设计模式——策略模式

把可能会变化的部分封装起来。

package Strategy_pattern;

interface FlyBehavior {
    public void fly();
}

interface QuackBehavior {
    public void quack();
}

// 鸭子抽象类
abstract class Duck {
    protected FlyBehavior flyBehavior;     // 每个鸭子都有的飞行为和叫行为
    protected QuackBehavior quackBehavior;
    public Duck() {

    }
    public abstract void display();
    public void performFly() {
        flyBehavior.fly();
    }
    public void performQuack() {
        quackBehavior.quack();
    }
    public void swim() {
        System.out.println("I like swimming!");
    }
}

class FlyNoWay implements FlyBehavior {
    @Override
    public void fly() {
        System.out.println("I can't fly");
    }
}

class QuackNoWay implements QuackBehavior {
    @Override
    public void quack() {
        System.out.println("I can't quack");
    }
}

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

    @Override
    public void display() {
        System.out.println("I am ModelDuck");
    }

}

// 测试
public class Main {
    public static void main(String args[]) {
        Duck duck = new ModelDuck();
        duck.display();
        duck.performFly();
        duck.performQuack();
        duck.swim();
    }
}