85 lines
2.3 KiB
C++
85 lines
2.3 KiB
C++
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/* This file is part of Mapnik (c++ mapping toolkit)
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* Copyright (C) 2005 Artem Pavlenko
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*
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* Mapnik is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version 2
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* of the License, or any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
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*/
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//$Id: factory.hpp 39 2005-04-10 20:39:53Z pavlenko $
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#ifndef FACTORY_HPP
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#define FACTORY_HPP
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#include <stdexcept>
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#include <map>
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#include "utils.hpp"
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namespace mapnik
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{
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template <typename key_type,
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typename product_type>
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class default_factory_error
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{
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public:
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struct factory_exception : public std::exception
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{
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const char* what() const throw()
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{
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return "uknown object type";
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}
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};
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static product_type* on_unknown_type(const key_type&)
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{
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return 0;
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}
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};
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template
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<
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typename product_type,
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typename key_type,
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typename product_creator=product_type* (*)(),
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template <typename,typename> class factory_error_policy=default_factory_error
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>
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class factory : public singleton<factory <product_type,key_type,product_creator,factory_error_policy> >,
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factory_error_policy <key_type,product_type>
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{
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private:
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typedef std::map<key_type,product_creator> product_map;
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product_map map_;
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public:
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bool register_product(const key_type& key,product_creator creator)
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{
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return map_.insert(typename product_map::value_type(key,creator)).second;
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}
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bool unregister_product(const key_type& key)
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{
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return map_.erase(key)==1;
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}
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product_type* create_object(const key_type& key,const std::string& file)
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{
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typename product_map::const_iterator pos=map_.find(key);
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if (pos!=map_.end())
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{
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return (pos->second)(file);
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}
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return on_unknown_type(key);
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}
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};
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}
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#endif //FACTORY_HPP
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