/**
  * {@inheritdoc}
  *
  * @see Symfony\Component\Form.AbstractTypeExtension::buildForm()
  */
 public function buildForm(FormBuilderInterface $builder, array $options)
 {
     $dataClass = $builder->getDataClass();
     $subscriber = new AddIdentifierSubscriber($builder->getFormFactory(), $this->getJsfv());
     $builder->addEventSubscriber($subscriber);
     if (!empty($options['validation_groups'])) {
         $builder->setAttribute('validation_groups', $options['validation_groups']);
     }
     if ($dataClass !== null) {
         $builder->setAttribute('data_class', $dataClass);
     }
 }