《HeadFirst设计模式(第二版)》第一章源码

代码文件目录结构：

 

FlyBehavior.java

package Chapter1_StrategyPattern.ch1_3_behavior.behaviors.fly;public interface FlyBehavior {void fly();
}

FlyNoWay.java

package Chapter1_StrategyPattern.ch1_3_behavior.behaviors.fly;public class FlyNoWay implements FlyBehavior{@Overridepublic void fly() {System.out.println("I can't fly!");}
}

FlyRocketPowered.java

package Chapter1_StrategyPattern.ch1_3_behavior.behaviors.fly;public class FlyRocketPowered implements FlyBehavior{@Overridepublic void fly() {System.out.println("I'm flying with a rocket!");}
}

FlyWithWings.java

package Chapter1_StrategyPattern.ch1_3_behavior.behaviors.fly;public class FlyWithWings implements FlyBehavior{public void fly(){System.out.println("I'm flying!");}
}

QuackBehavior.java

package Chapter1_StrategyPattern.ch1_3_behavior.behaviors.quack;public interface QuackBehavior {public void quack();
}

MuteQuack.java

package Chapter1_StrategyPattern.ch1_3_behavior.behaviors.quack;public class MuteQuack implements QuackBehavior{@Overridepublic void quack() {System.out.println("<< Silence >>");}
}

Quack.java

package Chapter1_StrategyPattern.ch1_3_behavior.behaviors.quack;public class Quack implements QuackBehavior{@Overridepublic void quack() {System.out.println("Quack!");}
}

Squeak.java

package Chapter1_StrategyPattern.ch1_3_behavior.behaviors.quack;public class Squeak implements QuackBehavior{@Overridepublic void quack() {System.out.println("Squeak!");}
}

Duck.java

package Chapter1_StrategyPattern.ch1_3_behavior;import Chapter1_StrategyPattern.ch1_3_behavior.behaviors.fly.FlyBehavior;
import Chapter1_StrategyPattern.ch1_3_behavior.behaviors.quack.QuackBehavior;public abstract class Duck {FlyBehavior flyBehavior;QuackBehavior quackBehavior;public Duck(){}public void setFlyBehavior(FlyBehavior flyBehavior) {this.flyBehavior = flyBehavior;}public void setQuackBehavior(QuackBehavior quackBehavior) {this.quackBehavior = quackBehavior;}public void performFly(){this.flyBehavior.fly();}public void performQuack(){this.quackBehavior.quack();}public void swim(){System.out.println("the duck is swimming!");}public abstract void display();
}

MallardDuck.java

package Chapter1_StrategyPattern.ch1_3_behavior;import Chapter1_StrategyPattern.ch1_3_behavior.behaviors.fly.FlyWithWings;
import Chapter1_StrategyPattern.ch1_3_behavior.behaviors.quack.Quack;//绿头鸭
public class MallardDuck extends Duck {public MallardDuck(){this.flyBehavior = new FlyWithWings();this.quackBehavior = new Quack();}@Overridepublic void display() {System.out.println("this is a MallardDuck!");}
}

RedHeadDuck.java

package Chapter1_StrategyPattern.ch1_3_behavior;import Chapter1_StrategyPattern.ch1_3_behavior.behaviors.fly.FlyWithWings;
import Chapter1_StrategyPattern.ch1_3_behavior.behaviors.quack.Quack;public class RedHeadDuck extends Duck {public RedHeadDuck(){this.flyBehavior = new FlyWithWings();this.quackBehavior = new Quack();}@Overridepublic void display() {System.out.println("this is a redHeadDuck!");}
}

RubberDuck.java

package Chapter1_StrategyPattern.ch1_3_behavior;import Chapter1_StrategyPattern.ch1_3_behavior.behaviors.fly.FlyNoWay;
import Chapter1_StrategyPattern.ch1_3_behavior.behaviors.quack.Squeak;public class RubberDuck extends Duck{public RubberDuck(){this.flyBehavior = new FlyNoWay();this.quackBehavior = new Squeak();}@Overridepublic void display() {System.out.println("this is a rubberDuck!");}
}

DecoyDuck.java

package Chapter1_StrategyPattern.ch1_3_behavior;import Chapter1_StrategyPattern.ch1_3_behavior.behaviors.fly.FlyNoWay;
import Chapter1_StrategyPattern.ch1_3_behavior.behaviors.quack.MuteQuack;public class DecoyDuck extends Duck {public DecoyDuck(){this.flyBehavior = new FlyNoWay();this.quackBehavior = new MuteQuack();}@Overridepublic void display() {System.out.println("this is a DecoyDuck!");}
}

ModelDuck.java

package Chapter1_StrategyPattern.ch1_3_behavior;import Chapter1_StrategyPattern.ch1_3_behavior.behaviors.fly.FlyNoWay;
import Chapter1_StrategyPattern.ch1_3_behavior.behaviors.quack.MuteQuack;public class ModelDuck extends Duck{public ModelDuck(){this.quackBehavior = new MuteQuack();this.flyBehavior = new FlyNoWay();}@Overridepublic void display() {System.out.println("I'm a model duck!");}
}

MiniDuckSimulator.java

package Chapter1_StrategyPattern.ch1_3_behavior;import Chapter1_StrategyPattern.ch1_3_behavior.behaviors.fly.FlyRocketPowered;public class MiniDuckSimulator {public static void main(String[] args) {Duck mallard = new MallardDuck();mallard.performFly();mallard.performQuack();Duck model = new ModelDuck();model.performFly();model.setFlyBehavior(new FlyRocketPowered());model.performFly();}
}

notes.txt

ch1_1直接使用继承来应付新增子类的问题问题：
1.当子类鸭子的数量越来越多的时候，继承就难以保证整个系统的可维护性，因为每次添加一个子类，都要对对应的属性是否要实现进行考虑
2.代码在多个子类重复
3.代码在运行时难以改变ch1_2将其中某些非共通的行为抽取出来作为接口问题：
1.对于具有同一个行为的每个子类都会重复代码，可维护性差ch1_31.将某一类行为抽取出来作为一系列行为类，从is-a转为has-a ==> 将继承转成组合
2.使用setter实现动态设置行为设计模式：定义一个算法族，分别封装起来，是的他们之间可以相互变换，使得算法的变化独立于使用他的客户（鸭子）

运行结果：