/*  PlyHashtableEntryImpl - Implements a hashtable entry for plies.  Copyright (C) 2003 The Java-Chess team <info@java-chess.de>  This program is free software; you can redistribute it and/or  modify it under the terms of the GNU General Public License  as published by the Free Software Foundation; either version 2  of the License, or (at your option) any later version.  This program is distributed in the hope that it will be useful,  but WITHOUT ANY WARRANTY; without even the implied warranty of  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the  GNU General Public License for more details.  You should have received a copy of the GNU General Public License  along with this program; if not, write to the Free Software  Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.*/ package de.java_chess.javaChess.engine.hashtable;import de.java_chess.javaChess.bitboard.*;import de.java_chess.javaChess.board.*;import de.java_chess.javaChess.piece.*;import de.java_chess.javaChess.ply.*;import de.java_chess.javaChess.position.*;// import java.util.zip.CRC32;/** * The class implements the functionality to store * chess plies in a hashtable. */public class PlyHashtableEntryImpl implements PlyHashtableEntry {    // Instance variables    /**     * The board before this ply.     */    private Board _board;    /**     * The ply to store.     */    private Ply _ply;    /**     * The search depth, that was used to compute this ply.     */    private int _searchDepth;        // Constructors    /**     * Create a new hashtable entry.     *     * @param board The board before the ply.     * @param ply The ply to store.     * @param searchDepth The search depth, that was used to compute the ply.     */    public PlyHashtableEntryImpl( Board board, Ply ply, int searchDepth) {	setBoard( board);	setPly( ply);	setSearchDepth( searchDepth);    }    // Methods    /**     * Get the board of this entry.     *     * @return The board of this entry.     */    public final Board getBoard() {	return _board;    }    /**     * Set a new board for this entry.     *     * @param board The new board.     */    public final void setBoard( Board board) {	_board = board;    }    /**     * Get the ply.     *     * @return The ply.     */    public final Ply getPly() {	return _ply;    }    /**     * Set the ply.     *     * @param ply The ply to set.     */    public final void setPly( Ply ply) {	_ply = ply;    }    /**     * Get the search depth for the computed ply.     *     * @return The search depth for the computed ply.     */    public final int getSearchDepth() {	return _searchDepth;    }    /**     * Set the search depth for the computed ply.     *     * @param searchDepth The search depth.     */    public final void setSearchDepth( int searchDepth) {	_searchDepth = searchDepth;    }    /**     * Check, if it's a move with white pieces.     *     * @return true, if it's a move with white pieces.     */    public final boolean isWhiteMove() {	return getBoard().getPiece( getPly().getSource()).getColor() == Piece.WHITE;    }        /**     * Get the hashcode for this ply.     *     * @return A hashcode for this ply.     */    public final long hashKey() {	return hashKey( getBoard(), isWhiteMove());    }    /**     * Get a hashcode for a given board and piece color.     *     * @param board The current board.     * @param white true, if it's a ply with the white pieces.     *     * @return A hashcode for the given board and color.     */    public static long hashKey( Board board, boolean white) {	return ZobristKeyImpl.getInstance().computeKey( (BitBoard)board, white);    }}