reflection2.cpp

#include <iostream>
#include <map>
#include <string>
using namespace std;

typedef void *(*PTRCreateObject)(void);

class ClassFactory {
private:
  map<string, PTRCreateObject> m_classMap;
  ClassFactory(){}; //构造函数私有化

public:
  void *getClassByName(string className);
  void registClass(string name, PTRCreateObject method);
  static ClassFactory &getInstance();
};

void *ClassFactory::getClassByName(string className) {
  map<string, PTRCreateObject>::const_iterator iter;
  iter = m_classMap.find(className);
  if (iter == m_classMap.end())
    return NULL;
  else
    return iter->second();
}

void ClassFactory::registClass(string name, PTRCreateObject method) {
  m_classMap.insert(pair<string, PTRCreateObject>(name, method));
}

ClassFactory &ClassFactory::getInstance() {
  static ClassFactory sLo_factory;
  return sLo_factory;
}

class RegisterAction {
public:
  RegisterAction(string className, PTRCreateObject ptrCreateFn) {
    ClassFactory::getInstance().registClass(className, ptrCreateFn);
  }
};

#define REGISTER(className)                                                    \
  className *objectCreator##className() { return new className; }              \
  RegisterAction g_creatorRegister##className(                                 \
      #className, (PTRCreateObject)objectCreator##className)

// test class
class TestClass {
public:
  void m_print() { cout << "hello TestClass" << endl; };
};
REGISTER(TestClass);

int main(int argc, char *argv[]) {
  TestClass *ptrObj =
      (TestClass *)ClassFactory::getInstance().getClassByName("TestClass");
  ptrObj->m_print();
}