class UserUid

class UserUid extends Name {

  /**
   * {@inheritdoc}
   */
  public function query() {

    // Because this handler thinks it's an argument for a field on the {node}
    // table, we need to make sure {tracker_user} is JOINed and use its alias
    // for the WHERE clause.
    $tracker_user_alias = $this->query
      ->ensureTable('tracker_user');

    // Cast scalars to array so we can consistently use an IN condition.
    $this->query
      ->addWhere(0, "{$tracker_user_alias}.uid", (array) $this->value, 'IN');
  }

}