protected function prepareQueryParameters(array $queryParameters = NULL) {
        $queryParameters = parent::prepareQueryParameters($queryParameters);

        $queryParameters['user.name'] = $this->datasource->username;

        return $queryParameters;
    }
    public function __construct(DataSourceMetaData $datasource) {
        $uri = "{$datasource->protocol}://{$datasource->host}:{$datasource->services->WebHDFS->port}";

        parent::__construct($uri, new WebHDFS_CURLHandlerOutputFormatter());
    }