test.java

《Java2图形设计卷II：Swing》配套光盘源码

import javax.swing.*;
import javax.swing.event.*;
import javax.swing.tree.*;
import java.awt.*;
import java.awt.event.*;

public class Test extends JFrame { 
	public Test() { 
		JTree tree = new JTree();
		getContentPane().add(tree);

		tree.addTreeWillExpandListener(
									new TreeWillExpandListener() {
			public void treeWillExpand(TreeExpansionEvent e) 
									  throws ExpandVetoException {
				TreePath path = e.getPath();
				TreeNode node = (TreeNode)
								path.getLastPathComponent();

				if(node.toString().equals("colors")) {
					JOptionPane.showMessageDialog(Test.this,
								"Can't Expand Colors",
								"Expansion Vetoed",
								JOptionPane.INFORMATION_MESSAGE);

					throw new ExpandVetoException(e); 
				}
			}
			public void treeWillCollapse(TreeExpansionEvent e) 
									  throws ExpandVetoException {
				TreePath path = e.getPath();
				TreeNode node = (TreeNode)
								path.getLastPathComponent();

				if(node.toString().equals("food")) {
					JOptionPane.showMessageDialog(Test.this,
								"Can't Collapse Food",
								"Collapse Vetoed",
								JOptionPane.INFORMATION_MESSAGE);

					throw new ExpandVetoException(e); 
				}
			}
		});
	}
	public static void main(String args[]) {
		GraphicJavaApplication.launch(new Test(), 
			"Vetoing Node Expansion/Collapse",300,300,300,200);
	}
}
class GraphicJavaApplication extends WindowAdapter {
	public static void launch(final JFrame f, String title,
							  final int x, final int y, 
							  final int w, int h) {
		f.setTitle(title);
		f.setBounds(x,y,w,h);
		f.setVisible(true);

		f.setDefaultCloseOperation(
							WindowConstants.DISPOSE_ON_CLOSE);

		f.addWindowListener(new WindowAdapter() {
			public void windowClosed(WindowEvent e) {
				System.exit(0);
			}
		});
	}
}