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import java.awt.Component;
import java.awt.Graphics;
import javax.swing.Icon;
import javax.swing.ImageIcon;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JTabbedPane;
public class ProxyTester {
public static void main(String[] args) {
JTabbedPane tabbedPane = new JTabbedPane();
for (String name : imageNames) {
JLabel label = new JLabel(new ImageProxy(name));
tabbedPane.add(name, label);
}
JFrame frame = new JFrame();
frame.add(tabbedPane);
frame.setSize(FRAME_WIDTH, FRAME_HEIGHT);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setVisible(true);
}
private static final String[] imageNames = { "A.gif", "B.gif",
"C.gif", "D.gif", "E.gif" };
private static final int FRAME_WIDTH = 500;
private static final int FRAME_HEIGHT = 300;
}
class ImageProxy implements Icon {
public ImageProxy(String name) {
this.name = name;
image = null;
}
public void paintIcon(Component c, Graphics g, int x, int y) {
ensureImageLoaded();
image.paintIcon(c, g, x, y);
}
public int getIconWidth() {
ensureImageLoaded();
return image.getIconWidth();
}
public int getIconHeight() {
ensureImageLoaded();
return image.getIconHeight();
}
private void ensureImageLoaded() {
if (image == null) {
System.out.println("Loading " + name);
image = new ImageIcon(name);
}
}
private String name;
private ImageIcon image;
}
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