final SchemaFactory schemaFactory = SchemaFactory.newInstance(XMLConstants.RELAXNG_NS_URI);
        if (!external) {
            disableExternalResources(schemaFactory);
        }
        return schemaFactory;
    }

    private static void disableExternalResources(final SchemaFactory schemaFactory) {
        try {
            schemaFactory.setProperty(XMLConstants.ACCESS_EXTERNAL_SCHEMA, "");