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("\n==============================分隔线==========================\n");

         //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("\n==============================分隔线==========================\n");

         //二、继承的方式
         //2.1代理时间
         Tank2Time t2 = new Tank2Time();
         t2.move();

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

         //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