@Override
	public Object getNextValue() {
		LocalDate nextDate = null;
		switch (calendarField) {
			case Calendar.DAY_OF_MONTH:
				nextDate = currentValue.plusDays(1);
				break;
			case Calendar.MONTH:
				nextDate = currentValue.plusMonths(1);
				break;
			case Calendar.YEAR:
				nextDate = currentValue.plusYears(1);
				break;
		}
		if (minDate != null && minDate.compareTo(nextDate) < 0) {
			return nextDate;
		}
		return null;
	}
Constructor

@param value initial value for spinner model
@param minDate minimum value for spinner model. (Can be null)
@param maxDate maximum value for spinner model. (Can be null)
@param calendarField specifies the year, month, or day to increment/decrement. One of:
 <ul>
   <li>{@link Calendar#YEAR}</li>
   <li>{@link Calendar#MONTH}</li>
   <li>{@link Calendar#DAY_OF_MONTH}</li>
 </ul>
Ghidra/Framework/Docking/src/main/java/docking/widgets/table/constrainteditor/LocalDateSpinnerModel.java