策略模式

1 package com.nwpulisz.strategypattren;
2 public class Quack implements QuackBehavior {
3     public void quack() {
4         // TODO Auto-generated method stub
5         System.out.println("Quack");
6     }
7 }

1 package com.nwpulisz.strategypattren;
2 public class FlyNoWay implements FlyBehavior {
3     public void fly() {
4         // TODO Auto-generated method stub
5         System.out.println("fly no way");
6     }
7 }

 1 package com.nwpulisz.strategypattren;
 2 public abstract class Duck {
 3     FlyBehavior flyBehavior;    //为行为接口类型声明两个引用变量，所有鸭子的子类都会继承它们；
 4     QuackBehavior quackBehavior;
 5     public Duck(){
 6         
 7     }
 8     public abstract void display();
 9     
10     public void performFly(){
11         flyBehavior.fly();   //行为的执行委托给行为类；
12     }
13     public void performQuack(){
14         quackBehavior.quack();
15     }
16     
17     public void setFlyBehavior(FlyBehavior flyBehavior) {
18         this.flyBehavior = flyBehavior;
19     }
20     public void setQuackBehavior(QuackBehavior quackBehavior) {
21         this.quackBehavior = quackBehavior;
22     }
23         
24 }

 1 package com.nwpulisz.strategypattren;
 2 public class MallardDuck extends Duck {
 3     public MallardDuck(){
 4         quackBehavior=new Quack();  //构造器中指定行为类；
 5         flyBehavior= new FlyWithWings();
 6     }
 7     @Override
 8     public void display() {
 9         // TODO Auto-generated method stub
10         System.out.println("Mallar Duck");
11     }
12 }

 1 package com.nwpulisz.strategypattren;
 2 public class DuckSimulator {
 3     
 4     public static void main(String[] args) {
 5         // TODO Auto-generated method stub
 6         Duck mallard = new MallardDuck();
 7         mallard.performQuack();   //构造器中指定行为类,output:Quack;
 8         mallard.performFly();  //构造器中指定行为类,output:fly with wings;
 9         
10         mallard.setFlyBehavior(new FlyNoWay());    //调用set方法，可以动态改变行为；
11         mallard.setQuackBehavior(new MuteQuack());  //调用set方法，可以动态改变行为；
12         mallard.performQuack(); //output:Mute Quck;
13         mallard.performFly();  //output:fly no way;
14     }
15 }