public function validateXml(\DOMDocument $domDocument, $schemaFile = null, $failOnErrors = false)
    {
        // if we got a specific schema file we will use it, otherwise we will use the one we got globally
        $schemaFileName = $this->schemaFile;
        if (!is_null($schemaFile)) {
            $schemaFileName = $schemaFile;
        }

        // validate the passed DOM document
        ConfigurationUtils::singleton()->validateXml($domDocument, $schemaFileName, $failOnErrors);

        // return TRUE if validation has been successfull
        return true;
    }