package binaryTree.visitor;

import binaryTree.*;
import ordering.*;

public class BSTFinder implements IVisitor
{
	/** @SBGen Singleton Variable   */
	public final static BSTFinder Singleton = new BSTFinder ();

	/** @SBGen Constructor   */
	private BSTFinder()
	{
	}

	/**
    * Returns null.
	 * @param host satisfies Binary Search Tree Property (BSTP).
	 * @param input an IOrdered.
	 */
	public Object emptyCase(BiTree host, Object input)
	{
		return null;
	}

	/**
    * Returns the object associated with the input key if host has it, otherwise returns null.
	 * @param host satisfies BSTP.
	 * @param input an IOrdered.
	 * @return
	 */
	public Object nonEmptyCase(BiTree host, Object input)
	{
      IOrdered root = (IOrdered)host.getRootDat();
      IOrdered inp = (IOrdered)input;
      int inpCompRoot = inp.compare (root);
      return
       inpCompRoot == IOrdered.LESS?
        host.getLeftSubTree().execute(this, input):
        inpCompRoot == IOrdered.GREATER?
          host.getRightSubTree().execute (this, input):
		    root;
	}
}