public function getRootsAsArray($id = null)
 {
     $criteria = Criteria::create()->where(Criteria::expr()->isNull('parent'));
     if ($id) {
         $criteria->andWhere(Criteria::expr()->neq('id', $id));
     }
     $list = parent::matching($criteria);
     $res = array();
     foreach ($list as $element) {
         $res[$element->getId()] = $element->getName();
     }
     return $res;
 }