Java装饰者模式的示例详解

public abstract class Coffee {
    private String desc;

    private float price;

    public abstract float cost();

    public String getDesc() {
        return desc;
    }

    public void setDesc(String desc) {
        this.desc = desc;
    }

    public float getPrice() {
        return price;
    }

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

public class Cappuccino extends Coffee{
    public Cappuccino(){
        setDesc("点了一杯卡布奇诺");
        setPrice(100);
    }

    @Override
    public float cost() {
        System.out.println("当前价格为：" + super.getPrice());
        return super.getPrice();
    }
}

public class Decorator extends Coffee{

    private Coffee coffee;

    public Decorator(Coffee coffee){
        this.coffee = coffee;
    }

    @Override
    public float cost() {
        return super.getPrice() + this.coffee.cost();
    }

    @Override
    public String getDesc() {
        return super.getDesc() + coffee.cost();
    }
}

public class HotMilk extends Decorator {
    public HotMilk(Coffee coffee){
        super(coffee);
        setPrice(200);
        setDesc("点了一杯热牛奶");
    }
}

public class Test {
    public static void main(String[] args) {
        // 点了一杯卡布奇诺，还加了一份热牛奶
        Coffee coffee = new Cappuccino();
        System.out.println(coffee.getDesc());
        //System.out.println(coffee.getPrice());
        System.out.println(coffee.cost());;

        HotMilk hotMilk = new HotMilk(coffee);
        System.out.println(hotMilk.getDesc());
        //System.out.println(hotMilk.getPrice());
        System.out.println(hotMilk.cost());
    }
}