【GOF23设计模式】享元模式

来源：http://www.bjsxt.com/ 
一、【GOF23设计模式】_享元模式、享元池、内部状态、外部状态、线程池、连接池

package com.test.flyweight;
/**
 * FlyWeight抽象享元类
 */
public interface ChessFlyWeight {
    void setColor(String c);
    String getColor();
    void display(Coordinate c);
}

/**
 * ConcreteFlyWeight具体享元类
 */
class ConcreteChess implements ChessFlyWeight {
    private String color;

    public ConcreteChess(String color) {
        super();
        this.color = color;
    }

    @Override
    public void setColor(String c) {
        this.color = c;
    }

    @Override
    public String getColor() {
        return color;
    }

    @Override
    public void display(Coordinate c) {
        System.out.println("棋子颜色："+color);
        System.out.println("棋子位置："+c.getX()+"------"+c.getY());
    }
}

package com.test.flyweight;
/**
 * 外部状态UnSharedConcreteFlyWeight非共享享元类
 */
public class Coordinate {
    private int x,y;

    public Coordinate(int x, int y) {
        super();
        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.test.flyweight;

import java.util.HashMap;
import java.util.Map;

/**
 * 享元工厂类
 */
public class ChessFlyWeightFactory {
    //享元池
    private static Map<String, ChessFlyWeight> map = new HashMap<String, ChessFlyWeight>();

    public static ChessFlyWeight getChess(String color) {
        if(map.get(color)!=null){
            return map.get(color);
        }else{
            ChessFlyWeight cfw = new ConcreteChess(color);
            map.put(color, cfw);
            return cfw;
        }
    }
}

package com.test.flyweight;

public class Client {
    public static void main(String[] args) {
        ChessFlyWeight chess1 = ChessFlyWeightFactory.getChess("黑色");
        ChessFlyWeight chess2 = ChessFlyWeightFactory.getChess("黑色");
        System.out.println(chess1);
        System.out.println(chess2);

        System.out.println("增加外部状态的处理============");
        chess1.display(new Coordinate(10,10));
        chess2.display(new Coordinate(20,20));  
    }
}

控制台输出：
com.test.flyweight.ConcreteChess@1db9742
com.test.flyweight.ConcreteChess@1db9742
增加外部状态的处理============
棋子颜色：黑色
棋子位置：10------10
棋子颜色：黑色
棋子位置：20------20