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From Rick McGuire <>
Subject Re: [OSGi] Support for RFC 124?
Date Wed, 01 Apr 2009 10:47:10 GMT
Davanum Srinivas wrote:
> Folks,
> Any interest in support for RFC 124, "A Component Model for OSGi"?
> This is in addition to typical J2EE artifacts that we already support.
> thanks,
> dims
Time, I think, to give this thread a kick. 

There are lots of different aspects to this, so I think we should first 
make an attempt at deciding what the target goal is here.  RFC 124 (aka, 
the "blueprint service") is inherently an OSGi thing, so first we need 
to address what it means to add OSGi to Geronimo.  And, I think, in 
general, this really means "OSGi as a Geronimo application programming 

This can have multiple meanings.  One approach, already under discussion 
in the "Whence Geronimo kernel?" thread would be rearchitect the 
Geronimo kernel around OSGi bundles and the OSGi classloading model.  In 
this mode, an application model should be fairly simple to add, though 
there may be some issues of bridging between the OSGi "bundle world" and 
the JEE programming model.  Additions like the blueprint service might 
be directly usable within the Geronimo kernel for assembly and injection. 

Another approach would be to add an OSGi application container to 
Geronimo.  This would allow OSGi/blueprint-based applications to be 
hosted on Geronimo, and there may be some Geronimo services that get 
exposed to the apps, but the apps run in their own separate environment. 

The container approach is, I believe, probably the easier path, but we I 
think we lose a lot of the advantages of the OSGi model in other 
places.  Also, OSGi is working on a number of additional RFCs that will 
add different JEE concepts to the platform.  I'd hate to think that 
Geronimo might need to maintain two versions of each of these pieces, 
one for the OSGi container and one for the non-OSGi world. 

Anyway, I think regardless of the implementation approach, we need to 
start discussing this in terms of "what does it mean to host an OSGi 
application on Geronimo?".  Here are a few questions that immediately 
come to mind:

1.  How are applications deployed?  Is there some higher-level 
deployment model than the bundle level?
2.  What services are available Geronimo application environment?  
Blueprint is certainly one service, what others do we need?
3.  How is the config-admin service managed?  Do we need Geronimo 
console access and editting of config admin properties?
4.  Are there any bridges from the OSGi world to the JEE world?  For 
example, is is possible to export service registry instances to JNDI?

I think this is a good starting point for discussing ideas....I'm sure 
there are additional questions that will come up in the discussions.


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