class Batch

class Batch extends DatabaseQueue {

  /**
   * Overrides Drupal\Core\Queue\System::claimItem().
   *
   * Unlike Drupal\Core\Queue\System::claimItem(), this method provides a
   * default lease time of 0 (no expiration) instead of 30. This allows the item
   * to be claimed repeatedly until it is deleted.
   */
  public function claimItem($lease_time = 0) {
    $item = db_query_range('SELECT data, item_id FROM {queue} q WHERE name = :name ORDER BY item_id ASC', 0, 1, array(
      ':name' => $this->name,
    ))
      ->fetchObject();
    if ($item) {
      $item->data = unserialize($item->data);
      return $item;
    }
    return FALSE;
  }

  /**
   * Retrieves all remaining items in the queue.
   *
   * This is specific to Batch API and is not part of the
   * Drupal\Core\Queue\QueueInterface.
   *
   * @return array
   *   An array of queue items.
   */
  public function getAllItems() {
    $result = array();
    $items = db_query('SELECT data FROM {queue} q WHERE name = :name ORDER BY item_id ASC', array(
      ':name' => $this->name,
    ))
      ->fetchAll();
    foreach ($items as $item) {
      $result[] = unserialize($item->data);
    }
    return $result;
  }

}