public class TraitementCombiner
        extends Reducer<TypCleI,TypValI, TypCleI,TypValI>
{
    @Override
    public void reduce(TypCleI cleI, Iterable<TypValI> listeI,
                Context context) throws Exception
    {
        for (TypValI val: listeI) {
        /** traitement: cleS = ..., valS = ... **/
        }
        context.write(new TypCleI(cleS), new TypValI(valS));
    }
}