On 2/26/10 7:43 AM, Niall Pemberton wrote:
On Thu, Feb 25, 2010 at 4:44 PM, Richard S. Hall<[email protected]> wrote:
On 2/26/10 12:40 AM, Guillaume Nodet wrote:
It does not seem to be sufficient to the commons guys as the want an
"official" and expert blessing from the felix community because it
kinda contradicts the earlier statement they had from Peter which said
that importing your exported packages is a best practice in osgi.
Well, they should have talked to us. ;-)
It came up in three separate threads, here and there was consistently
the same message :(
Sorry for being flippant.
http://felix.markmail.org/message/qp33zosdp43e2vnv
http://felix.markmail.org/message/tczwuc4qfdo3kpey
http://felix.markmail.org/message/4y6s7eqdsg5nirvg
http://felix.markmail.org/message/lg7w4qtetfvhncte
I admit, no one said anything to the contrary in these threads. I am not
sure why I didn't respond to the issue at all. Not sure when the FAQ was
created in relation...looks like it was created in April 2008, so
perhaps it was in response to these questions on the list.
Seriously, what more can we say?
We asked for confirmation from you guys because it had come up several
times and was the opposite of the advice we had been given here.
Clearly, this wasn't the best advice at the time even though we
apparently knew which advice to give as witnessed by the FAQ from around
the same time. The difficulty is that there often is no single answer,
so you often end up with the default "best practice" as opposed to the
best practice tailored to your specific scenario.
Sorry we weren't onl the ball back then to give the most appropriate
recommendation, but at this point going forward I'd follow the advice of
the FAQ and if it isn't clear or you have questions, let us know and
we'll try to do a better job at steering you in the correct direction
this time.
-> richard
Niall
The FAQ has existed for a fairly long time
and our story hasn't changed. Are you suggesting that we need to change the
FAQ in some way? Or are you saying that you want some official OSGi Alliance
statement on this?
As it stands, I think the FAQ tries to explain the issues for deciding what
you should do fairly well, but we're willing to improve it if it is not
clear.
-> richard
On Thu, Feb 25, 2010 at 17:23, Karl Pauls<[email protected]> wrote:
On Thu, Feb 25, 2010 at 5:17 PM, Guillaume Nodet<[email protected]>
wrote:
What is the best practices for libraries wrt to importing their own
exported packages.
Well, I still don't know what you want to discuss. We have this in the
FAQ:
The main time you want to export only, is if your bundle is purely a
library bundle, then its packages will only be used if they are
needed. Another case might be if you have tightly coupled bundles
sharing implementation packages. However, if your bundle will be
started and especially if the exported packages define service
interfaces or are referenced from service interfaces, then you will
generally want to export and import them.
which seems to be good and is what seems to be not followed in the
below use case - which causes a problem. If commons pool wouldn't
import what it exports then everything would have been fine no?
Obviously, there is now single answer to this problem but the FAQ
seems correct to me. I guess I'm still missing the point.
regards,
Karl
On Thu, Feb 25, 2010 at 17:15, Karl Pauls<[email protected]> wrote:
On Thu, Feb 25, 2010 at 5:11 PM, Guillaume Nodet<[email protected]>
wrote:
Guys, can we discuss that and come back with a statement we all agree
on ?
Discuss what?
regards,
Karl
---------- Forwarded message ----------
From: Niall Pemberton<[email protected]>
Date: Thu, Feb 25, 2010 at 16:26
Subject: Re: [all] OSGI - POOL-160
To: Commons Developers List<[email protected]>
On Thu, Feb 25, 2010 at 3:17 PM, Jörg Schaible<[email protected]>
wrote:
Hi Guillaime,
Guillaume Nodet wrote at Donnerstag, 25. Februar 2010 15:49:
I just had a lively chat with Peter who kinda agreed that
substitutability issue is mostly important for APIs.
Please have a look at the Felix FAQ entry:
http://felix.apache.org/site/apache-felix-osgi-
faq.html#ApacheFelixOSGiFAQ-Shouldabundleimportitsownexportedpackages%253F
I haven't written it, so I can't be blame for that one.
The last paragraph says:
"The main time you want to export only, is if your bundle is
purely a library bundle, then its packages will only be used if they
are needed."
what we are saying is, that none of us is an OSGi expert and before
we
published the first artifact with such information, we took the
advice of
the Apache Felix community. If they recommend now something
different, we'd
like to get some "official" blessing for the changes, simply because
we
cannot really review it.
+1
Niall
In all cases, the current imports *are* wrong and need to be fixed,
because the way they are written will fail if there is any
incompatible change ever introduced (whatever the version). And I
don't think we should guarantee that, especially across major
versions.
What has been released is final. We're not able to change that
anymore. All
we can do is to change the OSGi information for new releases.
Anyway, the problem is the following.
You install commons-pool 1.5 in the osgi framework.
Then you install commons-pool 1.4 later.
What you end up with is:
ka...@root> osgi:list -l | grep commons-pool
[ 100] [Active ] [ ] [ ] [ 60]
mvn:commons-pool/commons-pool/1.5.4
[ 124] [Active ] [ ] [ ] [ 60]
mvn:commons-pool/commons-pool/1.4
ka...@root> packages:exports 100
Commons Pool (100): org.apache.commons.pool.impl; version=1.5.4
Commons Pool (100): org.apache.commons.pool; version=1.5.4
ka...@root> packages:exports 124
Apache Commons Pool Bundle (124): No active exported packages.
ka...@root> packages:imports 124
Commons Pool (100): org.apache.commons.pool.impl; version=1.5.4
Commons Pool (100): org.apache.commons.pool; version=1.5.4
ka...@root> osgi:start 170
Error executing command: Unresolved constraint in bundle
org.apache.activemq.activemq-pool [129]: package;
(&(package=org.apache.commons.pool.impl)(version>=1.4.0)(!
(version>=1.5.0)))
While I see an error, it does not tell me a lot ;-)
- Jörg
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--
Cheers,
Guillaume Nodet
------------------------
Blog: http://gnodet.blogspot.com/
------------------------
Open Source SOA
http://fusesource.com
--
Karl Pauls
[email protected]
--
Cheers,
Guillaume Nodet
------------------------
Blog: http://gnodet.blogspot.com/
------------------------
Open Source SOA
http://fusesource.com
--
Karl Pauls
[email protected]
