Re: Re: [equinox-dev] Package access across plug-ins...

[Thomas Watson <tjwatson@xxxxxxxxxx>]

Kirby, 

Yes that clears some things up, but I still have some
questions about what you are trying to do.  See below ...

Tom.

equinox-dev-bounces@xxxxxxxxxxx wrote on 10/23/2006
09:12:40 AM:

> Thomas,
> 
>   Let me try and be a bit more formal about the description of
my issues:
> 
> If I have a host plug-in "plugin.host" and a fragment called
"plugin.frag".
> 
> plugin.host has an output directory of "bin/classes" and
plugin.frag has
> an output directory of "bin/test-classes", then
> 
> When given "plugin.host" to DevClassPathHelper, I get back
"bin/classes".  
> I'm reasonable sure that if I passed int "plugin.frag" to
DevClassPathHelper 
> I would get back "bin/test-classes" (if it doesn't, I can
just inspect the 
> property file myself).  So when I start using Bundle.findEntries(...),
if 
> the plugin.host and plugin.frag have the same output directories,
my current 
> code works.  If plugin.host and plugin.frag my current code fails,
as I 
> never find the classes "bin/test-classes".
> 

Why are you trying to find the class files here?  You
mentioned this before in another note.  Do you not know the class
names from the fragment bundles?  In other tests I've seen the testcase
typically knows the test class in the fragment bundle and it simply calls
Bundle.loadClass(<classname>) on the host bundle to access the class
from the fragment bundle.  Then it uses that class to create objects
and test the code in the host.  Is this not possible?  I highly
recommend using this approach if at all possible.  This is how the
Eclipse platform architects all of its tests that involve testing internal
API of a bundle, so it is much more likely to work for you.

> An extension point added to "plugin.frag", reports itself
as contributed via 
> "plugin.host", there is no way I can find to get the name
"plugin.frag" out 
> of the system using the string "plugin.host" as a starting
point.  The 
> bundle for "plugin.host" appears to have no interfaces for
providing you 
> back the fragments that have been attached.

If you really want to do this you can use the org.osgi.service.packageadmin.PackageAdmin
OSGi service provided by the framework.  It has a method PackageAdmin.getFragments(Bundle).
 This method will return an array a Bundle fragments to the specified
host Bundle.

> 
> What I meant by "connecting", was the possibility of listening
to bundle 
> startups via the Plug-in Activator (I believe with any bundle or bundle
> context you can register a listener).  If I observed all of the
startups, it 
> might be possible thru public calls to receive the name "plugin.frag".
 From 
> that point, build a data structure that associates "plugin.frag"
with it's 
> host "plugin.host".  This way, when I start searching
for classes available 
> thru the "plugin.host", I'll know to call DevClassPathHelper
with the bundle 
> identifier for the host and all of it's fragments (in this example
> plugin.host and plugin.frag).
> 

Fragment bundles cannot be activated so you will never
see an activation bundle event (STARTED) from a fragment bundle.  You
may be able to listen to RESOLVED events for fragment bundles.  But
I would recommend using PackageAdmin to figure out what bundles are attached
to a host bundle instead.

> Hopefully this is a clear description of the issues I am facing.
> 
>         Kirby
> 
> 
> >From: Thomas Watson <tjwatson@xxxxxxxxxx>
> >Reply-To: Equinox development mailing list <equinox-dev@xxxxxxxxxxx>
> >To: Equinox development mailing list <equinox-dev@xxxxxxxxxxx>
> >Subject: Re: Re: [equinox-dev] Package access across plug-ins...
> >Date: Mon, 23 Oct 2006 08:47:32 -0500
> >
> >equinox-dev-bounces@xxxxxxxxxxx wrote on 10/22/2006 09:19:56 PM:
> >
> > > Jeff,
> > >
> > >    Well, I feel stupid, I have attempted to reconstruct
this with a
> >trivial
> > > example I could upload, and I can't.  I'd swear it
was broken, but it
> >has
> > > since started working.  Using the commands you gave
me, I managed to get
> >my
> > > plug-ins and fragments working together in the example I
really care
> >about.
> > > So that was very helpful.
> > >
> > >    Now, I'm having problems, because the helpful
suggestions about using
> >
> > > DevClassPathHelper are less useful with fragments.  The
> >DevClassPathHelper
> > > doesn't report back the directories used by the fragment,
but the
> >Extension
> > > Point successfully hides bundle-id of the fragment.  So
I can't use the
> > > osgi.dev properties file to look it up without getting the
bundle id of
> >the
> > > fragment from somewhere.
> > >    The fragments are inside of the AbstractBundle,
but it's hidden
> >behind a
> > > protected accessor.
> > >
> > >     If the fragment and the plug-in use the same
directories it all
> >works
> > > (because overlay of bundles works great), but if the fragments
use a
> > > different directory it all stops working.
> >
> >I'm not sure what you mean by "same directories".  Do
you mean the output
> >folders you specify for the source folders of your projects (e.g.
bin/)?
> >The framework should be able to handle fragments having different
output
> >folders than their hosts.  If it is not handling this correctly
then there
> >is a bug.
> >
> >What do you mean by stops working, do you get class loading errors
or
> >package access errors etc.?  Can you create a sample host
and fragment
> >project which we can use to reproduce your problem?  You
should be able to
> >do everything you need to with a fragment without using any internal
API's
> >of the Equinox framework.
> >
> > > I'm getting fairly close to just
> > > using an extension point to enumerate the directories by
hand.  I can
> >fix up
> > > the auto-detection later if I find it a good way to do it.
> > >
> > >     A BundleListener might be useful, as performance
isn't very
> >important.
> > > If you can connect a fragment to the host bundle thru public
methods, it
> >
> > > might work out.
> >
> >Your fragments should be treated and any other fragment and get
> >automatically attached to your host bundle.  There is no
need to use API
> >to connect a fragment to a host yourself.
> >
> >Tom.
> >
> >
> > >    Just wanted to be sure and say thank you for
all of your help, you
> >guys
> > > have been very helpful in getting my little project on track.
> > >
> > >     Thanks,
> > >         Kirby
> > >
> > >
> > >
> > > >From: Jeff McAffer <Jeff_McAffer@xxxxxxxxxx>
> > > >Reply-To: Equinox development mailing list <equinox-dev@xxxxxxxxxxx>
> > > >To: Equinox development mailing list <equinox-dev@xxxxxxxxxxx>
> > > >Subject: Re: Re: [equinox-dev] Package access across
plug-ins...
> > > >Date: Sun, 22 Oct 2006 14:35:08 -0400
> > > >
> > > >Kirby wrote on 10/22/2006 02:18:59 PM:
> > > >
> > > > > My current problem is finding a
> > > > > canonical way to say "Always load this fragment".
> > > > >
> > > > >    Right now, I'm using:
> > > > > (| (osgi.ws=gtk) (!(osgi.ws=gtk)))
> > > > >
> > > > > Which is a tautology, it's just not as obvious
as I'd like it to be.
> > > > > Leaving it blank causes it to filter out, not
filter in.  It works
> >just
> > > >fine
> > > > > on my "win32" platform.  If anybody
has an answer for that, it'd be
> > > >worth
> > > > > knowing about.  I'm trying to track down
the code that does the
> >parsing
> > > > > right now.
> > > >
> > > >Hmmm, this feels like a bug/issue to me.  To clarify,
are you saying
> >that
> > > >if you omit the Eclipse-PlatformFilter header from the
fragment
> >manifest
> > > >that the fragment is somehow disabled?  If so,
please run with -console
> > > >and use "ss" and "diag NN" where
NN is the bundle id number of the
> > > >fragment bundle.  The fragment should be RESOLVED
and should show the
> >host
> > > >bundle id as "master".  If it is just
INSTALLED then diag should say
> >why
> > > >it is not RESOLVED.  It may be worthwhile opening
a bug report if the
> > > >fragment really is not getting resolved.
> > > >
> > > >Jeff
> > >
> > >
> > > >_______________________________________________
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> 
> 
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