Head First设计模式:策略模式-优快云博客

本文链接：https://blog.youkuaiyun.com/u011008029/article/details/78535369

本文通过鸭子的行为模拟，详细介绍了策略模式的设计理念与实现方式。展示了如何通过定义一系列算法，并将每个算法封装起来，使它们可以互相替换，从而让算法的变化独立于使用算法的客户。

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策略模式：

package com.zoey.allTest.pattern.headFirst.strategyPattern.book;

public abstract class Duck {
    FlyBehavior flyBehavior;
    QuackBehavior quackBehavior;

    public void performQuack(){
        quackBehavior.quack();

    public void swim(){
        System.out.println("all ducks float, even decoys");
    }

    public abstract void display();

    public void performFly(){
        flyBehavior.fly();
    }

    public void setFlyBehavior(FlyBehavior flyBehavior) {
        this.flyBehavior = flyBehavior;
    }

    public void setQuackBehavior(QuackBehavior quackBehavior) {
        this.quackBehavior = quackBehavior;
    }
}

package com.zoey.allTest.pattern.headFirst.strategyPattern.book;

public interface FlyBehavior {
    public void fly();
}

package com.zoey.allTest.pattern.headFirst.strategyPattern.book;

public interface QuackBehavior {
    public void quack();
}

package com.zoey.allTest.pattern.headFirst.strategyPattern.book;

public class FlyNoWay implements FlyBehavior {

    public void fly() {
        System.out.println("no way fly~~~");
    }
}

package com.zoey.allTest.pattern.headFirst.strategyPattern.book;

public class FlyWithWings implements FlyBehavior {

    public void fly() {
        System.out.println("fly~~~");
    }
}

package com.zoey.allTest.pattern.headFirst.strategyPattern.book;

public class Quack implements QuackBehavior {

    public void quack() {
        System.out.println("gua gua ~~~");
    }
}

package com.zoey.allTest.pattern.headFirst.strategyPattern.book;

public class Squeak implements QuackBehavior {

    public void quack() {
        System.out.println("zhi zhi ~~~");
    }
}

package com.zoey.allTest.pattern.headFirst.strategyPattern.book;

public class FlyRocketPowered implements FlyBehavior {

    public void fly() {
        System.out.println("flying with rocket");
    }
}

package com.zoey.allTest.pattern.headFirst.strategyPattern.book;

public class MallardDuck extends Duck {
    public MallardDuck() {
        quackBehavior = new Quack();
        flyBehavior = new FlyWithWings();
    }

    public void display() {
        System.out.println("real mallard duck.");
    }
}

package com.zoey.allTest.pattern.headFirst.strategyPattern.book;

public class ModelDuck extends Duck {
    public ModelDuck() {
        flyBehavior = new FlyNoWay();
        quackBehavior = new Quack();
    }

    @Override
    public void display() {
        System.out.println("model duck");
    }
}


package com.zoey.allTest.pattern.headFirst.strategyPattern.book;

public class MiniDuckSimulator {

    public static void main(String[] args) {
        Duck ma = new MallardDuck();
        ma.performFly();
        ma.performQuack();

        System.out.println("------------------");
        Duck model = new ModelDuck();
        model.performFly();
        model.setFlyBehavior(new FlyRocketPowered());
        model.performFly();

    }

}