Branch.java Source code

Introduction

Here is the source code for Branch.java

Source

// : c14:Trees.java
// Simple Swing tree. Trees can be vastly more complex.
// <applet code=Trees width=250 height=250></applet>
// From 'Thinking in Java, 3rd ed.' (c) Bruce Eckel 2002
// www.BruceEckel.com. See copyright notice in CopyRight.txt.

import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Container;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

import javax.swing.JApplet;
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;

// Takes an array of Strings and makes the first
// element a node and the rest leaves:
class Branch {
    private DefaultMutableTreeNode r;

    public Branch(String[] data) {
        r = new DefaultMutableTreeNode(data[0]);
        for (int i = 1; i < data.length; i++)
            r.add(new DefaultMutableTreeNode(data[i]));
    }

    public DefaultMutableTreeNode node() {
        return r;
    }
}

public class Trees extends JApplet {
    private String[][] data = { { "Colors", "Red", "Blue", "Green" }, { "Flavors", "Tart", "Sweet", "Bland" },
            { "Length", "Short", "Medium", "Long" }, { "Volume", "High", "Medium", "Low" },
            { "Temperature", "High", "Medium", "Low" }, { "Intensity", "High", "Medium", "Low" }, };

    private static int i = 0;

    private DefaultMutableTreeNode root, child, chosen;

    private JTree tree;

    private DefaultTreeModel model;

    public void init() {
        Container cp = getContentPane();
        root = new DefaultMutableTreeNode("root");
        tree = new JTree(root);
        // Add it and make it take care of scrolling:
        cp.add(new JScrollPane(tree), BorderLayout.CENTER);
        // Capture the tree's model:
        model = (DefaultTreeModel) tree.getModel();
        JButton test = new JButton("Press me");
        test.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                if (i < data.length) {
                    child = new Branch(data[i++]).node();
                    // What's the last one you clicked?
                    chosen = (DefaultMutableTreeNode) tree.getLastSelectedPathComponent();
                    if (chosen == null)
                        chosen = root;
                    // The model will create the appropriate event.
                    // In response, the tree will update itself:
                    model.insertNodeInto(child, chosen, 0);
                    // Puts the new node on the chosen node.
                }
            }
        });
        // Change the button's colors:
        test.setBackground(Color.BLUE);
        test.setForeground(Color.WHITE);
        JPanel p = new JPanel();
        p.add(test);
        cp.add(p, BorderLayout.SOUTH);
    }

    public static void main(String[] args) {
        run(new Trees(), 250, 250);
    }

    public static void run(JApplet applet, int width, int height) {
        JFrame frame = new JFrame();
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.getContentPane().add(applet);
        frame.setSize(width, height);
        applet.init();
        applet.start();
        frame.setVisible(true);
    }
} ///:~