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From "Joshua Smith" <j...@rationalpi.com>
Subject Re: JMS Threading Restriction
Date Sat, 14 Jun 2008 13:51:57 GMT
Thanks Rob.

Josh

On 6/14/08, Rob Davies <rajdavies@gmail.com> wrote:
>
>
> 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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