package binaryTree;

/**
 * Represents all extrinsic algorithms on a BiTree as a visitor to the
 * BiTree host structure.  The BiTree host will make the appropriate
 * call on this IAlgo's methods.
 *
 * @author Alan L. Cox
 * @author Dung X. Nguyen - Copyright 1999 - All rights reserved.
 * @since 4/5/01
 */
public interface IAlgo
{
    /**
     * Called by the host when the host is empty.
     *
     * @param host
     * @param input the input needed by the visiting algorithm.
     * @return the output produced by the visiting algorithm.
     */
    public Object emptyCase(BiTree host, Object input);

    /**
     * Called by the host when the host is not empty.
     *
     * @param host
     * @param input the input needed by the visiting algorithm.
     * @return the output produced by the visiting algorithm.
     */
    public Object nonEmptyCase(BiTree host, Object input);
}