Java设计模式之装饰模式详解

//快餐接口--抽象类或接口实现都可以
public abstract class FastFood {
    private float price;
    private String desc;
​
    public FastFood() {
    }
​
    public FastFood(float price, String desc) {
        this.price = price;
        this.desc = desc;
    }
​
    public void setPrice(float price) {
        this.price = price;
    }
​
    public float getPrice() {
        return price;
    }
​
    public String getDesc() {
        return desc;
    }
​
    public void setDesc(String desc) {
        this.desc = desc;
    }
​
    public abstract float cost();  //获取价格
}
​
//炒饭
public class FriedRice extends FastFood {
​
    public FriedRice() {
        super(10, "炒饭");
    }
​
    public float cost() {
        return getPrice();
    }
}
​
//炒面
public class FriedNoodles extends FastFood {
​
    public FriedNoodles() {
        super(12, "炒面");
    }
​
    public float cost() {
        return getPrice();
    }
}

package com.fupinng3.gar;
 
/**
 * 抽象装饰
 * 即继承自FastFood,又聚合FastFood
 */
public abstract class Garnish extends FastFood{
    private FastFood fastFood;
 
    public Garnish() {
    }
 
    public FastFood getFastFood() {
        return fastFood;
    }
 
    public void setFastFood(FastFood fastFood) {
        this.fastFood = fastFood;
    }
 
    public Garnish(FastFood fastFood,float price, String desc) {
        super(price, desc);
        this.fastFood = fastFood;
    }
}

package com.fupinng3.gar;
 
public class Egg extends Garnish{
    public Egg(FastFood fastFood) {
        super(fastFood, 2, "鸡蛋");
    }
 
    @Override
    public float cost() {
        return getPrice()+getFastFood().cost();
    }
 
    @Override
    public String getDesc() {
        String str1=super.getDesc();
        String str2=getFastFood().getDesc();
        return str1+str2;
    }
}
 
 
 
 
 
package com.fupinng3.gar;
 
public class Bacon extends Garnish{
 
    public Bacon(FastFood fastFood) {
        super(fastFood, 5, "培根");
    }
 
    public float cost() {
        return getPrice()+getFastFood().cost();
    }
 
    @Override
    public String getDesc() {
        return super.getDesc()+getFastFood().getDesc();
    }
}

package com.fupinng3.gar;
 
public class Test {
    public static void main(String[] args) {
        //来个炒面
        FastFood fastFood=new FriedNoodles();
        System.out.println(fastFood.getDesc()+"\t"+fastFood.cost()+"元");
 
        //加个鸡蛋
        fastFood=new Egg(fastFood);
        System.out.println(fastFood.getDesc()+"\t"+fastFood.cost()+"元");
 
        //再加个鸡蛋
        fastFood=new Egg(fastFood);
        System.out.println(fastFood.getDesc()+"\t"+fastFood.cost()+"元");
 
        //再加个培根
        fastFood=new Bacon(fastFood);
        System.out.println(fastFood.getDesc()+"\t"+fastFood.cost()+"元");
 
    }
 
}