I have been investigating how to change the frequency of a job on runtime with Java 8 and spring. This question was very useful but it did not totally solve my issue.
I can now configure the date when to job should be executed next. But If set the delay to 1 year, then I need to wait 1 year before the new configuration in taken into account.
My idea would be to stop the scheduled task if the configuration value is changed (so from another class). Then recalculate the next time the task should be executed. Perhaps there is an easier way of doing this.
Here is the code I have so far.
@Configuration
@EnableScheduling
public class RequestSchedulerConfig implements SchedulingConfigurer {
@Autowired
SchedulerConfigService schedulerConfigService;
@Bean
public RequestScheduler myBean() {
return new RequestScheduler();
}
@Bean(destroyMethod = "shutdown")
public Executor taskExecutor() {
return Executors.newScheduledThreadPool(100);
}
@Override
public void configureTasks(ScheduledTaskRegistrar taskRegistrar) {
taskRegistrar.setScheduler(taskExecutor());
taskRegistrar.addTriggerTask(
new Runnable() {
@Override public void run() {
myBean().startReplenishmentComputation();
}
},
new Trigger() {
@Override public Date nextExecutionTime(TriggerContext triggerContext) {
Duration d = schedulerConfigService.getIntervalFromDB();
return DateTime.now().plus(d).toDate();
}
}
);
}
}
This would be what I would like to do.
@RestController
@RequestMapping("/api/config/scheduler")
public class RequestSchedulerController {
@Autowired
ApplicationConfigWrapper applicationConfigWrapper;
@RequestMapping("/set/")
@ResponseBody
public String setRequestSchedulerConfig(@RequestParam(value = "frequency", defaultValue = "") final String frequencyInSeconds){
changeValueInDb(frequencyInSeconds);
myJob.restart();
return "Yeah";
}
}
TaskScheduler
. This will hold as state variables all ScheduledFuture
s, like private ScheduledFuture job1;
job1
.Future
(e.g job1
) 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);
}
}
}