package t234;

/**
* Represents nodes with only 2 subtrees of a 2-3-4 tree.
* It contains the data object, a left Tree234 and a right Tree234.
* @since 12/03/00
* @author Dung X. Nguyen, Copyright 2000 - All Rights Reserved.
*/
class Node2 extends ANode234
{
	private Tree234 _leftTree = new Tree234 ();    //Data invariant:  _leftTree  != null
   private Integer _data;	                       // Data invariant:  _data	  != null
	private Tree234 _rightTree = new Tree234 ();   //Data invariant:  _rightTree != null

   /**
   * Initializes this Node2 to contain n and two empty subtrees.
   * @param n != null
   */
   Node2(Integer n)
   {
  	   _data      = n;
   }

   /**
   * Initializes this Node2 to contain the given data and the given left and right subtrees.
   * @param lTree != null  the left subtree, all elements in lTree are less than n.
   * @param n != null less than all elements in rTree.
   * @param rTree != null  the right subtree
   */
   Node2(Tree234 lTree, Integer n, Tree234 rTree)
   {
  	   _data      = n;
  	   _leftTree  = lTree;
  	   _rightTree = rTree;
   }

   final boolean isEmpty (Tree234 owner)
   {
	   return false;
   }

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

   final void insertHelper (Tree234 ownerPo, Tree234 owner, Integer n)
   {
  	   owner.insert (n); // can call insert (owner, n) instead.
   }

   final void attach (Tree234 owner, 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);
      }
      owner.changeRoot (topNode);
   }

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