import java.util.Observable;

public class ChessBoard extends Observable {
    ChessFactory factory = new ChessFactory();

    private Chess ChessStatus[][] = new Chess[19][19];
    private short nowPlayer;
    private int step;
    private Rule rule;

    public ChessBoard(short Mode){
        // Clean Chess Board
        for(int i=0;i<19;i++){
            for(int j=0;j<19;j++){
                this.ChessStatus[i][j] = null;
            }
        }

        // First step = 0
        this.step = 0;

        // Black Chess First
        this.nowPlayer = Const.BLACK_CHESS;
    }

    private void setRule(short Mode){
        if(Mode == Const.GO_CHESS){
            this.rule = new GoRule();
        } else {
            this.rule = new GomokuRule();
        }
    }

    public void clickDot(Location loc) throws HasChessException {
        if (this.getStatus(loc) != Const.NO_CHESS){
            throw new HasChessException(loc);
        } else {
            // Make Chess
            this.ChessStatus[loc.getX()][loc.getY()] = factory.makeChess(this.nowPlayer, loc, this.step);


            // Check Finish
            if (this.checkFinish()) {
                // TODO:
            } else {
                this.changePlayer();
            }


            // Step ++
            this.step++;

            // Tell UI update
            notifyObservers();
        }

    }

    private short getStatus(Location loc){
        Chess target = this.ChessStatus[loc.getX()][loc.getY()];
        if (target == null){
            return Const.NO_CHESS;
        } else {
            return target.getColor();
        }
    }

    private boolean checkFinish(){
        return this.rule.check();
    }

    private void changePlayer(){
        if (this.nowPlayer == Const.BLACK_CHESS){
            this.nowPlayer = Const.WHITE_CHESS;
        } else {
            this.nowPlayer = Const.BLACK_CHESS;
        }
    }
}

class HasChessException extends Exception {
    public HasChessException(Location loc){
        System.out.println("Error: There is already having a chess at " + loc + ".");
    }
}
@@ -1353,16 +1353,51 @@
 servers(
+ChessStatus%5Bloc.getX()%5D%5Bloc.getY()%5D
 );%0A     
@@ -1719,16 +1719,27 @@
 e.check(
+ChessStatus
 );%0A    %7D

Set Chess to notify