public function setSortColumn($column)
    {
        $this->sortColumn = null;

        $found = false;
        foreach ($this->getColumns() as $id => $params) {
            if ($id == $column) {
                $found = ($params['sortable'] === true);
                break;
            }
        }

        if ($found)
            $this->sortColumn = $column;

        return $this;
    }