java设计模式-装饰者模式详解

public abstract class Drink {//抽象类
    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
    public abstract float cost();
}

public class Decorator extends Drink {//装饰者
    private Drink obj;
    public Decorator(Drink obj) { //组合
        this.obj = obj;
    }
    @Override
    public float cost() {
        // getPrice 自己价格
        return super.getPrice() + obj.cost();
    }
    @Override
    public String getDes() {
        // obj.getDes() 输出被装饰者的信息
        return des + " " + getPrice() + " && " + obj.getDes();
    }
}
public class Milk extends Decorator {//装饰者子类
    public Milk(Drink obj) {
        super(obj);
        setDes(" 牛奶 ");
        setPrice(2.0f);
    }
}
public class Suger extends Decorator {//装饰者子类
    public Suger(Drink obj) {
        super(obj);
        setDes(" 糖 ");
        setPrice(1.0f);
    }
}

public class Coffee  extends Drink {//被装饰者
    @Override
    public float cost() {
        return super.getPrice();
    }
}
public class Espresso extends Coffee {//被装饰者子类
    public Espresso() {
        setDes(" 意式咖啡 ");
        setPrice(6.0f);
    }
}
public class LongBlack extends Coffee {//被装饰者子类
    public LongBlack() {
        setDes(" 美式咖啡 ");
        setPrice(5.0f);
    }
}

public class Client {
    public static void main(String[] args) {
        // 阿姨的卡布奇诺：意式加两份牛奶、一份糖
        // 1. 点一份Espresso
        Drink order = new Espresso();
        System.out.println("order1 费用=" + order.cost());
        System.out.println("order1 描述=" + order.getDes());
        // 2.1 order 加一份牛奶
        order = new Milk(order);
        System.out.println("order 加入一份牛奶 费用 =" + order.cost());
        System.out.println("order 加入一份牛奶 描述 = " + order.getDes());
        // 2.2 order 再加一份牛奶
        order = new Milk(order);
        System.out.println("order 加入两份牛奶 费用 =" + order.cost());
        System.out.println("order 加入两份牛奶 描述 = " + order.getDes());
        // 3. order 加一份糖
        order = new Suger(order);
        System.out.println("order 两份牛奶、一份糖 费用 =" + order.cost());
        System.out.println("order 两份牛奶、一份糖 描述 = " + order.getDes());
        System.out.println("===========================");
        //美式咖啡加一份牛奶
        //1. 点一份LongBlack
        Drink order2 = new LongBlack();
        System.out.println("order2 费用 =" + order2.cost());
        System.out.println("order2 描述 = " + order2.getDes());
        //2. order2 加一份牛奶
        order2 = new Milk(order2);
        System.out.println("order2 加入一份牛奶 费用 =" + order2.cost());
        System.out.println("order2 加入一份牛奶 描述 = " + order2.getDes());
    }
}