How to define when my @Scheduled method should be called first time?

Question

The first time @Scheduled method is called when my project just started(it's not fully up).Can i defined when my @Scheduled method should be called first time(not using initial delay).I want all my @Scheduled method to start execution first time when my server is up.So my startup time will be reduced.

I have used fixed delay Scheduler:

 @Scheduled(fixedDelay = 1800000) // runs in every 30min
public void schedulerFunction(){}

when my server is up (all my beans are initialized). @DanielWosch — Nivi, Jan 27 '21 at 07:38
Is your @Scheduled task using any other beans? Because then you may use `@PostConstruct` to execute the logic manually and further define a method with an `@Scheduled` annotation to execute it at a certain time. Because `@PostConstruct` is called after all dependencies have been injected (AFAIR). Means you could depend of the injection of a given Bean and if that been has been injected you are sure that everything is up — Daniel Rafael Wosch, Jan 27 '21 at 07:47

score 1 · Answer 1 · answered Jan 27 '21 at 10:09

1

You could implement ApplicationListener and wait for a ContextReadyEvent:

@Component
public class YourClassHavingScheduledMethodimplements ApplicationListener<ContextRefreshedEvent> {

    private boolean contextInitialized = false;

    @Scheduled(...)
    public void someScheduledMethod() {
        if(this.contextInitialized) {
            // Execute logic here
        }
    }

    @Override
    public void onApplicationEvent(ContextRefreshedEvent event) {
        this.contextInitialized = true;
    }
}

answered Jan 27 '21 at 10:09

Hasan Can Saral

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Should it not be `ApplicationReadyEvent` ?. – Daniel Rafael Wosch Jan 27 '21 at 11:09
Further it can happen that `someScheduledMethod()` is not called after start - as `this.contextInitialized` may be `false` when `@Scheduled` is executed. – Daniel Rafael Wosch Jan 27 '21 at 11:14
Sorry, I automatically thought `@Scheduled` runs on a `cron`, periodically. And yes `ApplicationReadyEvent` also should work. – Hasan Can Saral Jan 27 '21 at 13:33
1

Sure but as I understand the OP correctly the task should be started after Spring is "ready" (easy spoken) and as by the expression. So it may happen that this will only get invoked when scheduled hits – Daniel Rafael Wosch Jan 27 '21 at 13:36
Is it possible that some of my scheduled method will be missed if i Implement using ApplicationListener? @HasanCanSaral – Nivi Jan 27 '21 at 16:12
Depends on the logic. If it's a cron job, then you may miss some depending on the sequence of initialization of your `@Bean`s. If it's set to run e.g. once, then it's not good. – Hasan Can Saral Jan 27 '21 at 19:40
Show your code. Show your `@Scheduled` annotation – Hasan Can Saral Jan 27 '21 at 19:41
I am using fixed delay scheduler(updated the code) but there will be chance that i will miss some scheduler function first time? @HasanCanSaral – Nivi Jan 29 '21 at 09:40
I guess, yes. Can you not try and see? – Hasan Can Saral Feb 01 '21 at 20:47

How to define when my @Scheduled method should be called first time?

1 Answers1