public function getColumnSortingUrl($column)
    {
        $data = array(
            FilterInvoker::FILTER_PARAM_PAGE => $this->getCurrentPageNumber(), 
            FilterInvoker::FILTER_PARAM_DESC => !$this->isSortedByDesc($column), 
            FilterInvoker::FILTER_PARAM_SORT => $column
        );        

        return FilterInvoker::createUrl(array_merge($this->query, $data), $this->route);
    }