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Synchronous to asynchronous mapping

 
Dasun Perera
Greenhorn
Posts: 13
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Hi,

Session bean has a method which sends an asynchronous message (MQ) to retrieve some data from a legacy system. Reply also comes as a MQ message and this data need to be returned from teh above session bean method. Anybody have any idea of what is thebest way to implement this?

Dasun Perera
 
Stan James
(instanceof Sidekick)
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If you go to native MQ APIs there is a getAndWait method that, um, waits and gets. We use it for synchronous request-response MQ all the time. If you use a JMS wrapper over MQ I think there are synchronous methods, too. Use these solid APIs if you possibly can.

If you have to roll your own make use of the correlation id. MQ gives you this id when it sends a message and includes the id on the response so you can match things up. I'm in deep water for me here, but maybe put some object in a shared Map with correlation id as key then wait() on it. The event handler for the asynchronous response could get the object by key and notify(). Does that kind of thing makes sense?
 
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