[REEF-1527] Graceful shutdown of the RuntimeClock is not so graceful: unconditionally clears the event queue

• Type: Sub-task
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 0.16
• Component/s: REEF-Common, Wake
• Labels: bug events
• Assignee: Sergiy Matusevych
• Reporter: Sergiy Matusevych
• Created: 12/Aug/16 19:35
• Updated: 12/Sep/16 19:58
• Resolved: 18/Aug/16 01:50

Description

REEF RuntimeClock.close() method that is supposed to perform a graceful shutdown of the event loop, contains the following code:

this.schedule.clear();
this.schedule.add(new StopTime(findAcceptableStopTime()));

The problem is that findAcceptableStopTime() searches the schedule for the last client alarm - when the schedule has been cleared already.

We need to schedule StopTime event without clearing the schedule to allow graceful shutdown, but close the clock so no events will be scheduled after it.

Issue Links

• is required by: REEF-1533 Make RuntimeClock more testable and create unit tests to check graceful and forceful shutdown of RuntimeClock
• is required by: REEF-1532 Pass Time object instead of numeric timestamp in Timer methods