/**
* Return a new dateTime with the same normalized value, but in a different timezone.
*
* @param timezone the new timezone offset, in minutes
* @return the date/time in the new timezone. This will be a new DateTimeValue unless no change
* was required to the original value
*/
public CalendarValue adjustTimezone(int timezone) {
if (!hasTimezone()) {
CalendarValue in = (CalendarValue) copyAsSubType(typeLabel);
in.setTimezoneInMinutes(timezone);
return in;
}
int oldtz = getTimezoneInMinutes();
if (oldtz == timezone) {
return this;
}
int tz = timezone - oldtz;
int h = hour;
int mi = minute;
mi += tz;
if (mi < 0 || mi > 59) {
h += Math.floor(mi / 60.0);
mi = (mi + 60 * 24) % 60;
}
if (h >= 0 && h < 24) {
return new DateTimeValue(
year, month, day, (byte) h, (byte) mi, second, microsecond, timezone);
}
// Following code is designed to handle the corner case of adjusting from -14:00 to +14:00 or
// vice versa, which can cause a change of two days in the date
DateTimeValue dt = this;
while (h < 0) {
h += 24;
DateValue t = DateValue.yesterday(dt.getYear(), dt.getMonth(), dt.getDay());
dt =
new DateTimeValue(
t.getYear(),
t.getMonth(),
t.getDay(),
(byte) h,
(byte) mi,
second,
microsecond,
timezone);
}
if (h > 23) {
h -= 24;
DateValue t = DateValue.tomorrow(year, month, day);
return new DateTimeValue(
t.getYear(),
t.getMonth(),
t.getDay(),
(byte) h,
(byte) mi,
second,
microsecond,
timezone);
}
return dt;
}
static int hashCode(
int year,
byte month,
byte day,
byte hour,
byte minute,
byte second,
int microsecond,
int tzMinutes) {
int tz = -tzMinutes;
int h = hour;
int mi = minute;
mi += tz;
if (mi < 0 || mi > 59) {
h += Math.floor(mi / 60.0);
mi = (mi + 60 * 24) % 60;
}
while (h < 0) {
h += 24;
DateValue t = DateValue.yesterday(year, month, day);
year = t.getYear();
month = t.getMonth();
day = t.getDay();
}
while (h > 23) {
h -= 24;
DateValue t = DateValue.tomorrow(year, month, day);
year = t.getYear();
month = t.getMonth();
day = t.getDay();
}
return (year << 4)
^ (month << 28)
^ (day << 23)
^ (h << 18)
^ (mi << 13)
^ second
^ microsecond;
}