On 14 Jun 2008, at 01:50, Joshua Smith wrote:
> All-
>
> I'm reading a number of references on JMS written some time between
> 2001 and
> now. The challenge that comes with that is knowing which things are
> still
> true today and which things were describing the state of affairs at
> that
> time. I found the following paragraph in the O'reilly Java Message
> Service
> (First Edition) book written in 2001 on p. 32. Can anyone confirm
> that this
> is still an accurate description of JMS?
>
>
> "The Chat application ((which is what they use for their JMS example
> in the
> book)) uses a separate session for the publisher and subscriber,
> pubSession
> and subSession, respectively. This is due to a threading restriction
> imposed
> by JMS. ***According to the JMS specification, a session may not be
> operated
> on my more than one thread at a time.*** In our example, two threads
> of
> control are active: the default main thread of the Chat application
> and the
> thread that invokes the onMessage() handler. The thread that invokes
> the
> onMessage() handler is owned by the JMS provider. Since the
> invocation of
> the onMessage() handler is asynchronous, it could be called while
> the main
> thread is publishing a message in the writeMessage() method. If both
> the
> publisher and subscriber had been created by the same session, the two
> threads could operate on these methods at the same time; in effect,
> they
> could operate on the same TopicSession - a condition that is
> prohibited."
> (emphasis mine)
>
>
> Thanks,
> Joshua Smith
Hi Joshua,
I used to have a copy of that book somewhere!
Yep - its still an accurate description of JMS
cheers,
Rob
http://open.iona.com/products/enterprise-activemq
http://rajdavies.blogspot.com/
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