protected function gatherRowData(array $data, array &$id, array &$nonemptyComponents)
 {
     $rowData = parent::gatherRowData($data, $id, $nonemptyComponents);
     foreach ($rowData['data'] as $dqlAlias => $data) {
         $class = $this->_rsm->aliasMap[$dqlAlias];
         $meta = $this->getClassMetadata($class);
         if ($meta->discriminatorMap) {
             $class = isset($data[$meta->discriminatorColumn['name']]) ? $meta->discriminatorMap[$data[$meta->discriminatorColumn['name']]] : null;
         }
         $rowData['data'][$dqlAlias]['__CLASS__'] = $class;
     }
     return $rowData;
 }