设计模式读书笔记：proxy（代理）

namespace NS_PROXY {

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

} /* namespace NS_PROXY */

#include <iostream>

namespace NS_PROXY {

class RealSubject {
public:
	RealSubject() {}
	virtual ~RealSubject() {}
	virtual void Request(void)
	{
		std::cout << "Request RealSubject." << std::endl;
	}
};

} /* namespace NS_PROXY */

#include "RealSubject.h"

namespace NS_PROXY {

class Proxy {
public:
	Proxy() : _realSubject(0) {}
	virtual ~Proxy()
	{
		if (_realSubject != 0)
			delete _realSubject;
	}
	virtual void Request(void)
	{
		if (_realSubject == 0)
			_realSubject = new RealSubject();

		_realSubject->Request();
	}

private:
	RealSubject *_realSubject;
};

} /* namespace NS_PROXY */

#include "Proxy/Proxy.h"
using namespace NS_PROXY;
int main(void)
{
	Proxy p;
	p.Request();
}