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C++ API DOCUMENTATION |
00001 /***************************************************************************** 00002 * 00003 * This file is part of Mapnik (c++ mapping toolkit) 00004 * 00005 * Copyright (C) 2006 Artem Pavlenko 00006 * 00007 * This library is free software; you can redistribute it and/or 00008 * modify it under the terms of the GNU Lesser General Public 00009 * License as published by the Free Software Foundation; either 00010 * version 2.1 of the License, or (at your option) any later version. 00011 * 00012 * This library is distributed in the hope that it will be useful, 00013 * but WITHOUT ANY WARRANTY; without even the implied warranty of 00014 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 00015 * Lesser General Public License for more details. 00016 * 00017 * You should have received a copy of the GNU Lesser General Public 00018 * License along with this library; if not, write to the Free Software 00019 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA 00020 * 00021 *****************************************************************************/ 00022 00023 //$Id$ 00024 00025 #ifndef FILTER_HPP 00026 #define FILTER_HPP 00027 00028 #include <mapnik/config.hpp> 00029 #include <mapnik/feature.hpp> 00030 00031 namespace mapnik 00032 { 00033 template <typename FeatureT> class filter_visitor; 00034 template <typename FeatureT> 00035 class MAPNIK_DECL filter 00036 { 00037 public: 00038 virtual bool pass(const FeatureT& feature) const=0; 00039 virtual filter<FeatureT>* clone() const=0; 00040 virtual void accept(filter_visitor<FeatureT>& v) = 0; 00041 virtual std::string to_string() const=0; 00042 virtual ~filter() {} 00043 }; 00044 00045 typedef boost::shared_ptr<filter<Feature> > filter_ptr; 00046 00047 template <typename FeatureT> 00048 class all_filter : public filter<FeatureT> 00049 { 00050 public: 00051 bool pass (const FeatureT&) const 00052 { 00053 return true; 00054 } 00055 00056 filter<FeatureT>* clone() const 00057 { 00058 return new all_filter<FeatureT>; 00059 } 00060 std::string to_string() const 00061 { 00062 return "true"; 00063 } 00064 void accept(filter_visitor<FeatureT>&) {} 00065 virtual ~all_filter() {} 00066 }; 00067 00068 template <typename FeatureT> 00069 class none_filter : public filter<FeatureT> 00070 { 00071 public: 00072 bool pass (const FeatureT&) const 00073 { 00074 return false; 00075 } 00076 00077 filter<FeatureT>* clone() const 00078 { 00079 return new none_filter<FeatureT>; 00080 } 00081 std::string to_string() const 00082 { 00083 return "false"; 00084 } 00085 void accept(filter_visitor<FeatureT>&) {} 00086 virtual ~none_filter() {} 00087 }; 00088 } 00089 00090 #endif //FILTER_HPP