TreeExpandSample.java Source code

Introduction

Here is the source code for TreeExpandSample.java

Source

import java.awt.BorderLayout;

import javax.swing.JFrame;
import javax.swing.JScrollPane;
import javax.swing.JTree;
import javax.swing.event.TreeExpansionEvent;
import javax.swing.event.TreeWillExpandListener;
import javax.swing.tree.DefaultMutableTreeNode;
import javax.swing.tree.ExpandVetoException;
import javax.swing.tree.TreePath;

public class TreeExpandSample {
    public static void main(String args[]) {
        String title = ("JTree Expand Sample");
        JFrame frame = new JFrame(title);
        JTree tree = new JTree();
        TreeWillExpandListener treeWillExpandListener = new TreeWillExpandListener() {
            public void treeWillCollapse(TreeExpansionEvent treeExpansionEvent) throws ExpandVetoException {
                TreePath path = treeExpansionEvent.getPath();
                DefaultMutableTreeNode node = (DefaultMutableTreeNode) path.getLastPathComponent();
                String data = node.getUserObject().toString();
                if (data.equals("colors")) {
                    throw new ExpandVetoException(treeExpansionEvent);
                }
            }

            public void treeWillExpand(TreeExpansionEvent treeExpansionEvent) throws ExpandVetoException {
                TreePath path = treeExpansionEvent.getPath();
                DefaultMutableTreeNode node = (DefaultMutableTreeNode) path.getLastPathComponent();
                String data = node.getUserObject().toString();
                if (data.equals("sports")) {
                    throw new ExpandVetoException(treeExpansionEvent);
                }
            }
        };
        tree.addTreeWillExpandListener(treeWillExpandListener);
        JScrollPane scrollPane = new JScrollPane(tree);
        frame.getContentPane().add(scrollPane, BorderLayout.CENTER);
        frame.setSize(300, 150);
        frame.setVisible(true);
    }
}