/**
* Add the specified month to the specified time instant. The amount added may be negative.
*
* <p>If the new month has less total days than the specified day of the month, this value is
* coerced to the nearest sane value. e.g.
*
* <p>07-31 - (1 month) = 06-30
*
* <p>03-31 - (1 month) = 02-28 or 02-29 depending
*
* <p>
*
* @see org.joda.time.DateTimeField#add
* @see org.joda.time.ReadWritableDateTime#addMonths(int)
* @param instant the time instant in millis to update.
* @param months the months to add (can be negative).
* @return the updated time instant.
*/
public long add(long instant, int months) {
if (months == 0) {
return instant; // the easy case
}
//
// Save time part first.
//
long timePart = iChronology.getMillisOfDay(instant);
//
//
// Get this year and month.
//
int thisYear = iChronology.getYear(instant);
int thisMonth = iChronology.getMonthOfYear(instant, thisYear);
// ----------------------------------------------------------
//
// Do not refactor without careful consideration.
// Order of calculation is important.
//
int yearToUse;
// Initially, monthToUse is zero-based
int monthToUse = thisMonth - 1 + months;
if (monthToUse >= 0) {
yearToUse = thisYear + (monthToUse / iMax);
monthToUse = (monthToUse % iMax) + 1;
} else {
yearToUse = thisYear + (monthToUse / iMax) - 1;
monthToUse = Math.abs(monthToUse);
int remMonthToUse = monthToUse % iMax;
// Take care of the boundary condition
if (remMonthToUse == 0) {
remMonthToUse = iMax;
}
monthToUse = iMax - remMonthToUse + 1;
// Take care of the boundary condition
if (monthToUse == 1) {
yearToUse += 1;
}
}
// End of do not refactor.
// ----------------------------------------------------------
//
// Quietly force DOM to nearest sane value.
//
int dayToUse = iChronology.getDayOfMonth(instant, thisYear, thisMonth);
int maxDay = iChronology.getDaysInYearMonth(yearToUse, monthToUse);
if (dayToUse > maxDay) {
dayToUse = maxDay;
}
//
// get proper date part, and return result
//
long datePart = iChronology.getYearMonthDayMillis(yearToUse, monthToUse, dayToUse);
return datePart + timePart;
}
/**
* Set the Month component of the specified time instant.
*
* <p>If the new month has less total days than the specified day of the month, this value is
* coerced to the nearest sane value. e.g.
*
* <p>07-31 to month 6 = 06-30
*
* <p>03-31 to month 2 = 02-28 or 02-29 depending
*
* <p>
*
* @param instant the time instant in millis to update.
* @param month the month (1,12) to update the time to.
* @return the updated time instant.
* @throws IllegalArgumentException if month is invalid
*/
public long set(long instant, int month) {
FieldUtils.verifyValueBounds(this, month, MIN, iMax);
//
int thisYear = iChronology.getYear(instant);
//
int thisDom = iChronology.getDayOfMonth(instant, thisYear);
int maxDom = iChronology.getDaysInYearMonth(thisYear, month);
if (thisDom > maxDom) {
// Quietly force DOM to nearest sane value.
thisDom = maxDom;
}
// Return newly calculated millis value
return iChronology.getYearMonthDayMillis(thisYear, month, thisDom)
+ iChronology.getMillisOfDay(instant);
}
// -----------------------------------------------------------------------
public long add(long instant, long months) {
int i_months = (int) months;
if (i_months == months) {
return add(instant, i_months);
}
// Copied from add(long, int) and modified slightly:
long timePart = iChronology.getMillisOfDay(instant);
int thisYear = iChronology.getYear(instant);
int thisMonth = iChronology.getMonthOfYear(instant, thisYear);
long yearToUse;
long monthToUse = thisMonth - 1 + months;
if (monthToUse >= 0) {
yearToUse = thisYear + (monthToUse / iMax);
monthToUse = (monthToUse % iMax) + 1;
} else {
yearToUse = thisYear + (monthToUse / iMax) - 1;
monthToUse = Math.abs(monthToUse);
int remMonthToUse = (int) (monthToUse % iMax);
if (remMonthToUse == 0) {
remMonthToUse = iMax;
}
monthToUse = iMax - remMonthToUse + 1;
if (monthToUse == 1) {
yearToUse += 1;
}
}
if (yearToUse < iChronology.getMinYear() || yearToUse > iChronology.getMaxYear()) {
throw new IllegalArgumentException("Magnitude of add amount is too large: " + months);
}
int i_yearToUse = (int) yearToUse;
int i_monthToUse = (int) monthToUse;
int dayToUse = iChronology.getDayOfMonth(instant, thisYear, thisMonth);
int maxDay = iChronology.getDaysInYearMonth(i_yearToUse, i_monthToUse);
if (dayToUse > maxDay) {
dayToUse = maxDay;
}
long datePart = iChronology.getYearMonthDayMillis(i_yearToUse, i_monthToUse, dayToUse);
return datePart + timePart;
}