Best practice for a pooling job?

[jgottschling]

We have a job that is pooling. It has to look into a directory and pick up files from there if there are some. A classic "hot folder".

At the moment we have a job with just one step. The reader returns null if there are no (more) files in the directory. The job is started with a delay of 30 seconds.

<task:scheduled ref="pdfImportStarter" method="startJob" fixed-delay="30000" />

For us that seams to be the natural way to do it. The problem: It fills the batch database tables with new jobs very fast. You really have to search the other jobs. We filter this, but it is not very nice.

What is the best practice for that use case? Implementing a blocking reader that may be never returns null? Or defining a precondition that we check in the pdfImportStarter? This seams to duplicate code.

[litius]

@jgottschling,

Spring Integration can help you here. You can create a file poller which will poll the directory ( every so often ) and will pass the files to create a "JobLaunchRequest" that will have your Job launched.

Something similar is available in Spring Batch Admin Samples ( from git.springsource.org ): http://bit.ly/dlwdgg

/Anatoly

[jgottschling]

Thank you, Anatoly. I'll have a look at this solution.

BR, Jörg