protected function getDefaultDirectory($entityTypeCode)
    {

        // query whether or not, a default configuration file for the passed entity type is available
        if (isset($this->defaultDirectories[$entityTypeCode])) {
            return $this->defaultDirectories[$entityTypeCode];
        }

        // throw an exception, if the passed entity type is not supported
        throw new \Exception(
            sprintf(
                'Entity Type Code \'%s\' not supported (MUST be one of catalog_product or catalog_category)',
                $entityTypeCode
            )
        );
    }