Proxy (C++实现）

// Proxy.cpp : 定义控制台应用程序的入口点。
//

#include "stdafx.h"
#include <iostream>

using namespace std;

class Subject
{
public:
 Subject()
 {}
 virtual ~Subject()
 {}
 virtual void Request()=0;
};

class RealSubject:public Subject
{
public:
 RealSubject()
 {
  cout<<"Construction of RealSubject"<<endl;
 }
 virtual ~RealSubject()
 {
  cout<<"Deconstruction of RealSubject"<<endl;
 }
 void Request ()
 {
  cout<<"-------------------------------------"<<endl;
 }
};

class Proxy:public Subject
{
public:
  Proxy():rs(NULL)
 {

  cout<<"Construction of Proxy for RealSubject"<<endl;
 }
 virtual ~Proxy()
 {
  delete rs;
  rs=NULL;
 }

 void Request()
 {
  if(NULL==rs)
  {
   cout<<"Create a new RealSubject and Reaquest"<<endl;
   rs=new RealSubject();
  }
  else
  {
   cout<<"The  RealSubject has been created"<<endl;
  }
  rs->Request();
 }
private:
 RealSubject* rs;
};
int _tmain(int argc, _TCHAR* argv[])
{
 Subject *pProxy=new Proxy();
 pProxy->Request();
 pProxy->Request();
 delete pProxy;
 
 return 0;
}