I have a scheduled job in Spring, I get its cron from my database. Every time it is executed, the next execution time is updated. So, if it is configured to run every 10 minutes, I can change the value into the database to schedule that job every 15 minutes.
The problem is that I have to wait for the execution to get the updated cron: if a job is scheduled every 15 minutes and I want to change this value to be every 2 minutes, I have to wait for the next execution (up to 15 minutes) to have this job every 2 minutes.
Is there a way to get this job rescheduled after I update the database?
I thought to destroy and refresh this bean, but it is not working (maybe it is not possible or something was wrong in my implementation). Maybe there is a way to trigger an event to execute method configureTask.
Here the snippet of my scheduled job.
@EnableScheduling
@Component
public class MyClass implements SchedulingConfigurer {
private static final String JOB = "My personal task";
@Autowired
JobRepository jobRepository;
@Override
public void configureTasks(ScheduledTaskRegistrar scheduledTaskRegistrar) {
scheduledTaskRegistrar.addTriggerTask(new Runnable() {
@Override
public void run() {
System.out.println("Hello World!");
}
}, new Trigger() {
@Override
public Date nextExecutionTime(TriggerContext triggerContext) {
JobScheduled byJobNameIgnoreCase = jobRepository.findByJobNameIgnoreCase(JOB); // read from database
String cron = byJobNameIgnoreCase.getCrontab();
CronTrigger trigger = new CronTrigger(cron);
return trigger.nextExecutionTime(triggerContext);
}
});
}
}
To manage this, I created a SchedulerOrchestrator, which manages my jobs. The jobs contain a SchedulerFuture.
Here the code that I hope can help someone else.
Let's start with an interface which will be implemented by my jobs:
public interface SchedulerObjectInterface {
void start();
void stop();
}
Every job needs a ScheduledFuture to stop and needs to autowire a TaskScheduler to be scheduled. Here a sample of one job (you can create as many as you want):
@Component
public class MyFirstJob implements SchedulerObjectInterface {
private static final Logger log = LoggerFactory.getLogger(MyFirstJob.class);
public static final String JOB = "MyFirstJob";
@Autowired
JobRepository jobRepository;
private ScheduledFuture future;
@Autowired
private TaskScheduler scheduler;
@Override
public void start() {
future = scheduler.schedule(new Runnable() {
@Override
public void run() {
System.out.println(JOB + " Hello World! " + new Date());
}
}, new Trigger() {
@Override
public Date nextExecutionTime(TriggerContext triggerContext) {
String cron = cronConfig();
System.out.println(cron);
CronTrigger trigger = new CronTrigger(cron);
return trigger.nextExecutionTime(triggerContext);
}
});
}
@Override
public void stop() {
future.cancel(false);
}
// retrieve cron from database
private String cronConfig() {
JobScheduled byJobNameIgnoreCase = jobRepository.findByJobNameIgnoreCase(JOB);
return byJobNameIgnoreCase.getCrontab();
}
}
Finally we can add our jobs to an orchestrator:
@Configuration
public class SchedulerOrchestrator {
private static final Logger log = LoggerFactory.getLogger(SchedulerOrchestrator.class);
private static Map<String, SchedulerObjectInterface> schduledJobsMap = new HashMap<>();
@Autowired
JobRepository jobRepository;
@Autowired
MyFirstJob myFirstJob;
@Autowired
MySecondJob mySecondJob;
@Autowired
TaskScheduler scheduler;
@PostConstruct
public void initScheduler() {
schduledJobsMap.put(MyFirstJob.JOB, myFirstJob);
schduledJobsMap.put(MySecondJob.JOB, mySecondJob);
startAll();
}
public void restart(String job) {
stop(job);
start(job);
}
public void stop(String job) {
schduledJobsMap.get(job).stop();
}
public void start(String job) {
schduledJobsMap.get(job).start();
}
public void startAll() {
for (SchedulerObjectInterface schedulerObjectInterface : schduledJobsMap.values()) {
schedulerObjectInterface.start();
}
}
@Bean
public TaskScheduler scheduler() {
return new ThreadPoolTaskScheduler();
}
}
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