EJB TimerService interval timer with end date

Question

I want to create an EJB Timer running with specific interval, but it also should stop being triggered at some point. EJB's TimerService seems to offer only 2 possibilities:

• You create infinitely recurring timer with specific interval.
• You create a calendar timer, which has start and end dates, and also allows to events to repeat every N seconds/minutes/hours. The problem is that this repetition does not "roll over", as the documentation clearly states. So if I create a timer to schedule every 5 hours, it'll be every 5 hours within the day, and that's not what I want.

The precision I need is hours, so any solution allowing hourly repetition which "rolls over" days is fine.

Thank you.

Answer 1

You can create 2 or more timers with same functionality. Or create single time timer, during execution calculate next execution date/time and create next single time timer

Answer 2

This method getTimers() gives you the lists of timers are currently active for the bean TimerService. For each timers from the list, perform getInfo() to get the timer's info. If this is null, then its the scheduler that you have started. Just perform the cancel() then, and it will stop your scheduler.

List<Timer> timerList = timerService.getTimers();
for(Timer t : timerList){
    if(t.getInfo() ==  null){
        t.cancel();
    }
}

So decide from where you want to use this.

Answer 3

You can do it with ScheduleExpression as:

ScheduleExpression schedule = new ScheduleExpression();
schedule.start(startDate);
schedule.hour("*/2");
schedule.end(endDate);
Timer timer = timerService.createCalendarTimer(schedule);

The above code trigers the Timer every 2 hours for example.