I guess the idea behind the way we currently do things is that we want
to be lazy. If we would check on the class of the object created by
the service factory we might trigger unnecessary service creations.
However, your case might force us to do that unless we can find a
smart way to figure out this information by looking at the wiring of
the bundles. From your description I doubt that this is possible but
we probably have to think about it.

Definitely sounds to me that you should create a JIRA issue and maybe
attach your example.

regards,

Karl

On Thu, May 7, 2009 at 1:49 PM, Guillaume Nodet <[email protected]> wrote:
> On Thu, May 7, 2009 at 13:41, Felix Meschberger <[email protected]> wrote:
>> Hi,
>>
>> I am bit confused, too ;-)
>>
>> Guillaume Nodet schrieb:
>>> I've just finished debugging a corner case in karaf  where a
>>> ServiceListener did not receive events when a matching service was
>>> registered.
>>> The problem is not very simple:
>>>   * the service is exposed via a ServiceFactory
>>
>> So, the ServiceFactory must create objects implementing the service
>> interface, right ?
>>
>>>   * the service factory does not belong to the same classloader as
>>> the interface of the exposed service
>>
>> No problem. In case the factory and service interface are in different
>> bundles, this is expected.
>>
>>>   * the bundle exporting the service does not have a direct import on
>>> the interface exposed
>>
>> You mean, the bundle registering the ServiceFactory ?
>>
>> In this case, I would assume, this is an invalid service registration,
>> since the registering bundle does not know about the service interface,
>> unless the service interface is contained in the same bundle as the
>> ServiceFactory implementation.
>>
>> This leads to the suspicion, that there are two actual service interface
>> class objects: The public one used by the listener and another one
>> (exported or not) used by the ServiceFactory implementation.
>>
>> Or are there three bundles ? (1) exporting the service interface, (2)
>> exporting the service implementation and (3) registering the
>> ServiceFactory as a service for the service interface defined by (1) and
>> creating implementations located in (2) ?
>>
>> Or, maybe, I am completely wrong ....
>
> In my case, the bundle exporting the service defines a class that
> indirectly implement the required interface by inheriting a class from
> another package.
> So I have 3 bundles:
>  * bundle A defines an interface R and a class S in different
> packages, whith S implementing R
>  * bundle B defines a class T extending S, it has an import statement
> on S package, but not on R package
>  * bundle C defines a ServiceFactory that export T service without
> any import on any package from R, S, T
> Maybe the service registration is invalid because bundle B does not
> import R package, but the service actually implement the right
> interface
>
>> Regards
>> Felix
>>
>>>
>>> This leads to the service listener not being invoked because
>>> Util.isServiceAssignable() returns false.
>>> I think it's a problem, but I've no idea how to solve it.  The only
>>> way I can think about is to actually check the service class returned
>>> by the factory instead of the factory, but it may cause side effects,
>>> not sure.
>>>
>>> Thoughts?
>>>
>>> --
>>> Cheers,
>>> Guillaume Nodet
>>> ------------------------
>>> Blog: http://gnodet.blogspot.com/
>>> ------------------------
>>> Open Source SOA
>>> http://fusesource.com
>>>
>>
>
>
>
> --
> Cheers,
> Guillaume Nodet
> ------------------------
> Blog: http://gnodet.blogspot.com/
> ------------------------
> Open Source SOA
> http://fusesource.com
>



-- 
Karl Pauls
[email protected]

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