class FeedForm

class FeedForm extends ContentEntityForm {
  
  /**
   * {@inheritdoc}
   */
  public function save(array $form, FormStateInterface $form_state) {
    $feed = $this->entity;
    $status = $feed->save();
    $label = $feed->label();
    $view_link = $feed->toLink($label, 'canonical')
      ->toString();
    if ($status == SAVED_UPDATED) {
      $this->messenger()
        ->addStatus($this->t('The feed %feed has been updated.', [
        '%feed' => $view_link,
      ]));
      $form_state->setRedirectUrl($feed->toUrl('canonical'));
    }
    else {
      $this->logger('aggregator')
        ->notice('Feed %feed added.', [
        '%feed' => $feed->label(),
        'link' => Link::fromTextAndUrl($this->t('View'), new Url('aggregator.admin_overview'))
          ->toString(),
      ]);
      $this->messenger()
        ->addStatus($this->t('The feed %feed has been added.', [
        '%feed' => $view_link,
      ]));
    }
  }

}