package binaryTree.visitor;

import binaryTree.*;

/**
 * Prints the binary tree host vertically.
 * @author Dung X. Nguyen
 */
public class VerticalPrintHelper implements IVisitor
{
	/** @SBGen Singleton Variable   */
	public final static VerticalPrintHelper Singleton = new VerticalPrintHelper ();

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

	/**
    * Prints [] on System.out and stays on the same line of output.
	 * @param host
	 * @param input an Integer indicating the level of the node.
	 * @return null
	 */
	public Object emptyCase(BiTree host, Object input)
	{
      int level = ((Integer)input).intValue ();
      printSpaces (level);
      System.out.print ("[]");
		return null;
	}

	/**
    * Prints the host tree vertically on System.out and stays on the same line of
    output as the last printed tree node.
	 * @param host
	 * @param input an Integer indicating the level of the node.
	 * @return null
	 */
	public Object nonEmptyCase(BiTree host, Object input)
	{
      int level = ((Integer)input).intValue ();
      printSpaces (level);
      System.out.println (host.getRootDat());
      host.getLeftSubTree().execute(this, new Integer (++level));
      System.out.println ();
      host.getRightSubTree().execute(this, new Integer (level));
		return (null);
	}

   /**
   * Prints n spaces.
   */
   private void printSpaces (int n)
   {
      for (int i = 0; i < n; i++)
      {
         System.out.print(' ');
      }
   }
}