设计模式-策略模式

1. 定义
   策略模式定义了算法族，分别封装起来，让它们之间可以互相替换，此模式让算法的变化独立于使用算法的客户

2. 代码实例

   interface Quack {
       void quack();
   }
   
   interface Fly {
       void fly();
   }
   
   class QuackBehavior implements Quack {
   
       @Override
       public void quack() {
           System.out.println("ga ga ga");
       }
   }
   
   class FlyBehavior implements Fly {
   
       @Override
       public void fly() {
           System.out.println("fly fly fly");
       }
   }
   
   abstract class Duck {
   
       private Quack quack;
       private Fly fly;
   
       public void setQuack(Quack quack) {
           this.quack = quack;
       }
   
       public void setFly(Fly fly) {
           this.fly = fly;
       }
   
       public void performQuack() {
           quack.quack();
       }
   
       public void performFly() {
           fly.fly();
       }
   }
   
   class RedheadDuck extends Duck {
       public RedheadDuck() {
           super();
           this.setQuack(new QuackBehavior());
           this.setFly(new FlyBehavior());
       }
       
       public static void main(String[] args) {
           Duck redheadDuck = new RedheadDuck();
           redheadDuck.performFly();
           redheadDuck.performQuack();
       }        
   }