Milen,

I don't really catch the issue, but by "via services" I mean that files inside 
a fragment are not services. If your UI needs something then it can be 
expressed via an API. Then you would have one or several implementation bundles 
which may come and go... as any usual bundle.

JP

[@@ OPEN @@]

-----Message d'origine-----
De : Milen Dyankov [mailto:milendyan...@gmail.com] 
Envoyé : jeudi 14 janvier 2016 12:53
À : users@felix.apache.org
Objet : Re: Specifying dependency between a bundle and a fragment bundle

I'm not sure what you mean by "via services". As for subsystems, my 
understanding is this is more of a packaging/delivery option. It may help but I 
still need a soliton that will work for deploying individual bundles.

Anyway, I experimented a bit more and it seams it's fully possible to use 
requirement and capabilities with fragment bundles.
I don't know why it wasn't working before but my understanding that 
capabilities related headers in fragment bundle are applied to the host bundle 
is wrong!

So, by putting

Fragment-Host: original.ui.bundle
Provide-Capability: myUI
Require-Capability: myService

in my UI bundle and then in my service bundle

Provide-Capability: myService
Require-Capability: myUI

I can actually define the dependency I need.
With that in place, I can uninstall (too bad I can not only unresolve) my 
service bundle if my service fails. There are still some quirks with refreshing 
the original UI bundle but it generally works.
It's probably not the best solution but I couldn't figure out anything better 
so far.

Thanks for your help!
Milen


On Wed, Jan 13, 2016 at 3:02 PM, CLEMENT Jean-Philippe < 
jean-philippe.clem...@fr.thalesgroup.com> wrote:

> I would have made this via services, but there might be other ways 
> such as subsystems (?)
>
> JP
>
> [@@ OPEN @@]
>
>
> -----Message d'origine-----
> De : Milen Dyankov [mailto:milendyan...@gmail.com] Envoyé : mercredi 
> 13 janvier 2016 14:49 À : users@felix.apache.org Objet : Re: 
> Specifying dependency between a bundle and a fragment bundle
>
> Conceptually I guess you can put it that way, yes.
>
> On Wed, Jan 13, 2016 at 2:43 PM, CLEMENT Jean-Philippe < 
> jean-philippe.clem...@fr.thalesgroup.com> wrote:
>
> > Do you mean ensure that fragments and services are deployed as a 
> > single transaction?
> >
> > JP
> >
> > [@@ OPEN @@]
> >
> >
> > -----Message d'origine-----
> > De : Milen Dyankov [mailto:milendyan...@gmail.com] Envoyé : mercredi
> > 13 janvier 2016 13:57 À : users@felix.apache.org Objet : Re:
> > Specifying dependency between a bundle and a fragment bundle
> >
> > Thank you for your thoughts regarding replacing the service. However 
> > that is not really my concern. There are 2 aspects in the picture - 
> > the service itself and the UI to communicate with it.
> > In traditional layered architecture one would refer to those as 
> > service layer an UI layer. Both are developed independenty and in 
> > more complex scenarios there could be N bundles providing UIs for 
> > working with M bundles providing services. In non-OSGi environment 
> > if I start application having correct modules (jar files and 
> > resources on the
> > classpath) at runtime, I am kind of guaranteed to have a consistent 
> > change in both layers. In OSGi (or any dynamic modular system I 
> > guess) one change can be applied and the other one not (due to 
> > configuration, resolve issues, removed dependencies, ...) which can 
> > lead to UI functionality not matching the actual underlying services 
> > providing it. So what I'm struggling with is finding a way to keep 
> > the changes consistent across both layers. As in this particular 
> > case the changes to the UI layer are applied via fragment bundles 
> > and the changes to the service layer are applied by providing 
> > "regular" bundles, I'm looking for a way to express the relationship 
> > between those. I guess using Requirements and Capabilities would be 
> > perfect but to my
> understanding you can not use it for fragments.
> >
> >
> >
> > On Wed, Jan 13, 2016 at 1:24 PM, CLEMENT Jean-Philippe < 
> > jean-philippe.clem...@fr.thalesgroup.com> wrote:
> >
> > > I'm not too sure what you need, but I would say first that you 
> > > consider what you have (a text file) rather than what you need (a 
> > > service or services). It seems you see things through the provider 
> > > instead of the consumer.
> > >
> > > So, you have a button which calls a service S. Fine. Then you want 
> > > S to be the best service. So you just have to implement a service 
> > > S which is a proxy to T services and which will forward calls to 
> > > the best
> > T service.
> > >
> > > You can even reuse S instead of another T service. So, S is a 
> > > proxy to other S services. The proxy has the better ranking in 
> > > order the button to "find it". The proxy has to exclude itself 
> > > from S service
> candidates.
> > >
> > > ...just a quick thought...
> > >
> > > JP
> > >
> > > [@@ OPEN @@]
> > >
> > > -----Message d'origine-----
> > > De : Milen Dyankov [mailto:milendyan...@gmail.com] Envoyé : 
> > > mercredi
> > > 13 janvier 2016 11:10 À : users@felix.apache.org Objet : 
> > > Specifying dependency between a bundle and a fragment bundle
> > >
> > > Lets say I have a UI bundle that renders a button from template. 
> > > The template is just a text file(s) inside UI bundle. Clicking the 
> > > button calls a service (for the purpose of this example say one 
> > > with the
> > highest rank).
> > >
> > > The requirement is: change both the service that is called and the 
> > > button in consistent manner.
> > >
> > > The first part is easy:
> > >  - To change the service one can simply provide a new bundle (call 
> > > it
> > > S) containing the new service implementation (with higher rank or 
> > > whatever else it takes to make it the one that service registry 
> > > will give to the UI bundle).
> > >  - To change the button (or even replace it with something else) 
> > > one can provide a fragment bundle (call it FB) with updated 
> > > template
> file(s).
> > >
> > > The question is, how to keep those consistent? That is, make sure 
> > > that either both S and FB are applied or none of them (lets assume 
> > > S will somehow ensure the service is registered or stop itself if 
> > > it can't do
> > so)!
> > >
> > > It seams one needs to somehow declare a bidirectional dependency 
> > > (I hate the way it sounds, but that's what it in fact is, isn't 
> > > it) between a bundle and a fragment bundle. AFAIK this is not 
> > > really possible as anything specified in fragment is applied to the host!
> > > Has anyone faced similar challenge before?
> > >
> > >
> > > --
> > > http://about.me/milen
> > >
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> >
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