelectedIndexes

public synchronized int[] getSelectedIndexes()
Returns An array whose elements are the indices of the currently selected entries.

getSelectedItem

public synchronized String getSelectedItem()
Returns Currently selected entry as a String, or null if nothing is selected, or if multiple entries are selected.

getSelectedItems

public synchronized String[] getSelectedItems()
Returns An array of strings whose elements are the labels of the currently selected entries.

getSelectedObjects

public Object[] getSelectedObjects() images

Implements ItemSelectable.getSelectedObjects()
Returns An array of strings whose elements are the labels of the currently selected entries.

getVisibleIndex

public int getVisibleIndex()
Returns The last index from a call to makeVisible().

isIndexSelected

public boolean isIndexSelected (int index) images

Parameters index Position to check.
Returns true if index selected, false otherwise.
Description Checks to see if a particular entry is currently selected.

isMultipleMode

public boolean isMultipleMode() images

Returns true if multiple selection is allowed, false otherwise.

isSelected

public boolean isSelected (int index) images

Parameters index Position to check.
Returns true if index selected, false otherwise.
Description Checks to see if a particular entry is currently selected. Replaced by isIndexSelected(int).

makeVisible

public synchronized void makeVisible (int index)
Parameters index Position to make visible on screen.
Description Ensures an item is displayed on the screen.

minimumSize

public Dimension minimumSize() images

Returns The minimum dimensions of the List. Replaced by getMinimumSize().
public Dimension minimumSize (int rows) images
Parameters rows Number of rows within List to size.
Returns The minimum dimensions of a List of the given size. Replaced by getMinimumSize(int).

preferredSize

public Dimension preferredSize() images

Returns The preferred dimensions of the List. Replaced by getPreferredSize().
public Dimension preferredSize (int rows) images
Parameters rows Number of rows within List to size.
Returns The preferred dimensions of a List of the given size. Replaced by getPreferredSize(int).

remove

public synchronized void remove (int position) images

Parameters position Position of item to remove.
Description Removes a single entry from the List.
public synchronized void remove (String item) images
Parameters item Item to remove.
Throws IllegalArgumentException
If item is not in the List.
Description Removes a single entry from the List.

removeActionListener

public void removeActionListener (ActionListener l) images

Parameters l One of this List's ActionListeners.
Description Remove an action event listener.

removeAll

public synchronized removeAll() images

Description Removes all items from the List.

removeItemListener

public void removeItemListener (ItemListener l) images

Parameters l The listener to be removed.
Implements ItemSelectable.removeItemListener (ItemListener l)
Description Removes the specified ItemListener so it will not receive ItemEvent objects from this List.

removeNotify

public void removeNotify()
Description Destroys the peer of the List.

replaceItem

public synchronized void replaceItem (String newItem, int
index)
Parameters newItem Label for entry to add.
index Position of entry to replace.
Description Replaces the contents at a particular position with a new entry.

select

public synchronized void select (int position)
Parameters position Position to make selected entry.
Description Makes the given entry the selected one for the List.

setMultipleMode

public synchronized void setMultipleMode (boolean b) images

Parameters b true to enable multiple selections; false to disable multiple selections.
Description Changes List's selection mode based upon flag.

setMultipleSelections

public synchronized void setMultipleSelections (boolean value) images

Parameters value true to enable multiple selections; false to disable multiple selections.
Description Changes List's selection mode based upon flag. Replaced by setMultipleMode(boolean).

Protected Instance Methods

paramString

protected String paramString()
Returns String with current settings of List.
Overrides Component.paramString()
Description Helper method for toString() to generate string of current settings.

processActionEvent

protected void processActionEvent (ActionEvent e) images

Parameters e The action event to process.
Description Action events are passed to this method for processing. Normally, this method is called by processEvent().

processEvent

protected void processEvent (AWTEvent e) images

Parameters e The event to process.
Description Low-level AWTEvents are passed to this method for processing.

processItemEvent

protected void processItemEvent(ItemEvent e) images

Parameters e The item event to process.
Description Item events are passed to this method for processing. Normally, this method is called by processEvent().

See Also

Component, Dimension, ItemSelectable, String

19.39 MediaTracker

images

Description

The MediaTracker class assists in the loading of multimedia objects across the network. It can be used to wait until an object (or group of objects) has been loaded completely. Tracked objects are assigned to groups; if there is more than one object in a group, you can only track the behavior of the group as a whole (i.e., it isn't possible to track an individual object unless it is the only object in its group). Currently (1.0.2 and 1.1) MediaTracker only works for Image objects; future releases may extend MediaTracker to other multi-media types.

Class Definition

public abstract class java.awt.MediaTracker extends java.lang.Object implements java.io.Serializable { // Constants public static final int ABORTED; public static final int COMPLETE; public static final int ERRORED; public static final int LOADING; // Constructors public MediaTracker (Component component); // Instance Methods public void addImage (Image image, int id); public synchronized void addImage (Image image, int id, int width, int height); public boolean checkAll(); public synchronized boolean checkAll (boolean load); public boolean checkID (int id); public synchronized boolean checkID (int id, boolean load); public synchronized Object[] getErrorsAny(); public synchronized Object[] getErrorsID (int id); public synchronized boolean isErrorAny(); public synchronized boolean isErrorID (int id); public synchronized void removeImage(Image image); images public synchronized void removeImage(Image image, int id); images public synchronized void removeImage(Image image, int id, int width, int height); public synchronized int statusAll (boolean load); public synchronized int statusID (int id, boolean load); public void waitForAll() throws InterruptedException; public synchronized boolean waitForAll (long ms) throws InterruptedException; public void waitForID (int id) throws InterruptedException; public synchronized boolean waitForID (int id, long ms) throws InterruptedException; }

Constants

ABORTED

public static final int ABORTED

Flag that indicates that the loading process aborted while loading a particular image.

COMPLETE

public static final int COMPLETE

Flag that indicates a particular image loaded successfully.

ERRORED

public static final int ERRORED

Flag that indicates an error occurred while a particular image was loading.

LOADING

public static final int LOADING

Flag that indicates a particular image is still loading.

Constructors

MediaTracker

public MediaTracker (Component component)
Parameters component Component that eventually renders objects being tracked.
Description Constructs an MediaTracker object.

Instance Methods

addImage

public void addImage (Image image, int id)
Parameters image Image to track.
id ID of a group.
Description Tells a MediaTracker to track the loading of image, placing the image in the group identified by id.
public synchronized void addImage (Image image, int id, int width, int height)
Parameters image Image to track.
id ID of a group.
width Eventual rendering width.
height Eventual rendering height.
Description Tells a MediaTracker to track the loading of image, which will be scaled to the given height and width, placing the image in the group identified by id.

checkAll

public boolean checkAll()
Returns true if images completed loading (successfully or unsuccessfully), false otherwise.
Description Determines if all images have finished loading.
public synchronized boolean checkAll (boolean load)
Parameters load Flag to force image loading to start.
Returns true if all images have completed loading (successfully or unsuccessfully), false otherwise.
Description Determines if all images have finished loading; the load parameter may be used to force images to start loading.

checkID

public boolean checkID (int id)
Parameters id ID of a group.
Returns true if all images have completed loading (successfully or unsuccessfully), false otherwise.
Description Determines if all images with the given ID tag have finished loading.
public synchronized boolean checkID (int id, boolean load)
Parameters id ID of a group.
load Flag to force image loading to start.
Returns true if all images have completed loading (successfully or unsuccessfully), false otherwise.
Description Determines if all images with the given ID tag have finished loading; the load parameter may be used to force images to start loading.

getErrorsAny

public synchronized Object[] getErrorsAny()
Returns An array of objects managed by this media tracker that encountered a loading error.
Description Checks to see if any media encountered an error while loading.

getErrorsID

public synchronized Object[] getErrorsID (int id)
Parameters id ID of a group.
Returns An array of objects that encountered a loading error.
Description Checks to see if any media with the given ID tag encountered an error while loading.

isErrorAny

public synchronized boolean isErrorAny()
Returns true if an error occurred, false otherwise.
Description Checks to see if any media monitored by this media tracker encountered an error while loading.

isErrorID

public synchronized boolean isErrorID (int id)
Parameters id ID of a group.
Returns true if error happened, false otherwise.
Description Checks to see if any media in the given group encountered an error while loading.

removeImage

public synchronized void removeImage (Image image) images

Parameters image The image to remove.
Description Removes the specified image from this MediaTracker.
public synchronized void removeImage (Image image, int id) images
Parameters image The image to remove.
id ID of a group.
Description Removes the specified image from this MediaTracker. Only instances matching the given id will be removed.
public synchronized void removeImage (Image image, int id, int width, int height) images
Parameters image The image to remove.
id ID of a group.
width Width of the scaled image, or -1 for unscaled.
height Height of the scaled image, or -1 for unscaled.
Description Removes the specified image from this MediaTracker. Only instances matching the given id and scale sizes will be removed.

statusAll

public synchronized int statusAll (boolean load)
Parameters load Flag to force image loading to start.
Returns MediaTracker status flags ORed together.
Description Checks load status of all the images monitored by this media tracker; the load parameter may be used to force images to start loading.

statusID

public synchronized int statusID (int id, boolean load)
Parameters id ID of a group.
load Flag to force image loading to start.
Returns MediaTracker status flags ORed together.
Description Checks load status of all the images in the given group; the load parameter may be used to force images to start loading.

waitForAll

public void waitForAll() throws InterruptedException
Throws InterruptedException
If waiting interrupted.
Description Waits for all the images monitored by this media tracker to load.
public synchronized boolean waitForAll (long ms) throws InterruptedException
Parameters ms Time to wait for loading.
Throws InterruptedException
If waiting interrupted.
Returns true if images fully loaded, false otherwise.
Description Waits at most ms milliseconds for all images monitored by this media tracker to load.

waitForID

public void waitForID (int id) throws InterruptedException
Parameters id ID of a group.
Throws InterruptedException
If waiting interrupted.
Description Waits for images in the given group to load.
public synchronized boolean waitForID (int id, long ms) throws InterruptedException
Parameters id ID of a group.
ms Maximum time to wait for loading.
Throws InterruptedException
If waiting interrupted.
Returns true if images fully loaded, false otherwise.
Description Waits at most ms milliseconds for the images in the given group to load.

See Also

Component, Image, Object

19.40 Menu

images

Description

The Menu class represents a group of MenuItem objects. Menus themselves are menu items, allowing you to build multi-level menus. Menus are always attached to MenuBars, which currently can only belong to frames.

Class Definition

public class java.awt.Menu extends java.awt.MenuItem implements java.awt.MenuContainer { // Constructors public Menu(); images public Menu (String label); public Menu (String label, boolean tearOff); // Instance Methods public synchronized MenuItem add (MenuItem item); public void add (String label); public void addNotify(); public void addSeparator(); public int countItems(); images public MenuItem getItem (int index); public int getItemCount(); images public void insert (String label, int index); images public synchronized void insert (MenuItem menuitem, int index); images public void insertSeparator (int index); images public boolean isTearOff(); public String paramString(); images public synchronized void remove (int index); public synchronized void remove (MenuComponent component); public synchronized void removeAll(); images public void removeNotify(); }

Constructors

Menu

public Menu() images

Description Constructs a Menu object.
public Menu (String label)
Parameters label Text that appears on Menu.
Description Constructs a Menu object with the given label.
public Menu (String label, boolean tearOff)
Parameters label Text that appears on Menu.
tearOff true to create a tear-off menu, false otherwise.
Description Constructs a Menu object; this will be a tear-off menu if tearOff is set to true.

Instance Methods

add

public synchronized MenuItem add (MenuItem item)
Parameters item A MenuItem to add to the Menu.
Returns Item just added.
Description Adds a new item to a Menu.
public void add (String label)
Parameters label Text for a MenuItem
Description Constructs a new MenuItem object with the given label, and adds it to a Menu.

addNotify

public void addNotify()
Overrides MenuItem.addNotify()
Description Creates a Menu peer, and peers for all MenuItem objects that appear on it.

addSeparator

public void addSeparator()
Description Adds a separator bar to the Menu.

countItems

public int countItems() images

Returns The number of items on the menu. Replaced by getItemCount().

getItem

public MenuItem getItem (int index)
Parameters index The position of the MenuItem to fetch; the first item has index 0.
Returns The MenuItem at the designated position.

getItemCount

public int getItemCount() images

Returns The number of items on the menu.

insert

public void insert (String label, int index) images

Parameters label The label for the new item.
index The position for the new item.
Description Adds a new item to this menu.
public synchronized void insert (MenuItem menuitem, int index) images
Parameters menuitem The item to add.
index The position for the new item.
Throws IllegalArgumentException
If index is less than zero.
Description Adds a new item to this menu.

insertSeparator

public void insertSeparator (int index) images

Parameters index The position for the separator.
Throws IllegalArgumentException
If index is less than zero.
Description Adds a separator to this menu.

isTearOff

public boolean isTearOff()
Returns true if the menu is a tear-off menu, false otherwise.

paramString

public String paramString() images

Returns String with current settings of Menu.
Overrides MenuItem.paramString()
Description Helper method for toString() to generate string of current settings.

remove

public synchronized void remove (int index)
Parameters index The position of the MenuItem to remove.
Description Removes an item from the Menu.
public synchronized void remove (MenuComponent component)
Parameters component The element to remove.
Implements MenuContainer.remove()
Description Removes an item from the Menu.

removeAll

public synchronized void removeAll() images

Description Removes all items from the Menu.

removeNotify

public void removeNotify()
Description Destroys Menu peer, and peers for all MenuItem objects that appear on it.

See Also

Frame, MenuComponent, MenuContainer, MenuItem, String

19.41 MenuBar

images

Description

A MenuBar holds menus. MenuBars are always attached to frames, and displayed on the top line of the Frame. One menu in a MenuBar may be designated a “help” menu.

Class Definition

public class java.awt.MenuBar extends java.awt.MenuComponent implements java.awt.MenuContainer { // Constructors public MenuBar(); // Instance Methods public synchronized Menu add (Menu m); public void addNotify(); public int countMenus(); images public void deleteShortcut (MenuShortcut s); images

public Menu getHelpMenu(); public Menu getMenu (int index); public int getMenuCount(); images public MenuItem getShortcutMenuItem (MenuShortcut s); images public synchronized void remove (int index); public synchronized void remove (MenuComponent component); public void removeNotify(); public synchronized void setHelpMenu (Menu m); public synchronized Enumeration shortcuts(); images }

Constructors

MenuBar

public MenuBar()
Description Constructs a MenuBar object.

Instance Methods

add

public synchronized Menu add (Menu m)
Parameters m A Menu to add to MenuBar.
Returns Item just added.
Description Adds a new menu to the MenuBar.

addNotify

public void addNotify()
Description Creates MenuBar's peer and peers of contained menus.

countMenus

public int countMenus() images

Returns The number of menus on the menu bar. Replaced by getMenuCount().

deleteShortcut

public void deleteShortcut (MenuShortcut s) images

Parameters s The shortcut to remove.
Description Removes a menu shortcut.

getHelpMenu

public Menu getHelpMenu()
Returns The menu that was designated the help menu.

getMenu

public Menu getMenu (int index)
Parameters index The position of the Menu to fetch.
Returns The Menu at the designated position.

getMenuCount

public int getMenuCount() images

Returns The number of menus on the menu bar.

getShortcutMenuItem

public MenuItem getShortcutMenuItem (MenuShortcut s) images

Parameters s A menu shortcut.
Returns The corresponding menu item.
Description Finds the MenuItem corresponding to the given MenuShortcut, or null if no match is found.

remove

public synchronized void remove (int index)
Parameters index The position of the Menu to remove.
Description Removes a Menu from the MenuBar.
public synchronized void remove (MenuComponent component)
Parameters component The element of the MenuBar to remove.
Implements MenuContainer.remove()
Description Removes a Menu from the MenuBar.

removeNotify

public void removeNotify()
Description Destroys the MenuBar peer, and peers for all Menu objects that appear on it.

setHelpMenu

public synchronized void setHelpMenu (Menu m)
Parameters m Menu to designate as the help menu.
Description Designates a Menu as the MenuBar's help menu.

shortcuts

public synchronized Enumeration shortcuts() images

Returns An Enumeration of MenuShortcut objects.
Description Returns an Enumeration of all MenuShortcut objects managed by this MenuBar.

See Also

Frame, Menu, MenuComponent, MenuContainer

19.42 MenuComponent

images

Description

The abstract MenuComponent class represents the parent of all menu GUI components.

Class Definition

public abstract class java.awt.MenuComponent extends java.lang.Object implements java.io.Serializable { // Instance Methods public final void dispatchEvent (AWTEvent e); images public Font getFont(); public String getName(); images public MenuContainer getParent(); public MenuComponentPeer getPeer(); images public boolean postEvent (Event e); images public void removeNotify(); public void setFont (Font f);

public void setName (String name); images public String toString(); // Protected Instance Methods protected String paramString(); images protected void processEvent (AWTEvent e); images }

Instance Methods

dispatchEvent

public final void dispatchEvent (AWTEvent e)
Parameters e The AWTEvent to process.
Description Tells the menu component to deal with the AWTEvent e.

getFont

public Font getFont()
Returns The font for the current MenuComponent.

getName

public Font getName() images

Returns The name for the current MenuComponent.

getParent

public MenuContainer getParent()
Returns The parent MenuContainer for the MenuComponent.

getPeer

public MenuComponentPeer getPeer() images

Returns A reference to the MenuComponent's peer.

postEvent

public boolean postEvent (Event e) images

Parameters e Event instance to post to component.
Returns Ignoredfor menus.
Description Tells the Frame that contains the MenuBar containing the MenuComponent to deal with Event.

removeNotify

public void removeNotify()
Description Removes peer of MenuComponent's subclass.

setFont

public void setFont (Font f)
Parameters f New font for MenuComponent.
Description Changes the font of the label of the MenuComponent.

setName

public void setName (String name) images

Parameters name New name for MenuComponent.
Description Changes the name of the MenuComponent.

toString

public String toString()
Returns A string representation of the MenuComponent object.
Overrides Object.toString()

Protected Instance Methods

paramString

protected String paramString() images

Returns String with current settings of MenuComponent.
Overrides Component.paramString()
Description Helper method for toString() to generate string of current settings.

processEvent

protected void processEvent (AWTEvent e) images

Parameters e The event to process.
Description Low-level AWTEvents are passed to this method for processing.

See Also

Event, Font, MenuBar, MenuComponentPeer, MenuContainer, MenuItem, Object, Serializable, String

19.43 MenuContainer

images

Description

MenuContainer is an interface that defines the responsibilities for objects that can have a menu.

Interface Definition

public abstract interface java.awt.MenuContainer extends java.lang.Object { // Interface Methods public abstract Font getFont(); public abstract boolean postEvent (Event e); images public abstract void remove (MenuComponent component); }

Interface Methods

getFont

public abstract Font getFont()
Returns Current font of the object implementing this method.

postEvent

public abstract boolean postEvent (Event e) images

Parameters e Event to post.
Returns Ignores return value.
Description Posts event to the object implementing this method.

remove

public abstract void remove (MenuComponent component)
Parameters component Menu object to remove
Description Tells the object implementing this method to remove a menu component.

See Also

Event, Font, Frame, Menu, MenuBar, MenuComponent, Object

19.44 MenuItem

images

Description

The MenuItem class represents a selectable item on a menu.

Class Definition

public class java.awt.MenuItem extends java.awt.MenuComponent { // Constructors public MenuItem(); images public MenuItem (String label); public MenuItem (String label, MenuShortcut s); images // Instance Methods public void addActionListener (ActionListener l); images public void addNotify(); public void deleteShortcut(); images public synchronized void disable(); images public synchronized void enable(); images public void enable (boolean condition); images public String getActionCommand(); images public String getLabel(); public MenuShortcut getShortcut(); images public boolean isEnabled(); public String paramString(); public void removeActionListener (ActionListener l); images

public void setActionCommand (String command); images public synchronized void setEnabled (boolean b); images public synchronized void setLabel (String label); public void setShortcut (MenuShortcut s); images // Protected Instance Methods protected final void disableEvents (long eventsToDisable); images protected final void enableEvents (long eventsToEnable); images protected void processActionEvent (ActionEvent e); images protected void processEvent (AWTEvent e); images }

Constructors

MenuItem

public MenuItem() images

Description Constructs a MenuItem object with no label or shortcut.
public MenuItem (String label)
Parameters label Text that appears on the MenuItem.
Description Constructs a MenuItem object.
public MenuItem (String label, MenuShortcut s) images
Parameters label Text that appears on the MenuItem.
s Shortcut for the MenuItem.
Description Constructs a MenuItem object with the given shortcut.

Instance Methods

addActionListener

public void addActionListener(ActionListener l) images

Parameters l An object that implements the ActionListener interface.
Description Add a listener for the action event.

addNotify

public void addNotify()
Description Creates the MenuItem's peer.

deleteShortcut

public void deleteShortcut() images

Description Removes the shortcut associated with this item.

disable

public synchronized void disable() images

Description Disables the menu component so that it is unresponsive to user interactions. Replaced by setEnabled(false).

enable

public synchronized void enable() images

Description Enables the menu component so that it is responsive to user interactions. Replaced by setEnabled(true).
public void enable (boolean condition) images
Parameters condition true to enable the menu component; false to disable it.
Description Enables or disables the menu component, depending on the condition parameter. Replaced by setEnabled(boolean).

getActionCommand

public String getActionCommand() images

Returns Current action command string.
Description Returns the string used for the action command.

getLabel

public String getLabel()
Returns The current text associated with the MenuItem.

getShortcut

public MenuShortcut getShortcut() images

Returns The current shortcut for this item, or null if there is none.

isEnabled

public boolean isEnabled()
Returns true if the menu item is enabled, false otherwise.

paramString

public String paramString()
Returns String with current settings of MenuItem.
Description Helper method for toString() to generate string of current settings.

removeActionListener

public void removeActionListener(ActionListener l) images

Parameters l One of this Button's ActionListeners.
Description Remove an action event listener.

setActionCommand

public void setActionCommand(String command) images

Parameters command New action command string.
Description Specify the string used for the action command.

setEnabled

public synchronized void setEnabled (boolean b) images

Parameters b true to enable the item, false to disable it.
Description Enables or disables the item. Replaces enable(), enable(boolean), and disable().

setLabel

public synchronized void setLabel (String label)
Parameters label New text to appear on MenuItem.
Description Changes the label of the MenuItem.

setShortcut

public void setShortcut (MenuShortcut s) images

Parameters s New shortcut for the MenuItem.
Description Changes the shortcut of the MenuItem.

Protected Instance Methods

disableEvents

protected final void disableEvents (long eventsToDisable) images

Parameters eventsToDisable
A value representing certain kinds of events. This can be constructed by ORing the event mask constants defined in java.awt.AWTEvent.
Description By default, a menu item receives events corresponding to the event listeners that have registered. If a menu item should not receive events of a certain type, even if there is a listener registered for that type of event, this method can be used to disable that event type.

enableEvents

protected final void enableEvents (long eventsToEnable) images

Parameters eventsToDisable
A value representing certain kinds of events. This can be constructed by ORing the event mask constants defined in java.awt.AWTEvent.
Description By default, a menu item receives events corresponding to the event listeners that have registered. If a menu item should receive other types of events as well, this method can be used to get them.

processActionEvent

protected void processActionEvent (ActionEvent e) images

Parameters e The action event to process.
Description Action events are passed to this method for processing. Normally, this method is called by processEvent().

processEvent

protected void processEvent (AWTEvent e) images

Parameters e The event to process.
Description Low-level AWTEvents are passed to this method for processing.

See Also

CheckboxMenuItem, Menu, MenuComponent, MenuShortcut, String

19.45 MenuShortcut images

images

Description

A MenuShortcut is used to associate a keystroke with a menu item. MenuShortcuts are constructed using their corresponding key; they are associated with menu items via MenuItem.setShortcut(MenuShortcut).

Class Definition

public class java.awt.MenuShortcut
    extends java.awt.Event {

  // Constructors
  public MenuShortcut (int key);
  public MenuShortcut (int key, boolean useShiftModifier);

  // Instance Methods
  public boolean equals (MenuShortcut s);
  public int getKey();
  public String toString();
  public boolean usesShiftModifier();

  // Protected Instance Methods
  protected String paramString();
}

Constructors

MenuShortcut

public MenuShortcut (int key)
Parameters key A keycode like those returned with key press Event objects.
Description Constructs a MenuShortcut object for the given key.
public MenuShortcut (int key, boolean useShiftModifier)
Parameters key A keycode like those returned with key press Event objects.
useShiftModifier true if the Shift key must be used, false otherwise.
Description Constructs a MenuShortcut object with the given values.

Instance Methods

equals

public boolean equals (MenuShortcut s)
Parameters s The MenuShortcut to compare.
Returns true if s is equal to this MenuShortcut, false otherwise.

getKey

public int getKey()
Returns The key for this MenuShortcut.

toString

public String toString()
Returns A string representation of the MenuShortcut object.
Overrides Event.toString()

usesShiftModifier

public boolean usesShiftModifier()
Returns true if this MenuShortcut must be invoked with the Shift key pressed, false otherwise.

Protected Instance Methods

paramString

protected String paramString()
Returns String with current settings of MenuShortcut.
Overrides Event.paramString()
Description Helper method for toString() to generate string of current settings.

See Also

Event, MenuItem

19.46 Panel

images

Description

The Panel class provides a generic Container within an existing display area.

Class Definition

public class java.awt.Panel extends java.awt.Container { // Constructors public Panel(); public Panel(LayoutManager layout); images // Instance Methods public void addNotify(); }

Constructors

Panel

public Panel()
Description Constructs a Panel object.
public Panel (LayoutManager layout) images
Description Constructs a Panel object with the specified layout manager.

Instance Methods

addNotify

public void addNotify()
Overrides Container.addNotify()
Description Creates Panel's peer and peers of contained components.

See Also

Applet, Container

19.47 Point

images

Description

The Point class encapsulates a pair of x and y coordinates within a single object.

Class Definition

public class java.awt.Point extends java.lang.Object implements java.io.Serializable { // Variables public int x; public int y; // Constructors public Point(); images public Point (int width, int height); public Point (Point p); images // Instance Methods public boolean equals (Object object); public Point getLocation(); images public int hashCode(); public void move (int x, int y); public void setLocation (int x, int y); images public void setLocation (Point p); images public String toString(); public void translate (int deltax, int deltay); }

Variables

x

public int x

The coordinate that represents the horizontal position.

y

public int y

The coordinate that represents the vertical position.

Constructors

Point

public Point() images

Description Constructs a Point object initialized to (0, 0).
public Point (int x, int y)
Parameters x Coordinate that represents the horizontal position.
y Coordinate that represents the vertical position.
Description Constructs a Point object with an initial position of (x, y).
public Point (Point p) images
Parameters p Initial position.
Description Constructs a Point object with the same position as p.

Instance Methods

equals

public boolean equals (Object object)
Parameters object The object to compare.
Returns true if both points have the same x and y coordinates, false otherwise.
Overrides Object.equals()
Description Compares two different Point instances for equivalence.

getLocation

public Point getLocation() images

Returns Position of this point.
Description Gets the current position of this Point.

hashCode

public int hashCode()
Returns A hashcode to use the Point is used as a key in a Hashtable.
Overrides Object.hashCode()
Description Generates a hashcode for the Point.

move

public void move (int x, int y)
Parameters x The new x coordinate.
y The new y coordinate.
Description Changes the Point's location to (x, y).

setLocation

public void setLocation (int x, int y) images

Parameters x The new x coordinate.
y The new y coordinate.
Description Changes the Point's location to (x, y).
public void setLocation (Point p) images
Parameters p The new location.
Description Changes the Point's location to p.

toString

public String toString()
Returns A string representation of the Point object.
Overrides Object.toString()

translate

public void translate (int deltax, int deltay)
Parameters deltax Amount to move horizontally.
deltay Amount to move vertically.
Description Moves the Point to the location (x+deltax, y+deltay).

See Also

Object, String

19.48 Polygon

images

Description

The Polygon class encapsulates a collection of points used to create a series of line segments.

Class Definition

public class java.awt.Polygon extends java.lang.Object implements java.awt.Shape, java.io.Serializable { // Variables protected Rectangle bounds; images public int npoints; public int xpoints[]; public int ypoints[]; // Constructors public Polygon(); public Polygon (int xpoints[], int ypoints, int npoints); // Instance Methods public void addPoint (int x, int y); public boolean contains (int x, int y); images public boolean contains (Point p); images public Rectangle getBoundingBox(); images public Rectangle getBounds(); images public boolean inside (int x,int y); images public void translate (int deltaX, int deltaY); images }

Variables

bounds

protected Rectangle bounds images

The rectangle that describes the boundaries of the Polygon.

npoints

public int npoints

The number of elements to use in the xpoints and ypoints arrays.

xpoints

public int xpoints[]

The array of x coordinates for each point.

ypoints

public int ypoints[]

The array of y coordinates for each point.

Constructors

Polygon

public Polygon()
Description Constructs an empty Polygon object with no points.
public Polygon (int xPoints[], int yPoints[], int numPoints)
Parameters xPoints[] The initial array of x coordinates for each point.
yPoints[] The initial array of y coordinates for each point.
numPoints The number of elements in both xPoints and yPoints arrays to use.
Throws ArrayIndexOutOfBoundsException
If numPoints > xPoints.length or numPoints > yPoints.length.
Description Constructs a Polygon object with the set of points provided.

Instance Methods

addPoint

public void addPoint (int x, int y)
Parameters x The x coordinate of the point to be added.
y The y coordinate of the point to be added.
Description Adds the point (x, y) to the end of the list of points for the Polygon.

contains

public boolean contains (int x, int y) images

Parameters x The x coordinate to test.
y The y coordinate to test.
Returns true if the Polygon contains the point; false otherwise.
public boolean contains (Point p) images
Parameters p The point to be tested.
Returns true if the Polygon contains the point; false otherwise.

getBoundingBox

public Rectangle getBoundingBox() images

Returns Bounding Rectangle of the points within the Polygon.
Description Returns the smallest Rectangle that contains all the points within the Polygon. Replaced by getBounds().

getBounds

public Rectangle getBounds() images

Implements Shape.getBounds()
Returns Bounding Rectangle of the points within the Polygon.
Description Returns the smallest Rectangle that contains all the points within the Polygon.

inside

public boolean inside (int x,int y) images

Parameters x The x coordinate of the point to be checked.
y The y coordinate of the point to be checked.
Returns true if (x, y) within Polygon, false otherwise.
Description Checks to see if the (x, y) point is within an area that would be filled if the Polygon was drawn with Graphics.fillPolygon(). Replaced by contains(int, int).

translate

public void translate (int deltaX, int deltaY) images

Parameters deltaX Amount to move horizontally.
deltaY Amount to move vertically.
Description Moves the Polygon to the location (x+deltaX, y+deltaY).

See Also

Graphics, Object, Rectangle

19.49 PopupMenu images

images

Description

A PopupMenu is a menu that can be popped up on a Component.

Class Definition

public class java.awt.PopupMenu
    extends java.awt.Menu {

  // Constructors
  public PopupMenu();
  public PopupMenu (String label);

  // Instance Methods
  public synchronized void addNotify();
  public void show (Component origin, int x, int y);
}

Constructors

PopupMenu

public PopupMenu()
Description Constructs a PopupMenu object.
public PopupMenu (String label)
Parameters label Text that appears on Menu.
Description Constructs a PopupMenu object with the given label.

Instance Methods

addNotify

public synchronized void addNotify()
Overrides Menu.addNotify()
Description Creates a Popup Menu peer.

show

public void show (Component origin, int x, int y)
Parameters origin The Component upon which the PopupMenu will be displayed.
x The PopupMenu's horizontal position on the component.
y The PopupMenu's vertical position on the component.
Description Shows the menu on the given Component. The origin specified must be contained in the hierarchy of the PopupMenu's parent component, which is determined by the call to Component. add(PopupMenu).

19.50 PrintGraphics images

images

Description

PrintGraphics is an interface for classes that provide a printing graphics context.

Interface Definition

public abstract interface java.awt.PrintGraphics {

  // Interface Methods
  public abstract PrintJob getPrintJob();
}

Interface Methods

getPrintJob

public abstract PrintJob getPrintJob()
Returns The PrintJob from which the PrintGraphics object originated.

See Also

PrintJob

19.51 PrintJob images

images

Description

PrintJob encapsulates printing information. When you call Toolkit.getPrintJob(), this is the object that is returned. From the PrintJob, you can access a Graphics object, which can be used for drawing to the printer.

Class Definition

public abstract class jav.awt.PrintJob
    extends java.lang.Object {

  // Instance Methods
  public abstract void end();
  public void finalize();
  public abstract Graphics getGraphics();
  public abstract Dimension getPageDimension();
  public abstract int getPageResolution();
  public abstract boolean lastPageFirst();
}

Instance Methods

end

public abstract void end()
Description Ends printing and cleans up.

finalize

public void finalize()
Overrides Object.finalize()
Description Cleans up when this object is garbage collected.

getGraphics

public abstract Graphics getGraphics()
Returns A Graphics object representing the next page. The object returned will also implement the PrintGraphics interface.
Description Returns a Graphics object for printing.

getPageDimension

public abstract Dimension getPageDimension()
Returns The page dimensions in pixels.

getPageResolution

public abstract int getPageResolution

Returns The page resolution, in pixels per inch.

lastPageFirst

public abstract boolean lastPageFirst()
Returns true if pages are printed in reverse order; false otherwise.

See Also

Dimension, Graphics, PrintGraphics, Toolkit

19.52 Rectangle

images

Description

The Rectangle class represents a rectangle by combining its origin (a pair of x and y coordinates) with its size (a width and a height).

Class Definition

public class java.awt.Rectangle extends java.lang.Object implements java.awt.Shape, java.io.Serializable { // Variables pubic int height; public int width; public int x; public int y; // Constructors public Rectangle(); public Rectangle (int width, int height); public Rectangle (int x, int y, int width, int height); public Rectangle (Dimension d); public Rectangle (Point p); public Rectangle (Point p, Dimension d); public Rectangle (Rectangle r); images // Instance Methods public void add (int newX, int newY); public void add (Point p); public void add (Rectangle r); public boolean contains (int x, int y); images public boolean contains (Point p); images public boolean equals (Object object); public Rectangle getBounds(); images public Point getLocation(); images public Dimension getSize(); images public void grow (int horizontal, int vertical); public int hashCode(); public boolean inside (int x, int y); images public Rectangle intersection (Rectangle r); public boolean intersects (Rectangle r);

public boolean isEmpty(); public void move (int x, int y); images public void reshape (int x, int y, int width, int height); images public void resize (int width, int height); images public void setBounds (Rectangle r); images public void setBounds (int x, int y, int width, int height); images public void setLocation (int x, int y); images public void setLocation (Point p); images public void setSize (int width, int height); images public void setSize (Dimension d); images public String toString(); public void translate (int x, int y); public Rectangle union (Rectangle r); }

Variables

height

public int height

The height of the Rectangle.

width

public int width

The width of the Rectangle.

x

public int x

The x coordinate of the Rectangle's upper left corner (its origin).

y

public int y

The y coordinate of the Rectangle's upper left corner (its origin).

Constructors

Rectangle

public Rectangle()
Description Constructs an empty Rectangle object with an origin of (0, 0) and dimensions of 0 × 0.
public Rectangle (int width, int height)
Parameters width width of Rectangle
height height of Rectangle
Description Constructs a Rectangle object with an origin of (0, 0) and dimensions of width x height.
public Rectangle (int x, int y, int width, int height)
Parameters x x coordinate of the Rectangle's origin
y y coordinate of the Rectangle's origin
width width of Rectangle
height height of Rectangle
Description Constructs a Rectangle object with an origin of (x, y) and dimensions of width x height.
public Rectangle (Dimension d)
Parameters d dimensions of Rectangle
Description Constructs a Rectangle object with an origin of (0, 0) and dimensions of d.width x d.height.
public Rectangle (Point p)
Parameters p origin of Rectangle
Description Constructs an empty Rectangle object with an origin of (p.x, p.y) and dimensions of 0 × 0.
public Rectangle (Point p, Dimension d)
Parameters p origin of Rectangle
d dimensions of Rectangle
Description Constructs a Rectangle object with an origin of (p.x, p.y) and dimensions of d.width x d.height.
public Rectangle (Rectangle r) images
Parameters r original Rectangle
Description Constructs copy of the given Rectangle.

Instance Methods

add

public void add (int newX, int newY)
Parameters newX The x-coordinate of a point to incorporate within the Rectangle.
newY The y-coordinate of a point to incorporate within the Rectangle.
Description Extends the Rectangle so that the point (newX, newY) is within it.
public void add (Point p)
Parameters p The new Point to add to the Rectangle.
Description Extends the Rectangle so that the point p is within it.
public void add (Rectangle r)
Parameters r The Rectangle being added to the current Rectangle.
Description Extends the Rectangle to include the Rectangle r.

contains

public boolean contains (int x, int y) images

Parameters x The x coordinate to test.
y The y coordinate to test.
Returns true if the Rectangle contains the point; false otherwise.
public boolean contains (Point p) images
Parameters p The point to be tested.
Returns true if the Rectangle contains the point; false otherwise.

equals

public boolean equals (Object object)
Parameters object The object to compare.
Returns true if both Rectangles have the same origin, width, and height; false otherwise.
Overrides Object.equals(Object)
Description Compares two different Rectangle instances for equivalence.

getBounds

public Rectangle getBounds() images

Implements Shape.getBounds()
Returns Bounding Rectangle.

getLocation

public Point getLocation() images

Returns Position of the rectangle.
Description Gets the current position of this Rectangle.

getSize

public Dimension getSize() images

Returns Dimensions of the rectangle.
Description Gets width and height of the rectangle.

grow

public void grow (int horizontal, int vertical)
Parameters horizontal Amount to extend Rectangle in horizontal direction on both the left and right sides.
vertical Amount to extend Rectangle in vertical direction on both the top and the bottom.
Description Increases the rectangle's dimensions.

hashCode

public int hashCode()
Returns A hashcode to use when using the Rectangle as a key in a Hashtable.
Overrides Object.hashCode()
Description Generates a hashcode for the Rectangle.

inside

public boolean inside (int x, int y) images

Parameters x The x coordinate to check.
y The y coordinate to check.
Returns true if (x, y) falls within the Rectangle, false otherwise.
Description Checks to see if the point (x, y) is within the Rectangle. Replaced by contains(int, int).

intersection

public Rectangle intersection (Rectangle r)
Parameters r Rectangle to add to the current Rectangle.
Returns A new Rectangle consisting of all points in both the current Rectangle and r.
Description Generates a new Rectangle that is the intersection of r and the current Rectangle.

intersects

public boolean intersects (Rectangle r)
Parameters r Rectangle to check.
Returns true if any points in r are also in the current Rectangle, false otherwise.
Description Checks to see if r crosses the Rectangle.

isEmpty

public boolean isEmpty()
Returns true if the Rectangle is empty, false otherwise.
Description Determines if the rectangle is dimensionless (i.e., width or height are less than or equal to 0).

move

public void move (int x, int y) images

Parameters x The new x coordinate of the Rectangle's upper left corner.
y The new y coordinate of the Rectangle's upper left corner.
Description Changes the Rectangle's origin to (x, y). Replaced by setLocation(int, int).

reshape

public void reshape (int x, int y, int width, int height) images

Parameters x The new x coordinate of the Rectangle's upper left corner.
y The new y coordinate of the Rectangle's upper left corner.
width The new width.
height The new height.
Description Changes Rectangle's origin and dimensions. Replaced by setBounds(int, int, int, int).

resize

public void resize (int width, int height) images

Parameters width The new width.
height The new height.
Description Changes Rectangle's dimensions. Replaced by setSize(int, int).

setBounds

public void setBounds (Rectangle r) images

Parameters r A Rectangle describing the new bounds.
Description Changes Rectangle's location and size.
public void setBounds (int x, int y, int width, int height) [New in 1.1]
Parameters x The new x coordinate of the Rectangle's upper left corner.
y The new y coordinate of the Rectangle's upper left corner.
width The new width.
height The new height.
Description Changes Rectangle's location and size.

setLocation

public void setLocation (int x, int y) images

Parameters x New horizontal position.
y New vertical position.
Description Relocates the rectangle.
public void setLocation (Point p) images
Parameters p New position for component.
Description Relocates the rectangle.

setSize

public void setSize (int width, int height) images

Parameters width New width.
height New height.
Description Resizes the rectangle.
public void setSize (Dimension d) images
Parameters d New dimensions.
Description Resizes the rectangle.

toString

public String toString()
Returns A string representation of the Rectangle object.
Overrides Object.toString()

translate

public void translate (int deltax, int deltay)
Parameters deltax Amount to move Rectangle horizontally.
deltay Amount to move Rectangle vertically.
Description Moves the Rectangle's origin to (x+deltax, y+deltay).

union

public Rectangle union (Rectangle r)
Parameters r Rectangle to determine union with.
Returns The smallest Rectangle containing both r and the current Rectangle.
Description Generates a new Rectangle by combining r and the current Rectangle.

See Also

Dimension, Object, Point, String

19.53 ScrollPane images

Description

The ScrollPane class provides automatic scrolling of a child component.

images

Class Definition

public class java.awt.ScrollPane extends java.awt.Container // Constants public final static int SCROLLBARS_ALWAYS; public final static int SCROLLBARS_AS_NEEDED; public final static int SCROLLBARS_NEVER; // Constructors public ScrollPane(); public ScrollPane (int scrollbarDisplayPolicy); // Public Instance Methods public void addNotify(); public void doLayout(); public Adjustable getHAdjustable(); public int getHScrollbarHeight(); public Point getScrollPosition(); public int getScrollbarDisplayPolicy(); public Adjustable getVAdjustable(); public int getVScrollbarWidth(); public Dimension getViewportSize(); public void layout(); images public String paramString(); public void printComponents (Graphics g); public final void setLayout (LayoutManager mgr); public void setScrollPosition (int x, int y); public void setScrollPosition (Point p); //Protected Instance Methods protected final void addImpl (Component comp, Object constraints, int index); }

Constants

SCROLLBARS_ALWAYS

public final static int SCROLLBARS_ALWAYS

Always show the scrollbars.

SCROLLBARS_AS_NEEDED

public final static int SCROLLBARS_AS_NEEDED

Only show the scrollbars if the contents of the ScrollPane are larger than what is visible.

SCROLLBARS_NEVER

public final static int SCROLLBARS_NEVER

Don't ever show the scrollbars. The ScrollPane can still be scrolled programmatically.

Constructors

ScrollPane

public ScrollPane()
Description Constructs a ScrollPane object with SCROLLBARS_AS_NEEDED.
public ScrollPane (int scrollbarDisplayPolicy)
Parameters scrollbarDisplayPolicy
One of the SCROLLBARS_ constants.
Description Constructs a ScrollPane object with the specified scrollbar display policy.

Instance Methods

addImpl

protected final void addImpl (Component comp, Object
constraints, int index)
Parameters comp The component to add to the Scrollpane.
constraints Layout constraints; ignored.
index The position at which to add the component; should always be less than or equal to 0.
Returns The component that was added.
Overrides Container.addImpl (Component, Object, int)
Throws IllegalArgumentException
If pos is greater than 0.
Description Adds a child component to the Scrollpane. If there already was a child component, it is replaced by the new component.

addNotify

public void addNotify()
Overrides Container.addNotify()
Description Creates ScrollPane's peer.

doLayout

public void doLayout()
Overrides Container.doLayout()
Description Lays out the ScrollPane. Resizes the child component to its preferred size.

getHAdjustable

public Adjustable getHAdjustable()
Returns The object implementing the Adjustable interface that is used to adjust the ScrollPane horizontally. Usually this is a Scrollbar.

getHScrollbarHeight

public int getHScrollbarHeight()
Returns The height a horizontal scrollbar would occupy, regardless of whether it's shown or not.

getScrollPosition

public Point getScrollPosition()
Returns Returns the position within the child component that is displayed at 0, 0 in the ScrollPane.

getScrollbarDisplayPolicy

public int getScrollbarDisplayPolicy()
Returns The display policy for the scrollbars (one of the SCROLLBARS_ constants).

getVAdjustable

public Adjustable getVAdjustable()
Returns The object implementing the Adjustable interface that is used to adjust the ScrollPane vertically. Usually this is a Scrollbar.

getVScrollbarWidth

public int getVScrollbarWidth()
Returns The width a vertical scrollbar would occupy, regardless of whether it's shown or not.

getViewportSize

public Dimension getViewportSize()
Returns The size of the ScrollPane's port (the area of the child component that is shown).

layout

public void layout() images

Overrides Container.layout()
Description Lays out component. Replaced by doLayout().

paramString

public String paramString()
Returns String with current settings of ScrollPane.
Overrides Container.paramString()
Description Helper method for toString() to generate string of current settings.

printComponents

public void printComponents (Graphics g)
Parameters g Graphics context.
Overrides Container.printComponents(Graphics)
Description Prints the ScrollPane's child component.

setLayout

public void setLayout (LayoutManager manager)
Parameters manager Ignored.
Overrides Container.setLayout(LayoutManager)
Description Does nothing. No layout manager is needed because there is only one child component.

setScrollPosition

public void setScrollPosition (int x, int y)
Parameters x New horizontal position.
y New vertical position.
Throws IllegalArgumentException
If the point given is not valid.
Description Scroll to the given position in the child component.
public void setScrollPosition (Point p)
Parameters p New position.
Throws IllegalArgumentException
If the point given is not valid.
Description Scroll to the given position in the child component.

See Also

Adjustable, Container, Point, Scrollbar

19.54 Scrollbar

images

Description

The Scrollbar is a Component that provides the means to get and set values within a predetermined range. For example, a scrollbar could be used for a volume control. Scrollbars are most frequently used to help users manipulate areas too large to be displayed on the screen (pre version 1.1) or to set a value within an integer range.

Class Definition

public class java.awt.Scrollbar extends java.awt.Component implements java.awt.Adjustable { // Constants public final static int HORIZONTAL; public final static int VERTICAL; // Constructors public Scrollbar(); public Scrollbar (int orientation); public Scrollbar (int orientation, int value, int visible, int minimum, int maximum); // Instance Methods public void addAdjustmentListener (AdjustmentListener l); images public void addNotify(); public int getBlockIncrement(); images public int getLineIncrement(); images public int getMaximum(); public int getMinimum(); public int getOrientation(); public int getPageIncrement(); images public int getUnitIncrement(); images public int getValue(); public int getVisible(); images public int getVisibleAmount(); images public void removeAdjustmentListener (AdjustmentListener l); images public synchronized void setBlockIncrement (int v); images public void setLineIncrement (int amount); images public synchronized void setMaximum (int newMaximum); images public synchronized void setMinimum (int newMinimum); images public synchronized void setOrientation (int orientation); images public void setPageIncrement (int amount); images public synchronized void setUnitIncrement(int v); images public synchronized void setValue (int value); public synchronized void setValues (int value, int visible, int minimum, int maximum); public synchronized void setVisibleAmount (int newAmount); images // Protected Instance Methods protected String paramString(); protected void processAdjustmentEvent (AdjustmentEvent e); images protected void processEvent (AWTEvent e); images }

Constants

HORIZONTAL

public final static int HORIZONTAL

Constant used for a Scrollbar with a horizontal orientation.

VERTICAL

public final static int VERTICAL

Constant used for a Scrollbar with a vertical orientation.

Constructors

Scrollbar

public Scrollbar()
Description Constructs a vertical Scrollbar object; slider size, minimum value, maximum value, and initial value are all zero.
public Scrollbar (int orientation)
Parameters orientation Scrollbar constant designating direction.
Throws IllegalArgumentException
If orientation is invalid.
Description Constructs a Scrollbar object, in the designated direction; slider size, minimum value, maximum value, and initial value are all zero.
public Scrollbar (int orientation, int value, int visible, int minimum, int maximum)
Parameters orientation Scrollbar constant designating direction.
value Initial value of Scrollbar.
visible Initial slider size.
minimum Initial minimum value.
maximum Initial maximum value.
Throws IllegalArgumentException
If orientation is invalid.
Description Constructs a Scrollbar object with the given values.

Instance Methods

addAdjustmentListener

public void addAdjustmentListener (AdjustmentListener l) images

Parameters l An object that implements the AdjustmentListener interface.
Implements Adjustable.addAdjustmentListener()
Description Add a listener for adjustment event.

addNotify

public void addNotify()
Overrides Component.addNotify()
Description Creates Scrollbar's peer.

getBlockIncrement

public int getBlockIncrement() images

Implements Adjustable.getBlockIncrement()
Returns The amount to scroll when a paging area is selected.

getLineIncrement

public int getLineIncrement() images

Returns The amount to scroll when one of the arrows at the ends of the scrollbar is selected. Replaced by getUnitIncrement().

getMaximum

public int getMaximum()
Implements Adjustable.getMaximum()
Returns The maximum value that the Scrollbar can take.

getMinimum

public int getMinimum()
Implements Adjustable.getMinimum()
Returns The minimum value that the Scrollbar can take.

getOrientation

public int getOrientation()
Implements Adjustable.getOrientation()
Returns A constant representing the direction of the Scrollbar.

getPageIncrement

public int getPageIncrement() images

Returns The amount to scroll when a paging area is selected. Replaced with getBlockIncrement().

getUnitIncrement

public int getUnitIncrement() images

Implements Adjustable.getUnitIncrement()
Returns The amount to scroll when one of the arrows at the ends of the scrollbar is selected.

getValue

public int getValue()
Implements Adjustable.getValue()
Returns The current setting for the Scrollbar.

getVisible

public int getVisible() images

Returns The current visible setting (i.e., size) for the slider. Replaced by getVisibleAmount().

getVisibleAmount

public int getVisibleAmount() images

Implements Adjustable.getVisibleAmount()
Returns The current visible setting (i.e., size) for the slider.

removeAdjustmentListener

public void removeAdjustmentListener (AdjustmentListener l) images

Parameters l One of this Scrollbar's AdjustmentListeners.
Implements Adjustable.removeAdjustmentListener()
Description Remove an adjustment event listener.

setBlockIncrement

public synchronized void setBlockIncrement (int amount) images

Parameters amount New paging increment amount.
Implements Adjustable.setBlockIncrement()
Description Changes the block increment amount for the Scrollbar; the default block increment is 10.

setLineIncrement

public void setLineIncrement (int amount) images

Parameters amount New line increment amount.
Description Changes the line increment amount for the Scrollbar. The default line increment is 1. Replaced by setUnitIncrement(int).

setMaximum

public synchronized void setMaximum (int newMaximum) images

Parameters newMaximum New maximum value.
Implements Adjustable.setMaximum()
Description Changes the maximum value for the Scrollbar.

setMinimum

public synchronized void setMinimum (int newMinimum) images

Parameters newMinimum New minimum value.
Implements Adjustable.setMinimum()
Description Changes the minimum value for the Scrollbar.

setOrientation

public synchronized void setOrientation (int orientation) images

Parameters orientation One of the orientation constants HORIZONTAL or VERTICAL.
Description Changes the orientation of the Scrollbar.

setPageIncrement

public void setPageIncrement (int amount) images

Parameters amount New paging increment amount.
Description Changes the paging increment amount for the Scrollbar; the default page increment is 10. Replaced by setBlockIncrement(int).

setUnitIncrement

public synchronized void setUnitIncrement (int amount) images

Parameters amount New line increment amount.
Implements Adjustable.setUnitIncrement()
Description Changes the unit increment amount for the Scrollbar. The default unit increment is 1.

setValue

public synchronized void setValue (int value)
Parameters value New Scrollbar value.
Implements Adjustable.setValue()
Description Changes the current value of the Scrollbar.

setValues

public synchronized void setValues (int value, int
visible, int minimum, int maximum)
Parameters value New Scrollbar value.
visible New slider width.
minimum New minimum value for Scrollbar.
maximum New maximum value for Scrollbar.
Description Changes the settings of the Scrollbar to the given amounts.

setVisibleAmount

public synchronized void setVisibleAmount (int newAmount) images

Parameters newAmount New amount visible.
Implements Adjustable.setVisibleAmount()
Description Changes the current visible amount of the Scrollbar.

Protected Instance Methods

paramString

protected String paramString()
Returns String with current settings of Scrollbar.
Overrides Component.paramString()
Description Helper method for toString() to generate string of current settings.

processAdjustmentEvent

protected void processAdjustmentEvent (AdjustmentEvent e) images

Parameters e The adjustment event to process.
Description Adjustment events are passed to this method for processing. Normally, this method is called by processEvent().

processEvent

protected void processEvent (AWTEvent e) images

Parameters e The event to process.
Description Low level AWTEvents are passed to this method for processing.

See Also

Adjustable, Component, String

19.55 Shape images

images

Description

Shape is an interface describing a two-dimensional geometric shape.

Interface Definition

public abstract interface java.awt.Shape {

  // Interface Methods
  public abstract Rectangle getBounds();
}

Interface Methods

getBounds

public abstract Rectangle getBounds()
Returns A Rectangle that completely encloses the shape.

See Also

Polygon, Rectangle

19.56 SystemColor images

images

Description

SystemColor provides information on the colors that the windowing system uses to display windows and other graphic components. Most windowing systems allow the user to choose different color schemes; SystemColor enables programs to find out what colors are in use in order to paint themselves in a consistent manner.

Class Definition

public final class java.awt.SystemColor
    extends java.awt.Color
    implements java.io.Serializable {

  // Constants
  public final static int ACTIVE_CAPTION;
  public final static int ACTIVE_CAPTION_BORDER;
  public final static int ACTIVE_CAPTION_TEXT;
  public final static int CONTROL;
  public final static int CONTROL_DK_SHADOW;
  public final static int CONTROL_HIGHLIGHT;
  public final static int CONTROL_LT_HIGHLIGHT;
  public final static int CONTROL_SHADOW;
  public final static int CONTROL_TEXT;
  public final static int DESKTOP;
  public final static int INACTIVE_CAPTION;
  public final static int INACTIVE_CAPTION_BORDER;
  public final static int INACTIVE_CAPTION_TEXT;
  public final static int INFO;
  public final static int INFO_TEXT;
  public final static int MENU;
  public final static int MENU_TEXT;
  public final static int NUM_COLORS;
  public final static int SCROLLBAR;
  public final static int TEXT;
  public final static int TEXT_HIGHLIGHT;
  public final static int TEXT_HIGHLIGHT_TEXT;
  public final static int TEXT_INACTIVE_TEXT;
  public final static int TEXT_TEXT;
public final static int WINDOW;
  public final static int WINDOW_BORDER;
  public final static int WINDOW_TEXT;
  public final static SystemColor activeCaption;
  public final static SystemColor activeCaptionBorder;
  public final static SystemColor activeCaptionText;
  public final static SystemColor control;
  public final static SystemColor controlDkShadow;
  public final static SystemColor controlHighlight;
  public final static SystemColor controlLtHighlight;
  public final static SystemColor controlShadow;
  public final static SystemColor controlText;
  public final static SystemColor desktop;
  public final static SystemColor inactiveCaption;
  public final static SystemColor inactiveCaptionBorder;
  public final static SystemColor inactiveCaptionText;
  public final static SystemColor info;
  public final static SystemColor infoText;
  public final static SystemColor menu;
  public final static SystemColor menuText;
  public final static SystemColor scrollbar;
  public final static SystemColor text;
  public final static SystemColor textHighlight;
  public final static SystemColor textHighlightText;
  public final static SystemColor textInactiveText;
  public final static SystemColor textText;
  public final static SystemColor window;
  public final static SystemColor windowBorder;
  public final static SystemColor windowText;

  // Public Instance Methods
  public int getRGB();
  public String toString();
}

Constants

ACTIVE_CAPTION

public static final int ACTIVE_CAPTION

ACTIVE_CAPTION_BORDER

public static final int ACTIVE_CAPTION_BORDER

ACTIVE_CAPTION_TEXT

public static final int ACTIVE_CAPTION_TEXT

CONTROL

public static final int CONTROL

CONTROL_DK_SHADOW

public static final int CONTROL_DK_SHADOW

CONTROL_HIGHLIGHT

public static final int CONTROL_HIGHLIGHT

CONTROL_LT_HIGHLIGHT

public static final int CONTROL_LT_HIGHLIGHT

CONTROL_SHADOW

public static final int CONTROL_SHADOW

CONTROL_TEXT

public static final int CONTROL_TEXT

DESKTOP

public static final int DESKTOP

INACTIVE_CAPTION

public static final int INACTIVE_CAPTION

INACTIVE_CAPTION_BORDER

public static final int INACTIVE_CAPTION_BORDER

INACTIVE_CAPTION_TEXT

public static final int INACTIVE_CAPTION_TEXT

INFO

public static final int INFO

INFO_TEXT

public static final int INFO_TEXT

MENU

public static final int MENU

MENU_TEXT

public static final int MENU_TEXT

NUM_COLORS

public static final int NUM_COLORS

SCROLLBAR

public static final int SCROLLBAR

TEXT

public static final int TEXT

TEXT_HIGHLIGHT

public static final int TEXT_HIGHLIGHT

TEXT_HIGHLIGHT_TEXT

public static final int TEXT_HIGHLIGHT_TEXT

TEXT_INACTIVE_TEXT

public static final int TEXT_INACTIVE_TEXT

TEXT_TEXT

public static final int TEXT_TEXT

WINDOW

public static final int WINDOW

WINDOW_BORDER

public static final int WINDOW_BORDER

WINDOW_TEXT

public static final int WINDOW_TEXT

activeCaption

public static final SystemColor activeCaption

Background color for captions in window borders.

activeCaptionBorder

public static final SystemColor activeCaptionBorder

Border color for captions in window borders.

activeCaptionText

public static final SystemColor activeCaptionText

Text color for captions in window borders.

control

public static final SystemColor control

Background color for controls.

controlDkShadow

public static final SystemColor controlDkShadow

Dark shadow color for controls.

controlHighlight

public static final SystemColor controlHighlight

Highlight color for controls.

controlLtHighlight

public static final SystemColor controlLtHighlight

Light highlight color for controls.

controlShadow

public static final SystemColor controlShadow

Shadow color for controls.

controlText

public static final SystemColor controlText

Text color for controls.

desktop

public static final SystemColor desktop

Desktop background color.

inactiveCaption

public static final SystemColor inactiveCaption

Background color for inactive captions in window borders.

inactiveCaptionBorder

public static final SystemColor inactiveCaptionBorder

Border color for inactive captions in window borders.

inactiveCaptionText

public static final SystemColor inactiveCaptionText

Text color for inactive captions in window borders.

info

public static final SystemColor info

Background color for informational text.

infoText

public static final SystemColor infoText

Text color for informational text.

menu

public static final SystemColor menu

Background color for menus.

menuText

public static final SystemColor menuText

Text color for menus.

scrollbar

public static final SystemColor scrollbar

Background color for scrollbars.

text

public static final SystemColor text

Background color for text components.

textHighlight

public static final SystemColor textHighlight

Background color for highlighted text.

textHighlightText

public static final SystemColor textHighlightText

Text color for highlighted text.

textInactiveText

public static final SystemColor textInactiveText

Text color for inactive text.

textText

public static final SystemColor textText

Text color for text components.

window

public static final SystemColor window

Background color for windows.

windowBorder

public static final SystemColor windowBorder

Border color for windows.

windowText

public static final SystemColor windowText

Text color for windows.

Instance Methods

getRGB

public int getRGB()
Returns Current color as a composite value
Overrides Color.getRGB()
Description Gets integer value of current system color.

toString

public String toString()
Returns A string representation of the SystemColor object.
Overrides Color.toString()

See Also

Color, Serializable, String

19.57 TextArea

images

Description

The TextArea class provides a multi-line Component for textual user input.

Class Definition

public class java.awt.TextArea extends java.awt.TextComponent { // Constants public final static int SCROLLBARS_BOTH; images public final static int SCROLLBARS_HORIZONTAL_ONLY; images public final static int SCROLLBARS_NONE; images public final static int SCROLLBARS_VERTICAL_ONLY; images // Constructors public TextArea(); public TextArea (int rows, int columns);

public TextArea (String text); public TextArea (String text, int rows, int columns); public TextArea (String text, int rows, int columns, int scrollbars); images // Instance Methods public void addNotify(); public synchronized void append (String string); images public void appendText (String string); images public int getColumns(); public Dimension getMinimumSize(); images public Dimension getMinimumSize (int rows, int columns); images public Dimension getPreferredSize(); images public Dimension getPreferredSize (int rows, int columns); images public int getRows(); public int getScrollbarVisibility(); images public synchronized void insert (String string, int position); images public void insertText (String string, int position); images public Dimension minimumSize(); images public Dimension minimumSize (int rows, int columns); images public Dimension preferredSize(); images public Dimension preferredSize (int rows, int columns); images public synchronized void replaceRange (String str, int start, int end); images public void replaceText (String string, int startPosition, int endPosition); images public void setColumns (int columns); images public void setRows (int rows); images // Protected Instance Methods protected String paramString(); }

Constants

SCROLLBARS_BOTH

public final static int SCROLLBARS_BOTH images

Show both the horizontal and vertical scrollbars.

SCROLLBARS_HORIZONTAL_ONLY

public final static int SCROLLBARS_HORIZONTAL_ONLY images

Show the horizontal scrollbar.

SCROLLBARS_NONE

public final static int SCROLLBARS_NONE images

Show no scrollbars.

SCROLLBARS_VERTICAL_ONLY

public final static int SCROLLBARS_VERTICAL_ONLY images

Show the vertical scrollbar.

Constructors

TextArea

public TextArea()
Description Constructs a TextArea object with the default size and no initial content. The default size of a text area varies widely from platform to platform, so it's best to avoid this constructor.
public TextArea (int rows, int columns)
Parameters rows Requested number of displayed rows.
columns Requested number of displayed columns.
Description Constructs a TextArea object of the given size and no initial content.
public TextArea (String text)
Parameters text Initial text for TextArea.
Description Constructs a TextArea object with the given initial content.
public TextArea (String text, int rows, int columns)
Parameters text Initial text for TextArea.
rows Requested number of displayed rows.
columns Requested number of displayed columns.
Description Constructs a TextArea object with the given content and size.
public TextArea (String text, int rows, int columns, int scrollbars) images
Parameters text Initial text for TextArea.
rows Requested number of displayed rows.
columns Requested number of displayed columns.
scrollbars Requested scrollbar visibility. Use one of the constants defined.
Description Constructs a TextArea object with the given content, size, and scrollbar visibility.

Instance Methods

addNotify

public void addNotify()
Overrides Component.addNotify()
Description Creates TextArea's peer.

append

public synchronized void append (String string) images

Parameters string Content to append to the end of the TextArea.
Description Appends the given text string to the text already displayed in the TextArea.

appendText

public void appendText (String string) images

Parameters string Content to append to end of TextArea.
Description Replaced by append(String).

getColumns

public int getColumns()
Returns The width of the TextArea in columns.

getMinimumSize

public Dimension getMinimumSize() images

Returns The minimum dimensions of the TextArea.
public Dimension getMinimumSize (int rows, int columns) images
Parameters rows Number of rows within TextArea to size.
columns Number of columns within TextArea to size.
Returns The minimum dimensions of a TextArea of the given size.

getPreferredSize

public Dimension getPreferredSize() images

Returns The preferred dimensions of the TextArea.
public Dimension getPreferredSize (int rows, int columns) images
Parameters rows Number of rows within TextArea to size.
columns Number of columns within TextArea to size.
Returns The preferred dimensions of a TextArea of the given size.

getRows

public int getRows()
Returns The height of the TextArea in rows.

getScrollbarVisibility

public int getScrollbarVisibility() images

Returns One of the SCROLLBAR_ constants indicating which scrollbars are visible.

insert

public synchronized void insert (String string, int position) images

Parameters string Content to place within TextArea content.
position Location to insert content.
Description Places additional text within the TextArea at the given position.

insertText

public void insertText (String string, int position) images

Parameters string Content to place within TextArea content.
position Location to insert content.
Description Places additional text within the TextArea at the given position. Replaced by insert(String, int).

minimumSize

public Dimension minimumSize() images

Returns The minimum dimensions of the TextArea. Replaced by getMinimumSize().
public Dimension minimumSize (int rows, int columns) images
Parameters rows Number of rows within TextArea to size.
columns Number of columns within TextArea to size.
Returns The minimum dimensions of a TextArea of the given size. Replaced by getMinimumSize(int, int).

preferredSize

public Dimension preferredSize() images

Returns The preferred dimensions of the TextArea. Replaced by getPreferredSize().
public Dimension preferredSize (int rows, int columns) images
Parameters rows Number of rows within TextArea to size.
columns Number of columns within TextArea to size.
Returns The preferred dimensions of a TextArea of the given size. Replaced by getPreferredSize(int, int).

replaceRange

public synchronized void replaceRange (String str, int start, int end) images

Parameters str New content to place in TextArea.
start Starting position of content to replace.
end Ending position of content to replace.
Description Replaces a portion of the TextArea's content with the given text.

replaceText

public void replaceText (String string, int startPosition, int endPosition) images

Parameters string New content to place in TextArea.
startPosition Starting position of content to replace.
endPosition Ending position of content to replace.
Description Replaces a portion of the TextArea's content with the given text. Replaced by replaceRange(String, int, int).

setColumns

public void setColumns (int columns) images

Parameters columns New number of columns.
Throws IllegalArgumentException
If columns is less than zero.
Description Changes the number of columns.

setRows

public void setRows (int rows) images

Parameters rows New number of columns.
Throws IllegalArgumentException
If rows is less than zero.
Description Changes the number of rows.

Protected Instance Methods

paramString

protected String paramString()
Returns String with current settings of TextArea.
Overrides TextComponent.paramString()
Description Helper method for toString() to generate string of current settings.

See Also

Dimension, TextComponent, String

19.58 TextComponent

images

Description

The abstract TextComponent class provides the base class for the text input components, TextArea and TextField.

Class Definition

public abstract class java.awt.TextComponent extends java.awt.Component { // Instance Methods public synchronized void addTextListener (TextListener l); images public int getCaretPosition(); images public synchronized String getSelectedText(); public synchronized int getSelectionEnd();

public synchronized int getSelectionStart(); public synchronized String getText(); public boolean isEditable(); public void removeNotify(); public void removeTextListener (TextListener l); images public synchronized void select (int selectionStart, int selectionEnd); public synchronized void selectAll(); public void setCaretPosition (int position); images public synchronized void setEditable (boolean state); public synchronized void setSelectionEnd (int selectionEnd); images public synchronized void setSelectionStart (int selectionStart); images public synchronized void setText (String text); // Protected Instance Methods protected String paramString(); protected void processEvent (AWTEvent e); images protected void processTextEvent (TextEvent e); images }

Instance Methods

addTextListener

public synchronized void addTextListener (TextListener l) images

Parameters l An object that implements the TextListener interface.
Description Add a listener for the text events.

getCaretPosition

public int getCaretPosition() images

Returns The position, in characters, of the caret (text cursor).

getSelectedText

public synchronized String getSelectedText()
Returns The currently selected text of the TextComponent.

getSelectionEnd

public synchronized int getSelectionEnd()
Returns The ending cursor position of any selected text.

getSelectionStart

public synchronized int getSelectionStart()
Returns The initial position of any selected text.

getText

public synchronized String getText()
Returns Current contents of the TextComponent.

isEditable

public boolean isEditable()
Returns true if editable, false otherwise.

removeNotify

public void removeNotify()
Description Destroys the peer of the TextComponent.

removeTextListener

public void removeTextListener (TextListener l) images

Parameters l One of this TextComponent's TextListeners.
Description Remove a text event listener.

select

public synchronized void select (int selectionStart, int
selectionEnd)
Parameters selectionStart Beginning position of text to select.
selectionEnd Ending position of text to select.
Description Selects text in the TextComponent.

selectAll

public synchronized void selectAll()
Description Selects all the text in the TextComponent.

setCaretPosition

public void setCaretPosition (int position) images

Parameters position The new character position for the caret.
Throws IllegalArgumentException
If position is less than zero.
Description Allows you to change the location of the caret.

setEditable

public synchronized void setEditable (boolean state)
Parameters state true to allow the user to edit the text in the TextComponent; false to prevent editing.
Description Allows you to make the TextComponent editable or read-only.

setSelectionEnd

public synchronized void setSelectionEnd (int selectionEnd) images

Parameters selectionEnd The character position of the end of the selection.
Description Allows you to change the location of the end of the selected text.

setSelectionStart

public synchronized void setSelectionStart (int selectionStart) images

Parameters selectionStart The character position of the start of the selection.
Description Allows you to change the location of the start of the selected text.

setText

public synchronized void setText (String text)
Parameters text New text for TextComponent.
Description Sets the content of the TextComponent.

Protected Instance Methods

paramString

protected String paramString()
Returns String with current settings of TextComponent.
Overrides Component.paramString()
Description Helper method for toString() to generate string of current settings.

processEvent

protected void processEvent (AWTEvent e) images

Parameters e The event to process.
Description Low-level AWTEvents are passed to this method for processing.

processTextEvent

protected void processTextEvent (TextEvent e) images

Parameters e The event to process.
Description Text events are passed to this method for processing. Normally, this method is called by processEvent().

See Also

Component, TextArea, TextField, String

19.59 TextField

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Description

The TextField class provides a single line Component for user input.

Class Definition

public class java.awt.TextField extends java.awt.TextComponent { // Constructors public TextField(); public TextField (int columns); public TextField (String text); public TextField (String text, int columns); // Instance Methods public void addActionListener (ActionListener l); images public void addNotify(); public boolean echoCharIsSet(); public int getColumns(); public char getEchoChar(); public Dimension getMinimumSize(); images public Dimension getMinimumSize (int columns); images public Dimension getPreferredSize(); images

public Dimension getPreferredSize (int columns); images public Dimension minimumSize(); images public Dimension minimumSize (int columns); images public Dimension preferredSize(); images public Dimension preferredSize (int columns); images public void removeActionListener (ActionListener l); images public void setColumns(int columns); images public void setEchoChar(char c); images public void setEchoCharacter (char c); images // Protected Instance Methods protected String paramString(); protected void processActionEvent (ActionEvent e); images protected void processEvent (AWTEvent e); images }

Constructors

TextField

public TextField()
Description Constructs a TextField object of the default size.
public TextField (int columns)
Parameters columns Requested number of displayed columns.
Description Constructs a TextField object of the given size.
public TextField (String text)
Parameters text Initial text for TextField.
Description Constructs a TextField object with the given content.
public TextField (String text, int columns)
Parameters text Initial text for TextField.
columns Requested number of displayed columns.
Description Constructs a TextField object with the given content and size.

Instance Methods

addActionListener

public void addActionListener (ActionListener l) images

Parameters l An object that implements the ActionListener interface.
Description Add a listener for the action event.

addNotify

public synchronized void addNotify()
Overrides Component.addNotify()
Description Creates TextField's peer.

echoCharIsSet

public boolean echoCharIsSet()
Returns true if the TextField has an echo character used as a response to any input character; false otherwise. An echo character can be used to create a TextField for hidden input, like a password; the same character (e.g., “x”) is used to echo all input.

getColumns

public int getColumns()
Returns The width of the TextField in columns.

getEchoChar

public char getEchoChar()
Returns The current echo character.

getMinimumSize

public Dimension getMinimumSize() images

Returns The minimum dimensions of the TextField.
public Dimension getMinimumSize (int columns) images
Parameters columns Number of columns within TextField to size.
Returns The minimum dimensions of a TextField of the given size.

getPreferredSize

public Dimension getPreferredSize() images

Returns The preferred dimensions of the TextField.
public Dimension getPreferredSize (int columns) images
Parameters columns Number of columns within TextField to size.
Returns The preferred dimensions of a TextField of the given size.

minimumSize

public Dimension minimumSize() images

Returns The minimum dimensions of the TextField. Replaced by getMinimumSize().
public Dimension minimumSize (int columns) images
Parameters columns Number of columns within TextField to size.
Returns The minimum dimensions of a TextField of the given size. Replaced by getMinimumSize(int).

preferredSize

public Dimension preferredSize() images

Returns The preferred dimensions of the TextField. Replaced by getPreferredSize().
public Dimension preferredSize (int columns) images
Parameters columns Number of columns within TextField to size.
Returns The preferred dimensions of a TextField of the given size. Replaced by getPreferredSize(int).

removeActionListener

public void removeActionListener (ActionListener l) images

Parameters l One of this TextField's ActionListeners.
Description Remove an action event listener.

setColumns

public void setColumns (int columns) images

Parameters columns New number of columns.
Throws IllegalArgumentException
If columns is less than zero.
Description Changes the number of columns.

setEchoChar

public void setEchoChar (char c) images

Parameters c The character to echo for all input. To echo the characters that the user types (the default), set the echo character to 0 (zero).
Description Changes the character that is used to echo all user input in the TextField.

setEchoCharacter

public void setEchoCharacter (char c) images

Parameters c The character to echo for all input. To echo the characters that the user types (the default), set the echo character to 0 (zero).
Description Replaced by setEchoChar(char) for consistency with getEchoChar().

Protected Instance Methods

paramString

protected String paramString()
Returns String with current settings of TextField.
Overrides TextComponent.paramString()
Description Helper method for toString() to generate string of current settings.

processActionEvent

protected void processActionEvent (ActionEvent e) images

Parameters e The action event to process.
Description Action events are passed to this method for processing. Normally, this method is called by processEvent().

processEvent

protected void processEvent (AWTEvent e) images

Parameters e The event to process.
Description Low-level AWTEvents are passed to this method for processing.

See Also

Dimension, TextComponent, String

19.60 Toolkit

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Description

The abstract Toolkit class provides access to platform-specific details like window size and available fonts. It also deals with creating all the components' peer objects when you call addNotify().

Class Definition

public abstract class java.awt.Toolkit extends java.lang.Object { // Class Methods public static synchronized Toolkit getDefaultToolkit(); protected static Container getNativeContainer (Component c); images public static String getProperty (String key, String defaultValue); images // Instance Methods public abstract void beep(); images public abstract int checkImage (Image image, int width, int height, ImageObserver observer); public abstract Image createImage (ImageProducer producer); public Image createImage (byte[] imagedata); images public abstract Image createImage (byte[ ] imagedata, int imageoffset, int imagelength); images public abstract ColorModel getColorModel(); public abstract String[] getFontList(); public abstract FontMetrics getFontMetrics (Font font); public abstract Image getImage (String filename); public abstract Image getImage (URL url); public int getMenuShortcutKeyMask(); images public abstract PrintJob getPrintJob (Frame frame, String jobtitle, Properties props); images public abstract int getScreenResolution(); public abstract Dimension getScreenSize(); public abstract Clipboard getSystemClipboard(); images public final EventQueue getSystemEventQueue(); images public abstract boolean prepareImage (Image image, int width, int height, ImageObserver observer); public abstract void sync(); // Protected Instance Methods protected abstract ButtonPeer createButton (Button b);

protected abstract CanvasPeer createCanvas (Canvas c); protected abstract CheckboxPeer createCheckbox (Checkbox cb); protected abstract CheckboxMenuItemPeer createCheckboxMenuItem (CheckboxMenuItem cmi); protected abstract ChoicePeer createChoice (Choice c); protected LightweightPeer createComponent(Component target); images protected abstract DialogPeer createDialog (Dialog d); protected abstract FileDialogPeer createFileDialog (FileDialog fd); protected abstract FramePeer createFrame (Frame f); protected abstract LabelPeer createLabel (Label l); protected abstract ListPeer createList (List l); protected abstract MenuPeer createMenu (Menu m); protected abstract MenuBarPeer createMenuBar (MenuBar mb); protected abstract MenuItemPeer createMenuItem (MenuItem mi); protected abstract PanelPeer createPanel (Panel p); protected abstract PopupMenuPeer createPopupMenu (PopupMenu target); images protected abstract ScrollPanePeer createScrollPane (ScrollPane target); images protected abstract ScrollbarPeer createScrollbar (Scrollbar sb); protected abstract TextAreaPeer createTextArea (TextArea ta); protected abstract TextFieldPeer createTextField (TextField tf); protected abstract WindowPeer createWindow (Window w); protected abstract FontPeer getFontPeer (String name, int style); images protected abstract EventQueue getSystemEventQueueImpl(); images protected void loadSystemColors (int[] systemColors); images }

Class Methods

getDefaultToolkit

public static synchronized Toolkit getDefaultToolkit()
Throws AWTError If the toolkit for the current platform cannot be found.
Returns The system's default Toolkit.

getNativeContainer

protected static Container getNativeContainer (Component c) images

Returns The native container for the given component. The component's immediate parent may be a lightweight component.

getProperty

public static String getProperty (String key, String defaultValue) images

Parameters key The name of a property.
defaultValue A default value to return if the property is not found.
Returns The value of the property described by key, or defaultValue if it is not found.

Instance Methods

beep

public abstract void beep() images

Description Produces an audible beep.

checkImage

public abstract int checkImage (Image image, int width,
int height, ImageObserver observer)
Parameters image Image to check.
width Width of the scaled image; -1 if image will be rendered unscaled.
height Height of the scaled image; -1 if image will be rendered unscaled.
observer The Component that image will be rendered on.
Returns The ImageObserver flags ORed together for the data that is now available.
Description Checks on the status of the construction of a screen representation of image on observer.

createImage

public abstract Image createImage (ImageProducer producer)
Parameters producer An ImageProducer that generates data for the desired image.
Returns Newly created Image.
Description Creates a new Image from an ImageProducer.
public abstract Image createImage (byte[] imagedata) images
Parameters imagedata Raw data representing an image.
Returns Newly created Image.
Description Creates a new Image from the imagedata provided.
public abstract Image createImage (byte[] imagedata, int imageoffset, int imagelength) images
Parameters imagedata Raw data representing one or more images.
imageoffset An offset into the data given.
imagelength The length of data to use.
Returns Newly created Image.
Description Creates a new Image from the imagedata provided, starting at imageoffset bytes and reading imagelength bytes.

getColorModel

public abstract ColorModel getColorModel()
Returns The current ColorModel used by the system.

getFontList

public abstract String[] getFontList()
Returns A String array of the set of Java fonts available with this Toolkit.

getFontMetrics

public abstract FontMetrics getFontMetrics (Font font)
Parameters font A Font whose metrics are desired
Returns The current FontMetrics for the font on the user's system.

getImage

public abstract Image getImage (String filename)
Parameters filename Location of Image on local filesystem
Returns The Image that needs to be fetched.
Description Fetches an image from the local file system.
public abstract Image getImage (URL url)
Parameters url Location of Image.
Returns The Image that needs to be fetched.
Description Fetches an image from a URL.

getMenuShortcutKeyMask

public int getMenuShortcutKeyMask() images

Returns The modifier key mask used for menu shortcuts. This will be one of the mask constants defined in java.awt.Event.

getPrintJob

public abstract PrintJob getPrintJob (Frame frame, String jobtitle, Properties props) images

Parameters frame The frame to be used as the parent of a platform- specific printing dialog.
jobtitle The name of the job.
props Properties for this print job.
Returns A PrintJob object. If the user canceled the printing operation, null is returned.

getScreenResolution

public abstract int getScreenResolution()
Returns The current resolution of the user's screen, in dots-per-inch.

getScreenSize

public abstract Dimension getScreenSize()
Returns The size of the screen available to the Toolkit, in pixels, as a Dimension object.

getSystemClipboard

public abstract Clipboard getSystemClipboard() images

Returns A Clipboard object that can be used for cut, copy, and paste operations.

getSystemEventQueue

public final EventQueue getSystemEventQueue() images

Returns A reference to the system's event queue, allowing the program to post new events or inspect the queue.

prepareImage

public abstract boolean prepareImage (Image image, int
width, int height, ImageObserver observer)
Parameters image Image to check.
width Width of the scaled image; -1 if image will be rendered unscaled.
height Height of the scaled image; -1 if image will be rendered unscaled.
observer The Component that image will be rendered on.
Returns true if image fully loaded, false otherwise.
Description Forces the system to start loading the image.

sync

public abstract void sync()
Description Flushes the display of the underlying graphics context.

Protected Instance Methods

createButton

protected abstract ButtonPeer createButton (Button b)
Parameters b Component whose peer needs to be created.
Returns Newly created peer.
Description Creates a peer for the Button.

createCanvas

protected abstract CanvasPeer createCanvas (Canvas c)
Parameters c Component whose peer needs to be created.
Returns Newly created peer.
Description Creates a peer for the Canvas.

createCheckbox

protected abstract CheckboxPeer createCheckbox (Checkbox
cb)
Parameters cb Component whose peer needs to be created.
Returns Newly created peer.
Description Creates a peer for the Checkbox.

createCheckboxMenuItem

protected abstract CheckboxMenuItemPeer
createCheckboxMenuItem (CheckboxMenuItem cmi)
Parameters cmi Component whose peer needs to be created.
Returns Newly created peer.
Description Creates a peer for the CheckboxMenuItem.

createChoice

protected abstract ChoicePeer createChoice (Choice c)
Parameters c Component whose peer needs to be created.
Returns Newly created peer.
Description Creates a peer for the Choice.

createComponent

protected LightweightPeer createComponent (Component target) images

Parameters target Component whose peer needs to be created.
Returns Newly created peer.
Description Creates a peer for the Component.

createDialog

protected abstract DialogPeer createDialog (Dialog d)
Parameters d Component whose peer needs to be created.
Returns Newly created peer.
Description Creates a peer for the Dialog.

createFileDialog

protected abstract FileDialogPeer createFileDialog
(FileDialog fd)
Parameters fd Component whose peer needs to be created.
Returns Newly created peer.
Description Creates a peer for the FileDialog.

createFrame

protected abstract FramePeer createFrame (Frame f)
Parameters f Component whose peer needs to be created.
Returns Newly created peer.
Description Creates a peer for the Frame.

createLabel

protected abstract LabelPeer createLabel (Label l)
Parameters l Component whose peer needs to be created.
Returns Newly created peer.
Description Creates a peer for the Label.

createList

protected abstract ListPeer createList (List l)
Parameters l Component whose peer needs to be created.
Returns Newly created peer.
Description Creates a peer for the List.

createMenu

protected abstract MenuPeer createMenu (Menu m)
Parameters m Menu whose peer needs to be created.
Returns Newly created peer.
Description Creates a peer for the given Menu.

createMenuBar

protected abstract MenuBarPeer createMenuBar (MenuBar mb)
Parameters mb MenuBar whose peer needs to be created.
Returns Newly created peer.
Description Creates a peer for the MenuBar.

createMenuItem

protected abstract MenuItemPeer createMenuItem (MenuItem
mi)
Parameters mi MenuItem whose peer needs to be created.
Returns Newly created peer.
Description Creates a peer for the MenuItem.

createPanel

protected abstract PanelPeer createPanel (Panel p)
Parameters p Component whose peer needs to be created.
Returns Newly created peer.
Description Creates a peer for the Panel.

createPopupMenu

protected abstract PopupMenuPeer createPopupMenu (PopupMenu target) images

Parameters target Component whose peer needs to be created.
Returns Newly created peer.
Description Creates a peer for the PopupMenu.

createScrollPane

protected abstract ScrollPanePeer createScrollPane (ScrollPane target) images

Parameters target Component whose peer needs to be created.
Returns Newly created peer.
Description Creates a peer for the ScrollPane.

createScrollbar

protected abstract ScrollbarPeer createScrollbar
(Scrollbar sb)
Parameters sb Component whose peer needs to be created.
Returns Newly created peer.
Description Creates a peer for the Scrollbar.

createTextArea

protected abstract TextAreaPeer createTextArea (TextArea
ta)
Parameters ta Component whose peer needs to be created.
Returns Newly created peer.
Description Creates a peer for the TextArea.

createTextField

protected abstract TextFieldPeer createTextField
(TextField tf)
Parameters tf Component whose peer needs to be created.
Returns Newly created peer.
Description Creates a peer for the TextField.

createWindow

protected abstract WindowPeer createWindow (Window w)
Parameters w Component whose peer needs to be created.
Returns Newly created peer.
Description Creates a peer for the Window.

getFontPeer

protected abstract FontPeer getFontPeer (String name, int style) images

Parameters name Name of the font to be created.
style Style of the font to be created.
Returns Newly created peer.
Description Creates a FontPeer.

getSystemEventQueueImpl

protected abstract getSystemEventQueueImpl() images

Returns A toolkit-specific EventQueue object.

loadSystemColors

protected abstract void loadSystemColors (int[] systemColors) images

Description Fills the given integer array with the current system colors.

See Also

Button, ButtonPeer, Canvas, CanvasPeer, Checkbox, CheckboxMenuItem, CheckboxMenuItemPeer, CheckboxPeer, Choice, ChoicePeer, Clipboard, ColorModel, Component, Container, Dialog, DialogPeer, Dimension, FileDialog, FileDialogPeer, Font, FontMetrics, FontPeer, Frame, FramePeer, Image, ImageObserver, ImageProducer, Label, LabelPeer, LightweightPeer, List, ListPeer, Menu, MenuBar, MenuBarPeer, MenuItem, MenuItemPeer, MenuPeer, Panel, PanelPeer, PrintJob, Scrollbar, ScrollbarPeer, ScrollPane, ScrollPanePeer, String, TextArea, TextAreaPeer, TextField, TextFieldPeer, Window, WindowPeer

19.61 Window

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Description

The Window class serves as a top-level display area that exists outside the browser or applet area you may be working in. A window must have a parent Frame.

Class Definition

public class java.awt.Window extends java.awt.Container { // Constructors public Window (Frame parent); // Instance Methods public void addNotify(); public synchronized void addWindowListener (WindowListener l); images public void dispose(); public Component getFocusOwner(); images public Locale getLocale(); images public Toolkit getToolkit(); public final String getWarningString(); public boolean isShowing(); images public void pack(); public boolean postEvent (Event e); images public synchronized void remove WindowListener (WindowListener l); images public void show(); public void toBack(); public void toFront(); //Protected Instance Methods protected void processEvent (AWTEvent e); images protected void processWindowEvent (WindowEvent e); images }

Constructors

Window

public Window (Frame parent)
Parameters parent Frame that is to act as the parent of Window.
Description Constructs a Window object.

Instance Methods

addNotify

public void addNotify()
Overrides Container.addNotify()
Description Creates Window's peer and peers of contained components.

removeWindowListener

public synchronized void removeWindowListener(WindowListener l) images

Parameters l One of this Frame's WindowListeners.
Description Remove an event listener.

addWindowListener

public synchronized void addWindowListener (WindowListener l) images

Parameters l An object that implements the WindowListener interface.
Description Add a listener for windowing events.

dispose

public void dispose()
Returns Releases the resources of the Window.

getFocusOwner

public Component getFocusOwner() images

Returns The child component that currently has the input focus.

getLocale

public Locale getLocale() images

Returns The locale for this Window.
Overrides Window.getLocale()

getToolkit

public Toolkit getToolkit()
Returns Toolkit of Window.
Overrides Component.getToolkit()

getWarningString

public final String getWarningString()
Returns String that will be displayed on the bottom of insecure Window instances.

isShowing

public boolean isShowing()
Returns true if the Window is showing on the screen, false otherwise.

pack

public void pack()
Description Resizes Window to getPreferredSize() of contained components.

postEvent

public boolean postEvent (Event e) images

Parameters e Event instance to post to window.
Returns If Event is handled, true is returned. Otherwise, false is returned.
Description Tells the Window to deal with Event.

removeWindowListener

public synchronized void removeWindowListener (WindowListener l) images

Parameters l One of this Frame's WindowListeners.
Description Remove an event listener.

show

public void show()
Description Show the Window and validate its components.
Overrides Component.show()

toBack

public void toBack()
Description Puts the Window in the background of the display.

toFront

public void toFront()
Description Brings the Window to the foreground of the display.

Protected Instance Methods

processEvent

protected void processEvent (AWTEvent e) images

Parameters e The event to process.
Description Low level AWTEvents are passed to this method for processing.

processWindowEvent

protected void processWindowEvent (WindowEvent e) images

Parameters e The event to process.
Description Window events are passed to this method for processing. Normally, this method is called by processEvent().

See Also

Component, Container, Dialog, Frame, String, Toolkit

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