ObjectRegistrar.h

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#ifndef _utl_ObjectRegistrar_h_
#define _utl_ObjectRegistrar_h_

#include <utl/ObjectFactory.h>


namespace utl {

  template<class ObjectType, class ObjectFactory>
  class StandardCreator {

  public:
    static typename ObjectFactory::CreatorType GetCreator()
    { return ObjectType::Create; }

  };


  template<class ObjectType,
           class ObjFactoryType,
           class CreatorPolicy = StandardCreator<ObjectType, ObjFactoryType> >
  class ObjectRegistrar {

  public:
    typedef ObjFactoryType ObjectFactoryType;
    typedef typename ObjFactoryType::ObjectPtrType ObjectPtrType;

    // The default constructor is required to force the instantiation
    // of the static member variable fgAutoRegistrar whose
    // initialization triggers the registration with the factory
    ObjectRegistrar()
    {
      if (!fgAutoRegistrar)
        fgAutoRegistrar = new ObjectRegistrar(true);
    }

  private:
    // This constructor in needed to avoid recursion during
    // initialization of fgAutoRegistrar. The bool argument is ignored
    ObjectRegistrar(bool) { }

    static
    ObjectRegistrar*
    AutoRegister()
    {
      ObjectFactoryType::Register(ObjectType::GetRegistrationId(),
                                  CreatorPolicy::GetCreator());
      return new ObjectRegistrar(true);
    }

    static const ObjectRegistrar* fgAutoRegistrar;

  }; // ObjectRegistrar


  template<class Object, class ObjectFactory, class CreatorPolicy>
  const ObjectRegistrar<Object, ObjectFactory, CreatorPolicy>*
  ObjectRegistrar<Object, ObjectFactory, CreatorPolicy>::fgAutoRegistrar =
    ObjectRegistrar<Object, ObjectFactory, CreatorPolicy>::AutoRegister();

} // utl


#endif // _utl_ObjectRegistrar_h_

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