設計模式理解（十）結構型——享元（Flyweight）

最後一個結構型，享元。沒有太多的項目經驗，對這種模式只有一種概念上的理解，就是爲了節約內存等資源，把可重用的東西只申請一次，而後到處調用，同時用Hash進行管理。

    直接上圖：

 

代碼：

/*********  大話設計模式上的代碼 ************/

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

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

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