Factory.h

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#ifndef AMPGEN_FACTORY_H
#define AMPGEN_FACTORY_H
 
#include <cxxabi.h>
#include <map>
 
#include "AmpGen/MsgService.h"
#include "AmpGen/Utilities.h"
 
#define REGISTER(BASE_CLASS, DERIVED_CLASS) std::string DERIVED_CLASS::_id = AmpGen::Factory<BASE_CLASS>::Register(#DERIVED_CLASS, new DERIVED_CLASS())
#define REGISTER_WITH_KEY(BASE_CLASS, DERIVED_CLASS, KEY, KEY_TYPE)                                                                                            \
  KEY_TYPE DERIVED_CLASS::_id = AmpGen::Factory<BASE_CLASS, KEY_TYPE>::Register(KEY, new DERIVED_CLASS())
 
namespace AmpGen {
  template <class TYPE, class KEY_TYPE = std::string> class Factory {
  public:
    std::map<KEY_TYPE, TYPE *> m_terms;    
    static Factory<TYPE, KEY_TYPE> *gImpl; 
 
    static Factory<TYPE, KEY_TYPE> *getMe() {
      if(!gImpl) gImpl = new Factory<TYPE, KEY_TYPE>();
      return gImpl;
    }
    static TYPE *get(const KEY_TYPE &type, const bool quiet = false) {
      auto ptrToStatic = getMe();
      auto raw_base = ptrToStatic->m_terms.find(type);
      if(raw_base == ptrToStatic->m_terms.end()) {
        if(!quiet) ERROR(type << " not found in Factory<" << type_string<TYPE>() << type_string<KEY_TYPE>() << " >");
        return nullptr;
      }
      auto objectToReturn = raw_base->second->create();
      return objectToReturn;
    }
    static KEY_TYPE Register(const KEY_TYPE &key, TYPE *object) {
      getMe()->m_terms[key] = object;
      return key;
    }
  };
 
  template <class TYPE, class KEY_TYPE> Factory<TYPE, KEY_TYPE> *Factory<TYPE, KEY_TYPE>::gImpl = nullptr;
} // namespace AmpGen
 
#endif