Lazy UIResources : UIManager « Swing « Java Tutorial

1. Java Tutorial
2. Swing
3. UIManager

import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Component;
import java.awt.Graphics;
import java.awt.Polygon;

import javax.swing.Icon;
import javax.swing.JFrame;
import javax.swing.JScrollPane;
import javax.swing.JTree;
import javax.swing.UIDefaults;
import javax.swing.UIManager;

public class LazySample {
  public static void main(String args[]) {
    JFrame frame = new JFrame("Lazy Example");
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

    Integer fifteen = new Integer(15);
    Object lazyArgs[] = new Object[] { Color.GREEN, Boolean.TRUE, fifteen, fifteen };
    Object lazyDiamond = new UIDefaults.ProxyLazyValue("MyIcon", lazyArgs);
    UIManager.put("Tree.openIcon", lazyDiamond);

    JTree tree = new JTree();
    JScrollPane scrollPane = new JScrollPane(tree);

    frame.add(scrollPane, BorderLayout.CENTER);
    frame.setSize(200, 200);
    frame.setVisible(true);
  }
}

class MyIcon implements Icon {
  public MyIcon(Object obj) {
  }
  public int getIconHeight() {
    return 20;
  }
  public int getIconWidth() {
    return 20;
  }
  public void paintIcon(Component c, Graphics g, int x, int y) {
    g.setColor(Color.RED);
    g.fillRect(1,1,20,20);
  }
}

14.122.UIManager
	14.122.1.	UIResource Collection
	14.122.2.	Lazy UIResources
	14.122.3.	Active UIResources
	14.122.4.	Retrieve information of all available UIManager defaults