src/filter_factory.hpp

   1 /* $Id: filter_factory.hpp,v 1.5 2005-11-07 21:57:10 adam Exp $
   2    Copyright (c) 2005, Index Data.
   3
   4 %LICENSE%
   5  */
   6
   7 #ifndef FILTER_FACTORY_HPP
   8 #define FILTER_FACTORY_HPP
   9
  10 #include <stdexcept>
  11 #include <iostream>
  12 #include <string>
  13 #include <map>
  14
  15 #include "filter.hpp"
  16
  17
  18 namespace yp2 {
  19
  20     namespace filter {
  21
  22     class FilterFactoryException : public std::runtime_error {
  23     public:
  24         FilterFactoryException(const std::string message)
  25             : std::runtime_error("FilterException: " + message){
  26         };
  27     };
  28
  29         class FilterFactory {
  30
  31         public:
  32             typedef yp2::filter::Base* (*CreateFilterCallback)();
  33             /// true if registration ok
  34
  35             FilterFactory(){};
  36
  37             bool add_creator(std::string fi, CreateFilterCallback cfc);
  38             /// true if unregistration ok
  39
  40             bool drop_creator(std::string fi);
  41
  42             /// factory create method
  43
  44             yp2::filter::Base* create(std::string fi);
  45
  46         private:
  47             typedef std::map<std::string, CreateFilterCallback> CallbackMap;
  48             CallbackMap m_fcm;
  49
  50         private:
  51             /// disabled because class is singleton
  52             FilterFactory(const FilterFactory &);
  53
  54             /// disabled because class is singleton
  55             FilterFactory& operator=(const FilterFactory &);
  56         };
  57
  58     }
  59
  60     bool yp2::filter::FilterFactory::add_creator(std::string fi,
  61                                     CreateFilterCallback cfc)
  62     {
  63         return m_fcm.insert(CallbackMap::value_type(fi, cfc)).second;
  64     }
  65
  66
  67     bool yp2::filter::FilterFactory::drop_creator(std::string fi)
  68     {
  69         return m_fcm.erase(fi) == 1;
  70     }
  71
  72     yp2::filter::Base* yp2::filter::FilterFactory::create(std::string fi)
  73     {
  74         CallbackMap::const_iterator i = m_fcm.find(fi);
  75
  76         if (i == m_fcm.end()){
  77             std::string msg = "filter type '" + fi + "' not found";
  78             throw yp2::filter::FilterFactoryException(msg);
  79         }
  80         // call create function
  81         return (i->second());
  82     }
  83
  84
  85
  86 }
  87
  88 #endif
  89 /*
  90  * Local variables:
  91  * c-basic-offset: 4
  92  * indent-tabs-mode: nil
  93  * c-file-style: "stroustrup"
  94  * End:
  95  * vim: shiftwidth=4 tabstop=8 expandtab
  96  */