CODEWITHSUNDEEP
quartz-scheduler
Nurullah Yılmaz
Nurullah Yılmaz

Reputation: 31

quartz-scheduler depend jobs

I'm working on a project with Quartz and has been a problem with the dependencies with jobs.

we have a setup where A and B aren't dependent on eachother, though C is:

A and B can run at the same time, but C can only run when both A and B are complete.

Is there a way to set this kind of scenario up in Quartz, so that C will only trigger when A and B finish?

Upvotes: 3

Views: 1432

Answers (1)

fvu
fvu

Reputation: 32953

Not directly AFAIK, but it should be not too hard to use a TriggerListener to implement such a functionality (a TriggerListener is run both a start and end of jobs, and you can set them up for individual triggers or trigger groups).

EDIT: there is even a specific FAQ Topic about this problem:

There currently is no "direct" or "free" way to chain triggers with Quartz. However there are several ways you can accomplish it without much effort. Below is an outline of a couple approaches:

One way is to use a listener (i.e. a TriggerListener, JobListener or SchedulerListener) that can notice the completion of a job/trigger and then immediately schedule a new trigger to fire. This approach can get a bit involved, since you'll have to inform the listener which job follows which - and you may need to worry about persistence of this information. See the listener org.quartz.listeners.JobChainingJobListener which ships with Quartz - as it already has some of this functionality.

Another way is to build a Job that contains within its JobDataMap the name of the next job to fire, and as the job completes (the last step in its execute() method) have the job schedule the next job. Several people are doing this and have had good luck. Most have made a base (abstract) class that is a Job that knows how to get the job name and group out of the JobDataMap using pre-defined keys (constants) and contains code to schedule the identified job. This abstract Job's implementation of execute() delegates to an abstract template method such as "doWork()" (where the extending Job class's real work goes) and then it contains the code for scheduling the follow-up job. Then they simply make extensions of this class that included the work the job should do. The usage of 'durable' jobs, or the overloaded addJob(JobDetail, boolean, boolean) method (added in Quartz 2.2) helps the application define all the jobs at once with their proper data, without yet creating triggers to fire them (other than one trigger to fire the first job in the chain).

In the future, Quartz will provide a much cleaner way to do this, but until then, you'll have to use one of the above approaches, or think of yet another that works better for you.

Upvotes: 3

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