/**
* Returns the offset of this time zone from UTC at the specified date. If Daylight Saving Time is
* in effect at the specified date, the offset value is adjusted with the amount of daylight
* saving.
*
* @param date the date represented in milliseconds since January 1, 1970 00:00:00 GMT
* @return the amount of time in milliseconds to add to UTC to get local time.
* @see Calendar#ZONE_OFFSET
* @see Calendar#DST_OFFSET
* @see #getOffset(long, boolean, int[])
* @stable ICU 2.8
*/
public int getOffset(long date) {
int[] result = new int[2];
getOffset(date, false, result);
return result[0] + result[1];
}
/**
* {@icu} Checks if the time zone has equivalent transitions in the time range. This method
* returns true when all of transition times, from/to standard offsets and DST savings used by
* this time zone match the other in the time range.
*
* @param tz The instance of <code>TimeZone</code>
* @param start The start time of the evaluated time range (inclusive)
* @param end The end time of the evaluated time range (inclusive)
* @param ignoreDstAmount When true, any transitions with only daylight saving amount changes will
* be ignored, except either of them is zero. For example, a transition from rawoffset
* 3:00/dstsavings 1:00 to rawoffset 2:00/dstsavings 2:00 is excluded from the comparison, but
* a transtion from rawoffset 2:00/dstsavings 1:00 to rawoffset 3:00/dstsavings 0:00 is
* included.
* @return true if the other time zone has the equivalent transitions in the time range. When tz
* is not a <code>BasicTimeZone</code>, this method returns false.
* @stable ICU 3.8
*/
public boolean hasEquivalentTransitions(
TimeZone tz, long start, long end, boolean ignoreDstAmount) {
if (hasSameRules(tz)) {
return true;
}
if (!(tz instanceof BasicTimeZone)) {
return false;
}
// Check the offsets at the start time
int[] offsets1 = new int[2];
int[] offsets2 = new int[2];
getOffset(start, false, offsets1);
tz.getOffset(start, false, offsets2);
if (ignoreDstAmount) {
if ((offsets1[0] + offsets1[1] != offsets2[0] + offsets2[1])
|| (offsets1[1] != 0 && offsets2[1] == 0)
|| (offsets1[1] == 0 && offsets2[1] != 0)) {
return false;
}
} else {
if (offsets1[0] != offsets2[0] || offsets1[1] != offsets2[1]) {
return false;
}
}
// Check transitions in the range
long time = start;
while (true) {
TimeZoneTransition tr1 = getNextTransition(time, false);
TimeZoneTransition tr2 = ((BasicTimeZone) tz).getNextTransition(time, false);
if (ignoreDstAmount) {
// Skip a transition which only differ the amount of DST savings
while (true) {
if (tr1 != null
&& tr1.getTime() <= end
&& (tr1.getFrom().getRawOffset() + tr1.getFrom().getDSTSavings()
== tr1.getTo().getRawOffset() + tr1.getTo().getDSTSavings())
&& (tr1.getFrom().getDSTSavings() != 0 && tr1.getTo().getDSTSavings() != 0)) {
tr1 = getNextTransition(tr1.getTime(), false);
} else {
break;
}
}
while (true) {
if (tr2 != null
&& tr2.getTime() <= end
&& (tr2.getFrom().getRawOffset() + tr2.getFrom().getDSTSavings()
== tr2.getTo().getRawOffset() + tr2.getTo().getDSTSavings())
&& (tr2.getFrom().getDSTSavings() != 0 && tr2.getTo().getDSTSavings() != 0)) {
tr2 = ((BasicTimeZone) tz).getNextTransition(tr2.getTime(), false);
} else {
break;
}
}
}
boolean inRange1 = false;
boolean inRange2 = false;
if (tr1 != null) {
if (tr1.getTime() <= end) {
inRange1 = true;
}
}
if (tr2 != null) {
if (tr2.getTime() <= end) {
inRange2 = true;
}
}
if (!inRange1 && !inRange2) {
// No more transition in the range
break;
}
if (!inRange1 || !inRange2) {
return false;
}
if (tr1.getTime() != tr2.getTime()) {
return false;
}
if (ignoreDstAmount) {
if (tr1.getTo().getRawOffset() + tr1.getTo().getDSTSavings()
!= tr2.getTo().getRawOffset() + tr2.getTo().getDSTSavings()
|| tr1.getTo().getDSTSavings() != 0 && tr2.getTo().getDSTSavings() == 0
|| tr1.getTo().getDSTSavings() == 0 && tr2.getTo().getDSTSavings() != 0) {
return false;
}
} else {
if (tr1.getTo().getRawOffset() != tr2.getTo().getRawOffset()
|| tr1.getTo().getDSTSavings() != tr2.getTo().getDSTSavings()) {
return false;
}
}
time = tr1.getTime();
}
return true;
}