Expression Tree : JTree Node « Swing « Java Tutorial

1. Java Tutorial
2. Swing
3. JTree Node

import java.util.Enumeration;
import java.util.Stack;

import javax.swing.JFrame;
import javax.swing.JTree;
import javax.swing.tree.DefaultMutableTreeNode;

public class ExpressionTree extends JFrame {

  public ExpressionTree() {
    setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

    DefaultMutableTreeNode root = new DefaultMutableTreeNode("+");
    root.add(new DefaultMutableTreeNode(new Integer(3)));
    DefaultMutableTreeNode node = new DefaultMutableTreeNode("*");
    node.add(new DefaultMutableTreeNode(new Integer(4)));
    node.add(new DefaultMutableTreeNode(new Integer(5)));
    root.add(node);

    JTree tree = new JTree(root);
    getContentPane().add(tree);
    pack();
    setVisible(true);

    Stack stack = new Stack(); 
    Enumeration e = root.postorderEnumeration();
    while (e.hasMoreElements()) { 
      DefaultMutableTreeNode node1 = (DefaultMutableTreeNode) (e.nextElement());
      Object obj = node1.getUserObject();
      if (obj instanceof Integer) {
        stack.push(obj);
      } else {
        String operator = (String) obj;
        Integer v1 = (Integer) stack.pop();
        Integer v2 = (Integer) stack.pop();

        if (operator.equals("+")) {
          stack.push(new Integer(v2.intValue() + v1.intValue()));
        } else {
          stack.push(new Integer(v2.intValue() * v1.intValue()));
        }
      }
    }
    System.out.println(stack.pop());
  }

  public static void main(String[] args) {
    ExpressionTree t = new ExpressionTree();
  }
}

14.67.JTree Node
	14.67.1.	Get child count, depth, leaf count
	14.67.2.	Adding a Node to a JTree Component
	14.67.3.	Delete tree node
	14.67.4.	Removing a Node to a JTree Component
	14.67.5.	Expression Tree
	14.67.6.	Swing Tree
	14.67.7.	JTree node mouse click event
	14.67.8.	A JTree subclass that displays the tree of AWT or Swing component that make up a GUI
	14.67.9.	Tree with custom icon
	14.67.10.	CheckBox Tree node
	14.67.11.	Get path for all expanded or not expanded tree pathes
	14.67.12.	Converting All Nodes in a JTree Component to a TreePath Array
	14.67.13.	Expanding or Collapsing All Nodes in a JTree Component
	14.67.14.	JTree root cannot be removed with removeNodeFromParent(), use DefaultTreeModel.setRoot() to remove the root
	14.67.15.	Searching node in a JTree