设计模式理解（十）结构型——享元（Flyweight）

最后一个结构型，享元。没有太多的项目经验，对这种模式只有一种概念上的理解，就是为了节约内存等资源，把可重用的东西只申请一次，然后处处调用，同时用Hash进行管理。

    直接上图：

 

代码：

/*********  大话设计模式上的代码 ************/

abstract class Flyweight{
    public abstract void Operation(int extrinsicstate); 
}

class ConcreteFlyweight : Flyweight{
    public override void Operation(int extrinsicstate){
        Console.WriteLine("具体Flyweight : " +　extrinsicstate);
    }
}

class UnshareConcreteFlyweight : Flyweight{
    public override void Operation(int extrinsicstate){
        Console.WriteLine("不共享的具体Flyweight : " + extrinsicstate);
    }
}

class FlyweightFactory{
    private Hashtable flyweights = new Hashtable();
    public FlyweightFactory(){
        flyweights.add("X",new ConcreteFlyweight());
        flyweights.add("Y",new ConcreteFlyweight());
    }
    public Flyweight GetFlyweight(string key){
        return ((Flyweight)flyweights[key]);
    }
}