Calendar reminder algorythm

• Type: Bug
• Status: Closed
• Resolution: Won't Fix
• Affects Version/s: 6.1.1 CE GA2, 7.0.0 M7
• Fix Version/s: 6.2.0 CE GA1
• Component/s: Calendar
• Labels:
  • smashing_june17
• Fix Priority: 3

Hi!

I face some issues with Calendar portlet: it can send one of two configured reminders; or sometimes it sends double notification for a single reminder..

I looked through the sources and found the algorithm of sending to be quite strange.

protected void remindUser(
CalEvent event, User user, Calendar startCalendar,
Calendar nowCalendar) {

Date startDate = startCalendar.getTime();

long startTime = startDate.getTime();

Date nowDate = nowCalendar.getTime();

long nowTime = nowDate.getTime();

if (startTime < nowTime)

{ return; }

long diff = (startTime - nowTime) / _CALENDAR_EVENT_CHECK_INTERVAL;

if ((diff ==
(event.getFirstReminder() / _CALENDAR_EVENT_CHECK_INTERVAL)) ||
(diff ==
(event.getSecondReminder() / _CALENDAR_EVENT_CHECK_INTERVAL)))

{ remindUser(event, user, startCalendar); }

}

https://github.com/liferay/liferay-portal/blob/62941e6773b54d697961006c07f5070991e1c631/portal-impl/src/com/liferay/portlet/calendar/service/impl/CalEventLocalServiceImpl.java#L1312

It seems to do its job in most of cases, but the code looks over-engineered.

What is more important, it can send double reminders, e.g.:

• scheduler runs every 5 minutes: 9:55, 10:00, 10:05,..
• I've configured the calendar to send a single reminder 5 minutes before the event that starts at 10:00

nowTime is not exact time (in ms). It might be a bit greater or less than it is expected, thus e.g. at 9.55 (startTime - nowTime) might be either 300000 or 299999 and 'diff' might be either 1 or 0. The next time when scheduler runs (10:00) it may happen that diff will become 0, once again. As a result - double reminders. We may lose notifications, as well, for the same reason.

For the moment I don't know exactly if this is the reason for my issue, but I deem the code of this method should be somehow rewritten to be more robust and easier to understand.