public function getFilename(Garp_Util_Configuration $params) {
        $className = Garp_Content_Api::modelAliasToClass($params['model']);
        $model = new $className();
        $filename  = 'export_';
        $filename .= $model->getName();
        $filename .= '_' . date('Y_m_d');
        $filename .= '.';
        $filename .= $this->_extension;
        return $filename;
    }