Quartz Scheduler that runs every x months

[joei salijado]

Hi!

I have a cron trigger that is scheduled to run once every month. This works fine but when I change the schedule to run every x months, let's say, every 3 months, it will not be followed. Regardless of the start date, it will always run on March, June, Sept, and Dec of every year. Here's my cron expression:

     0 30 10 20 */3 ? *

I recently came across with the documentation of Quartz's cron expression and was enlightened by the explanation on the "/" character.
     The "/" character simply helps you turn on every "nth" value in the given set. Thus "7/6" in the month field only turns on month "7",
     it does NOT mean every 6th month, please note that subtlety.

Now I'm wondering if it's possible to schedule a cron trigger that runs every x months and what will be the correct cron expression for this.
Badly need your help guys.. Thanks!

[James Ward]

How about using the Quartz (Java) library itself to do your task?

[joei salijado]

James Ward wrote:How about using the Quartz (Java) library itself to do your task?

Hi James,
I'm not quite sure what you mean but I'm using Quartz's CronTrigger class in defining the details of the schedule as such:
    

Scheduler scheduler = StdSchedulerFactory.getDefaultScheduler();
JobDetail jobDetail = new JobDetail(jobName, jobGroup, jobClass);
CronTrigger cronTrigger = new CronTrigger(triggerName, triggerGroup, triggerCronExpression);
  where triggerCronExpression = "0 30 10 20 */3 ? *"
   :
scheduler.scheduleJob(jobDetail, cronTrigger);

[James Ward]

Oh Ok...

I guess then you would have see the APIs (http://quartz.sourceforge.net/javadoc/index.html)

TriggerUtils class has many convenience methods (to avoid figuring out cron expressions!) like makeHourlyTrigger, makeMonthlyTrigger etc.

This is pseudo code, just to give you an idea:

Trigger trigger =  TriggerUtils.getMonthyTrigger(...);
sched.scheduleJob(jobDetail, trigger);//jobDetail is an instance of JobDetail class.

You can put additional logic in your jobDetail class to do-whatever-you-want or not-do, to achieve for example doing-your-task only on even months etc.

I have used these APIs in the past to set triggers instead of CronTrigger class.

[joei salijado]

Ok thanks. My monthly cron trigger schedule (fires every month) is working fine so I'm still checking if I can continue using CronTrigger as my trigger and just change something in JobDetail like you said.

[joei salijado]

Hi.. Can you elaborate further on how this can be done in JobDetail?
Thanks.

[James Ward]

joei salijado wrote:Hi.. Can you elaborate further on how this can be done in JobDetail?
Thanks.

Well some custom logic...

If you store when actual 'Job' ran succesfully last time; you can always refer that information to decide whether it should run 'this' time or not etc.