opencv/3rdparty/flann/util/object_factory.h

/***********************************************************************
 * Software License Agreement (BSD License)
 *
 * Copyright 2008-2009  Marius Muja (mariusm@cs.ubc.ca). All rights reserved.
 * Copyright 2008-2009  David G. Lowe (lowe@cs.ubc.ca). All rights reserved.
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 * THE BSD LICENSE
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#ifndef OBJECT_FACTORY_H_
#define OBJECT_FACTORY_H_

#include <map>

namespace cvflann
{

template<typename BaseClass, typename DerivedClass>
BaseClass* createObject()
{
	return new DerivedClass();
}

template<typename BaseClass, typename UniqueIdType>
class ObjectFactory
{
	typedef BaseClass* (*CreateObjectFunc)();
	std::map<UniqueIdType, CreateObjectFunc> object_registry;

	// singleton class, private constructor
	ObjectFactory() {};

public:
   typedef typename std::map<UniqueIdType, CreateObjectFunc>::iterator Iterator;


   template<typename DerivedClass>
   bool register_(UniqueIdType id)
   {
      if (object_registry.find(id) != object_registry.end())
               return false;

      object_registry[id] = &createObject<BaseClass, DerivedClass>;
      return true;
   }

   bool unregister(UniqueIdType id)
   {
      return (object_registry.erase(id) == 1);
   }

   BaseClass* create(UniqueIdType id)
   {
      Iterator iter = object_registry.find(id);

      if (iter == object_registry.end())
         return NULL;

      return ((*iter).second)();
   }

   static ObjectFactory<BaseClass,UniqueIdType>& instance()
   {
	   static ObjectFactory<BaseClass,UniqueIdType> the_factory;
	   return the_factory;
   }

};

}

#endif /* OBJECT_FACTORY_H_ */