设计模式之策略模式

Duck.java

package duck;
import quack.QuackBehavior;
import fly.FlyBehavior;

public abstract class Duck {

    FlyBehavior flyBehavior;
    QuackBehavior quackBehavior;

    public Duck(){
    }

    public abstract void display();

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

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

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

    public void setFlyBehavior(FlyBehavior fb){
        flyBehavior = fb;
    }

    public void setQuackBehavior(QuackBehavior qb){
        quackBehavior = qb;
    }
}

MallardDuck.java

package duck;
import quack.Quack;
import fly.FlyWithWings;

public class MallardDuck extends Duck {

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

    @Override
    public void display() {
        System.out.println("I‘m a real Mallard duck");
    }

}

ModelDuck.java

package duck;
import quack.Quack;
import fly.FlyNoWay;

public class ModelDuck extends Duck {

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

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

}

FlyBehavior.java

package fly;

public interface FlyBehavior {

    public void fly();

}

FlyNoWay.java

package fly;

public class FlyNoWay implements FlyBehavior {

    @Override
    public void fly() {
        System.out.println("I can‘t fly");
    }
}

FlyRocketPowered.java

package fly;
public class FlyRocketPowered implements FlyBehavior {

    @Override
    public void fly() {
        System.out.println("I‘m flying with a rocket!");
    }

}

FlyWithWings.java

package fly;

public class FlyWithWings implements FlyBehavior {

    @Override
    public void fly() {
        System.out.println("I‘m flying!!");
    }
}

QuackBehavior.java

package quack;

public interface QuackBehavior {

    public void quack();

}

Quack.java

package quack;

public class Quack implements QuackBehavior {

    @Override
    public void quack() {
        System.out.println("Quack");
    }
}

MuteQuack.java

package quack;
public class MuteQuack implements QuackBehavior {

    @Override
    public void quack() {
        System.out.println("<<Silence>>");
    }
}

Squeak.java

package quack;
public class Squeak implements QuackBehavior {

    @Override
    public void quack() {
        System.out.println("Squeak");
    }
}