Flyweight

#include <iostream>

#include <vector>



using namespace std;







#define SHARE_FLAG string

#define DESTROY_POINTER(ptr) if (ptr) { delete ptr; ptr = NULL; }









class Flyweight

{

public:

    Flyweight(SHARE_FLAG flag) : m_shareFlag(flag) {}



    virtual void Operation()=0;

    virtual SHARE_FLAG GetShareFlag() { return m_shareFlag; }



protected:

    SHARE_FLAG m_shareFlag;

};





class ConcreteFlyweight : public Flyweight

{

public:

    ConcreteFlyweight(SHARE_FLAG flag) : Flyweight(flag) {}

    ~ConcreteFlyweight() {}



    void Operation() { cout<<"share flag:"<<m_shareFlag<<endl; }

};





class FactoryFlyweight

{

public:

    FactoryFlyweight() {}

    ~FactoryFlyweight();

    Flyweight* CreateFlyweight(SHARE_FLAG flag);



private:

    vector<Flyweight*> m_objectList;

};



FactoryFlyweight::~FactoryFlyweight()

{

    for (unsigned int i = 0; i < m_objectList.size(); i++)

    {

        Flyweight* pTmp = m_objectList[i];

        DESTROY_POINTER(pTmp);

    }



    m_objectList.clear();

}



Flyweight* FactoryFlyweight::CreateFlyweight(SHARE_FLAG flag)

{

    for (unsigned int i = 0; i < m_objectList.size(); i++)

    {

        if (m_objectList[i]->GetShareFlag() == flag)

        {

            cout<<"cache object["<<m_objectList[i]->GetShareFlag()<<"]"<<endl;

            return m_objectList[i];

        }

    }



    ConcreteFlyweight* newObj = new ConcreteFlyweight(flag);

    m_objectList.push_back(newObj);



    return newObj;

}







int main(int argc, char *argv[])

{

    FactoryFlyweight* pFactory = NULL;

    Flyweight* pFlyweight = NULL;





    pFactory = new FactoryFlyweight;

    pFlyweight = pFactory->CreateFlyweight("object1");

    pFlyweight = pFactory->CreateFlyweight("object2");

    pFlyweight = pFactory->CreateFlyweight("object3");

    pFlyweight = pFactory->CreateFlyweight("object1");

    pFlyweight = pFactory->CreateFlyweight("object3");

    



    DESTROY_POINTER(pFactory);



    return 0;

}