C++ handler

写下来，备忘：

类似于MFC中的：

// handler.h

#ifndef _HANDLER_H_
#define _HANDLER_H_

#define COMMAND_FIRST 1
#define COMMAND_SECOND 2
#define COMMAND_THIRD 3

class CHandler
{
public:
 CHandler(){}
 ~CHandler(){}

 int Process(int command);

private:
 int OnFirst(int first);
 int OnSecond(int second);
 int OnThird(int third);

private:
 typedef int (CHandler::*PHANDLER)(int id);
 struct HandlerEntry
 {
  char bCommand;
  PHANDLER pHandler;
 };

 static const HandlerEntry m_handlers[];
};

#endif

 

// handler.cpp

#include "handler.h"
#include

const CHandler::HandlerEntry CHandler::m_handlers[] =
{
 {COMMAND_FIRST, &CHandler::OnFirst},
 {COMMAND_SECOND, &CHandler::OnSecond},
 {COMMAND_THIRD, &CHandler::OnThird}
};

int CHandler::Process(int command)
{
 if (command < 0)
 {
  return command;
 }

 const int handlerCount = sizeof(m_handlers) / sizeof(HandlerEntry);
 for (int i = 0; i < handlerCount; ++i)
 {
  if (m_handlers[i].bCommand == command)
  {
   PHANDLER pHandler = m_handlers[i].pHandler;
   return (this->*pHandler)(command);
  }
 }

 return -1;
}

int CHandler::OnFirst(int first)
{
 printf("OnFirst\n");
 return first;
}

int CHandler::OnSecond(int second)
{
 printf("OnSecond\n");
 return second;
}

int CHandler::OnThird(int third)
{
 printf("OnThird\n");
 return third;
}

 

// 调用

#include "handler.h"
#include "compares.h"

int main()
{
 CHandler *pHandler = new CHandler();
 for (int i = -1; i < 4; ++i)
 {
  int result = pHandler->Process(i);
  if (result < 0)
  {
   printf("Bad Command\n");
   continue;
  }
 }

 

 return 0;
}