Sushi/src/suicideChess/MoveComparator.java

package suicideChess;

import java.util.Comparator;

import suicideChess.Board.NoPieceOnSquare;
import suicideChess.Square.NotAValidSquare;

/**
 * This class is used to sort Moves in the alpha beta pruning.
 * 
 * @author Jean-Baptiste Hétier
 * @version $LastChangedRevision$, $LastChangedDate$
 * 
 */
class MoveCompare implements Comparator<Move> {
    
    private Board bitboard; //the bitboard to do the moves from
    private int sortOrder; //increasing or decreasing order
    
    /**
     * Constructor
     * @param bitboard, the bitboard to do the moves from
     * @param order, who is playing (black or white) -> will give the order in which to sort (black minimises and white maximises)
     */
    public MoveCompare(Board bitboard) {
        this.bitboard = bitboard;
        if(this.bitboard.getCurrentPlayer()==Piece.BLACK) {
            // low scores are considered "smaller" than high ones and thus will be first after ordering
            sortOrder= -1; 
        } else {
            //  high scores are consideres "smaller" than low ones
            sortOrder= +1;
        }
    }
    
    public int compare(Move one, Move another) {
        Board oneBoardCopy = new Board(bitboard);
        Board anotherBoardCopy = new Board(bitboard);
        try {
            oneBoardCopy.doMove(one);
            anotherBoardCopy.doMove(another);
        } catch (NoPieceOnSquare e) {
            e.printStackTrace();
        } catch (NotAValidSquare e) {
            e.printStackTrace();
        }
        if(oneBoardCopy.getBoardValue()<anotherBoardCopy.getBoardValue()) {
            return sortOrder;
        } else if (oneBoardCopy.getBoardValue()==anotherBoardCopy.getBoardValue()) {
            return 0;
        }
        return -sortOrder;
    }
}