软件设计享元模式

设计一个围棋软件，在系统中只存在一个白棋对象和一个黑棋对象，但是它们可以在棋盘的不同位置显示多次。

package com;


class BlackIgoChessman extends IgoChessman{
 
    @Override
    public String getColor() {
        // TODO Auto-generated method stub
        return "黑色";
    }
 
}

package com;


class Coordinates {
    
    private int x;
    private int y;
    
    public Coordinates(int x,int y) {
        // TODO Auto-generated constructor stub
        this.x = x;
        this.y = y;
    }
 
    public int getX() {
        return x;
    }
 
    public void setX(int x) {
        this.x = x;
    }
 
    public int getY() {
        return y;
    }
 
    public void setY(int y) {
        this.y = y;
    }
    
}

package com;


abstract class IgoChessman {
    
    public abstract String getColor();
    public void locate(Coordinates coord){
        System.out.println("棋子颜色："+this.getColor()+",棋子位置："+coord.getX()+","+coord.getY());
    }
}

package com;

import java.util.Hashtable;

public class IgoChessmanFactory {
    
    private static IgoChessmanFactory instance = new IgoChessmanFactory();
    private static Hashtable ht;
    
    public IgoChessmanFactory() {
        // TODO Auto-generated constructor stub
        ht = new Hashtable();
        IgoChessman black,white;
        black = new BlackIgoChessman();
        ht.put("b", black);
        white = new WhiteIgoChessman();
        ht.put("w", white);
    }
    
    public static IgoChessmanFactory getInstance(){
        return instance;
    }
    
    public static IgoChessman getIgoChessman(String color){
        return (IgoChessman)ht.get(color);
    }
}

package com;

class WhiteIgoChessman extends IgoChessman{
     
    @Override
    public String getColor() {
        // TODO Auto-generated method stub
        return "白色";
    }
 
}

package com;

public class Client {
    
    public static void main(String[] args) {
        IgoChessman black1,black2,black3,white1,white2;
        IgoChessmanFactory factory;
        factory = IgoChessmanFactory.getInstance();
        black1 = factory.getIgoChessman("b");
        black2 = factory.getIgoChessman("b");
        black3 = factory.getIgoChessman("b");
        System.out.println("判断两颗黑棋是否相同："+(black1==black2));
        white1 = factory.getIgoChessman("w");
        white2 = factory.getIgoChessman("w");
        System.out.println("判断两颗白棋是否相同："+(white1==white2));
        black1.locate(new Coordinates(1, 2));
        black2.locate(new Coordinates(3, 4));
        black3.locate(new Coordinates(1, 3));
        white1.locate(new Coordinates(2, 5));
        white2.locate(new Coordinates(2, 4));
    }
}