How to use Java Constant as a part of @Scheduler expression annotation in Spring?

Question

I am using Spring scheduler as given bellow.

 @Scheduled(fixedDelay = ((10 * 60 * 1000) / 2))
    public void runDynamic()
    {
      //doing my stuff
    }

Now suppose I have one constant like this

public static final Integer VARIANCE_TIME_IN_MIN = 10;

And I want to use this constant as a part of my expression something like this :

@Scheduled(fixedDelay = ((MyConstants.VARIANCE_TIME_IN_MIN * 60 * 1000) / 2))
public void runDynamic()
{
//doing my stuff
}

but it is giving my compile time error. Any ideas? Thanks in Advance..!

Hi @NimChimpsky, Thanks for your reply, but I cannot find any example using Java Constant in your given link. Is it impossible ? — Vishal Zanzrukia, May 06 '14 at 11:48

NimChimpsky · Accepted Answer · 2014-05-06T12:31:54.780

7

Java annotations take compile time constants, which are defined as final primitives or strings.

SO change your definition to

   public static final int VARIANCE_TIME = 10;
   public static final long FIXED_DELAY = ((VARIANCE_TIME * 60 * 1000) / 2)

   @Scheduled(fixedDelay = FIXED_DELAY)
   public void runDynamic()

edited May 06 '14 at 12:31

answered May 06 '14 at 12:26

NimChimpsky

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score 0 · Answer 2 · edited May 23 '17 at 11:54

0

Use Task scheduling using cron expression from properties file

@Scheduled(cron = "${cronTrigger.expression}")
public void runDynamic()
    {
      //doing my stuff
    }

Config in XML File:

<bean id="cronTrigger" class="org.springframework.scheduling.quartz.CronTriggerBean">
    <property name="jobDetail" ref="exampleJob" />
    <!-- run every morning at 6 AM -->
    <property name="expression" value="0 0 6 * * ?" />
</bean>

This link1 and doc might help you

You can also create the Tash Scheduler dynamically(programatically) as explained here

edited May 23 '17 at 11:54

Community

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answered May 06 '14 at 11:43

Jeba Prince

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but it's from property file, not from Java Constant. – Vishal Zanzrukia May 06 '14 at 11:47
You cannot schedule a task through Java constants. Why do you need to use this constant? can't you reuse ${cronTrigger.expression} itself!! – Jeba Prince May 06 '14 at 11:50

visionken · Answer 3 · 2018-01-19T15:58:48.473

0

private static final long VARIANCE_TIME_IN_MIN = 10l;

@Scheduled(fixedDelay = ((VARIANCE_TIME_IN_MIN * 60 * 1000) / 2))
public void runDynamic() {
    // ...
}

edited Jan 19 '18 at 15:58

answered Jan 19 '18 at 15:52

visionken

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could've also explained that you changed the type to long, as it's not easily visible – Alex Savitsky Jan 19 '18 at 16:15
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While this code may answer the question, providing additional context regarding **how** and **why** it solves the problem would improve the answer's long-term value. – Alexander Jan 19 '18 at 16:55

How to use Java Constant as a part of @Scheduler expression annotation in Spring?

3 Answers3