mapnik/include/mapnik/factory.hpp
2017-05-05 13:02:01 +02:00

72 lines
2.1 KiB
C++

/*****************************************************************************
*
* This file is part of Mapnik (c++ mapping toolkit)
*
* Copyright (C) 2017 Artem Pavlenko
*
* 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
*
*****************************************************************************/
#ifndef MAPNIK_FACTORY_HPP
#define MAPNIK_FACTORY_HPP
// mapnik
#include <mapnik/util/singleton.hpp>
// stl
#include <stdexcept>
#include <map>
namespace mapnik {
template
<
typename product_type,
typename key_type,
typename ...Args >
class factory : public singleton<factory <product_type,
key_type,
Args...> >
{
private:
using product_creator = product_type* (*) (Args...);
using product_map = std::map<key_type,product_creator>;
product_map map_;
public:
bool register_product(key_type const& key, product_creator creator)
{
return map_.insert(typename product_map::value_type(key,creator)).second;
}
bool unregister_product(const key_type& key)
{
return map_.erase(key)==1;
}
product_type* create_object(key_type const& key, Args...args)
{
typename product_map::const_iterator pos=map_.find(key);
if (pos!=map_.end())
{
return (pos->second)(args...);
}
return 0;
}
};
}
#endif // MAPNIK_FACTORY_HPP