protected function addSortCriteria(&$c)
 {
     if ($sort_column = $this->getUser()->getAttribute('sort', NULL, 'opp_votazione/sort')) {
         switch ($this->getUser()->getAttribute('sort', NULL, 'opp_votazione/sort')) {
             case 'parlamentare':
                 $sort_column = OppPoliticoPeer::translateFieldName($sort_column, BasePeer::TYPE_FIELDNAME, BasePeer::TYPE_COLNAME);
                 break;
             case 'gruppo':
                 $sort_column = 'nome';
                 $sort_column = OppGruppoPeer::translateFieldName($sort_column, BasePeer::TYPE_FIELDNAME, BasePeer::TYPE_COLNAME);
                 break;
             case 'circoscrizione':
                 $sort_column = OppCaricaPeer::translateFieldName($sort_column, BasePeer::TYPE_FIELDNAME, BasePeer::TYPE_COLNAME);
                 break;
             case 'voto':
                 $sort_column = OppVotazioneHasCaricaPeer::translateFieldName($sort_column, BasePeer::TYPE_FIELDNAME, BasePeer::TYPE_COLNAME);
                 break;
         }
         if ($this->getUser()->getAttribute('type', NULL, 'opp_votazione/sort') == 'asc') {
             $c->addAscendingOrderByColumn($sort_column);
         } else {
             $c->addDescendingOrderByColumn($sort_column);
         }
     }
 }