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ExpressionFilter.h

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00001 #ifndef TAGCOLL_EXPRESSION_FILTER_H
00002 #define TAGCOLL_EXPRESSION_FILTER_H
00003 
00004 /*
00005  * TagcollFilter that filters items using a tag expression
00006  * 
00007  * Copyright (C) 2003  Enrico Zini <enrico@debian.org>
00008  *
00009  * This library is free software; you can redistribute it and/or
00010  * modify it under the terms of the GNU Lesser General Public
00011  * License as published by the Free Software Foundation; either
00012  * version 2.1 of the License, or (at your option) any later version.
00013  *
00014  * This library is distributed in the hope that it will be useful,
00015  * but WITHOUT ANY WARRANTY; without even the implied warranty of
00016  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
00017  * Lesser General Public License for more details.
00018  *
00019  * You should have received a copy of the GNU Lesser General Public
00020  * License along with this library; if not, write to the Free Software
00021  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307  USA
00022  */
00023 
00024 #pragma interface
00025 
00026 #include <tagcoll/TagcollFilter.h>
00027 #include <tagcoll/tagexpr/Tagexpr.h>
00028 
00029 #include <string>
00030 
00031 namespace Tagcoll
00032 {
00033 
00034 class ExpressionFilter : public TagcollFilter<std::string>
00035 {
00036 protected:
00037     Tagexpr* expr;
00038     int matched;
00039 
00040     bool match(const OpSet<std::string>& ts) const throw ();
00041     
00042 public:
00043     enum MatchType { PLAIN, INVERTED };
00044 
00045 protected:
00046     MatchType matchType;
00047 
00048 public: 
00049     ExpressionFilter() throw () : expr(0), matched(0), matchType(PLAIN) {}
00050     virtual ~ExpressionFilter() throw () { if (expr) delete expr; }
00051 
00052     // Set the expression to use for this filter
00053     // Return false if parsing the expression failed
00054     bool setExpression(const std::string& expression) throw ();
00055 
00056     void setMatchType(MatchType type) throw () { matchType = type; }
00057 
00058     int countMatched() const throw () { return matched; }
00059 
00060     virtual void consume(const std::string& item) throw ()
00061     {
00062         if (match(OpSet<std::string>()))
00063         {
00064             matched++;
00065             consumer->consume(item);
00066         }
00067     }
00068 
00069     virtual void consume(const std::string& item, const OpSet<std::string>& tags) throw ()
00070     {
00071         if (match(tags))
00072         {
00073             matched++;
00074             consumer->consume(item, tags);
00075         }
00076     }
00077 
00078     virtual void consume(const OpSet<std::string>& items) throw ()
00079     {
00080         if (match(OpSet<std::string>()))
00081         {
00082             matched += items.size();
00083             consumer->consume(items);
00084         }
00085     }
00086 
00087     virtual void consume(const OpSet<std::string>& items, const OpSet<std::string>& tags) throw ()
00088     {
00089         if (match(tags))
00090         {
00091             matched += items.size();
00092             consumer->consume(items, tags);
00093         }
00094     }
00095 };
00096 
00097 };
00098 
00099 // vim:set ts=4 sw=4:
00100 #endif

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