// Demonstrate JTree.

import java.awt.*;

import javax.swing.event.*;

import javax.swing.*;

import javax.swing.tree.*;

/*

<applet code="JTreeDemo" width=400 height=200>

</applet>

*/

public class JTreeDemo extends JApplet {

JTree tree;

JLabel jlab;

public void init() {

try {

SwingUtilities.invokeAndWait(

new Runnable() {

public void run() {

makeGUI();

}

}

);

} catch (Exception exc) {

System.out.println("Can't create because of " + exc);

}

}

private void makeGUI() {

// Create top node of tree.

DefaultMutableTreeNode top = new DefaultMutableTreeNode("Options");

// Create subtree of "A".

DefaultMutableTreeNode a = new DefaultMutableTreeNode("A");

top.add(a);

DefaultMutableTreeNode a1 = new DefaultMutableTreeNode("A1");

a.add(a1);

DefaultMutableTreeNode a2 = new DefaultMutableTreeNode("A2");

a.add(a2);

// Create subtree of "B".

DefaultMutableTreeNode b = new DefaultMutableTreeNode("B");

top.add(b);

DefaultMutableTreeNode b1 = new DefaultMutableTreeNode("B1");

b.add(b1);

DefaultMutableTreeNode b2 = new DefaultMutableTreeNode("B2");

b.add(b2);

DefaultMutableTreeNode b3 = new DefaultMutableTreeNode("B3");

b.add(b3);

// Create the tree.

tree = new JTree(top);

// Add the tree to a scroll pane.

JScrollPane jsp = new JScrollPane(tree);

// Add the scroll pane to the content pane.

add(jsp);

// Add the label to the content pane.

jlab = new JLabel();

add(jlab, BorderLayout.SOUTH);

// Handle tree selection events.

tree.addTreeSelectionListener(new TreeSelectionListener() {

public void valueChanged(TreeSelectionEvent tse) {

jlab.setText("Selection is " + tse.getPath());

}

});

}

}