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I need to be able to achieve two threading tasks in a container and need to understand the best practices for doing this. Here are the two classes of task I need to accomplish:

  1. During a web services call, I need to start a thread that continues processing after the response has been sent. No message is required back to the original sender when processing is complete.
  2. A web services call may need to spawn multiple threads that need to run in parallel to each other. The response to the original request should be blocked until all the workers have completed. Elements of the response will be drawn from pieces of each of the thread's results.

Of course, I could create my own instance of a java.util.concurrent.Executor and use it, but I suspect containers might be smart enough to provide one that they manage.

FWIW - I'm using WebSphere 6.1 on JDK 1.5.0 (I know, ancient...but it is what it is). I am running web services developed using Apache CXF, so I'm in the servlet container, but configured with Spring.

Jared
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  • Related: http://stackoverflow.com/questions/5357033/background-timer-task-in-jsp-web-application/5357856#5357856 The answer ultimately boils down to: "Depends on the container, read its documentation/manual". You might want to reframe your question to "How to utilize a WebSphere managed thread pool?" if you fail in deciphering the IBM documentation. – BalusC May 17 '11 at 21:53

2 Answers2

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For 1) you might want to look at Asynchronous Beans. Alternatively use a Message Driven Bean which picks up and actions a message you send to a Queue. There's the Quartz stuff from Spring you might want to look at too. I think with Servlet 3 (no chance on WAS 6.1!) you might get the async support without the Async Work Manager or JMS approach, but until then I don't know a better way than these patterns.

For 2) generally blocking the request is a risky business (what if you hit the timeout). However, you're in the servlet container so you're ok using something from java.util.concurrent e.g. ExecutorService as you mentioned. Alternatively use messaging to send the work off somewhere else and block until it completes.

planetjones
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Generally, I wouldn't start threads from inside a container because there is the chance that j2ee full compliance is turned on and your app would die. Under full compliance threads are not allowed to be created. What you want to do is set up a JMS queue that you submit your "work to be done" to. You can then have an MDB listening to the queue which performs that actual operation that your thread would have done.

Adrian Rodriguez
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