How to restart scheduled task on runtime with EnableScheduling annotation in spring?
- Create a singleton bean that gets an injected
TaskScheduler
. This will hold as state variables allScheduledFuture
s, likeprivate ScheduledFuture job1;
- On deployment, load from databases all schedule data and start the jobs, filling in all state variables like
job1
. - On change of scheduling data, cancel the corresponding
Future
(e.gjob1
) and then start it again with the new scheduling data.
The key idea here is to get control on the Future
s as they are created, so to save them in some state variables, so that when something in scheduling data changes, you can cancel them.
Here is the working code:
applicationContext.xml
<task:annotation-driven />
<task:scheduler id="infScheduler" pool-size="10"/>
The singleton bean, that holds the Future
s
@Component
public class SchedulerServiceImpl implements SchedulerService {
private static final Logger logger = LoggerFactory.getLogger(SchedulerServiceImpl.class);
@Autowired
@Qualifier(value="infScheduler")
private TaskScheduler taskScheduler;
@Autowired
private MyService myService;
private ScheduledFuture job1;//for other jobs you can add new private state variables
//Call this on deployment from the ScheduleDataRepository and everytime when schedule data changes.
@Override
public synchronized void scheduleJob(int jobNr, long newRate) {//you are free to change/add new scheduling data, but suppose for now you only want to change the rate
if (jobNr == 1) {//instead of if/else you could use a map with all job data
if (job1 != null) {//job was already scheduled, we have to cancel it
job1.cancel(true);
}
//reschedule the same method with a new rate
job1 = taskScheduler.scheduleAtFixedRate(new ScheduledMethodRunnable(myService, "methodInMyServiceToReschedule"), newRate);
}
}
}