/**
  * Handle
  *
  * @param Transaction                         $transaction Transaction
  * @param CrudEntityInterface|ArrayCollection $data        Data
  * @param ConstraintViolationList|null        $violations  Violations
  *
  * @throws FeatureNotImplementedException
  *
  * @return CrudEntityInterface|CollectionResponse
  */
 public function handle(Transaction $transaction, $data, ConstraintViolationList $violations = null)
 {
     $this->errorBuilder->processViolations($violations);
     $this->errorBuilder->setTransactionErrors($transaction);
     $success = !$this->errorBuilder->hasErrors();
     $status = $success ? Transaction::STATUS_CREATED : Transaction::STATUS_CONFLICT;
     $transaction->setStatus($status);
     $transaction->setSuccess($success);
     if ($data instanceof ArrayCollection) {
         if ($data->isEmpty()) {
             $data = $this->handleEmptyCollection($transaction, $data);
         } else {
             $data = $this->handleCollection($transaction, $data);
         }
     } else {
         if ($data instanceof CrudEntityInterface) {
             $this->handleEntity($transaction, $data);
         } else {
             throw new FeatureNotImplementedException(get_class($data) . ' class is not supported by transactions (POST). Instance of ArrayCollection needed.');
         }
     }
     if (!$transaction->getSuccess()) {
         if ($data instanceof ArrayCollection) {
             $data->getItems()->clear();
         } else {
             $transaction->setRelatedIds(null);
             $data = new CollectionResponse(new ArrayCollection(array()));
             $data->setShowAssociations(true);
         }
     }
     return $data;
 }
 /**
  * Handle individual entity
  *
  * @param Transaction         $transaction Transaction
  * @param CrudEntityInterface $entity      Entity
  *
  * @return void
  */
 private function handleEntity($transaction, CrudEntityInterface $entity)
 {
     $transaction->setRequestSource(Transaction::SOURCE_SERVICE);
     $transaction->setId(UUID::generate());
     $transaction->setRequestId(microtime());
     $transaction->setRelatedIds($entity->getIds());
     $errors = $this->errorBuilder->getEntityErrors($entity->getPrimaryKey());
     $messages = new ArrayCollection();
     $success = $errors->isEmpty();
     $status = $success ? Transaction::STATUS_CREATED : Transaction::STATUS_CONFLICT;
     $transaction->setStatus($status);
     $transaction->setSuccess($success);
     if ($success) {
         $this->noticeBuilder->addSuccess();
     } else {
         $messages->set('errors', $errors);
         $this->noticeBuilder->addFail();
     }
     $transaction->setMessages($messages);
     $em = $this->registry->getManagerForClass(get_class($transaction));
     $em->persist($transaction);
     $entity->setTransaction($transaction);
 }