五个角色:抽象轻量级类(Flyweight)、具体轻量级类(ConcreteFlyweight)、不共享具体轻量级类(UnsharedConcreteFlyweight)、轻量级类工厂(FlyweightFactory)、客户端(Client)
抽象轻量级类(Flyweight):声明一个接口并且有一些属性可以设置对象的状态
具体轻量级类(ConcreteFlyweight):实现接口,并且有相关的状态
不共享具体轻量级类(UnsharedConcreteFlyweight):不被共享的具体轻量级类
轻量级类工厂(FlyweightFactory):创建并且管理Flyweight对象,当客户端发出轻量级类请求时提供一个已创建或者未创建的对象
客户端(Client) :只需要使用轻量级类工厂调用相应的轻量级类即可。
实现思路:客户端调用轻量级类工厂,工厂去查找是否已经有轻量级类实例,如果有则直接返回给客户端,如果没有则根据条件创建相应的实例给客户端。
类图:
<a target="_blank" href="http://blog.51cto.com/attachment/201204/163712996.gif"></a>
应用场景:游戏中的衣服实对象有很多种,会背穿在很多人的身上。
分析:游戏中的衣服它穿在很多人的身上,如果为每个人身上的衣服设置一个实例,那么对服务器的压力将不言而喻,这时如果在衣服内部设置很多种状态属性,在客户端调用的时候,使用轻量级类工厂来创建选择即可。
下面我们在控制台程序去演示一下如何使用Flyweight Pattern:
一、抽象轻量级类(Flyweight)
//抽象轻量级类(Flyweight)
abstract class Clothes
{
public string Name { get; set; }
public int Defense { get; set; }
public abstract void GetDefense();
}
二、具体轻量级类(ConcreteFlyweight)
//具体轻量级类(ConcreteFlyweight)
class LowClothes : Clothes
public LowClothes()
{
Name = "青铜圣衣";
Defense = 50;
}
public override void GetDefense()
Console.WriteLine(Name + "的防御是" + Defense);
class MiddleClothes : Clothes
public MiddleClothes()
Name = "白银圣衣";
Defense = 80;
class HighClothes : Clothes
public HighClothes()
Name = "黄金圣衣";
Defense = 100;
三、轻量级类工厂(FlyweightFactory)
//轻量级类工厂(FlyweightFactory)
class ClothesFactory
private Hashtable clothesHT = new Hashtable();
public Clothes GetClothes(string clothesName)
Clothes clothes = (Clothes)clothesHT[clothesName];
if (clothes == null)
{
switch (clothesName)
{
case "青铜圣衣": clothes = new LowClothes();
break;
case "白银圣衣": clothes = new MiddleClothes();
case "黄金圣衣": clothes = new HighClothes();
}
clothesHT.Add(clothesName, clothes);
}
return clothes;
四、客户端(Client)
//客户端(Client)
class Program
static void Main(string[] args)
ClothesFactory fac = new ClothesFactory();
fac.GetClothes("黄金圣衣").GetDefense();
fac.GetClothes("白银圣衣").GetDefense();
fac.GetClothes("青铜圣衣").GetDefense();
Console.ReadLine();
本文转自程兴亮 51CTO博客,原文链接:http://blog.51cto.com/chengxingliang/827013