* @param chronology the chronology, null means use converter
* @throws IllegalArgumentException if the date is invalid
*/
protected BasePartial(Object instant, Chronology chronology) {
super();
PartialConverter converter = ConverterManager.getInstance().getPartialConverter(instant);
chronology = converter.getChronology(instant, chronology);
chronology = DateTimeUtils.getChronology(chronology);
iChronology = chronology.withUTC();
iValues = converter.getPartialValues(this, instant, chronology);
}