Java IO 之 装饰模式

Java  处理流相当于对节点流(以File 或Byte 开头的类)进行了包装装饰，装饰模式原理如下

package com.sxt.io;

/**
 * 模拟咖啡
 * 1、抽象组件:需要装饰的抽象对象(接口或抽象父类)
 * 2、具体组件:需要装饰的对象
 * 3、抽象装饰类:包含了对抽象组件的引用以及装饰着共有的方法
 * 4、具体装饰类:被装饰的对象
 *
 * @author TW
 */
public class DecorateTest02
{
	public static void main(String[] args)
	{
		Drink coffee = new Coffee();
		Drink suger = new Suger(coffee); //装饰
		System.out.println(suger.info() + "-->" + suger.cost());

		Drink milk = new Milk(coffee);//装饰
		System.out.println(milk.info() + "-->" + milk.cost());

		milk = new Milk(suger);//装饰
		System.out.println(milk.info() + "-->" + milk.cost());
	}
}

//抽象组件
interface Drink
{
	double cost(); //费用

	String info(); //说明
}

//具体组件
class Coffee implements Drink
{
	private String name = "原味咖啡";

	@Override
	public double cost()
	{

		return 10;
	}

	@Override
	public String info()
	{

		return name;
	}

}

//抽象装饰类
abstract class Decorate implements Drink
{
	//对抽象组件的引用
	private Drink drink;
	public Decorate(Drink drink)
	{
		this.drink = drink;
	}
	@Override
	public double cost()
	{

		return this.drink.cost();
	}
	@Override
	public String info()
	{
		return this.drink.info();
	}
}

//具体装饰类
class Milk extends Decorate
{
	public Milk(Drink drink)
	{
		super(drink);
	}
	@Override
	public double cost()
	{
		return super.cost() * 4;
	}
	@Override
	public String info()
	{
		return super.info() + "加入了牛奶";
	}
}

class Suger extends Decorate
{
	public Suger(Drink drink)
	{
		super(drink);
	}
	@Override
	public double cost()
	{
		return super.cost() * 2;
	}
	@Override
	public String info()
	{
		return super.info() + "加入了蔗糖";
	}
}

装饰者模式跟代理模式