/**
  * @param USER $user The user for which items are to be retrieved.
  */
 public function __construct($user)
 {
     parent::__construct($user->app);
     $this->_user = $user;
     $this->add_table("{$this->app->table_names->folders} fldr", 'act.access_id = fldr.id');
     $this->restrict('NOT (act.object_type = \'' . History_item_user . '\') AND NOT (act.object_type = \'' . History_item_group . '\')');
 }