#pragma once

#ifndef FLYWEIGHT_H 

#define FLYWEIGHT_H 

#include <string> 
#include <list> 

typedef std::string STATE; 

class Flyweight 
{ 
public: 
  virtual ~Flyweight(){} 
  STATE GetIntrinsicState(); 
  virtual void Operation(STATE& ExtrinsicState) = 0; 

protected: 
  Flyweight(const STATE& state) 
    :m_State(state) 
  { 
  } 

private: 
  STATE m_State; 
}; 

class FlyweightFactory 
{ 
public: 
  FlyweightFactory(){} 
  ~FlyweightFactory(); 
  Flyweight* GetFlyweight(const STATE& key); 

private: 
  std::list<Flyweight*>    m_listFlyweight; 
}; 

class ConcreateFlyweight : public Flyweight 
{ 
public: 
  ConcreateFlyweight(const STATE& state) 
    : Flyweight(state) 
  { 
  } 
  virtual ~ConcreateFlyweight(){} 
  virtual void Operation(STATE& ExtrinsicState); 
}; 

#endif


#include "StdAfx.h"
#include "flyweight_impl.h"

#include <iostream> 

inline STATE Flyweight::GetIntrinsicState() 
{ 
  return m_State; 
} 

FlyweightFactory::~FlyweightFactory() 
{ 
  for (std::list<Flyweight*>::iterator iter = m_listFlyweight.begin();
    iter != m_listFlyweight.end(); ++iter) 
  { 
    delete (*iter);
  } 
  m_listFlyweight.clear(); 
} 

Flyweight* FlyweightFactory::GetFlyweight(const STATE& key) 
{
  for (std::list<Flyweight*>::iterator iter = m_listFlyweight.begin();
    iter != m_listFlyweight.end(); ++iter) 
  { 
    if ((*iter)->GetIntrinsicState() == key) 
    { 
      std::cout << "The Flyweight:" << key << " already exits"<< std::endl; 
      return (*iter); 
    } 
  } 

  std::cout << "Creating a new Flyweight:" << key << std::endl; 
  Flyweight* flyweight = new ConcreateFlyweight(key); 
  m_listFlyweight.push_back(flyweight); 

  return flyweight;
} 

void ConcreateFlyweight::Operation(STATE& ExtrinsicState) 
{ 
  std::cout<<ExtrinsicState<<std::endl;
}


// FlyWeight.cpp : 定义控制台应用程序的入口点。
//

#include "stdafx.h"
#include "flyweight_impl.h"
#include <stdlib.h>

//运用共享技术有效地支持大量细粒度的对象。

int _tmain(int argc, _TCHAR* argv[])
{
  FlyweightFactory flyweightfactory; 

  flyweightfactory.GetFlyweight("hello"); 
  flyweightfactory.GetFlyweight("world"); 
  flyweightfactory.GetFlyweight("hello"); 

  system("pause"); 
  return 0;
}