Как получить результаты выполнения из ThreadPoolTaskScheduler ⇐ JAVA

[Anonymous]

In my application I retrieve from the database some metadata and from it I build an instance of MyJob class implementing Runnable interface and then submit it to ThreadPoolTaskScheduler. Here is the code that does it.

@Scheduled(fixedRateString = "${check.rate.minutes}", timeUnit = TimeUnit.MINUTES) public void checkForJobs() { LOG.info("Executing check at {}", Instant.now().toString()); int avail = threadPool.getPoolSize() - threadPool.getActiveCount(); // will retrieve jobs metadata to fill vacancies List availableJobs = this.repository.getAvailableJobs(avail); if(!(availableJobs == null || availableJobs.isEmpty())) { LOG.info("Retrieved {} jobs for scheduling", availableJobs.size()); for (MetaJob job : availableJobs) { scheduleJob(job); } } else { LOG.info("No available jobs at this moment"); } } private void scheduleJob(MetaJob job) { JobSchedule schedule = job.getSchedule(); JobRunner jobRunner = getExecutor(job); // Creating Runnable out of metadata if(schedule == null) { threadPool.schedule(jobRunner, Instant.now()); } else { Trigger trigger; if(schedule.getType() == SchedType.CRON) { trigger = new CronTrigger(schedule.getExpression()); } else { trigger = new PeriodicTrigger(Duration.parse(schedule.getExpression())); } threadPool.schedule(jobRunner, trigger); } } My job is being executed as expected, but I need to process results of its completion or failure. I.e. if number of execution exceeds limit specified in the metadata, I need to cancel subsequent executions. I also need to update database with some results stored within MyJob instance. If job fails, I do need to analyze the cause of failure. If it was due to some temporary outage, I will let job run again, otherwise I also need to cancel it.

So, I saw that ThreadPoolTaskScheduler has this protected method

afterExecute(Runnable task, @Nullable Throwable ex) and thought that it can solve my problem. I wrote a class MyJobScheduler extending ThreadPoolTaskScheduler and overload that method with the following code:

@Override protected void afterExecute(Runnable task, Throwable ex) { super.afterExecute(task, ex); if(ex == null) { MyJubRunner runner = (MyJobRunner)task; MyJob job = runner.getJob(); // whatever I need to do with it } else { // analyze the exception } } I placed a breakpoint inside this function and found that it is called twice before and after job execution. Secondly, I got ClassCastException because the Runnable this function receives as a parameter is not the task I have submitted, but an instance of java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask. I tried to do my own mapping between the MyJob and ScheduledFuture instance that is received upon submitting my job to a scheduler, but found out that this parameter received by afterExecute function has nothing in common with mentioned above ScheduledFuture instance.

My application can have dozens of jobs processed simultaneously and I do need to find which one has finished and how.

My question is quite clear: is it possible to find out which task was completed from afterExecute method. If it is possible - how to do it. If not, what would be other way to monitor completion of scheduled jobs? If someone can help me to find it out, I will appreciate it greatly.


Источник: https://stackoverflow.com/questions/780 ... kscheduler