[jboss-as7-dev] subsytem interdependency

[Jason T. Greene]

If we are talking optional module dependencies thats fine. Service 
dependencies usually can't be optional across subsystems though, as it 
will cause a race.

An example of the service problem is transactions and iiop. If JBoss 
Transactions is in JTS mode, it requires special interceptors to be 
enabled in the orb before it launches. From a service startup 
perspective both can't wait on the other. So right now we have an ugly 
solution where both subsystems have to be configured to match 
(transactions in jts mode, iiop with the transaction flag on).

Awhile back we talked about addressing optional subsystem interdeps by 
introducing a generic capabilities api before the runtime stage 
executes. I think Kabir had a prototype somewhere. The idea was that 
after the model is built, there is a hook where subsystems can add some 
kind of indicator for what features they have made available, and other 
subsystems would then be able to define their service deps accordingly.

On 7/11/12 11:16 AM, Thomas Diesler wrote:
> If there is no recommended alternative I would add optional dependencies
> to integration modules to the osgi subsystem.
>
> On 07/11/2012 05:22 PM, Thomas Diesler wrote:
>> The poor man's approach could be to promote the org.osgi.core and and
>> some org.osgi.service APIs to core modules similar to javax.*
>>
>>
>> On 07/11/2012 05:14 PM, Thomas Diesler wrote:
>>> Folks,
>>>
>>> related to [web,ejb,cdi,etc]/osgi integration an issue came up whereby
>>> those ee subsystems don't want to have a dependency on osgi because osgi
>>> is not a core component of the server. Likewise, osgi should not have a
>>> dependency on these ee subsystems because it may be configured to run
>>> independently.
>>>
>>> More general if foo and bar are both optional subsystems where do we put
>>> the code that integrates foo and bar. foo-bar integration might require
>>> to add a some DUPs. How are these registered?
>>>
>>> cheers
>>> -thomas
>>>
>


-- 
Jason T. Greene
JBoss AS Lead / EAP Platform Architect
JBoss, a division of Red Hat