设计模式之装饰者模式

装饰者模式
1.装饰者模式就像打包一个快递
（1）主体：陶瓷，衣服。
（2）报纸填充，塑料泡沫，纸板，木板
2.Component
3.ConcreteComponent和Decorator
4.装饰者模式：动态的将新功能附加到对象上。在对象功能扩展方面，它比继承更有弹性。

5.有些递归的意思

类结构图

示例代码

package com.coffeebar.main;

public abstract class Drink {
	public String description = "";
	private float price = 0f;
	public String getDescription() {
		return description;
	}
	public void setDescription(String description) {
		this.description = description;
	}
	public float getPrice() {
		return price;
	}
	public void setPrice(float price) {
		this.price = price;
	}
	
	public abstract float cost();
	
}

package com.coffeebar.coffee;

import com.coffeebar.main.Drink;

public class Coffee extends Drink {

	@Override
	public float cost() {
		// TODO Auto-generated method stub
		return super.getPrice();
	}

}

package com.coffeebar.coffee;

import com.coffeebar.main.Drink;

public class Decaf extends Coffee {

	public Decaf() {
		super.setDescription("Decaf");
		super.setPrice(3.0f);
	}

}

package com.coffeebar.coffee;

public class Espresso extends Coffee {
	public Espresso() {
		super.setDescription("Espresso");
		super.setPrice(4.0f);
	}
}

package com.coffeebar.coffee;

public class LongBlack extends Coffee {
	public LongBlack() {
		super.setDescription("LongBlack");
		super.setPrice(5.5f);
	}
}

package com.coffeebar.coffee;

public class ShortBlack extends Coffee {
	public ShortBlack() {
		super.setDescription("ShortBlack");
		super.setPrice(6.0f);
	}
}

package com.coffeebar.decorator;

import com.coffeebar.main.Drink;

public class Decorator extends Drink {
	private Drink Obj;
	
	public Decorator(Drink Obj) {
		this.Obj = Obj;
	}

	@Override
	public float cost() {
		// TODO Auto-generated method stub
		return super.getPrice() + Obj.cost();
	}

	public String Description() {
		return super.description+"-"+super.getPrice()+"&&"+Obj.getDescription();
	}
}

package com.coffeebar.decorator;

import com.coffeebar.main.Drink;

public class Chocolate extends Decorator {

	public Chocolate(Drink Obj) {
		super(Obj);
		// TODO Auto-generated constructor stub
		super.setDescription("Chocolate");
		super.setPrice(3.0f);
	}
	
}

package com.coffeebar.decorator;

import com.coffeebar.main.Drink;

public class Milk extends Decorator {

	public Milk(Drink Obj) {
		super(Obj);
		// TODO Auto-generated constructor stub
		super.setDescription("Milk");
		super.setPrice(2.0f);
	}

}

package com.coffeebar.decorator;

import com.coffeebar.main.Drink;

public class Soy extends Decorator {

	public Soy(Drink Obj) {
		super(Obj);
		// TODO Auto-generated constructor stub
		super.setDescription("Soy");
		super.setPrice(1.5f);
	}

}

package com.coffeebar.main;

import com.coffeebar.coffee.Decaf;
import com.coffeebar.coffee.LongBlack;
import com.coffeebar.decorator.Chocolate;
import com.coffeebar.decorator.Milk;

public class Coffeebar {

	/**
	 * @param args
	 */
	public static void main(String[] args) {
		// TODO Auto-generated method stub
		Drink order;
		order = new Decaf();
		System.out.println("order1 price: " + order.cost());
		System.out.println("order1 desc: " +order.getDescription());
		
		System.out.println("*******************");
		order = new LongBlack();
		order = new Milk(order);
		order = new Chocolate(order);
		order = new Chocolate(order);
		System.out.println("order2 price: " + order.cost());
		System.out.println("order2 desc: " + order.getDescription());
	}

}

 输出结果

order1 price: 3.0
order1 desc: Decaf
*******************
order2 price: 13.5
order2 desc: Chocolate