设计模式之装饰者模式

装饰者模式的定义

装饰者模式原理

package com.cedric.decorator;

public class Coffee extends Drink{
    @Override
    public float cost() {
        return super.getPrice();
    }
}

package com.cedric.decorator;

public class LongBlack extends Coffee{

    public LongBlack(){
        setDes("LongBlack");
        setPrice(5.0f);
    }
}

package com.cedric.decorator;

public class ShortBlack extends Coffee{

    public ShortBlack(){
        setDes("ShortBlack");
        setPrice(7.0f);
    }
}

package com.cedric.decorator;

public class DeCaf extends Coffee{
    public DeCaf(){
        setDes("无因咖啡");
        setPrice(9.0f);
    }
}
           

package com.cedric.decorator;

public abstract class Drink {

    public String des;//描述
    private float price = 0.0f;

    public String getDes() {
        return des;
    }

    public void setDes(String des) {
        this.des = des;
    }

    public float getPrice() {
        return price;
    }

    public void setPrice(float price) {
        this.price = price;
    }

    // 计算费用的抽象方法
    // 子类来实现
    public abstract float cost();
}
           

package com.cedric.decorator;
// 具体的Decorator,这里就是调味品
public class Chocolate extends Decorator{
    public Chocolate(Drink obj) {
        super(obj);
        setDes("巧克力");
        setPrice(3.0f);// 调味品的价格
    }
}

package com.cedric.decorator;

public class Milk extends Decorator{

    public Milk(Drink obj) {
        super(obj);
        setDes("牛奶");
        setPrice(2.0f);
    }
}


package com.cedric.decorator;

public class Soy extends Decorator{
    public Soy(Drink obj) {
        super(obj);
        setDes("豆浆");
        setPrice(1.5f);
    }
}
           

package com.cedric.decorator;

public class CofferBar {
    public static void main(String[] args) {
        // 装饰者模式下的订单：2份巧克力 + 一份牛奶的LongBlack

        // 1.点一份LongBlack
        Drink order = new LongBlack();
        System.out.println(order.getDes() + ":"+ order.cost());

        // 2.加入一份牛奶
        order = new Milk(order);
        System.out.println("加入一份牛奶 ：" + order.getDes() + ":"+ order.cost());

        // 3.order加入一份巧克力
        order = new Chocolate(order);
        System.out.println("加入一份牛奶 和 巧克力 ：" + order.getDes() + ":"+ order.cost());

        // 4.order又加入一份巧克力
        order = new Chocolate(order);
        System.out.println("加入一份牛奶 和 两份巧克力 ：" + order.getDes() + ":"+ order.cost());

        // 点一份DeCaf
        Drink drink = new DeCaf();
        System.out.println(drink.getDes() + drink.getPrice());
    }
}
           

package com.cedric.decorator;

public class Decorator extends Drink{
    private Drink obj;

    public Decorator(Drink obj){ //组合
        this.obj = obj;
    }
    @Override
    public float cost() {
        //getPrice自己的价格
        return super.getPrice() + obj.cost();
    }

    @Override
    public String getDes() {
         // obj.getDes()输出被装饰者信息
        return super.des + " " + super.getDes() + "&&" + obj.getDes();
    }
}