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

1 public interface Movable {

2     public void move();

3 }

 

2.Tank.java

 1 import java.util.Random;

 2 

 3 public class Tank implements Movable {

 4 

 5     @Override

 6     public void move() {

 7         System.out.println("Tank moving.......");

 8         try {

 9             Thread.sleep(new Random().nextInt(5000));

10         } catch (InterruptedException e) {

11             e.printStackTrace();

12         }

13     }

14 

15 }

 

3.TankTimeProxy.java

 1 public class TankTimeProxy implements Movable {

 2 

 3     Movable m;

 4     

 5     public TankTimeProxy(Movable m) {

 6         this.m = m;

 7     }

 8 

 9     @Override

10     public void move() {

11         System.out.println("Time Proxy start...........");

12         long start = System.currentTimeMillis();

13         m.move();

14         long end = System.currentTimeMillis();

15         System.out.println("花费时间："+(end - start));

16         System.out.println("Time Proxy end...........");

17     }

18 

19 }

 

4.TankLogProxy.java

 1 public class TankLogProxy implements Movable {

 2 

 3     Movable m;

 4     

 5     public TankLogProxy(Movable m) {

 6         this.m = m;

 7     }

 8 

 9     @Override

10     public void move() {

11         System.out.println("Log Proxy start...........");

12         m.move();

13         System.out.println("Log Proxy end...........");

14     }

15 

16 }

 

5.Tank2Time.java

 1 public class Tank2Time extends Tank {

 2 

 3     public void move(){

 4         System.out.println("Tank2 time  start...........");

 5         long start = System.currentTimeMillis();

 6         super.move();

 7         long end = System.currentTimeMillis();

 8         System.out.println("花费时间："+(end - start));

 9         System.out.println("Tank2 time end...........");

10     }

11 }

 

6.Tank3Log.java

1 public class Tank3Log extends Tank2Time {

2 

3     public void move(){

4         System.out.println("Tank3Log  start...........");

5         super.move();

6         System.out.println("Tank3Log  end...........");

7     }

8 }

 

7.Client.java

 1 public class Client {

 2 

 3     @Test

 4     public void testProxy(){

 5         

 6         Tank t = new Tank();

 7         Movable m;

 8         

 9         //一、聚合的方式(较灵活，因为实现了接口)

10         //1.1聚合方式的代理,先日志代理，后时间代理

11         TankTimeProxy ttp1 = new TankTimeProxy(t);

12         TankLogProxy tlp1 = new TankLogProxy(ttp1);

13         

14         m = tlp1;

15         m.move();

16         

17         System.out.println("\n==============================分隔线==========================\n");

18         

19         //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)

20         TankLogProxy tlp2 = new TankLogProxy(t);

21         TankTimeProxy ttp2 = new TankTimeProxy(tlp2);

22         

23         m = ttp2;

24         m.move();

25         

26         System.out.println("\n==============================分隔线==========================\n");

27         

28         //二、继承的方式

29         //2.1代理时间

30         Tank2Time t2 = new Tank2Time();

31         t2.move();

32         

33         System.out.println("\n==============================分隔线==========================\n");

34         

35         //2.2先代理日志，后时间，不能灵活切换

36         Tank3Log t3 = new Tank3Log();

37         t3.move();

38         

39         

40         

41     }

42 }

 

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