trait EntityTypeEventSubscriberTrait

trait EntityTypeEventSubscriberTrait {

  /**
   * Gets the subscribed events.
   *
   * @return array
   *   An array of subscribed event names.
   *
   * @see \Symfony\Component\EventDispatcher\EventSubscriberInterface::getSubscribedEvents()
   */
  public static function getEntityTypeEvents() {
    $event = [
      'onEntityTypeEvent',
      100,
    ];
    $events[EntityTypeEvents::CREATE][] = $event;
    $events[EntityTypeEvents::UPDATE][] = $event;
    $events[EntityTypeEvents::DELETE][] = $event;
    return $events;
  }

  /**
   * Listener method for any entity type definition event.
   *
   * @param \Drupal\Core\Entity\EntityTypeEvent $event
   *   The field storage definition event object.
   * @param string $event_name
   *   The event name.
   */
  public function onEntityTypeEvent(EntityTypeEvent $event, $event_name) {
    switch ($event_name) {
      case EntityTypeEvents::CREATE:
        $this
          ->onEntityTypeCreate($event
          ->getEntityType());
        break;
      case EntityTypeEvents::UPDATE:
        $this
          ->onEntityTypeUpdate($event
          ->getEntityType(), $event
          ->getOriginal());
        break;
      case EntityTypeEvents::DELETE:
        $this
          ->onEntityTypeDelete($event
          ->getEntityType());
        break;
    }
  }

  /**
   * {@inheritdoc}
   */
  public function onEntityTypeCreate(EntityTypeInterface $entity_type) {
  }

  /**
   * {@inheritdoc}
   */
  public function onFieldableEntityTypeCreate(EntityTypeInterface $entity_type, array $field_storage_definitions) {
  }

  /**
   * {@inheritdoc}
   */
  public function onEntityTypeUpdate(EntityTypeInterface $entity_type, EntityTypeInterface $original) {
  }

  /**
   * {@inheritdoc}
   */
  public function onFieldableEntityTypeUpdate(EntityTypeInterface $entity_type, EntityTypeInterface $original, array $field_storage_definitions, array $original_field_storage_definitions, array &$sandbox = NULL) {
  }

  /**
   * {@inheritdoc}
   */
  public function onEntityTypeDelete(EntityTypeInterface $entity_type) {
  }

}