TreeIconDemo2.java Source code

Java tutorial

Introduction

Here is the source code for TreeIconDemo2.java

Source

/* From http://java.sun.com/docs/books/tutorial/index.html */
/*
 * Copyright (c) 2006 Sun Microsystems, Inc. All Rights Reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * -Redistribution of source code must retain the above copyright notice, this
 *  list of conditions and the following disclaimer.
 *
 * -Redistribution in binary form must reproduce the above copyright notice,
 *  this list of conditions and the following disclaimer in the documentation
 *  and/or other materials provided with the distribution.
 *
 * Neither the name of Sun Microsystems, Inc. or the names of contributors may
 * be used to endorse or promote products derived from this software without
 * specific prior written permission.
 *
 * This software is provided "AS IS," without a warranty of any kind. ALL
 * EXPRESS OR IMPLIED CONDITIONS, REPRESENTATIONS AND WARRANTIES, INCLUDING
 * ANY IMPLIED WARRANTY OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE
 * OR NON-INFRINGEMENT, ARE HEREBY EXCLUDED. SUN MIDROSYSTEMS, INC. ("SUN")
 * AND ITS LICENSORS SHALL NOT BE LIABLE FOR ANY DAMAGES SUFFERED BY LICENSEE
 * AS A RESULT OF USING, MODIFYING OR DISTRIBUTING THIS SOFTWARE OR ITS
 * DERIVATIVES. IN NO EVENT WILL SUN OR ITS LICENSORS BE LIABLE FOR ANY LOST
 * REVENUE, PROFIT OR DATA, OR FOR DIRECT, INDIRECT, SPECIAL, CONSEQUENTIAL,
 * INCIDENTAL OR PUNITIVE DAMAGES, HOWEVER CAUSED AND REGARDLESS OF THE THEORY
 * OF LIABILITY, ARISING OUT OF THE USE OF OR INABILITY TO USE THIS SOFTWARE,
 * EVEN IF SUN HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES.
 *
 * You acknowledge that this software is not designed, licensed or intended
 * for use in the design, construction, operation or maintenance of any
 * nuclear facility.
 */
/**
 * A 1.4 application that requires the following additional files:
 *   TreeDemoHelp.html
 *    arnold.html
 *    bloch.html
 *    chan.html
 *    jls.html
 *    swingtutorial.html
 *    tutorial.html
 *    tutorialcont.html
 *    vm.html
 */

import javax.swing.JEditorPane;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JSplitPane;

import javax.swing.JTree;
import javax.swing.tree.DefaultMutableTreeNode;
import javax.swing.tree.TreeSelectionModel;
import javax.swing.event.TreeSelectionEvent;
import javax.swing.event.TreeSelectionListener;
import javax.swing.tree.DefaultTreeCellRenderer;
import javax.swing.ToolTipManager;
import javax.swing.ImageIcon;
import javax.swing.Icon;

import java.net.URL;
import java.io.IOException;
import java.awt.Dimension;
import java.awt.GridLayout;
import java.awt.Component;

public class TreeIconDemo2 extends JPanel implements TreeSelectionListener {
    private JEditorPane htmlPane;
    private JTree tree;
    private URL helpURL;
    private static boolean DEBUG = false;

    public TreeIconDemo2() {
        super(new GridLayout(1, 0));

        //Create the nodes.
        DefaultMutableTreeNode top = new DefaultMutableTreeNode("The Java Series");
        createNodes(top);

        //Create a tree that allows one selection at a time.
        tree = new JTree(top);
        tree.getSelectionModel().setSelectionMode(TreeSelectionModel.SINGLE_TREE_SELECTION);

        //Enable tool tips.
        ToolTipManager.sharedInstance().registerComponent(tree);

        //Set the icon for leaf nodes.
        ImageIcon tutorialIcon = createImageIcon("images/middle.gif");
        if (tutorialIcon != null) {
            tree.setCellRenderer(new MyRenderer(tutorialIcon));
        } else {
            System.err.println("Tutorial icon missing; using default.");
        }

        //Listen for when the selection changes.
        tree.addTreeSelectionListener(this);

        //Create the scroll pane and add the tree to it. 
        JScrollPane treeView = new JScrollPane(tree);

        //Create the HTML viewing pane.
        htmlPane = new JEditorPane();
        htmlPane.setEditable(false);
        initHelp();
        JScrollPane htmlView = new JScrollPane(htmlPane);

        //Add the scroll panes to a split pane.
        JSplitPane splitPane = new JSplitPane(JSplitPane.VERTICAL_SPLIT);
        splitPane.setTopComponent(treeView);
        splitPane.setBottomComponent(htmlView);

        Dimension minimumSize = new Dimension(100, 50);
        htmlView.setMinimumSize(minimumSize);
        treeView.setMinimumSize(minimumSize);
        splitPane.setDividerLocation(100); //XXX: ignored in some releases
                                           //of Swing. bug 4101306
                                           //workaround for bug 4101306:
                                           //treeView.setPreferredSize(new Dimension(100, 100)); 

        splitPane.setPreferredSize(new Dimension(500, 300));

        //Add the split pane to this panel.
        add(splitPane);
    }

    /** Required by TreeSelectionListener interface. */
    public void valueChanged(TreeSelectionEvent e) {
        DefaultMutableTreeNode node = (DefaultMutableTreeNode) tree.getLastSelectedPathComponent();

        if (node == null)
            return;

        Object nodeInfo = node.getUserObject();
        if (node.isLeaf()) {
            BookInfo book = (BookInfo) nodeInfo;
            displayURL(book.bookURL);
            if (DEBUG) {
                System.out.print(book.bookURL + ":  \n    ");
            }
        } else {
            displayURL(helpURL);
        }
        if (DEBUG) {
            System.out.println(nodeInfo.toString());
        }
    }

    private class BookInfo {
        public String bookName;
        public URL bookURL;

        public BookInfo(String book, String filename) {
            bookName = book;
            bookURL = TreeIconDemo2.class.getResource(filename);
            if (bookURL == null) {
                System.err.println("Couldn't find file: " + filename);
            }
        }

        public String toString() {
            return bookName;
        }
    }

    private void initHelp() {
        String s = "TreeDemoHelp.html";
        helpURL = TreeIconDemo2.class.getResource(s);
        if (helpURL == null) {
            System.err.println("Couldn't open help file: " + s);
        } else if (DEBUG) {
            System.out.println("Help URL is " + helpURL);
        }

        displayURL(helpURL);
    }

    private void displayURL(URL url) {
        try {
            if (url != null) {
                htmlPane.setPage(url);
            } else { //null url
                htmlPane.setText("File Not Found");
                if (DEBUG) {
                    System.out.println("Attempted to display a null URL.");
                }
            }
        } catch (IOException e) {
            System.err.println("Attempted to read a bad URL: " + url);
        }
    }

    private void createNodes(DefaultMutableTreeNode top) {
        DefaultMutableTreeNode category = null;
        DefaultMutableTreeNode book = null;

        category = new DefaultMutableTreeNode("Books for Java Programmers");
        top.add(category);

        //original Tutorial
        book = new DefaultMutableTreeNode(
                new BookInfo("The Java Tutorial: A Short Course on the Basics", "tutorial.html"));
        category.add(book);

        //Tutorial Continued
        book = new DefaultMutableTreeNode(
                new BookInfo("The Java Tutorial Continued: The Rest of the JDK", "tutorialcont.html"));
        category.add(book);

        //JFC Swing Tutorial
        book = new DefaultMutableTreeNode(
                new BookInfo("The JFC Swing Tutorial: A Guide to Constructing GUIs", "swingtutorial.html"));
        category.add(book);

        //Bloch
        book = new DefaultMutableTreeNode(new BookInfo("Effective Java Programming Language Guide", "bloch.html"));
        category.add(book);

        //Arnold/Gosling
        book = new DefaultMutableTreeNode(new BookInfo("The Java Programming Language", "arnold.html"));
        category.add(book);

        //Chan
        book = new DefaultMutableTreeNode(new BookInfo("The Java Developers Almanac", "chan.html"));
        category.add(book);

        category = new DefaultMutableTreeNode("Books for Java Implementers");
        top.add(category);

        //VM
        book = new DefaultMutableTreeNode(new BookInfo("The Java Virtual Machine Specification", "vm.html"));
        category.add(book);

        //Language Spec
        book = new DefaultMutableTreeNode(new BookInfo("The Java Language Specification", "jls.html"));
        category.add(book);
    }

    /** Returns an ImageIcon, or null if the path was invalid. */
    protected static ImageIcon createImageIcon(String path) {
        java.net.URL imgURL = TreeIconDemo2.class.getResource(path);
        if (imgURL != null) {
            return new ImageIcon(imgURL);
        } else {
            System.err.println("Couldn't find file: " + path);
            return null;
        }
    }

    /**
     * Create the GUI and show it.  For thread safety,
     * this method should be invoked from the
     * event-dispatching thread.
     */
    private static void createAndShowGUI() {
        //Make sure we have nice window decorations.
        JFrame.setDefaultLookAndFeelDecorated(true);

        //Create and set up the window.
        JFrame frame = new JFrame("TreeIconDemo2");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        //Create and set up the content pane.
        TreeIconDemo2 newContentPane = new TreeIconDemo2();
        newContentPane.setOpaque(true); //content panes must be opaque
        frame.setContentPane(newContentPane);

        //Display the window.
        frame.pack();
        frame.setVisible(true);
    }

    public static void main(String[] args) {
        //Schedule a job for the event-dispatching thread:
        //creating and showing this application's GUI.
        javax.swing.SwingUtilities.invokeLater(new Runnable() {
            public void run() {
                createAndShowGUI();
            }
        });
    }

    private class MyRenderer extends DefaultTreeCellRenderer {
        Icon tutorialIcon;

        public MyRenderer(Icon icon) {
            tutorialIcon = icon;
        }

        public Component getTreeCellRendererComponent(JTree tree, Object value, boolean sel, boolean expanded,
                boolean leaf, int row, boolean hasFocus) {

            super.getTreeCellRendererComponent(tree, value, sel, expanded, leaf, row, hasFocus);
            if (leaf && isTutorialBook(value)) {
                setIcon(tutorialIcon);
                setToolTipText("This book is in the Tutorial series.");
            } else {
                setToolTipText(null); //no tool tip
            }

            return this;
        }

        protected boolean isTutorialBook(Object value) {
            DefaultMutableTreeNode node = (DefaultMutableTreeNode) value;
            BookInfo nodeInfo = (BookInfo) (node.getUserObject());
            String title = nodeInfo.bookName;
            if (title.indexOf("Tutorial") >= 0) {
                return true;
            }

            return false;
        }
    }
}