I took Ron's very interesting answer and improved the getTimeAfter Method, In order to adjust it to server GMT running and possible differences when scheduling 'Once a year' cron expressions.
@Override
public Date getTimeAfter(Date date) {
Date nextDate = super.getTimeAfter(date);
if(nextDate == null){
return null;
}
DateTime date1 = new DateTime(nextDate);
if (getTimeZone().inDaylightTime(date1.toDate()) && !getTimeZone().inDaylightTime(date)) {
DateTimeZone dtz = DateTimeZone.forTimeZone(getTimeZone());
DateTime dstEndDateTime = new DateTime(new Date(dtz.nextTransition(date.getTime())));
int dstEndHour = dstEndDateTime.getHourOfDay();
int dstDuration = (dtz.getOffset(date1.getMillis()) - dtz.getStandardOffset(date1.getMillis())) / (60 * 60 * 1000);
int hour = date1.getHourOfDay();
// Verifies if the scheduled hour is within a phantom hour (dissapears upon DST change)
if (hour < dstEndHour && hour >= dstEndHour-dstDuration){
// Verify if the date is a skip, otherwise it is a date in the future (like threads that run once a year)
if(dstEndDateTime.getDayOfYear() == date1.minusDays(1).getDayOfYear()){
return dstEndDateTime.toDate();
}else{
return nextDate;
}
}else{
return nextDate;
}
} else{
return nextDate;
}
}
Please note my server runs in GMT mode, therefore I do not use some of the offset conversions present in Ron's answer.
Also I discovered a Quartz bug, in which if you use the following configuration, it will fail because it is not capable of processing the cron expression correctly:
SimpleDateFormat sdf = new SimpleDateFormat("dd/MM/yyyy HH:mm:ss");
String cron = "0 15 2 8 3 ? 2015";
FailsafeCronExpression cronExpression = new FailsafeCronExpression(cron);
cronExpression.setTimeZone(DateTimeZone.forID("America/Vancouver"));
DateTime nextDate = new DateTime(cronExpression.getTimeAfter(sdf.parse("12/11/2014 10:15:00")));
This actually seems to happen because DST change takes place during 9th of March 2am for Vancouver and seems the Quartz internal implementation of the super.getTimeAfter(date) method will always send null.
I hope this information is useful.