享元模式

//Flyweight.h
#include "stdafx.h"
#include <iostream>
#include <map>
#include <string>
using namespace std;

class User
{
private :
        string m_name;
public :
       User( string name) :m_name( name){}
        string GetName()
       {
               return m_name;
       }
};

class Flyweight
{
public :
        virtual ~Flyweight(){}
        virtual void Operation( User* pUser) = 0;
};

class ConcreteFlyweight :public Flyweight
{
public :
        virtual void Operation( User* pUser)
       {
              cout << "具体Flyweight：" <<pUser ->GetName()<< endl;
       }
};

class UnsharedConcreteFlyweight :public Flyweight
{
public :
        virtual void Operation( User* pUser)
       {
              cout << "不共享的具体Flyweight：" << pUser->GetName() << endl;
       }
};


class FlyweightFactory
{
private :
        map< string, Flyweight*> Flyweights;
public :
       FlyweightFactory()
       {
               /*Flyweights.insert(make_pair("x", new ConcreteFlyweight()));
              Flyweights.insert(make_pair("y", new ConcreteFlyweight()));
              Flyweights.insert(make_pair("z", new ConcreteFlyweight()));*/
       }

        Flyweight* GetFlyweight( string key)
       {
               map< string, Flyweight*>:: iterator it = Flyweights.find( key);
               if (it == Flyweights.end()) //如果不存在，实例化一个
              {
                      ConcreteFlyweight * cf = new ConcreteFlyweight ();
                     Flyweights.insert(make_pair( key, cf));
                      return cf;
              }
               return it->second;
       }

        int GetCount()
       {
               return Flyweights.size();
       }
};

// FlyweightPattern.cpp : Defines the entry point for the console application.
//

#include "stdafx.h"
#include "Flyweight.h"

int _tmain (int argc , _TCHAR * argv [])
{
        FlyweightFactory * flyFactory = new FlyweightFactory ();

        Flyweight* fx = flyFactory->GetFlyweight( "x" );
       fx->Operation( new User( "小x" ));

        Flyweight* fy = flyFactory->GetFlyweight( "y" );
       fy->Operation( new User( "小y" ));

        Flyweight* fz = flyFactory->GetFlyweight( "z" );
       fz->Operation( new User( "小z" ));

        UnsharedConcreteFlyweight * uf = new UnsharedConcreteFlyweight ();
       uf->Operation( new User( "UnsharedConcreteFlyweight" ));

       cout << "共有" << flyFactory->GetCount() << "种类型" << endl;
       getchar();
        return 0;
}