public class BinarySearchTree extends BinaryTree implements Tree {
  	//Data
  	protected java.util.Comparator c;

  	//Constructors
  	public BinarySearchTree() { this(new NaturalComparator()); }
  	public BinarySearchTree(java.util.Comparator c) { this(c,null); }
  	public BinarySearchTree(java.util.Comparator c,TreeNode n) { super; this.c = c; }

	//Access methods - inherited from class BinaryTree
	public java.util.Comparator getComparator() { return c; }
	
  	//Override methods	
	public BinaryTree getLeftSubtree() {
		return isEmpty() ? null : new BinarySearchTree(c,root.left);
	}
	
	public BinaryTree getRightSubtree() {
		return isEmpty() ? null : new BinarySearchTree(c,root.right);
	}
	
	//Tree methods - inherited from class BinaryTree

  	//Override methods
  	public void add(Object element) {
		if(isEmpty()) root = new TreeNode(element);
		else if(c.compare(element,root.data) <= 0)
        	if(root.left == null) root.left = new TreeNode(element);
            else getLeftSubtree().add(element);
		else 
      		if(root.right == null) root.right = new TreeNode(element);
      		else getRightSubtree().add(element);
  	}
  	
  	public Object remove(Object element)  {
    	throw new UnsupportedOperationException();
  	}
  	
  	public boolean contains(Object element) {
    	throw new UnsupportedOperationException();
  	}
}