package binaryTree.visitor;

import binaryTree.*;

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

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

	/**
    * Prints [] on System.out and stays on the same line of output.
	 * @param host
	 * @param input not used.
	 * @return null
	 */
	public Object emptyCase(BiTree host, Object input)
	{
      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)
	{
      return host.execute(VerticalPrintHelper.Singleton, new Integer (0));
	}
}