I think we should separate legacy from "modern" MDB's as well.
On Fri, Sep 11, 2015 at 7:07 AM, Josh Juneau <juneau001_at_gmail.com> wrote:
> +1. I agree with the new proposal. It is less confusing to make a clear
> distinction between "legacy" JMS MDBs and "new-style".
>
> Josh Juneau
>
>
>
> On Tue, Sep 8, 2015 at 6:29 AM, Nigel Deakin <nigel.deakin_at_oracle.com>
> wrote:
>
>> (This email refers to my proposals to improve JMS MDBs at
>> <https://java.net/projects/jms-spec/pages/JMSListener2>
>> https://java.net/projects/jms-spec/pages/JMSListener2)
>>
>> The next issue I'd like to discuss is the
>>
>> *Relationship between the old and new ways to define a JMS MDB *This
>> boils down to the question "should the new annotations be allowed for MDBs
>> that implement the javax.jms.MessageListener interface?"
>>
>> There are two possible cases we need to consider:
>>
>> - Allowing these new annotations to be used on the legacy onMessage
>> method of a javax.jms.MessageListener
>>
>> Version 2
>> <https://java.net/projects/jms-spec/pages/JMSListener2#Specifying_the_callback_method>
>> proposed any of the new annotations could be specified. However the
>> requirement that the @JMSListener always be specified could not apply
>> since that would break existing MDBs.
>>
>>
>> - Allowing these new annotations to be used to define additional
>> callback methods (i.e. in addition to the onMessage method).
>>
>> Version 2
>> <https://java.net/projects/jms-spec/pages/JMSListener2#Specifying_the_callback_method>
>> proposed that this be allowed so long as the MDB also implemented the
>> no-method javax.jms.JMSMessageDrivenBean marker interface.
>>
>> On reflection, I'm wondering whether this is introducing unnecessary
>> complexity. It means that lots of additional use cases need to be defined
>> in the spec, implemented, and tested, whilst bringing little benefits to
>> users who can convert to a new-style JMS MDB easily enough.
>>
>> In addition, since we're seeking EJB spec changes to remove the need for
>> the javax.jms.JMSMessageDrivenBean marker interface completely, it
>> doesn't make any sense to introduce a requirement to use it here.
>>
>> I'm therefore wondering whether it would be better to make a clear
>> distinction between "legacy" JMS MDBs and "new-style" JMS 2.1 MDBs. Here's
>> what I'm suggesting:
>>
>> - Legacy JMS MDBs would implement javax.jms.MessageListener and be
>> configured as they are now.
>>
>>
>> - New-style MDBs would not implement javax.jms.MessageListener. They
>> would use the new annotations to specify the callback methods. They would
>> also implement the javax.jms.JMSMessageDrivenBean marker interface,
>> though we're seeking EJB spec changes to remove the need for this.
>>
>>
>> - If the new annotations were used on a MDB which implements
>> javax.jms.MessageListener then deployment would fail. This would be a
>> mandatory requirement on the application server or resource adapter.
>>
>> There are other options for combining these features, but I'm suggesting
>> that keeping them separate will make things simpler.
>>
>> What do you think? is this better, or would you prefer the original
>> proposal?
>>
>> Nigel
>>
>
>
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