EventException example

  public function dispatchEvent(DatabaseEvent $event, ?string $eventName = NULL): DatabaseEvent {
    if (\Drupal::hasService('event_dispatcher')) {
      return \Drupal::service('event_dispatcher')->dispatch($event, $eventName);
    }
    throw new EventException('The event dispatcher service is not available. Database API events can only be fired if the container is initialized');
  }

  /** * Determine the last non-database method that called the database API. * * Traversing the call stack from the very first call made during the * request, we define "the routine that called this query" as the last entry * in the call stack that is not any method called from the namespace of the * database driver, is not inside the Drupal\Core\Database namespace and does * have a file (which excludes call_user_func_array(), anonymous functions * and similar). That makes the climbing logic very simple, and handles the * variable stack depth caused by the query builders. * * See the @link http://php.net/debug_backtrace debug_backtrace() @endlink * function. * * @return array * This method returns a stack trace entry similar to that generated by * debug_backtrace(). However, it flattens the trace entry and the trace * entry before it so that we get the function and args of the function that * called into the database system, not the function and args of the * database call itself. */