factory.hpp

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/*
  CLAW - a C++ Library Absolutely Wonderful

  CLAW is a free library without any particular aim but being useful to 
  anyone.

  Copyright (C) 2005-2011 Julien Jorge

  This library is free software; you can redistribute it and/or
  modify it under the terms of the GNU Lesser General Public
  License as published by the Free Software Foundation; either
  version 2.1 of the License, or (at your option) any later version.

  This library is distributed in the hope that it will be useful,
  but WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  Lesser General Public License for more details.

  You should have received a copy of the GNU Lesser General Public
  License along with this library; if not, write to the Free Software
  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA

  contact: julien.jorge@gamned.org
*/
#ifndef __CLAW_FACTORY_HPP__
#define __CLAW_FACTORY_HPP__

#ifdef CLAW_FACTORY_IS_SINGLETON
#include <claw/basic_singleton.hpp>
#endif

#include <claw/exception.hpp>
#include <map>

namespace claw
{
  namespace pattern
  {
    class bad_type_identifier:
      public exception
    {
    public:
      bad_type_identifier() throw()
        : exception("No type has this identifier.")
      { }
    }; // class bad_type_identifier

    template<typename BaseClass, typename IdentifierType>
#ifdef CLAW_FACTORY_IS_SINGLETON
    class factory:
      public basic_singleton< factory<BaseClass, IdentifierType> >
#else
    class factory
#endif
    {
    private:
      class class_creator_base
      {
      public:
        virtual ~class_creator_base();
        virtual BaseClass* create() const = 0;

      }; // class class_creator_base

      template<typename Derived>
      class class_creator:
        public class_creator_base
      {
      public:
        virtual Derived* create() const;

      }; // class class_creator

      typedef IdentifierType identifier_type;

      typedef BaseClass base_class;

      typedef std::map<identifier_type, class_creator_base*> class_map;

    public:
      ~factory();

      template<typename T>
      bool register_type( const identifier_type& id );

      base_class* create( const identifier_type& id ) const;

      bool is_known_type( const identifier_type& id ) const;

    private:
      class_map m_classes;

    }; // class factory

  } // namespace pattern
} // namespace claw

#include <claw/impl/factory.tpp>

#endif // __CLAW_FACTORY_HPP__