Prentice.Hall.Introduction.to.Java.Programming,.Brief.Version.9th.(2014).[sharethefiles.com]

In graph theory, depth-first traversal is defined the
same as preorder traversal, but in the
depthFirstEnumeration() method in DefaultMutableTreeNode,
it is the same as postorder traversal.
NOTE
You can create a JTree from a root using new
JTree(TreeNode) or from a model using new
JTree(TreeModel). To create a tree model, you first
create an instance of TreeNode to represent the root of
the tree, and then create an instance of DefaultTreeModel
fitted with the root.
Listing 40.14 gives an example that creates two trees to display
world, continents, countries, and states. The two trees share the
same nodes and thus display identical contents. The program also
displays the properties of the tree in a text area, as shown in
Figure 40.24.
Figure 40.24
The two trees have the same data because their roots are the same.
Listing 40.14 TreeNodeDemo.java
1 import java.awt.*;
2 import javax.swing.*;
3 import javax.swing.tree.*;
4 import java.util.*;
5
6 public class TreeNodeDemo extends JApplet {
7 public TreeNodeDemo() {
8 // Create the first tree
9 DefaultMutableTreeNode root, europe, northAmerica, us;
10
11 europe = new DefaultMutableTreeNode("Europe");
12 europe.add(new DefaultMutableTreeNode("UK"));
13 europe.add(new DefaultMutableTreeNode("Germany"));
39