OptFrame/Parallel/MapReduce++/SeqMR/reducer.hpp

#ifndef REDUCER_HPP
#define REDUCER_HPP

template<class KeyA, class A, class KeyB, class B, class C>
class SeqMR_Reducer : public Reducer<KeyA,A,KeyB,B,C>
{ 
public:
        SeqMR_Reducer(MapReduce<KeyA,A,KeyB,B,C> * _mapReduce):mapReduce(_mapReduce){};
#ifndef MRI_USE_MULTIMAP
        virtual vector< pair<KeyB,C> > run( vector< pair<KeyB,B> > & _mapped) {
                multimap<KeyB,B> mapped;
                for (int i = 0 ; i < _mapped.size() ; i++) mapped.insert(_mapped[i]);
#else
        virtual vector< pair<KeyB,C> > run( multimap<KeyB,B> & mapped) {
#endif
                vector< pair<KeyB,C> > reduced;

                typename std::multimap<KeyB,B>::iterator it = mapped.begin();
                KeyB lastKey = (*it).first;
                vector<B> toReduce;
                for( ; it != mapped.end() ; ++it)
                {
                        if ((*it).first != lastKey) {
                                pair<KeyB,C> r = reduce( pair<KeyB, vector<B> >( lastKey , toReduce ) ); toReduce.clear();
                                reduced.push_back( r );
                                lastKey = (*it).first;
                        }
                        toReduce.push_back( (*it).second );
                }

                pair<KeyB,C> r = reduce( pair<KeyB, vector<B> >( lastKey , toReduce ) ); toReduce.clear();
                reduced.push_back( r );

                return reduced;
        };
        virtual pair<KeyB,C> reduce( pair<KeyB, vector<B> > ) = 0 ;
protected:
        MapReduce<KeyA,A,KeyB,B,C> * mapReduce;
};

class SeqMR_StrReducer : public SeqMR_Reducer<string,string,string,string,string> 
{
public:
        SeqMR_StrReducer(MapReduce<string,string,string,string,string> * _mapReduce)
                :SeqMR_Reducer<string,string,string,string,string>(_mapReduce){};       
};

#endif /* REDUCER_HPP */