/** * @param $entityname * @return BaseTransformer * @throws \Exception */ public function getTransformer($entityname = null) { if (!$this->transformer || $entityname !== null && $this->transformer->getCurrentResourceKey() !== $entityname) { if (null === $entityname) { throw new \Exception('transformer is empty, specify the entity name into the parameter'); } $this->transformer = $this->transformerResolver->resolve($entityname); } return $this->transformer; }