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From "Richard S. Hall" <he...@ungoverned.org>
Subject Re: OBR Resolver.deploy() and framework start level
Date Thu, 01 Jan 1970 00:00:00 GMT

Felix,

Couldn't you still express the bundle list of a Set Bundle as some sort capability/requirement
relationship of the Set Bundle that OBR could automatically resolve? The rest of the processing
could be the same by the management agent, but you would leverage OBR's generic dependency
mechanism to describe your bundle list.

Or is there some reason you need to be able (or want) to install the Set Bundle independently
of its bundle list?

The only thing that doesn't seem to cleanly fit is the ability for the Set Bundle to contain
other bundles, but this case could still probably be handled by the management agent in a
similar fashion as you currently do, I imagine.

-> richard

-----Original Message-----

From:  "Felix Meschberger" <Felix.Meschberger@day.com>
Subj:  Re: OBR Resolver.deploy() and framework start level
Date:  Tue 13. Feb 2007 2:36
Size:  2K
To:  felix-dev@incubator.apache.org

On 2/12/07, Steven E. Harris <seh@panix.com> wrote:
>
> Felix Meschberger <Felix.Meschberger@day.com> writes:
>
> > Actually, the bundle set descriptor is a bundle itself, which has a
> > special manifest header naming other bundles (or resources in OBR
> > speak) to be managed. The reference is by bundle symbolic name and a
> > version range.
>
> This is interesting. The "set bundle" refers to the other bundles not
> in the abstract (by exported packages), but as concrete references to
> symbolic name and version. It sounds kind of like the Require-Bundle
> header. Is there a reason why you don't use Require-Bundle, other than
> it not having been implemented in Felix until recently?


The "Set Bundle" is - conceptually - not the same as the Require-Bundle
thing. Require-Bundle to me is more like another way of expressing real code
dependency (which IMHO is better done through Import-Package...). The bundle
list of a "Set Bundle" is more like installation instructions targeted at a
management agent (bundle).

Unlike Require-Bundle not only the symbolic names and versions of the bundle
to install but also the start level and whether the installed bundles are to
be started/stopped when the "Set Bundle" is started/stopped may be specified
and whether the bundles to install are contained as entries in the "Set
Bundle" itself is declared in the "Set Bundle". This goes beyond the
functionality of Require-Bundle.

Does the "set bundle" start all its related bundles when it itself is
> told to start, and stop all the others when it stops?


Yes, and  the bundles contained in the "Set Bundle" are uninstalled when the
"Set Bundle" is uninstalled. This, however, may be controlled with a flag in
the "Set Bundle" to prevent this "locking into the Set Bundle lifecycle".

Do you deploy this "set bundle" through OBR? If so, it sounds like the
> "set bundle's" bundle associations aren't known to OSGi (being
> specified by this special header you mention above), so how do the
> associated bundles get discovered through OBR? Or does the "set
> bundle" itself use OBR to deploy all its associated bundles?


Yes, as the "Set Bundle" is a normal bundle. And yes, the depdencies are not
known to OBR, as these are not declared in the "Set Bundle". Instead, the
management agent recognizes the installation of the "Set Bundle" and handles
the next steps accordingly, including getting the bundles referred to by the
"Set Bundle" and their dependencies from the OBR. It is more like a two-step
process.

BTW: We call these "Set Bundles" "Assembly Bundles" or "Assembly" for short
- lacking a better name :-) [ On the other hand "Bundle Set" does not sound
too bad ]

Regards
Felix



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