设计模式-行为-命令

#pragma once

#ifndef COMMAND_H 

#define COMMAND_H 

class Command 
{ 
public: 
  virtual ~Command() {} 
  virtual void Execute() = 0; 
}; 

class Receiver 
{ 
public: 
  void Action(); 
}; 

class Invoker 
{ 
public: 
  Invoker(Command *pCommand); 
  ~Invoker(); 
  void Invoke(); 

private: 
  Command *m_pCommand; 
}; 

class ConcreateComand : public Command 
{ 
public: 
  ConcreateComand(Receiver* pReceiver); 
  virtual ~ConcreateComand(); 
  virtual void Execute(); 

private: 
  Receiver* m_pReceiver; 
}; 

#endif

#include "StdAfx.h"
#include "command_impl.h"

#include <iostream> 

void Receiver::Action() 
{ 
  std::cout << "Receiver Action\n"; 
} 

Invoker::Invoker(Command *pCommand) 
: m_pCommand(pCommand) 
{ 
} 

Invoker::~Invoker() 
{ 
  delete m_pCommand; 
  m_pCommand = NULL; 
} 

void Invoker::Invoke() 
{ 
  if (NULL != m_pCommand) 
  { 
    m_pCommand->Execute(); 
  } 
} 

ConcreateComand::ConcreateComand(Receiver* pReceiver) 
: m_pReceiver(pReceiver) 
{ 
} 

ConcreateComand::~ConcreateComand() 
{ 
  delete m_pReceiver; 
  m_pReceiver = NULL; 
} 

void ConcreateComand::Execute() 
{ 
  if (NULL != m_pReceiver) 
  { 
    m_pReceiver->Action(); 
  } 
  std::cout << "Execute by ConcreateComand\n"; 
}

// Command.cpp : 定义控制台应用程序的入口点。
//

#include "stdafx.h"

#include "command_impl.h"
#include <stdlib.h>

//将一个请求封装为一个对象,从而使你可用不同的请求对客户进行参数化;
//对请求排队或记录请求日志,以及支持可撤消的操作. 
int _tmain(int argc, _TCHAR* argv[])
{
  Receiver* pReceiver = new Receiver();//回调处理事务 
  Command* pCommand   = new ConcreateComand(pReceiver);//回调函数 

  //invoker并不知道命令的接收者
  Invoker* pInvoker   = new Invoker(pCommand); //注册回调

  pInvoker->Invoke(); //先处理注册回调，在回调中处理具体事务

  delete pInvoker; 

  system("pause"); 
  return 0;
}