commit 1fd4f2655406b7ce0f9e9b8c0d954d1941e60880
author andrey-me <andreym@microsoft.com> Fri Oct 14 15:57:12 2016 -0700
committer Julia Wang <jwang98052@yahoo.com> Mon Nov 21 12:21:54 2016 -0800
tree e41fb5b8111e363ec95b3ea1cfbfe200d46f12bd
parent 4e4e568faa3c3d625433b17bb4d15e0cd7897d7a

[REEF-1448] Support for upstream heartbeats
Adding job cancellation functionality into IMRU driver.
And exposing ICancellationDetector interface in API which enables client to provide custom cancellation detection from upstream.
Implementation: JobLifecycleManager is registered as IjobCancelled event source.
the manager checks IsJobCancelled method of configured CancellationonDetector on each timer event and
if cancellation signal is detected JobLifecycleManager fires JobCancelled event.
IMRU driver is registered as IJobCancelled observable and if event is fired, shuts down all evaluators and moves to Fail state.
Similar to failure handling, when job is cancelled, IMRU driver fires and exception instead of retrying the job.
(there is no other way to communicate driver status)
In addition, JobLifecycleManager is making a request to RM to try to kill current job - if succeeded, this will mark job status as KILLED instead of FAILED.

Client can provide implementation of IJobCancelledDetector in job definition.
This configuration is optional, if no implementation is configured in the definition, the driver assumes there is no cancellation signal.

JIRA:
  [REEF-1448] (https://issues.apache.org/jira/browse/REEF-1448)

This closes #1161