19
java.awt Reference
19.1 AWTError
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 
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
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; }
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)
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)
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
| 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
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
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
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
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;
public final static String EAST;
public final static String NORTH;
public final static String SOUTH;
public final static String WEST;
// Constructors
public BorderLayout();
public BorderLayout (int hgap, int vgap);
// Instance Methods
public void addLayoutComponent (Component comp, Object constraints);
public void addLayoutComponent (String name, Component component); 
public int getHgap();
public abstract float getLayoutAlignmentX(Container target);
public abstract float getLayoutAlignmentY(Container target);
public int getVgap();
public abstract void invalidateLayout(Container target);
public void layoutContainer (Container target);
public abstract Dimension maximumLayoutSize(Container target);
public Dimension minimumLayoutSize (Container target);
public Dimension preferredLayoutSize (Container target);
public void removeLayoutComponent (Component component);
public void setHgap (int hgap);
public void setVgap (int vgap);
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)
| 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
| 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()
| Returns | The horizontal gap for this BorderLayout instance. |
getLayoutAlignmentX
public abstract float getLayoutAlignmentX (Container
target)
| 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)
| 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()
| Returns | The vertical gap for this BorderLayout instance. |
invalidateLayout
public abstract void invalidateLayout (Container target)
| 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)
| 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
| Parameters | component | Component to stop tracking. |
| Implements | LayoutManager.removeLayoutComponent() | |
| Description | Removes component from any internal tracking systems. | |
setHgap
public void setHgap (int hgap)
| Parameters | hgap | The horizontal gap value. |
| Description | Sets the horizontal gap between components. | |
setVgap
public void setVgap (int vgap)
| 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
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);
public void addNotify();
public String getActionCommand();
public String getLabel();
public void removeActionListener (ActionListener l);
public void setActionCommand (String command);
public synchronized void setLabel (String label);
// Protected Instance Methods
protected String paramString();
protected void processActionEvent (ActionEvent e);
protected void processEvent (AWTEvent e);
}
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)
| Parameters | l | An object that implements the ActionListener interface. |
| Description | Add a listener for the action event. | |
addNotify
| Overrides | Component.addNotify() |
| Description | Creates Button's peer. |
getActionCommand
public String getActionCommand()
| 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)
| Parameters | l | One of this Button's ActionListeners. |
| Description | Remove an action event listener. | |
setActionCommand
public void setActionCommand (String command)
| 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)
| 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)
| 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
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
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);
public void addLayoutComponent (String name, Component component);
public void first (Container parent);
public int getHgap();
public abstract float getLayoutAlignmentX(Container target);
public abstract float getLayoutAlignmentY(Container target);
public int getVgap();
public abstract void invalidateLayout(Container target);
public void last (Container parent);
public void layoutContainer (Container target);
public abstract Dimension maximumLayoutSize(Container target);
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);
public void setVgap (int vgap);
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)
| 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)
| 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()
| Returns | The horizontal gap for this CardLayout instance. |
getLayoutAlignmentX
public abstract float getLayoutAlignmentX (Container
target)
| 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)
getVgap
public int getVgap()
| Returns | The vertical gap for this CardLayout instance. |
invalidateLayout
public abstract void invalidateLayout (Container target)
| 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)
| 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)
| 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)
| 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
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);
public Checkbox (String label, boolean state, CheckboxGroup group);
public Checkbox (String label, CheckboxGroup group, boolean state);
// Instance Methods
public void addItemListener (ItemListener l);
public void addNotify();
public CheckboxGroup getCheckboxGroup();
public String getLabel();
public Object[] getSelectedObjects();
public boolean getState();
public void removeItemListener (ItemListener l);
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);
protected void processItemEvent (ItemEvent e);
}
Constructors
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) |
||
| 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) |
||
| 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)
| 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()
| 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)
| 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)
| Parameters | e | The event to process. |
| Description | Low level AWTEvents are passed to this method for processing. | |
processItemEvent
protected void processItemEvent(ItemEvent e)
| 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
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();
public Checkbox getSelectedCheckbox()
public synchronized void setCurrent (Checkbox checkbox);
public synchronized void setSelectedCheckbox (Checkbox checkbox);
public String toString();
}
Constructors
CheckboxGroup
public CheckboxGroup()
| Description | Constructs a CheckboxGroup object. |
Instance Methods
getCurrent
public Checkbox getCurrent()
| Returns | The currently selected Checkbox within the CheckboxGroup. |
| Description | Replaced by the more aptly named getSelectedCheckbox(). |
getSelectedCheckbox
public Checkbox getSelectedCheckbox()
| Returns | The currently selected Checkbox within the CheckboxGroup. |
setCurrent
public synchronized void setCurrent (Checkbox checkbox)
| 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)
| 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
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();
public CheckboxMenuItem (String label);
public CheckboxMenuItem (String label, boolean state);
// Instance Methods
public void addItemListener (ItemListener l);
public void addNotify();
public Object[] getSelectedObjects();
public boolean getState();
public String paramString();
public void removeItemListener (ItemListener l);
public synchronized void setState (boolean condition);
// Protected Instance Methods
protected void processEvent (AWTEvent e);
protected void processItemEvent (ItemEvent e);
}
Constructors
CheckboxMenuItem
public CheckboxMenuItem()
| 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) |
||
| 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)
| 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()
| 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)
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)
| 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)
| 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
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);
public synchronized void addItem (String item);
public void addItemListener (ItemListener l);
public void addNotify();
public int countItems();
public String getItem (int index);
public int getItemCount();
public int getSelectedIndex();
public synchronized String getSelectedItem();
public synchronized Object[] getSelectedObjects();
public synchronized void insert (String item, int index);
public synchronized void remove (int position);
public synchronized void remove (String item);
public synchronized void removeAll();
public void removeItemListener (ItemListener l);
public synchronized void select (int pos);
public synchronized void select (String str);
// Protected Instance Methods
protected String paramString();
protected void processEvent (AWTEvent e);
protected void processItemEvent (ItemEvent e);
}
Constructors
Choice
public Choice()
| Description | Constructs a Choice object. |
Instance Methods
add
public synchronized void add (String item)
| 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)
| Parameters | item | Text for new entry. |
| Throws | NullPointerException | |
| If item is null. | ||
| Description | Replaced by add(String). | |
addItemListener
public void addItemListener (ItemListener l)
| 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()
| 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()
| 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()
| Implements | ItemSelectable.getSelectedObjects() | |
| Description | A single-item array containing the current selection. | |
insert
public synchronized void insert (String item, int index)
| 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)
| 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) |
||
| 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
| Description | Removes all the entries from the Choice. |
removeItemListener
public void removeItemListener (ItemListener l)
| 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)
| Parameters | e | The event to process. |
| Description | Low level AWTEvents are passed to this method for processing. | |
processItemEvent
protected void processItemEvent (ItemEvent e)
| 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
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);
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)
| 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)
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)
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
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;
public final static float CENTER_ALIGNMENT;
public final static float LEFT_ALIGNMENT;
public final static float RIGHT_ALIGNMENT;
public final static float TOP_ALIGNMENT;
// Variables
protected Locale locale;
// Constructors
protected Component();
// Instance Methods
public boolean action (Event e, Object o);
public synchronized void add (PopupMenu popup);
public synchronized void addComponentListener
(ComponentListener l);
public synchronized void addFocusListener (FocusListener l);
public synchronized void addKeyListener (KeyListener l);
public synchronized void addMouseListener (MouseListener l);
public synchronized void addMouseMotionListener
(MouseMotionListener l);
public void addNotify();
public Rectangle bounds();
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);
public boolean contains (Point p);
public Image createImage (ImageProducer producer);
public Image createImage (int width, int height);
public void deliverEvent (Event e);
public void disable();
public final void dispatchEvent (AWTEvent e)
public void doLayout();
public void enable();
public void enable (boolean condition);
public float getAlignmentX();
public float getAlignmentY();
public Color getBackground();
public Rectangle getBounds();
public synchronized ColorModel getColorModel();
public Component getComponentAt (int x, int y);
public Component getComponentAt (Point p);
public Cursor getCursor();
public Font getFont();
public FontMetrics getFontMetrics (Font f);
public Color getForeground();
public Graphics getGraphics();
public Locale getLocale();
public Point getLocation();
public Point getLocationOnScreen();
public Dimension getMaximumSize();
public Dimension getMinimumSize();
public String getName();
public Container getParent();
public ComponentPeer getPeer();
public Dimension getPreferredSize();
public Dimension getSize();
public Toolkit getToolkit();
public final Object getTreeLock();
public boolean gotFocus (Event e, Object o);
public boolean handleEvent (Event e);
public void hide();
public boolean imageUpdate (Image image, int infoflags, int x, int y,
int width, int height);
public boolean inside (int x, int y);
public void invalidate();
public boolean isEnabled();
public boolean isFocusTraversable();
public boolean isShowing();
public boolean isValid();
public boolean isVisible();
public boolean keyDown (Event e, int key);
public boolean keyUp (Event e, int key);
public void layout();
public void list();
public void list (PrintStream out);
public void list (PrintStream out, int indentation);
public void list (PrintWriter out);
public void list (PrintWriter out, int indentation);
public Component locate (int x, int y);
public Point location();
public boolean lostFocus (Event e, Object o);
public Dimension minimumSize();
public boolean mouseDown (Event e, int x, int y);
public boolean mouseDrag (Event e, int x, int y);
public boolean mouseEnter (Event e, int x, int y);
public boolean mouseExit (Event e, int x, int y);
public boolean mouseMove (Event e, int x, int y);
public boolean mouseUp (Event e, int x, int y);
public void move (int x, int y);
public void nextFocus();
public void paint (Graphics g);
public void paintAll (Graphics g);
public boolean postEvent (Event e);
public Dimension preferredSize();
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);
public synchronized void removeComponentListener
(ComponentListener l);
public synchronized void removeFocusListener (FocusListener l);
public synchronized void removeKeyListener (KeyListener l);
public synchronized void removeMouseListener (MouseListener l);
public synchronized void removeMouseMotionListener
(MouseMotionListener l);
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);
public void resize (Dimension d);
public void resize (int width, int height);
public void setBackground (Color c);
public void setBounds (int x, int y, int width, int height);
public void setBounds (Rectangle r);
public synchronized void setCursor (Cursor cursor);
public void setEnabled (boolean b);
public synchronized void setFont (Font f);
public void setForeground (Color c);
public void setLocale (Locale l);
public void setLocation (int x, int y);
public void setLocation (Point p);
public void setName (String name);
public void setSize (int width, int height);
public void setSize (Dimension d);
public void setVisible (boolean b);
public void show();
public void show (boolean condition);
public Dimension size();
public String toString();
public void transferFocus();
public void update (Graphics g);
public void validate();
// Protected Instance Methods
protected final void disableEvents (long eventsToDisable);
protected final void enableEvents (long eventsToEnable);
protected String paramString();
protected void processComponentEvent (ComponentEvent e);
protected void processEvent (AWTEvent e);
protected void processFocusEvent (FocusEvent e);
protected void processKeyEvent (KeyEvent e);
protected void processMouseEvent (MouseEvent e);
protected void processMouseMotionEvent (MouseEvent e);
}
Constants
BOTTOM_ALIGNMENT
public final static float BOTTOM_ALIGNMENT
Constant representing bottom alignment in getAlignmentY().
CENTER_ALIGNMENT
public final static float CENTER_ALIGNMENT
Constant representing center alignment in getAlignmentX() and getAlignmentY().
LEFT_ALIGNMENT
public final static float LEFT_ALIGNMENT
Constant representing left alignment in getAlignmentX().
RIGHT_ALIGNMENT
public final static float RIGHT_ALIGNMENT
Constant representing right alignment in getAlignmentX().
TOP_ALIGNMENT
public final static float TOP_ALIGNMENT
Constant representing top alignment in getAlignmentY().
Variables
locale
protected Locale locale
| Description | The locale for the component. Used for internationalization support. |
Constructors
Component
protected Component()
| 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)
| 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)
| 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)
| Description | Adds a listener for the ComponentEvent objects this Component generates. |
addFocusListener
public void addFocusListener (FocusListener l)
| Description | Adds a listener for the FocusEvent objects this Component generates. |
addKeyListener
public void addKeyListener (KeyListener l)
| Description | Adds a listener for the KeyEvent objects this Component generates. |
addMouseListener
public void addMouseListener (MouseListener l)
| Description | Adds a listener for the MouseEvent objects this Component generates. |
addMouseMotionListener
public void addMouseMotionListener (MouseMotionListener l)
| 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()
| 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)
contains
public boolean contains (int x, int y)
| 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) |
||
| 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)
| Parameters | e | Event instance to deliver. |
| Description | Delivers event to the component for processing. | |
disable
public void disable()
| Description | Disables component so that it is unresponsive to user interactions. Replaced by setEnabled(false). |
dispatchEvent
public final void dispatchEvent (AWTEvent e)
| Parameters | e | The AWTEvent to process. |
| Description | Tells the component to deal with the AWTEvent e. | |
doLayout
public void doLayout()
| Description | Lays out component. This method is a replacement for layout(). |
enable
public void enable()
| Description | Enables component so that it is responsive to user interactions. Use setEnabled(true) instead. | |
| public void enable (boolean condition) |
||
| 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()
| 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()
| 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()
| 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)
| 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) |
||
| 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()
| 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()
| 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()
| Returns | Position of component. |
| Description | Gets the current position of this Component in its parent's coordinate space. |
getLocationOnScreen
public Point getLocationOnScreen()
| Returns | Position of component. |
| Description | Gets the current position of this Component in the screen's coordinate space. |
getMaximumSize
public Dimension getMaximumSize()
| Returns | The maximum dimensions of the component. |
| Description | By default, a maximal Dimension is returned. |
getMinimumSize
public Dimension getMinimumSize()
| Returns | The minimum dimensions of the component. |
getName
public String getName()
| 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()
| Returns | Peer of Component. |
getPreferredSize
public Dimension getPreferredSize()
| Returns | The preferred dimensions of the component. |
getSize
public Dimension getSize()
| Returns | Dimensions of component. |
| Description | Gets width and height of component. |
getToolkit
public Toolkit getToolkit()
| Returns | Toolkit of Component. |
getTreeLock
public final Object getTreeLock()
| 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)
| 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)
| 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()
| 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)
inside
public boolean inside (int x, int y)
| 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()
| 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
| 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)
| 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)
| 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
| 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)
| 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()
| 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)
| 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()
| Returns | The minimum dimensions of the component. Replaced by getMinimumSize(). |
mouseDown
public boolean mouseDown (Event e, int x, int y)
| 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)
mouseEnter
public boolean mouseEnter (Event e, int x, int y)
| 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)
| 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)
mouseUp
public boolean mouseUp (Event e, int x, int y)
| 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)
| 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()
| Description | Moves focus from current component to next one in parent container. Replaced by transferFocus(). |
paint
| 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)
| 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()
| Returns | The preferred dimensions of the component. Replaced by getPreferredSize(). |
prepareImage
public boolean prepareImage (Image image, ImageObserver observer)
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)
| 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)
| Description | Removes the specified ComponentListener from this Component. |
removeFocusListener
public void removeFocusListener (FocusListener l)
| Description | Removes the specified FocusListener from this Component. |
removeKeyListener
public void removeKeyListener (KeyListener l)
| Description | Removes the specified KeyListener from this Component. |
removeMouseListener
| Description | Removes the specified MouseListener from this Component. |
removeMouseMotionListener
public void removeMouseMotionListener (MouseMotionListener
l)
| Description | Removes the specified MouseMotionListener from this Component. |
removeNotify
public void removeNotify()
| Description | Removes peer of Component's subclass. |
repaint
public void repaint()
requestFocus
public void requestFocus()
| Description | Requests the input focus for this Component. |
reshape
public void reshape (int x, int y, int width, int height)
| 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)
| Parameters | d | New dimensions for the component. |
| Description | Resizes component. Replaced by setSize(Dimension). | |
| public void resize (int width, int height) |
||
| 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)
setCursor
public synchronized void setCursor (Cursor cursor)
| Parameters | cursor | The new cursor for the component. |
| Description | Changes the component's cursor. | |
setEnabled
public void setEnabled (boolean b)
| 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)
| Parameters | l | The locale object for the component. |
| Description | Sets the Component's locale. | |
setLocation
public void setLocation (int x, int y)
| Parameters | x | New horizontal position for component. |
| y | New vertical position for component. | |
| Description | Relocates the component. | |
| public void setLocation (Point p) |
||
| Parameters | p | New position for component. |
| Description | Relocates the component. | |
setName
public void setName (String name)
| Parameters | name | New name for component. |
| Description | Sets the component's name. | |
setSize
public void setSize (int width, int height)
| Parameters | width | New width for component. |
| height | New height for component. | |
| Description | Resizes the component. | |
| public void setSize (Dimension d) |
||
| Parameters | d | New dimensions for the component. |
| Description | Resizes the component. | |
setVisible
public void setVisible (boolean b)
| 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()
| Description | Replaced by setVisible(true). | |
| public void show (boolean condition) |
||
| Parameters | condition | true to show the component, false to hide it. |
| Description | Replaced by setVisible(boolean). | |
size
public Dimension size()
| 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()
| 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)
| 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)
| 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)
| 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)
| Parameters | e | The event to process. |
| Description | Low level AWTEvents are passed to this method for processing. | |
processFocusEvent
protected void processFocusEvent(FocusEvent e)
| 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)
| 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)
| 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)
| 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();
// Instance Methods
public Component add (Component component);
public Component add (Component component, int position);
public void add (Component comp, Object constraints);
public void add (Component comp, Object constraints,
int position);
public Component add (String name, Component component);
public synchronized void addContainerListener (ContainerListener l);
public void addNotify();
public int countComponents();
public void deliverEvent (Event e);
public void doLayout();
public float getAlignmentX();
public float getAlignmentY();
public Component getComponent (int n);
public Component getComponentAt (int x, int y);
public Component getComponentAt (Point p);
public int getComponentCount();
public Component[] getComponents();
public Insets getInsets();
public LayoutManager getLayout();
public Dimension getMaximumSize();
public Dimension getMinimumSize();
public Dimension getPreferredSize();
public Insets insets();
public void invalidate();
public boolean isAncestorOf (Component c);
public void layout();
public void list (PrintStream out, int indentation);
public void list (PrintWriter out, int indentation);
public Component locate (int x, int y);
public Dimension minimumSize();
public void paint (Graphics g);
public void paintComponents (Graphics g);
public Dimension preferredSize();
public void print (Graphics g);
public void printComponents (Graphics g);
public void remove (int index);
public void remove (Component component);
public void removeAll();
public void removeContainerListener (ContainerListener l);
public void removeNotify();
public void setLayout (LayoutManager manager);
public void validate();
// Protected Instance Methods
protected void addImpl (Component comp, Object constraints,
int index);
protected String paramString();
protected void processContainerEvent (ContainerEvent e);
protected void processEvent (AWTEvent e);
protected void validateTree();
}
Constructors
Container
protected Container()
| 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)
addContainerListener
public synchronized void addContainerListener (ContainerListener l)
| 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)
| 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()
| Description | Lays out the container. This method is a replacement for layout(). |
getAlignmentX
public float getAlignmentX()
| 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()
| 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)
| 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) |
||
| 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()
| 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()
| Overrides | Component.getMaximumSize() |
| Returns | The maximum dimensions of the component. |
getMinimumSize
public Dimension getMinimumSize()
| Overrides | Component.getMinimumSize() |
| Returns | The minimum dimensions of the component. |
getPreferredSize
public Dimension getPreferredSize()
| Returns | The preferred dimensions of the component. |
insets
public Insets insets()
| 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)
| Parameters | c | The component in question. |
| Returns | If c is contained in the container's hierarchy, returns true; otherwise false. | |
layout
public void layout()
| 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)
| 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()
| 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()
| Returns | Preferred dimensions of contained objects. |
| Overrides | Component.preferredSize() |
| Description | Replaced by getPreferredSize(). |
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)
| 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)
| 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)
| 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)
| 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)
| Parameters | e | The event to process. |
| Overrides | Component.processEvent() | |
| Description | Low level AWTEvents are passed to this method for processing. | |
validateTree
protected void validateTree()
| 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
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
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);
public Dialog (Frame parent, boolean modal);
public Dialog (Frame parent, String title);
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);
public synchronized void setResizable (boolean resizable);
public synchronized void setTitle (String title);
public void show();
// Protected Instance Methods
protected String paramString();
}
Constructors
Dialog
public Dialog (Frame parent)
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)
| 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()
| 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
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);
public Dimension getSize();
public void setSize (Dimension d);
public void setSize (int width, int height);
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()
Instance Methods
equals
public boolean equals (Object obj)
| 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()
| Returns | The size of the Dimension. |
setSize
public void setSize (Dimension d)
| Parameters | d | The new size. |
| Description | Changes the size of the Dimension. | |
| public void setSize (int width, int height) |
||
| 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
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;
public static final int CAPS_LOCK;
public static final int CTRL_MASK;
public static final int DELETE;
public static final int DOWN;
public static final int END;
public static final int ENTER;
public static final int ESCAPE;
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;
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;
public static final int PAUSE;
public static final int PGDN;
public static final int PGUP;
public static final int PRINT_SCREEN;
public static final int RIGHT;
public static final int SAVE_FILE;
public static final int SCROLL_ABSOLUTE;
public static final int SCROLL_BEGIN;
public static final int SCROLL_END;
public static final int SCROLL_LINE_DOWN;
public static final int SCROLL_LINE_UP;
public static final int SCROLL_LOCK;
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;
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
ID constant for Backspace.
CAPS_LOCK
public static final int CAPS_LOCK
ID constant for Caps Lock key.
CTRL_MASK
public static final int CTRL_MASK
Mask for Control key.
DELETE
public static final int DELETE
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
ID constant for Enter key.
ESCAPE
public static final int ESCAPE
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
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
ID constant for Num Lock key.
PAUSE
public static final int PAUSE
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
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
ID constant for Begin Scroll Event.
SCROLL_END
public static final int SCROLL_ END
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
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
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
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
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
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);
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);
// 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)
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)
| 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
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();
public int getHgap();
public int getVgap();
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);
public void setHgap (int hgap);
public void setVgap (int vgap);
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()
| Returns | The alignment constant for this FlowLayout. |
getHgap
public int getHgap()
| Returns | The horizontal gap between components. |
getVgap
public int getVgap()
| 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)
| Parameters | alignment | Alignment of components within container |
| Description | Sets the alignment for the FlowLayout. | |
setHgap
public void setHgap(int hgap)
| Parameters | hgap | The horizontal gap value. |
| Description | Sets the horizontal gap between components. | |
setVgap
public void setVgap(int vgap)
| 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
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);
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();
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)
| 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()
| 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
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)
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
| Returns | A string representation of the FontMetrics object. |
| Overrides | Object.toString() |
See Also
Font, Object, String
19.26 Frame
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();
public Image getIconImage();
public MenuBar getMenuBar();
public String getTitle();
public boolean isResizable();
public synchronized void remove (MenuComponent component);
public synchronized void setCursor (int cursorType);
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
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
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()
| 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)
| 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
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);
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);
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);
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();
public abstract Rectangle getClipBounds();
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);
public abstract void setClip (Shape clip);
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)
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)
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)
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 ()
| Returns | Shape describing the clipping are of the graphics context. |
getClipBounds
public abstract Rectangle getClipBounds()
| Returns | Rectangle describing the clipping area of the graphics context. |
getClipRect
public abstract Rectangle getClipRect()
| 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
| 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) |
||
| 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
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
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
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);
public void addLayoutComponent (String name, Component component);
public GridBagConstraints getConstraints (Component component);
public abstract float getLayoutAlignmentX(Container target);
public abstract float getLayoutAlignmentY(Container target);
public int[][] getLayoutDimensions();
public Point getLayoutOrigin();
public double[][] getLayoutWeights();
public abstract void invalidateLayout(Container target);
public void layoutContainer (Container target);
public Point location (int x, int y);
public abstract Dimension maximumLayoutSize(Container target);
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)
| 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)
| 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
| 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)
| 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)
| 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
| 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
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();
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();
public int getHgap();
public int getRows();
public int getVgap();
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);
public int setHgap(int hgap);
public int setRows(int rows);
public int setVgap(int vgap);
public String toString();
}
Constructors
GridLayout
public GridLayout()
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()
| Returns | The number of columns. |
getHgap
public int getHgap()
| Returns | The horizontal gap for this GridLayout instance. |
getRows
public int getRows()
| Returns | The number of rows. |
getVgap
public int getVgap()
| 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)
| Parameters | cols | The new number of columns. |
| Description | Sets the number of columns. | |
setHgap
public void setHgap(int hgap)
| Parameters | hgap | The horizontal gap value. |
| Description | Sets the horizontal gap between components. | |
setRows
public void setRows(int rows)
| Parameters | rows | The new number of rows. |
| Description | Sets the number of rows. | |
setVgap
public void setVgap(int vgap)
| 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
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
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;
public final static int SCALE_DEFAULT;
public final static int SCALE_FAST;
public final static int SCALE_REPLICATE;
public final static int SCALE_SMOOTH;
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);
public abstract ImageProducer getSource();
public abstract int getWidth (ImageObserver observer);
}
Constants
SCALE_AREA_AVERAGING
public final static int SCALE_AREA_AVERAGING
Flag that requests use of AreaAveragingScaleFilter.
SCALE_DEFAULT
public final static int SCALE_DEFAULT
Flag that requests use of the default image scaling algorithm.
SCALE_FAST
public final static int SCALE_FAST
Flag that requests use of an image scaling algorithm that is faster rather than smoother.
SCALE_REPLICATE
public final static int SCALE_REPLICATE
Flag that requests use of ReplicateScaleFilter.
SCALE_SMOOTH
public final static int SCALE_SMOOTH
Flag that requests use of an image scaling algorithm that is smoother rather than faster.
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)
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
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);
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)
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)
| 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
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);
}
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.
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
| 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
| 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); }
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)
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
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
| 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
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);
public List (int rows, boolean multipleSelections);
// Instance Methods
public void add (String item);
public synchronized void add (String item, int index);
public void addActionListener (ActionListener l);
public void addItem (String item);
public synchronized void addItem (String item, int index);
public void addItemListener (ItemListener l);
public void addNotify();
public boolean allowsMultipleSelections();
public synchronized void clear();
public int countItems();
public synchronized void delItem (int position);
public synchronized void delItems (int start, int end);
public synchronized void deselect (int index);
public String getItem (int index);
public int getItemCount();
public synchronized String[] getItems();
public Dimension getMinimumSize();
public Dimension getMinimumSize (int rows);
public Dimension getPreferredSize();
public Dimension getPreferredSize (int rows);
public int getRows();
public synchronized int getSelectedIndex();
public synchronized int[] getSelectedIndexes();
public synchronized String getSelectedItem();
public synchronized String[] getSelectedItems();
public Object[] getSelectedObjects();
public int getVisibleIndex();
public boolean isIndexSelected(int index);
public boolean isMultipleMode();
public boolean isSelected (int index);
public synchronized void makeVisible (int index);
public Dimension minimumSize();
public Dimension minimumSize (int rows);
public Dimension preferredSize();
public Dimension preferredSize (int rows);
public synchronized void remove (int position);
public synchronized void remove (String item);
public void removeActionListener (ActionListener l);
public synchronized void removeAll();
public void removeItemListener (ItemListener l);
public void removeNotify();
public synchronized void replaceItem (String newItem, int index);
public synchronized void select (int position);
public synchronized void setMultipleMode (boolean b);
public synchronized void setMultipleSelections (boolean value);
// Protected Instance Methods
protected String paramString();
protected void processActionEvent (ActionEvent e);
protected void processEvent (AWTEvent e);
protected void processItemEvent (ItemEvent e);
}
Constructors
List
public List()
| Description | Constructs a List object in single-selection mode. | |
| public List (int rows) |
||
| 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)
| Parameters | item | Text for entry to add. |
| Description | Adds a new entry to the available choices. | |
| public synchronized void add (String item, int index) |
||
| 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)
| 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) |
||
| 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)
| 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()
| Returns | true if multi-selection active, false otherwise. Replaced by isMultipleMode(). |
clear
public synchronized void clear()
| Description | Clears all the entries out of the List. Replaced by removeAll(). |
countItems
public int countItems()
| 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)
| 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()
| Returns | Number of items in the List. |
getItems
public String[] getItems()
| Returns | The string items in the List. |
getMinimumSize
public Dimension getMinimumSize()
| Returns | The minimum dimensions of the List. | |
| public Dimension getMinimumSize (int rows) |
||
| Parameters | rows | Number of rows within List to size. |
| Returns | The minimum dimensions of a List of the given size. | |
getPreferredSize
public Dimension getPreferredSize()
| Returns | The preferred dimensions of the List. | |
| public Dimension getPreferredSize (int rows) |
||
| 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()
| 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)
| 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()
| Returns | true if multiple selection is allowed, false otherwise. |
isSelected
public boolean isSelected (int index)
| 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()
preferredSize
public Dimension preferredSize()
| Returns | The preferred dimensions of the List. Replaced by getPreferredSize(). | |
| public Dimension preferredSize (int rows) |
||
| 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)
| Parameters | position | Position of item to remove. |
| Description | Removes a single entry from the List. | |
| public synchronized void remove (String item) |
||
| 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)
| Parameters | l | One of this List's ActionListeners. |
| Description | Remove an action event listener. | |
removeAll
public synchronized removeAll()
| Description | Removes all items from the List. |
removeItemListener
public void removeItemListener (ItemListener l)
| 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)
| 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)
| 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)
| 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)
| Parameters | e | The event to process. |
| Description | Low-level AWTEvents are passed to this method for processing. | |
processItemEvent
protected void processItemEvent(ItemEvent e)
| 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
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);
public synchronized void removeImage(Image image, int id);
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)
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)
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
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
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();
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();
public MenuItem getItem (int index);
public int getItemCount();
public void insert (String label, int index);
public synchronized void insert (MenuItem menuitem, int index);
public void insertSeparator (int index);
public boolean isTearOff();
public String paramString();
public synchronized void remove (int index);
public synchronized void remove (MenuComponent component);
public synchronized void removeAll();
public void removeNotify();
}
Constructors
Menu
public Menu()
| 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()
| 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()
| Returns | The number of items on the menu. |
insert
public void insert (String label, int index)
| 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) |
||
| 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)
| 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()
| 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)
removeAll
public synchronized void removeAll()
| 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
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();
public void deleteShortcut (MenuShortcut s);
public Menu getHelpMenu();
public Menu getMenu (int index);
public int getMenuCount();
public MenuItem getShortcutMenuItem (MenuShortcut s);
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();
}
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()
| Returns | The number of menus on the menu bar. Replaced by getMenuCount(). |
deleteShortcut
public void deleteShortcut (MenuShortcut s)
| 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()
| Returns | The number of menus on the menu bar. |
getShortcutMenuItem
public MenuItem getShortcutMenuItem (MenuShortcut s)
| 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()
| 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
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);
public Font getFont();
public String getName();
public MenuContainer getParent();
public MenuComponentPeer getPeer();
public boolean postEvent (Event e);
public void removeNotify();
public void setFont (Font f);
public void setName (String name);
public String toString();
// Protected Instance Methods
protected String paramString();
protected void processEvent (AWTEvent e);
}
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()
| Returns | The name for the current MenuComponent. |
getParent
public MenuContainer getParent()
| Returns | The parent MenuContainer for the MenuComponent. |
getPeer
public MenuComponentPeer getPeer()
| Returns | A reference to the MenuComponent's peer. |
postEvent
public boolean postEvent (Event e)
| 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)
| 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()
| 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)
| 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
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);
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)
| 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
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();
public MenuItem (String label);
public MenuItem (String label, MenuShortcut s);
// Instance Methods
public void addActionListener (ActionListener l);
public void addNotify();
public void deleteShortcut();
public synchronized void disable();
public synchronized void enable();
public void enable (boolean condition);
public String getActionCommand();
public String getLabel();
public MenuShortcut getShortcut();
public boolean isEnabled();
public String paramString();
public void removeActionListener (ActionListener l);
public void setActionCommand (String command);
public synchronized void setEnabled (boolean b);
public synchronized void setLabel (String label);
public void setShortcut (MenuShortcut s);
// Protected Instance Methods
protected final void disableEvents (long eventsToDisable);
protected final void enableEvents (long eventsToEnable);
protected void processActionEvent (ActionEvent e);
protected void processEvent (AWTEvent e);
}
Constructors
MenuItem
public MenuItem()
| 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) |
||
| 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)
| 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()
| Description | Removes the shortcut associated with this item. |
disable
public synchronized void disable()
| Description | Disables the menu component so that it is unresponsive to user interactions. Replaced by setEnabled(false). |
enable
public synchronized void enable()
| Description | Enables the menu component so that it is responsive to user interactions. Replaced by setEnabled(true). | |
| public void enable (boolean condition) |
||
| 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()
| 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()
| 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)
| Parameters | l | One of this Button's ActionListeners. |
| Description | Remove an action event listener. | |
setActionCommand
public void setActionCommand(String command)
| Parameters | command | New action command string. |
| Description | Specify the string used for the action command. | |
setEnabled
public synchronized void setEnabled (boolean b)
| 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)
| Parameters | s | New shortcut for the MenuItem. |
| Description | Changes the shortcut of the MenuItem. | |
Protected Instance Methods
disableEvents
protected final void disableEvents (long eventsToDisable)
| 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)
| 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)
| 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)
| 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
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)
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
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);
// Instance Methods
public void addNotify();
}
Constructors
Panel
public Panel()
| Description | Constructs a Panel object. |
| public Panel (LayoutManager layout) |
|
| 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
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();
public Point (int width, int height);
public Point (Point p);
// Instance Methods
public boolean equals (Object object);
public Point getLocation();
public int hashCode();
public void move (int x, int y);
public void setLocation (int x, int y);
public void setLocation (Point p);
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()
| 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) |
||
| 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()
| 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)
| 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) |
||
| 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
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;
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);
public boolean contains (Point p);
public Rectangle getBoundingBox();
public Rectangle getBounds();
public boolean inside (int x,int y);
public void translate (int deltaX, int deltaY);
}
Variables
bounds
protected Rectangle bounds
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)
| 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) |
||
| Parameters | p | The point to be tested. |
| Returns | true if the Polygon contains the point; false otherwise. | |
getBoundingBox
public Rectangle getBoundingBox()
| 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()
| 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)
| 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)
| 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
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
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
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
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);
// 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);
public boolean contains (Point p);
public boolean equals (Object object);
public Rectangle getBounds();
public Point getLocation();
public Dimension getSize();
public void grow (int horizontal, int vertical);
public int hashCode();
public boolean inside (int x, int y);
public Rectangle intersection (Rectangle r);
public boolean intersects (Rectangle r);
public boolean isEmpty();
public void move (int x, int y);
public void reshape (int x, int y, int width, int height);
public void resize (int width, int height);
public void setBounds (Rectangle r);
public void setBounds (int x, int y, int width, int height);
public void setLocation (int x, int y);
public void setLocation (Point p);
public void setSize (int width, int height);
public void setSize (Dimension d);
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()
Instance Methods
add
public void add (int newX, int newY)
contains
public boolean contains (int x, int y)
| 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) |
||
| 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()
| Implements | Shape.getBounds() |
| Returns | Bounding Rectangle. |
getLocation
public Point getLocation()
| Returns | Position of the rectangle. |
| Description | Gets the current position of this Rectangle. |
getSize
public Dimension getSize()
| 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)
| 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)
| 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)
resize
public void resize (int width, int height)
| 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)
| 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)
| Parameters | x | New horizontal position. |
| y | New vertical position. | |
| Description | Relocates the rectangle. | |
| public void setLocation (Point p) |
||
| Parameters | p | New position for component. |
| Description | Relocates the rectangle. | |
setSize
public void setSize (int width, int height)
| Parameters | width | New width. |
| height | New height. | |
| Description | Resizes the rectangle. | |
| public void setSize (Dimension d) |
||
| 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
Description
The ScrollPane class provides automatic scrolling of a child component.
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();
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)
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()
| 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
| 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
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);
public void addNotify();
public int getBlockIncrement();
public int getLineIncrement();
public int getMaximum();
public int getMinimum();
public int getOrientation();
public int getPageIncrement();
public int getUnitIncrement();
public int getValue();
public int getVisible();
public int getVisibleAmount();
public void removeAdjustmentListener (AdjustmentListener l);
public synchronized void setBlockIncrement (int v);
public void setLineIncrement (int amount);
public synchronized void setMaximum (int newMaximum);
public synchronized void setMinimum (int newMinimum);
public synchronized void setOrientation (int orientation);
public void setPageIncrement (int amount);
public synchronized void setUnitIncrement(int v);
public synchronized void setValue (int value);
public synchronized void setValues (int value, int visible,
int minimum, int maximum);
public synchronized void setVisibleAmount (int newAmount);
// Protected Instance Methods
protected String paramString();
protected void processAdjustmentEvent (AdjustmentEvent e);
protected void processEvent (AWTEvent e);
}
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
| 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()
| Implements | Adjustable.getBlockIncrement() |
| Returns | The amount to scroll when a paging area is selected. |
getLineIncrement
public int getLineIncrement()
| 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()
| Returns | The amount to scroll when a paging area is selected. Replaced with getBlockIncrement(). |
getUnitIncrement
public int getUnitIncrement()
| 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()
| Returns | The current visible setting (i.e., size) for the slider. Replaced by getVisibleAmount(). |
getVisibleAmount
public int getVisibleAmount()
| Implements | Adjustable.getVisibleAmount() |
| Returns | The current visible setting (i.e., size) for the slider. |
removeAdjustmentListener
public void removeAdjustmentListener (AdjustmentListener
l)
| Parameters | l | One of this Scrollbar's AdjustmentListeners. |
| Implements | Adjustable.removeAdjustmentListener() | |
| Description | Remove an adjustment event listener. | |
setBlockIncrement
| 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)
| 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)
| Parameters | newMaximum | New maximum value. |
| Implements | Adjustable.setMaximum() | |
| Description | Changes the maximum value for the Scrollbar. | |
setMinimum
public synchronized void setMinimum (int newMinimum)
| Parameters | newMinimum | New minimum value. |
| Implements | Adjustable.setMinimum() | |
| Description | Changes the minimum value for the Scrollbar. | |
setOrientation
public synchronized void setOrientation (int orientation)
| Parameters | orientation | One of the orientation constants HORIZONTAL or VERTICAL. |
| Description | Changes the orientation of the Scrollbar. | |
setPageIncrement
public void setPageIncrement (int amount)
| 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)
| 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)
| 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)
| 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)
| 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
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
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
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
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
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;
public final static int SCROLLBARS_HORIZONTAL_ONLY;
public final static int SCROLLBARS_NONE;
public final static int SCROLLBARS_VERTICAL_ONLY;
// 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);
// Instance Methods
public void addNotify();
public synchronized void append (String string);
public void appendText (String string);
public int getColumns();
public Dimension getMinimumSize();
public Dimension getMinimumSize (int rows, int columns);
public Dimension getPreferredSize();
public Dimension getPreferredSize (int rows, int columns);
public int getRows();
public int getScrollbarVisibility();
public synchronized void insert (String string, int position);
public void insertText (String string, int position);
public Dimension minimumSize();
public Dimension minimumSize (int rows, int columns);
public Dimension preferredSize();
public Dimension preferredSize (int rows, int columns);
public synchronized void replaceRange (String str, int start, int end);
public void replaceText (String string, int startPosition, int endPosition);
public void setColumns (int columns);
public void setRows (int rows);
// Protected Instance Methods
protected String paramString();
}
Constants
SCROLLBARS_BOTH
public final static int SCROLLBARS_BOTH
Show both the horizontal and vertical scrollbars.
SCROLLBARS_HORIZONTAL_ONLY
public final static int SCROLLBARS_HORIZONTAL_ONLY
Show the horizontal scrollbar.
SCROLLBARS_NONE
Show no scrollbars.
SCROLLBARS_VERTICAL_ONLY
public final static int SCROLLBARS_VERTICAL_ONLY
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) |
||
| 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)
| 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)
| 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()
| Returns | The minimum dimensions of the TextArea. | |
| public Dimension getMinimumSize (int rows, int columns) |
||
| 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()
getRows
public int getRows()
| Returns | The height of the TextArea in rows. |
getScrollbarVisibility
public int getScrollbarVisibility()
| Returns | One of the SCROLLBAR_ constants indicating which scrollbars are visible. |
insert
public synchronized void insert (String string, int
position)
| 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)
| 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()
| Returns | The minimum dimensions of the TextArea. Replaced by getMinimumSize(). | |
| public Dimension minimumSize (int rows, int columns) |
||
| 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()
| Returns | The preferred dimensions of the TextArea. Replaced by getPreferredSize(). | |
| public Dimension preferredSize (int rows, int columns) |
||
| 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)
| 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)
| 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)
| 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)
| 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
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);
public int getCaretPosition();
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);
public synchronized void select (int selectionStart, int selectionEnd);
public synchronized void selectAll();
public void setCaretPosition (int position);
public synchronized void setEditable (boolean state);
public synchronized void setSelectionEnd (int selectionEnd);
public synchronized void setSelectionStart (int selectionStart);
public synchronized void setText (String text);
// Protected Instance Methods
protected String paramString();
protected void processEvent (AWTEvent e);
protected void processTextEvent (TextEvent e);
}
Instance Methods
addTextListener
public synchronized void addTextListener (TextListener l)
| Parameters | l | An object that implements the TextListener interface. |
| Description | Add a listener for the text events. | |
getCaretPosition
public int getCaretPosition()
| 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)
| 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)
| 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)
| 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)
| 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)
| Parameters | e | The event to process. |
| Description | Low-level AWTEvents are passed to this method for processing. | |
processTextEvent
protected void processTextEvent (TextEvent e)
| 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
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);
public void addNotify();
public boolean echoCharIsSet();
public int getColumns();
public char getEchoChar();
public Dimension getMinimumSize();
public Dimension getMinimumSize (int columns);
public Dimension getPreferredSize();
public Dimension getPreferredSize (int columns);
public Dimension minimumSize();
public Dimension minimumSize (int columns);
public Dimension preferredSize();
public Dimension preferredSize (int columns);
public void removeActionListener (ActionListener l);
public void setColumns(int columns);
public void setEchoChar(char c);
public void setEchoCharacter (char c);
// Protected Instance Methods
protected String paramString();
protected void processActionEvent (ActionEvent e);
protected void processEvent (AWTEvent e);
}
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)
| 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()
| Returns | The minimum dimensions of the TextField. | |
| public Dimension getMinimumSize (int columns) |
||
| Parameters | columns | Number of columns within TextField to size. |
| Returns | The minimum dimensions of a TextField of the given size. | |
getPreferredSize
public Dimension getPreferredSize()
| Returns | The preferred dimensions of the TextField. | |
| public Dimension getPreferredSize (int columns) |
||
| Parameters | columns | Number of columns within TextField to size. |
| Returns | The preferred dimensions of a TextField of the given size. | |
minimumSize
public Dimension minimumSize()
| Returns | The minimum dimensions of the TextField. Replaced by getMinimumSize(). | |
| public Dimension minimumSize (int columns) |
||
| 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()
| Returns | The preferred dimensions of the TextField. Replaced by getPreferredSize(). | |
| public Dimension preferredSize (int columns) |
||
| 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)
| Parameters | l | One of this TextField's ActionListeners. |
| Description | Remove an action event listener. | |
setColumns
public void setColumns (int columns)
| 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)
setEchoCharacter
public void setEchoCharacter (char c)
| 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)
| 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)
| 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
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);
public static String getProperty (String key, String defaultValue);
// Instance Methods
public abstract void beep();
public abstract int checkImage (Image image, int width, int height,
ImageObserver observer);
public abstract Image createImage (ImageProducer producer);
public Image createImage (byte[] imagedata);
public abstract Image createImage (byte[ ] imagedata, int imageoffset,
int imagelength);
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();
public abstract PrintJob getPrintJob (Frame frame, String jobtitle,
Properties props);
public abstract int getScreenResolution();
public abstract Dimension getScreenSize();
public abstract Clipboard getSystemClipboard();
public final EventQueue getSystemEventQueue();
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);
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);
protected abstract ScrollPanePeer createScrollPane (ScrollPane target);
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);
protected abstract EventQueue getSystemEventQueueImpl();
protected void loadSystemColors (int[] systemColors);
}
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)
| Returns | The native container for the given component. The component's immediate parent may be a lightweight component. |
getProperty
| 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()
| 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)
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()
| 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)
| 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()
| Returns | A Clipboard object that can be used for cut, copy, and paste operations. |
getSystemEventQueue
public final EventQueue getSystemEventQueue()
| Returns | A reference to the system's event queue, allowing the program to post new events or inspect the queue. |
prepareImage
| 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)
| 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
| 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)
| 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)
| 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)
| 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()
| Returns | A toolkit-specific EventQueue object. |
loadSystemColors
protected abstract void loadSystemColors
(int[] systemColors)
| 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
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);
public void dispose();
public Component getFocusOwner();
public Locale getLocale();
public Toolkit getToolkit();
public final String getWarningString();
public boolean isShowing();
public void pack();
public boolean postEvent (Event e);
public synchronized void remove WindowListener (WindowListener l);
public void show();
public void toBack();
public void toFront();
//Protected Instance Methods
protected void processEvent (AWTEvent e);
protected void processWindowEvent (WindowEvent e);
}
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)
| Parameters | l | One of this Frame's WindowListeners. |
| Description | Remove an event listener. | |
addWindowListener
public synchronized void addWindowListener (WindowListener
l)
| 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()
| Returns | The child component that currently has the input focus. |
getLocale
| 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)
| 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)
| 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)
| Parameters | e | The event to process. |
| Description | Low level AWTEvents are passed to this method for processing. | |
processWindowEvent
protected void processWindowEvent (WindowEvent e)
| 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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