TreeEditTest.java Source code

Introduction

Here is the source code for TreeEditTest.java

Source

/*
   This program is a part of the companion code for Core Java 8th ed.
   (http://horstmann.com/corejava)
    
   This program is free software: you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation, either version 3 of the License, or
   (at your option) any later version.
    
   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.
    
   You should have received a copy of the GNU General Public License
   along with this program.  If not, see <http://www.gnu.org/licenses/>.
*/

import java.awt.BorderLayout;
import java.awt.EventQueue;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTree;
import javax.swing.tree.DefaultMutableTreeNode;
import javax.swing.tree.DefaultTreeModel;
import javax.swing.tree.TreeNode;
import javax.swing.tree.TreePath;

/**
 * This program demonstrates tree editing.
 * @version 1.03 2007-08-01
 * @author Cay Horstmann
 */
public class TreeEditTest {
    public static void main(String[] args) {
        EventQueue.invokeLater(new Runnable() {
            public void run() {
                JFrame frame = new TreeEditFrame();
                frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
                frame.setVisible(true);
            }
        });
    }
}

/**
 * A frame with a tree and buttons to edit the tree.
 */
class TreeEditFrame extends JFrame {
    public TreeEditFrame() {
        setTitle("TreeEditTest");
        setSize(DEFAULT_WIDTH, DEFAULT_HEIGHT);

        // construct tree

        TreeNode root = makeSampleTree();
        model = new DefaultTreeModel(root);
        tree = new JTree(model);
        tree.setEditable(true);

        // add scroll pane with tree

        JScrollPane scrollPane = new JScrollPane(tree);
        add(scrollPane, BorderLayout.CENTER);

        makeButtons();
    }

    public TreeNode makeSampleTree() {
        DefaultMutableTreeNode root = new DefaultMutableTreeNode("World");
        DefaultMutableTreeNode country = new DefaultMutableTreeNode("USA");
        root.add(country);
        DefaultMutableTreeNode state = new DefaultMutableTreeNode("California");
        country.add(state);
        DefaultMutableTreeNode city = new DefaultMutableTreeNode("San Jose");
        state.add(city);
        city = new DefaultMutableTreeNode("San Diego");
        state.add(city);
        state = new DefaultMutableTreeNode("Michigan");
        country.add(state);
        city = new DefaultMutableTreeNode("Ann Arbor");
        state.add(city);
        country = new DefaultMutableTreeNode("Germany");
        root.add(country);
        state = new DefaultMutableTreeNode("Schleswig-Holstein");
        country.add(state);
        city = new DefaultMutableTreeNode("Kiel");
        state.add(city);
        return root;
    }

    /**
     * Makes the buttons to add a sibling, add a child, and delete a node.
     */
    public void makeButtons() {
        JPanel panel = new JPanel();
        JButton addSiblingButton = new JButton("Add Sibling");
        addSiblingButton.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent event) {
                DefaultMutableTreeNode selectedNode = (DefaultMutableTreeNode) tree.getLastSelectedPathComponent();

                if (selectedNode == null)
                    return;

                DefaultMutableTreeNode parent = (DefaultMutableTreeNode) selectedNode.getParent();

                if (parent == null)
                    return;

                DefaultMutableTreeNode newNode = new DefaultMutableTreeNode("New");

                int selectedIndex = parent.getIndex(selectedNode);
                model.insertNodeInto(newNode, parent, selectedIndex + 1);

                // now display new node

                TreeNode[] nodes = model.getPathToRoot(newNode);
                TreePath path = new TreePath(nodes);
                tree.scrollPathToVisible(path);
            }
        });
        panel.add(addSiblingButton);

        JButton addChildButton = new JButton("Add Child");
        addChildButton.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent event) {
                DefaultMutableTreeNode selectedNode = (DefaultMutableTreeNode) tree.getLastSelectedPathComponent();

                if (selectedNode == null)
                    return;

                DefaultMutableTreeNode newNode = new DefaultMutableTreeNode("New");
                model.insertNodeInto(newNode, selectedNode, selectedNode.getChildCount());

                // now display new node

                TreeNode[] nodes = model.getPathToRoot(newNode);
                TreePath path = new TreePath(nodes);
                tree.scrollPathToVisible(path);
            }
        });
        panel.add(addChildButton);

        JButton deleteButton = new JButton("Delete");
        deleteButton.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent event) {
                DefaultMutableTreeNode selectedNode = (DefaultMutableTreeNode) tree.getLastSelectedPathComponent();

                if (selectedNode != null && selectedNode.getParent() != null)
                    model.removeNodeFromParent(selectedNode);
            }
        });
        panel.add(deleteButton);
        add(panel, BorderLayout.SOUTH);
    }

    private DefaultTreeModel model;
    private JTree tree;
    private static final int DEFAULT_WIDTH = 400;
    private static final int DEFAULT_HEIGHT = 200;
}