* W3C XML Schemaのための{@link SchemaFactory}を生成します。
     *
     * @return W3C XML Schemaのための{@link SchemaFactory}
     */
    public static SchemaFactory newW3cXmlSchemaFactory() {
        return newW3cXmlSchemaFactory(false);
    }

    public static SchemaFactory newW3cXmlSchemaFactory(final boolean external) {
        final SchemaFactory schemaFactory = SchemaFactory.newInstance(XMLConstants.W3C_XML_SCHEMA_NS_URI);
        if (!external) {