private function applyOrderByExpression(QueryBuilder $queryBuilder, Sorter $sorter) { if ($sorter->getAssociation() !== null) { $alias = $this->getAlias('o.' . $sorter->getAssociation()) . '.' . $sorter->getProperty(); } else { $alias = 'o.' . $sorter->getProperty(); } return $queryBuilder->addOrderBy($alias, $sorter->getDirection()); }