Asynchronous simultaneous processing from EJB

Question

Hi all,
Imagine you needed to do some bulky task (say processing of a very big XML doc). The thing takes say 15 min, and you find that unacceptable.
In a normal standalone app, I would split that XML in smaller chunks, and kick off a few threads to process it simultaneously. That would generally do the job a lot quicker (tested).
Now, imagine I wanted to pack that functionality in a Session bean (stateless). The spec bans me from doing threads, as the container should take care of that.
What do I do to achieve the effect of multithreading in EJB?
Note: You can make many instances of your processing Session Bean and feed them chunks, but you can't call them simultaneously, as these calls will be synchronous, and therefore the next chunk of work won't start until the current one has finished.
PS: I guess I could use Message Beans and send them messages, but that sort of seems fishy... Is it?
Thanks a lot,
George

Answer 1

1. Dave's idea worth a try, but I probably would have the helper class take a the xml directly in its constructor instead of calling EJB from each thread. So you can use your standalone java application directly. The only thing is, if we want to stick to the specification, since this helper class is instantiated by an EJB so it is still likely that the container will need to be responsible for it. I guess we can test this through the WebSphere Test Environment on Visual Age for Java. I did not do this kind of test before so this is just a guess. But this leads to the next thought:
2. If your EJB can take the xml and save it in a database and read the result from the database after it is processed, you can have a standalone daemon to process it automatically whenever there is such a xml record saved to the database. Actually, I would do it using io even though it is 'banned' by the specification also. I would have the EJB save the xml into a directory (if it has to be done by an EJB), my daemon will run forever and check this directory every certain time to see if there is any new file saved there. If the answer is yes, it will kick out threads to process it and write the result to (database, calling an EJB method, etc...) and then delete the file.
PC