in java/util/JapaneseImperialCalendar.java [535:961]
public void roll(int field, int amount) {
// If amount == 0, do nothing even the given field is out of
// range. This is tested by JCK.
if (amount == 0) {
return;
}
if (field < 0 || field >= ZONE_OFFSET) {
throw new IllegalArgumentException();
}
// Sync the time and calendar fields.
complete();
int min = getMinimum(field);
int max = getMaximum(field);
switch (field) {
case ERA:
case AM_PM:
case MINUTE:
case SECOND:
case MILLISECOND:
// These fields are handled simply, since they have fixed
// minima and maxima. Other fields are complicated, since
// the range within they must roll varies depending on the
// date, a time zone and the era transitions.
break;
case HOUR:
case HOUR_OF_DAY:
{
int unit = max + 1; // 12 or 24 hours
int h = internalGet(field);
int nh = (h + amount) % unit;
if (nh < 0) {
nh += unit;
}
time += ONE_HOUR * (nh - h);
// The day might have changed, which could happen if
// the daylight saving time transition brings it to
// the next day, although it's very unlikely. But we
// have to make sure not to change the larger fields.
CalendarDate d = jcal.getCalendarDate(time, getZone());
if (internalGet(DAY_OF_MONTH) != d.getDayOfMonth()) {
d.setEra(jdate.getEra());
d.setDate(internalGet(YEAR),
internalGet(MONTH) + 1,
internalGet(DAY_OF_MONTH));
if (field == HOUR) {
assert (internalGet(AM_PM) == PM);
d.addHours(+12); // restore PM
}
time = jcal.getTime(d);
}
int hourOfDay = d.getHours();
internalSet(field, hourOfDay % unit);
if (field == HOUR) {
internalSet(HOUR_OF_DAY, hourOfDay);
} else {
internalSet(AM_PM, hourOfDay / 12);
internalSet(HOUR, hourOfDay % 12);
}
// Time zone offset and/or daylight saving might have changed.
int zoneOffset = d.getZoneOffset();
int saving = d.getDaylightSaving();
internalSet(ZONE_OFFSET, zoneOffset - saving);
internalSet(DST_OFFSET, saving);
return;
}
case YEAR:
min = getActualMinimum(field);
max = getActualMaximum(field);
break;
case MONTH:
// Rolling the month involves both pinning the final value to [0, 11]
// and adjusting the DAY_OF_MONTH if necessary. We only adjust the
// DAY_OF_MONTH if, after updating the MONTH field, it is illegal.
// E.g., <jan31>.roll(MONTH, 1) -> <feb28> or <feb29>.
{
if (!isTransitionYear(jdate.getNormalizedYear())) {
int year = jdate.getYear();
if (year == getMaximum(YEAR)) {
CalendarDate jd = jcal.getCalendarDate(time, getZone());
CalendarDate d = jcal.getCalendarDate(Long.MAX_VALUE, getZone());
max = d.getMonth() - 1;
int n = getRolledValue(internalGet(field), amount, min, max);
if (n == max) {
// To avoid overflow, use an equivalent year.
jd.addYear(-400);
jd.setMonth(n + 1);
if (jd.getDayOfMonth() > d.getDayOfMonth()) {
jd.setDayOfMonth(d.getDayOfMonth());
jcal.normalize(jd);
}
if (jd.getDayOfMonth() == d.getDayOfMonth()
&& jd.getTimeOfDay() > d.getTimeOfDay()) {
jd.setMonth(n + 1);
jd.setDayOfMonth(d.getDayOfMonth() - 1);
jcal.normalize(jd);
// Month may have changed by the normalization.
n = jd.getMonth() - 1;
}
set(DAY_OF_MONTH, jd.getDayOfMonth());
}
set(MONTH, n);
} else if (year == getMinimum(YEAR)) {
CalendarDate jd = jcal.getCalendarDate(time, getZone());
CalendarDate d = jcal.getCalendarDate(Long.MIN_VALUE, getZone());
min = d.getMonth() - 1;
int n = getRolledValue(internalGet(field), amount, min, max);
if (n == min) {
// To avoid underflow, use an equivalent year.
jd.addYear(+400);
jd.setMonth(n + 1);
if (jd.getDayOfMonth() < d.getDayOfMonth()) {
jd.setDayOfMonth(d.getDayOfMonth());
jcal.normalize(jd);
}
if (jd.getDayOfMonth() == d.getDayOfMonth()
&& jd.getTimeOfDay() < d.getTimeOfDay()) {
jd.setMonth(n + 1);
jd.setDayOfMonth(d.getDayOfMonth() + 1);
jcal.normalize(jd);
// Month may have changed by the normalization.
n = jd.getMonth() - 1;
}
set(DAY_OF_MONTH, jd.getDayOfMonth());
}
set(MONTH, n);
} else {
int mon = (internalGet(MONTH) + amount) % 12;
if (mon < 0) {
mon += 12;
}
set(MONTH, mon);
// Keep the day of month in the range. We
// don't want to spill over into the next
// month; e.g., we don't want jan31 + 1 mo ->
// feb31 -> mar3.
int monthLen = monthLength(mon);
if (internalGet(DAY_OF_MONTH) > monthLen) {
set(DAY_OF_MONTH, monthLen);
}
}
} else {
int eraIndex = getEraIndex(jdate);
CalendarDate transition = null;
if (jdate.getYear() == 1) {
transition = eras[eraIndex].getSinceDate();
min = transition.getMonth() - 1;
} else {
if (eraIndex < eras.length - 1) {
transition = eras[eraIndex + 1].getSinceDate();
if (transition.getYear() == jdate.getNormalizedYear()) {
max = transition.getMonth() - 1;
if (transition.getDayOfMonth() == 1) {
max--;
}
}
}
}
if (min == max) {
// The year has only one month. No need to
// process further. (Showa Gan-nen (year 1)
// and the last year have only one month.)
return;
}
int n = getRolledValue(internalGet(field), amount, min, max);
set(MONTH, n);
if (n == min) {
if (!(transition.getMonth() == BaseCalendar.JANUARY
&& transition.getDayOfMonth() == 1)) {
if (jdate.getDayOfMonth() < transition.getDayOfMonth()) {
set(DAY_OF_MONTH, transition.getDayOfMonth());
}
}
} else if (n == max && (transition.getMonth() - 1 == n)) {
int dom = transition.getDayOfMonth();
if (jdate.getDayOfMonth() >= dom) {
set(DAY_OF_MONTH, dom - 1);
}
}
}
return;
}
case WEEK_OF_YEAR:
{
int y = jdate.getNormalizedYear();
max = getActualMaximum(WEEK_OF_YEAR);
set(DAY_OF_WEEK, internalGet(DAY_OF_WEEK)); // update stamp[field]
int woy = internalGet(WEEK_OF_YEAR);
int value = woy + amount;
if (!isTransitionYear(jdate.getNormalizedYear())) {
int year = jdate.getYear();
if (year == getMaximum(YEAR)) {
max = getActualMaximum(WEEK_OF_YEAR);
} else if (year == getMinimum(YEAR)) {
min = getActualMinimum(WEEK_OF_YEAR);
max = getActualMaximum(WEEK_OF_YEAR);
if (value > min && value < max) {
set(WEEK_OF_YEAR, value);
return;
}
}
// If the new value is in between min and max
// (exclusive), then we can use the value.
if (value > min && value < max) {
set(WEEK_OF_YEAR, value);
return;
}
long fd = cachedFixedDate;
// Make sure that the min week has the current DAY_OF_WEEK
long day1 = fd - (7 * (woy - min));
if (year != getMinimum(YEAR)) {
if (gcal.getYearFromFixedDate(day1) != y) {
min++;
}
} else {
CalendarDate d = jcal.getCalendarDate(Long.MIN_VALUE, getZone());
if (day1 < jcal.getFixedDate(d)) {
min++;
}
}
// Make sure the same thing for the max week
fd += 7 * (max - internalGet(WEEK_OF_YEAR));
if (gcal.getYearFromFixedDate(fd) != y) {
max--;
}
break;
}
// Handle transition here.
long fd = cachedFixedDate;
long day1 = fd - (7 * (woy - min));
// Make sure that the min week has the current DAY_OF_WEEK
LocalGregorianCalendar.Date d = getCalendarDate(day1);
if (!(d.getEra() == jdate.getEra() && d.getYear() == jdate.getYear())) {
min++;
}
// Make sure the same thing for the max week
fd += 7 * (max - woy);
jcal.getCalendarDateFromFixedDate(d, fd);
if (!(d.getEra() == jdate.getEra() && d.getYear() == jdate.getYear())) {
max--;
}
// value: the new WEEK_OF_YEAR which must be converted
// to month and day of month.
value = getRolledValue(woy, amount, min, max) - 1;
d = getCalendarDate(day1 + value * 7);
set(MONTH, d.getMonth() - 1);
set(DAY_OF_MONTH, d.getDayOfMonth());
return;
}
case WEEK_OF_MONTH:
{
boolean isTransitionYear = isTransitionYear(jdate.getNormalizedYear());
// dow: relative day of week from the first day of week
int dow = internalGet(DAY_OF_WEEK) - getFirstDayOfWeek();
if (dow < 0) {
dow += 7;
}
long fd = cachedFixedDate;
long month1; // fixed date of the first day (usually 1) of the month
int monthLength; // actual month length
if (isTransitionYear) {
month1 = getFixedDateMonth1(jdate, fd);
monthLength = actualMonthLength();
} else {
month1 = fd - internalGet(DAY_OF_MONTH) + 1;
monthLength = jcal.getMonthLength(jdate);
}
// the first day of week of the month.
long monthDay1st = LocalGregorianCalendar.getDayOfWeekDateOnOrBefore(month1 + 6,
getFirstDayOfWeek());
// if the week has enough days to form a week, the
// week starts from the previous month.
if ((int)(monthDay1st - month1) >= getMinimalDaysInFirstWeek()) {
monthDay1st -= 7;
}
max = getActualMaximum(field);
// value: the new WEEK_OF_MONTH value
int value = getRolledValue(internalGet(field), amount, 1, max) - 1;
// nfd: fixed date of the rolled date
long nfd = monthDay1st + value * 7 + dow;
// Unlike WEEK_OF_YEAR, we need to change day of week if the
// nfd is out of the month.
if (nfd < month1) {
nfd = month1;
} else if (nfd >= (month1 + monthLength)) {
nfd = month1 + monthLength - 1;
}
set(DAY_OF_MONTH, (int)(nfd - month1) + 1);
return;
}
case DAY_OF_MONTH:
{
if (!isTransitionYear(jdate.getNormalizedYear())) {
max = jcal.getMonthLength(jdate);
break;
}
// TODO: Need to change the spec to be usable DAY_OF_MONTH rolling...
// Transition handling. We can't change year and era
// values here due to the Calendar roll spec!
long month1 = getFixedDateMonth1(jdate, cachedFixedDate);
// It may not be a regular month. Convert the date and range to
// the relative values, perform the roll, and
// convert the result back to the rolled date.
int value = getRolledValue((int)(cachedFixedDate - month1), amount,
0, actualMonthLength() - 1);
LocalGregorianCalendar.Date d = getCalendarDate(month1 + value);
assert getEraIndex(d) == internalGetEra()
&& d.getYear() == internalGet(YEAR) && d.getMonth()-1 == internalGet(MONTH);
set(DAY_OF_MONTH, d.getDayOfMonth());
return;
}
case DAY_OF_YEAR:
{
max = getActualMaximum(field);
if (!isTransitionYear(jdate.getNormalizedYear())) {
break;
}
// Handle transition. We can't change year and era values
// here due to the Calendar roll spec.
int value = getRolledValue(internalGet(DAY_OF_YEAR), amount, min, max);
long jan0 = cachedFixedDate - internalGet(DAY_OF_YEAR);
LocalGregorianCalendar.Date d = getCalendarDate(jan0 + value);
assert getEraIndex(d) == internalGetEra() && d.getYear() == internalGet(YEAR);
set(MONTH, d.getMonth() - 1);
set(DAY_OF_MONTH, d.getDayOfMonth());
return;
}
case DAY_OF_WEEK:
{
int normalizedYear = jdate.getNormalizedYear();
if (!isTransitionYear(normalizedYear) && !isTransitionYear(normalizedYear - 1)) {
// If the week of year is in the same year, we can
// just change DAY_OF_WEEK.
int weekOfYear = internalGet(WEEK_OF_YEAR);
if (weekOfYear > 1 && weekOfYear < 52) {
set(WEEK_OF_YEAR, internalGet(WEEK_OF_YEAR));
max = SATURDAY;
break;
}
}
// We need to handle it in a different way around year
// boundaries and in the transition year. Note that
// changing era and year values violates the roll
// rule: not changing larger calendar fields...
amount %= 7;
if (amount == 0) {
return;
}
long fd = cachedFixedDate;
long dowFirst = LocalGregorianCalendar.getDayOfWeekDateOnOrBefore(fd, getFirstDayOfWeek());
fd += amount;
if (fd < dowFirst) {
fd += 7;
} else if (fd >= dowFirst + 7) {
fd -= 7;
}
LocalGregorianCalendar.Date d = getCalendarDate(fd);
set(ERA, getEraIndex(d));
set(d.getYear(), d.getMonth() - 1, d.getDayOfMonth());
return;
}
case DAY_OF_WEEK_IN_MONTH:
{
min = 1; // after having normalized, min should be 1.
if (!isTransitionYear(jdate.getNormalizedYear())) {
int dom = internalGet(DAY_OF_MONTH);
int monthLength = jcal.getMonthLength(jdate);
int lastDays = monthLength % 7;
max = monthLength / 7;
int x = (dom - 1) % 7;
if (x < lastDays) {
max++;
}
set(DAY_OF_WEEK, internalGet(DAY_OF_WEEK));
break;
}
// Transition year handling.
long fd = cachedFixedDate;
long month1 = getFixedDateMonth1(jdate, fd);
int monthLength = actualMonthLength();
int lastDays = monthLength % 7;
max = monthLength / 7;
int x = (int)(fd - month1) % 7;
if (x < lastDays) {
max++;
}
int value = getRolledValue(internalGet(field), amount, min, max) - 1;
fd = month1 + value * 7 + x;
LocalGregorianCalendar.Date d = getCalendarDate(fd);
set(DAY_OF_MONTH, d.getDayOfMonth());
return;
}
}
set(field, getRolledValue(internalGet(field), amount, min, max));
}