Trees.java

//: c14:Trees.java
// Simple Swing tree. Trees can be vastly more complex.
// <applet code=Trees width=250 height=250></applet>
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
import javax.swing.tree.*;
import com.bruceeckel.swing.*;

// 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) {
    Console.run(new Trees(), 250, 250);
  }
} ///:~