mapnik/include/mapnik/factory.hpp

101 lines
2.8 KiB
C++

/*****************************************************************************
*
* This file is part of Mapnik (c++ mapping toolkit)
*
* Copyright (C) 2011 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/utils.hpp>
// stl
#include <stdexcept>
#include <map>
namespace mapnik {
template <typename key_type,
typename product_type>
class default_factory_error
{
public:
struct factory_exception : public std::exception
{
const char* what() const throw()
{
return "unknown object type";
}
};
static product_type* on_unknown_type(const key_type&)
{
return 0;
}
};
template
<
typename product_type,
typename key_type,
typename product_creator=product_type* (*)(),
template <typename,typename> class factory_error_policy=default_factory_error
>
class factory : public singleton<factory <product_type,
key_type,
product_creator,factory_error_policy> >,
factory_error_policy <key_type,product_type>
{
private:
typedef std::map<key_type,product_creator> product_map;
product_map map_;
public:
bool register_product(const key_type& 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(const key_type& key,std::string const& file)
{
typename product_map::const_iterator pos=map_.find(key);
if (pos!=map_.end())
{
return (pos->second)(file);
}
return 0;
}
product_type* create_object(const key_type& key, char const* data, std::size_t size)
{
typename product_map::const_iterator pos=map_.find(key);
if (pos!=map_.end())
{
return (pos->second)(data, size);
}
return 0;
}
};
}
#endif // MAPNIK_FACTORY_HPP