Java-马士兵设计模式学习笔记-代理模式-聚合与继承方式比较

一、概述

1.目标：要在Tank的move()方法做时间代理及日志代理(可以设想以后还要增加很多代理处理)，且代理间的顺序可活更换

2.思路：

(1)聚合：代理类聚合了被代理类，且代理类及被代理类都实现了movable接口，则可实现灵活多变，具体看代码

(2)继承：继承不够灵活，具体看代码

二、代码

1.Movable.java

2.Tank.java

3.TankTimeProxy.java

4.TankLogProxy.java

5.Tank2Time.java

6.Tank3Log.java

7.Client.java

1.Movable.java

public interface Movable {
    public void move();
}

2.Tank.java

import java.util.Random;

public class Tank implements Movable {

    @Override
    public void move() {
        System.out.println("Tank moving.......");
        try {
            Thread.sleep(new Random().nextInt(5000));
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
    }

}

3.TankTimeProxy.java

public class TankTimeProxy implements Movable {

    Movable m;
    
    public TankTimeProxy(Movable m) {
        this.m = m;
    }

    @Override
    public void move() {
        System.out.println("Time Proxy start...........");
        long start = System.currentTimeMillis();
        m.move();
        long end = System.currentTimeMillis();
        System.out.println("花费时间："+(end - start));
        System.out.println("Time Proxy end...........");
    }

}

4.TankLogProxy.java

public class TankLogProxy implements Movable {

    Movable m;
    
    public TankLogProxy(Movable m) {
        this.m = m;
    }

    @Override
    public void move() {
        System.out.println("Log Proxy start...........");
        m.move();
        System.out.println("Log Proxy end...........");
    }

}

5.Tank2Time.java

public class Tank2Time extends Tank {

    public void move(){
        System.out.println("Tank2 time  start...........");
        long start = System.currentTimeMillis();
        super.move();
        long end = System.currentTimeMillis();
        System.out.println("花费时间："+(end - start));
        System.out.println("Tank2 time end...........");
    }
}

6.Tank3Log.java

public class Tank3Log extends Tank2Time {

    public void move(){
        System.out.println("Tank3Log  start...........");
        super.move();
        System.out.println("Tank3Log  end...........");
    }
}

7.Client.java

public class Client {

    @Test
    public void testProxy(){
        
        Tank t = new Tank();
        Movable m;
        
        //一、聚合的方式(较灵活，因为实现了接口)
        //1.1聚合方式的代理,先日志代理，后时间代理
        TankTimeProxy ttp1 = new TankTimeProxy(t);
        TankLogProxy tlp1 = new TankLogProxy(ttp1);
        
        m = tlp1;
        m.move();
        
        System.out.println("
==============================分隔线==========================
");
        
        //1.2聚合方式的代理,先时间代理，后日志代理(可以灵活切换顺序)
        TankLogProxy tlp2 = new TankLogProxy(t);
        TankTimeProxy ttp2 = new TankTimeProxy(tlp2);
        
        m = ttp2;
        m.move();
        
        System.out.println("
==============================分隔线==========================
");
        
        //二、继承的方式
        //2.1代理时间
        Tank2Time t2 = new Tank2Time();
        t2.move();
        
        System.out.println("
==============================分隔线==========================
");
        
        //2.2先代理日志，后时间，不能灵活切换
        Tank3Log t3 = new Tank3Log();
        t3.move();
        
        
        
    }
}

三、运行结果

四、小结

凡是要求灵活多变的功能，多数用接口多态实现