package binaryTree.visitor;

import binaryTree.*;

/**
* Replaces the root of the input tree with the minimum of the host, if any,
* otherwise removes the input's root.
*/
public class RightDelDontAsk implements IVisitor
{
	public final static RightDelDontAsk Singleton = new RightDelDontAsk ();

	private RightDelDontAsk()
	{
   }

	/**
    * Asks the input BiTree to remove its root.
	 * @param host the right subtree of input.
	 * @param input a <code>BiTree</code> with the binary search property.
	 * @return
	 */
	public Object emptyCase(BiTree host, Object input)
	{
      ((BiTree)input).remRoot ();
      return null;
	}

	/**
    * Asks the input to set its root to the minimum value in the host, and removes
    * this minimum value from the host.
	 * @param host the right subtree of input.
	 * @param input a <code>BiTree</code> with the binary search property.
	 * @return
	 */
	public Object nonEmptyCase(BiTree host, Object input)
	{
      BiTree parent = (BiTree)input;
      BiTree minTree = (BiTree)host.execute (MinTreeFinder.Singleton, null);
      Object min = minTree.getRootDat();
      parent.setRootDat(min);
      minTree.execute (OOBSTDeleter.Singleton, min);
		return null;
	}
}