/**
* 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;
}
/**
* Compare the value to another dateTime value, following the XPath comparison semantics
*
* @param other The other dateTime value
* @param context XPath dynamic evaluation context
* @return negative value if this one is the earler, 0 if they are chronologically equal, positive
* value if this one is the later. For this purpose, dateTime values with an unknown timezone
* are considered to be values in the implicit timezone (the Comparable interface requires a
* total ordering).
* @throws ClassCastException if the other value is not a DateTimeValue (the parameter is declared
* as CalendarValue to satisfy the interface)
* @throws NoDynamicContextException if the implicit timezone is needed and is not available
*/
public int compareTo(CalendarValue other, XPathContext context) throws NoDynamicContextException {
if (!(other instanceof DateTimeValue)) {
throw new ClassCastException("DateTime values are not comparable to " + other.getClass());
}
DateTimeValue v2 = (DateTimeValue) other;
if (getTimezoneInMinutes() == v2.getTimezoneInMinutes()) {
// both values are in the same timezone (explicitly or implicitly)
if (year != v2.year) {
return IntegerValue.signum(year - v2.year);
}
if (month != v2.month) {
return IntegerValue.signum(month - v2.month);
}
if (day != v2.day) {
return IntegerValue.signum(day - v2.day);
}
if (hour != v2.hour) {
return IntegerValue.signum(hour - v2.hour);
}
if (minute != v2.minute) {
return IntegerValue.signum(minute - v2.minute);
}
if (second != v2.second) {
return IntegerValue.signum(second - v2.second);
}
if (microsecond != v2.microsecond) {
return IntegerValue.signum(microsecond - v2.microsecond);
}
return 0;
}
return normalize(context).compareTo(v2.normalize(context), context);
}