/* This file is part of Mapnik (c++ mapping toolkit) * Copyright (C) 2005 Artem Pavlenko * * Mapnik is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License * as published by the Free Software Foundation; either version 2 * of the License, or any later version. * * This program 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 General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */ //$Id$ #ifndef ATTRIBUTE_COLLECTOR #define ATTROBUTE_COLLECTOR #include "filter.hpp" #include "expression.hpp" #include "feature_layer_desc.hpp" #include <set> namespace mapnik { template <typename FeatureT> class attribute_collector : public filter_visitor<FeatureT> { public: attribute_collector(std::set<std::string>& names) : names_(names) {} void visit(filter<FeatureT>& /*filter*/) { //not interested } void visit(expression<FeatureT>& exp) { property<FeatureT>* pf; if ((pf = dynamic_cast<property<FeatureT>*>(&exp))) { names_.insert(pf->name()); } } virtual ~attribute_collector() {} private: // no copying attribute_collector(attribute_collector const&); attribute_collector& operator=(attribute_collector const&); private: std::set<std::string>& names_; }; } #endif //ATTRIBUTE_COLLECTOR_HPP