Travel to all the nodes in a JTree with Pre Order Enumeration in Java
Description
The following code shows how to travel to all the nodes in a JTree with Pre Order Enumeration.
preOrderEnumeration(): The first node is the node itself. The next node is that node's first child, then it's the first child of that first child. Once a leaf node with no children is found, the next child of its parent is put in the Enumeration and its children are added to the list accordingly until no nodes are left.
Example
//from ww w. j a va 2s . c om
import java.awt.BorderLayout;
import java.util.Enumeration;
import javax.swing.JFrame;
import javax.swing.JScrollPane;
import javax.swing.JTree;
import javax.swing.tree.DefaultMutableTreeNode;
import javax.swing.tree.TreeNode;
public class Main {
public static void main(String args[]) {
JFrame frame = new JFrame();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
DefaultMutableTreeNode root = new DefaultMutableTreeNode("Root");
DefaultMutableTreeNode mercury = new DefaultMutableTreeNode("Mercury");
root.add(mercury);
DefaultMutableTreeNode venus = new DefaultMutableTreeNode("Venus");
root.add(venus);
DefaultMutableTreeNode mars = new DefaultMutableTreeNode("java2s.com");
root.add(mars);
JTree tree = new JTree(root);
JScrollPane scrollPane = new JScrollPane(tree);
frame.add(scrollPane, BorderLayout.CENTER);
frame.setSize(300, 150);
frame.setVisible(true);
Enumeration e = root.preorderEnumeration();
while(e.hasMoreElements()){
System.out.println(e.nextElement());
}
}
}
The code above generates the following result.
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