/*
6/25/97   DXN

This file contains the code for class Node2 which represents nodes with only
2 subtrees of a 2-3-4 tree.  It contains the data object, a left Tree234 and
a right Tree234.

Copyright 1997,  Dung X. Nguyen - All Rights Reserved.

*/

class Node2 extends ANode234
{
  /** @SBGen Variable (,,,64)   */
	private Tree234 _leftTree;    //Data invariant:  _leftTree  != null
  private Integer _data;	      /**
	 * Data invariant:  _data	  != null
	 * @SBGen Variable (,,,64)
	 */
	private Tree234 _rightTree;   //Data invariant:  _rightTree != null


  Node2(Integer n)
  //pre: n != null
  {
  	_data      = n;
  	_leftTree  = new Tree234 ();
  	_rightTree = new Tree234 ();
  	//Data invariants are maintained.
  }

  Node2(Tree234 lTree, Integer n, Tree234 rTree)
  //Pre: lTree, n, and rTree are not null.
  //Post: node contains n and lTree, rTree as left and right subtree.
  {
  	_data      = n;
  	_leftTree  = lTree;
  	_rightTree = rTree;
  }

  final boolean isEmpty ()
  {
	  return false;
  }

  final void drawRootAndSubtrees (int level)
  {
  	System.out.println (_data);
  	_leftTree.drawAtLevel (level + 1);
  	System.out.println ();
  	_rightTree.drawAtLevel (level + 1);
  }

  final void insert (Tree234 parent, Integer n)
  {
    int dataVal = _data.intValue ();
    int key     = n.intValue ();
    if ( key == dataVal)
      return;
    if (isLeafNode())
	  parent.changeRoot (new Node3 (n, _data));
    else
    {//parent is parent of left and right subtrees.
      if (key < dataVal)
        _leftTree.insertHelper (parent, n);
	    else // (dataVal < key)
        _rightTree.insertHelper (parent, n);
    }
  }

  final void insertHelper (Tree234 grandPo, Tree234 parent, Integer n)
  {
      insert (parent, n);
  }

  final void attach (Tree234 parent, Tree234 lTree, Integer n, Tree234 rTree)
  {
    Node3 topNode;
    if (n.intValue () < _data.intValue ())
      topNode = new Node3 (lTree, n, rTree, _data, _rightTree);
    else
      topNode = new Node3 (_leftTree, _data, lTree, n, rTree);
    parent.changeRoot (topNode);
  }

  private final boolean isLeafNode ()
  {
      return (_leftTree.isEmpty () && _rightTree.isEmpty ());
  }
}