/** * Adds one filter * @param App_ListFilter_Interface $filter * @param string $name * @return App_ListFilter_CollectionAbstract */ public function addFilter(App_ListFilter_Interface $filter, $name = null) { if ($filter->isValid()) { if (is_null($name)) { $this->_filters[] = $filter; } else { $this->_filters[$name] = $filter; } } return $this; }