class DateFormatListBuilder

class DateFormatListBuilder extends ConfigEntityListBuilder {
  
  /**
   * The date formatter service.
   *
   * @var \Drupal\Core\Datetime\DateFormatterInterface
   */
  protected $dateFormatter;
  
  /**
   * Constructs a new DateFormatListBuilder object.
   *
   * @param \Drupal\Core\Entity\EntityTypeInterface $entity_type
   *   The entity type definition.
   * @param \Drupal\Core\Entity\EntityStorageInterface $storage
   *   The entity storage class.
   * @param \Drupal\Core\Datetime\DateFormatterInterface $date_formatter
   *   The date formatter service.
   */
  public function __construct(EntityTypeInterface $entity_type, EntityStorageInterface $storage, DateFormatterInterface $date_formatter) {
    parent::__construct($entity_type, $storage);
    $this->dateFormatter = $date_formatter;
  }
  
  /**
   * {@inheritdoc}
   */
  public static function createInstance(ContainerInterface $container, EntityTypeInterface $entity_type) {
    return new static($entity_type, $container->get('entity_type.manager')
      ->getStorage($entity_type->id()), $container->get('date.formatter'));
  }
  
  /**
   * {@inheritdoc}
   */
  public function buildHeader() {
    $header['label'] = t('Name');
    $header['pattern'] = t('Pattern');
    return $header + parent::buildHeader();
  }
  
  /**
   * {@inheritdoc}
   */
  public function buildRow(EntityInterface $entity) {
    $row['label'] = $entity->label();
    $row['pattern'] = $this->dateFormatter
      ->format(REQUEST_TIME, $entity->id());
    return $row + parent::buildRow($entity);
  }

}