I totally agree with peter. If the container takes the
"Dups-ok-acknowledge" setting and implements it just like the
"Auto-acknowledge" setting, the container's contract with the client would
still be vaild.
Regards,
Hiram
----- Original Message -----
From: "Peter Antman" <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Sent: Monday, May 28, 2001 3:02 AM
Subject: Re: [JBoss-dev] MDB Auto-_-_Acknowledge
> On 28 Maj, Vincent Harcq wrote:
> > Hi,
> > After implementing MDB in ejbdoclet, one of the developer find out
> > that jboss does not follow the spec for <acknowledge-mode> on MDB.
> > Page 462:
> > <!--
> > The acknowledge-mode element specifies whether JMS AUTO_ACKNOWLEDGE
> > or DUPS_OK_ACKNOWLEDGE message acknowledgment semantics should be
> > used for the onMessage message of a message-driven bean that uses bean
> > managed transaction demarcation.
> > The acknowledge-mode element must be one of the two following:
> > <acknowledge-mode>Auto-acknowledge</acknowledge-mode>
> > <acknowledge-mode>Dups-ok-acknowledge</acknowledgemode>
> > Used in: message-driven
> > -->
> >
> > So - for MDB and _ for JMS
> >
> > Stupidity of the spec maybe, but we need to change jboss to have full
> > compliance. I can commit the change and I propose to keep both
> > possibilities for safety.
> >
>
> Well, I don't think it is that easy. First we had support for it. Then
> Hiram added support for XA transactions in JBossMQ and added support for
> that in the MDB container, but broke support for ACK modes. We had some
> arguing about this, and finally decided that we did not need to support
> DUPS_OK_ACKNOWLEDGE.
>
> Was this bad or god? Well, I would interpret it this way.
>
> 1. With bean managed transaction we support AUTO_ACKNOWLEDGE semantics,
> i.e every message is automtically acked. Yes, we are doing it with a
> transacted session, but that is an implementation question and
> nothing else (who cares that non XA transactions in JBossMQ is
> actually managed with single commit XA transactions under the hood?
>
> 2. DUP_OK. To my knowledge this is a flag that the JMS provider MAY
> obay (i.e it is completly up to the JMS provider how to implement
> support for this - it may even be done as AUTO_ACKNOWLEDGE). What it
> says is that if it is used ,the client have to be aware that there
> may be some resent messages.
>
> Therefore I would say that the MDB container is spec compliant. You may
> specify AUTO_ACKNOWLEDGE or DUP_OK in the deployment descriptor, but the
> implementation does not care (which in my view probably is not a breach
> with the spec). If it is possible to show that DUPS_OK if used could
> lead to dramatic increase in performance, that would be another
> question.
>
> That to say, if you are able enough to reimplement support for DUPS_PK
> without braking anything, please go ahead.
>
> file://Peter
>
> > Vincent.
> >
> >
> >
> >
> > _______________________________________________
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> > [EMAIL PROTECTED]
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>
> --
> Jobba hos oss: http://www.tim.se/weblab
> ------------------------------------------------------------
> Peter Antman Technology in Media, Box 34105 100 26 Stockholm
> Systems Architect WWW: http://www.tim.se
> Email: [EMAIL PROTECTED] WWW: http://www.backsource.org
> Phone: +46-(0)8-506 381 11 Mobile: 070-675 3942
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