On Wed, Sep 29, 2010 at 7:24 PM, Raymond Feng <[email protected]> wrote:
> To me, the "extension" is just a "feature" that contains only the modules
> that make up the "extension" :-). For example, I can model the binding.ws
> extension as feature-binding-ws (a pom project that list feature-base,
> binding-ws, binding-ws-runtime-axis2, etc.).

Absolutely you could do that and still can in fact. I was thinking of
the extensions slightly differently though in that the extension
dependencies should exclude the dependencies for base. I.e. you always
need base and then add whatever extensions you want. So, for example,
if I wanted to run Tuscany with binding.ws and binding.rmi I don't
need a bindingws+rmi feature I just use base + ws + rmi. Now you may
very well have a  feature caled "banana" that happens to contain base,
ws and rmi. Nothing wrong with that, it's just that that's a slightly
different world view.

So what I've found with this exercise is that different people have
different ways of looking at the problem. And as is the way with these
things it seems that reaching absolute agreement may be tricky.
However with the beta we have the opportunity to actually try them out
and see what value the different approaches bring. We may decide we
want them all, one of them or something different.

> I don't know a way to combine more than one config.ini. But if we generate
> the config.ini per feature, it will contain the bundles from the base. Isn't
> that good enough? I understand it doesn't support the case where you start
> Equinox with base and then try to add the extension.

k, thanks. I'd concluded the same so maybe this is a restriction and
we don't generate the config.ini for extensions. So maybe this is the
real difference between extensions and features. Features can be
installed directly into OSGi extensions don't have config.ini support
and manual configuration is required. This doesn't mean that I believe
extensions have any less value. In fact recent experience of this
suggests that setting up an OSGi environment for Tuscany in
combination with other products isn't a carefree as just dumping all
the Tuscany jars in there. Care and attention is required to avoid
nasty wiring conflicts.

Simon

-- 
Apache Tuscany committer: tuscany.apache.org
Co-author of a book about Tuscany and SCA: tuscanyinaction.com

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