/** A NodeOperator that prints each node. 
 *
 *  Taken from Core Web Programming from 
 *  Prentice Hall and Sun Microsystems Press,
 *  http://www.corewebprogramming.com/.
 *  © 2001 Marty Hall and Larry Brown;
 *  may be freely used or adapted. 
 */

class PrintOperator implements NodeOperator {
  public void operateOn(Node node) {
    System.out.println(node.getNodeValue());
  }
}

/** A sample tree representing a parse tree of
 *  the sentence "Java hackers hack Java", using
 *  some simple context-free grammar.
 */

public class TreeTest {
  public static void main(String[] args) {
    Node adjective =
      new Node("  Adjective", new Leaf("   Java"));
    Node noun1 =
      new Node("  Noun", new Leaf("   hackers"));
    Node verb =
      new Node("  TransitiveVerb", new Leaf("   hack"));
    Node noun2 =
      new Node("  Noun", new Leaf("   Java"));
    Node np = new Node(" NounPhrase", adjective, noun1);
    Node vp = new Node(" VerbPhrase", verb, noun2);
    Node sentence = new Node("Sentence", np, vp);
    PrintOperator printOp = new PrintOperator();
    System.out.println("Depth first traversal:");
    sentence.depthFirstSearch(printOp);
    System.out.println("\nBreadth first traversal:");
    sentence.breadthFirstSearch(printOp);
  }
}