设计模式之装饰器模式 Decorator 包装模式 wrapper 优点 缺点 使用场景 以及简化方法

package decorator;
/**
* Created by noteless on 2018/9/6.
* Description:手抓饼接口 描述抽象的手抓饼
*/
public interface HandPancake {
/**
* 提供手抓饼
*/
String offerHandPancake();
/**计算手抓饼的价格
* @return
*/
Integer calcCost();
}

package decorator;
/**
* Created by noteless on 2018/9/6.
* Description: Noteless 家的手抓饼
*/
public class NotelessHandPancake implements HandPancake {
/**
* 提供noteless 家的手抓饼一份
*/
@Override
public String offerHandPancake() {
return " noteless 家的手抓饼";
}
/**计算 noteless 家 一份手抓饼的价格
* @return
*/
@Override
public Integer calcCost() {
return 3;
}
}

package decorator;
/**
* Created by noteless on 2018/9/6.
* Description:装饰器类实现了手抓饼接口,具有了手抓饼的类型
*/
public abstract class Decorator implements HandPancake{
private HandPancake handPancake;
Decorator(HandPancake handPancake){
this.handPancake = handPancake;
}
/**提供手抓饼
* @return
*/
@Override
public String offerHandPancake() {
return handPancake.offerHandPancake();
}

/**提供手抓饼的价格
* @return
*/
@Override
public Integer calcCost() {
return handPancake.calcCost();
}
}

package decorator;
/**
* Created by noteless on 2018/9/6.
* Description:培根
*/
public class Bacon extends Decorator {
    Bacon(HandPancake handPancake){
        super(handPancake);
    }

    @Override
    public String offerHandPancake() {
        return super.offerHandPancake()+" 加培根";
    }
    @Override
    public Integer calcCost() {
        return super.calcCost()+4;
    }
}

package decorator;
/**
* Created by noteless on 2018/9/6.
* Description:鸡蛋
*/
public class Egg extends Decorator {
    Egg(HandPancake handPancake){
        super(handPancake);
    }
    @Override
    public String offerHandPancake() {
        return super.offerHandPancake()+"加鸡蛋";
    }
    @Override
    public Integer calcCost() {
        return super.calcCost()+2;
    }
}

package decorator;
/**
* Created by noteless on 2018/9/6.
* Description:烤肠
*/
public class Sausage extends Decorator {
    Sausage(HandPancake handPancake){
        super(handPancake);
    }
    @Override
    public String offerHandPancake() {
        return super.offerHandPancake()+" 加香肠";
    }
    @Override
    public Integer calcCost() {
        return super.calcCost()+3;
    }
}

package decorator;
/**
* Created by noteless on 2018/9/6.
* Description:青菜
*/
public class Vegetable extends Decorator {
    Vegetable(HandPancake handPancake){
        super(handPancake);
    }
    @Override
    public String offerHandPancake() {
        return super.offerHandPancake()+" 加青菜";
    }
    @Override
    public Integer calcCost() {
        return super.calcCost()+1;
    }

}

package decorator;
/**
* Created by noteless on 2018/9/6.
* Description:顾客具有名字,然后购买手抓饼
*/
public class Customer {
private String name;
Customer(String name){
this.name = name;
}

public void buy(HandPancake handPancake){
　　System.out.println(name+"购买了 : "+handPancake.offerHandPancake()+
　　" 一份, 花了 : "+handPancake.calcCost()+"块钱~");
　　System.out.println();
}
}

package decorator;

/**
* Created by noteless on 2018/9/6.
* Description:
* 手抓饼3块
* Sausage 烤肠 3块
* Bacon 培根 4块
* Egg 鸡蛋2块
* Vegetable 青菜 1块
*/

public class Test {
public static void main(String ...strings){

//有一个顾客张三,他想吃手抓饼了,来了一个原味的
Customer customerA = new Customer("张三");
customerA.buy(new NotelessHandPancake());

//有一个顾客李四,他想吃手抓饼了,他加了一根烤肠
Customer customerB = new Customer("李四");
customerB.buy(new Sausage(new NotelessHandPancake()));

//有一个顾客王五,他想吃手抓饼了,他加了一根烤肠 又加了培根
Customer customerC = new Customer("王五");
customerC.buy(new Bacon(new Sausage(new NotelessHandPancake())));

//有一个顾客王五的兄弟,他想吃手抓饼了,他加了培根 又加了烤肠
Customer customerC1 = new Customer("王五的兄弟");
customerC1.buy(new Sausage(new Bacon(new NotelessHandPancake())));

//有一个顾客赵六,他想吃手抓饼了,他加了一根烤肠 又加了2份培根
Customer customerD = new Customer("赵六");
customerD.buy(new Bacon(new Bacon(new Sausage(new NotelessHandPancake()))));

//有一个顾客 王二麻子,他想吃手抓饼了,特别喜欢吃青菜 来了三分青菜
Customer customerE = new Customer("王二麻子");
customerE.buy(new Vegetable(new Vegetable(new Vegetable(new NotelessHandPancake()))));

//有一个顾客 有钱人 王大富 来了一个全套的手抓饼
Customer customerF = new Customer("王大富");
customerF.buy(new Egg(new Vegetable(new Bacon(new Sausage(new NotelessHandPancake())))));
}
}