public GregorianDateTimeValue createInstance(XMLGregorianCalendar value) {
final DatatypeFactory factory = XsDatatypeFactory.getDatatypeFactory();
int year = value.getYear();
int tz = value.getTimezone();
XMLGregorianCalendar cal = factory.newXMLGregorianCalendarDate(year, DatatypeConstants.FIELD_UNDEFINED, DatatypeConstants.FIELD_UNDEFINED, tz);
return new GregorianDateTimeValue(cal, GYEAR);
}