Design Patterns Java™ Workbook

Proxy (Chapter 11)

SOLUTION 11.1

The image-display methods of ImageIconProxy forward their calls to the current image: public int getIconHeight() { return current.getIconHeight(); } public int getIconWidth() { return current.getIconWidth(); } public synchronized void paintIcon( Component c, Graphics g, int x, int y) { current.paintIcon(c, g, x, y); }

SOLUTION 11.2

The load() method sets the image to Loading…, whereas the run() method, executing in a separate thread, loads the desired image: public void load(JFrame callbackFrame) { this.callbackFrame = callbackFrame; setImage(LOADING.getImage()); callbackFrame.repaint(); new Thread(this).start(); } public void run() { setImage(new ImageIcon(filename).getImage()); callbackFrame.pack(); }