1  import java.util.Iterator;

  2  

  3  /**

  4     This program demonstrates tree traversal.

  5  */

  6  public class TraversalDemo

  7  {

  8     public static void main(String[] args)

  9     {

 10        Tree t1 = new Tree("Anne");

 11        Tree t2 = new Tree("Peter");

 12        t1.addSubtree(t2);

 13        Tree t3 = new Tree("Zara");

 14        t1.addSubtree(t3);

 15        Tree t4 = new Tree("Savannah");

 16        t2.addSubtree(t4);

 17  

 18        // Count short names with visitor

 19        class ShortNameCounter implements Tree.Visitor

 20        {

 21           public int counter = 0;

 22           public void visit(Object data)

 23           {

 24              System.out.println(data);

 25              if (data.toString().length() <= 5) { counter++; }

 26           }

 27        }

 28  

 29        ShortNameCounter v = new ShortNameCounter();

 30  

 31        t1.preorder(v);

 32        System.out.println("Short names: " + v.counter);

 33  

 34        // Count short names with iterator

 35        Iterator iter = t1.iterator();

 36        int counter = 0;

 37        while (iter.hasNext())

 38        {

 39           Object data = iter.next();

 40           System.out.println(data);

 41           if (data.toString().length() <= 5) { counter++; }

 42        }

 43        System.out.println("Short names: " + counter);         

 44     }

 45  }