public function toPersistenceValue(SPIValue $value) { // @todo Evaluate if creating the sortKey in every case is really needed // Couldn't this be retrieved with a method, which would initialize // that info on request only? return new PersistenceValue(array('data' => $this->toHash($value), 'externalData' => null, 'sortKey' => $this->getSortInfo($value))); }