Changing timer after startup in Java EE TimerService

Question

In this code I use a TimerService on startup to initiate a task that will run every four seconds. What if I need to change the frequency after startup?

@Startup
@Singleton
public class ProgrammaticScheduler {
 
    @Resource
    TimerService timerService;
 
    @PostConstruct
    public void initialize() {
        timerService.createTimer(0, 4000, "Every four seconds timer");
    }
 
    @Timeout
    public void programmaticTimeout(Timer timer) {
        System.out.println("timeout triggered");
    }
}

score 2 · Accepted Answer · edited Aug 28 '20 at 21:23

It's been a while since with Java EE but I guess the only option is to cancel the original timer and create a new. So adding something like this in your ProgrammaticScheduler:

private Timer timerToChange;

@PostConstruct
public void initialize() {
    timerToChange = timerService.createTimer(0, 4000, "Every four seconds timer");
}

public void changeTimer(**NEW_PARAMS**) {
    timerToChange.cancel();
    timerToChange = timerService.createTimer(**NEW_PARAMS**);
}

Changing timer after startup in Java EE TimerService

1 Answers1