scheduling tasks on JBoss with clustering

Question

I need to be able to run some scheduled tasks (reports) for an EJB application running on JBoss 4.2.

In my initial implementation I am using a servlet in an associated WAR to read some configuration from a properties file and then reset the scheduled tasks using the Timer Service API. This works but it seems a bit awkward to have the initialization off in a web project. Also I'm not sure if this will work as expected when the app is deployed in a clustered environment.

What are the best practice for accomplishing this type of task? Should I be using something other than Timer Service and is there a better way to initialize the timers when the server starts?

Answer 1

Maybe have a look at Quartz Scheduler. Quoting its website:

Quartz is a full-featured, open source job scheduling system that can be integrated with, or used along side virtually any J2EE or J2SE application - from the smallest stand-alone application to the largest e-commerce system. Quartz can be used to create simple or complex schedules for executing tens, hundreds, or even tens-of-thousands of jobs; jobs whose tasks are defined as standard Java components or EJBs. The Quartz Scheduler includes many enterprise-class features, such as JTA transactions and clustering.

I've used it in the past to trigger EJB jobs and the whole solution was working very well, with very good scalability. To use it with EJB, you'll need to use the JobStoreCMT to store scheduling information (job, triggers and calendars). To tune resources for jobs execution, have a look at the Configure ThreadPool Settings doc. Then, just let the EJB client do its job to load balance requests over the different instances if EJBs are deployed on a cluster.

Quartz itself can also be clustered to get both high availability and scalability through fail-over and load balancing if required.

Regarding the properties file you mentioned, I'm not sure of what kind of data you need to read exactly but, without a servlet, if you need to read something, you'll have to read it from the database.