Am 25.08.2011 um 16:28 schrieb Marshall Schor:

> ...
> The various existing OSGi tools seem to support multiple styles of creating
> bundles: if you have an Annotator that depends on other Jars, you can either
> incorporate those Jars within the bundle, or you can depend on them (in the 
> OSGi
> import-package/bundle sense), and keep your bundle small.  This latter way 
> seems
> the preferable approach.
> ...

I agree that this depending (in the OSGi sense) is the preferable way, but the 
problem is, that not all jars are available as OSGi bundles. Also, not all OSGi 
frameworks support that drop-in mechanism for JARs that you explain (I think 
Equinox has nothing like this). Even if a framework provides such a mechanism, 
I wonder how is handles cases where I have two annotators A and B depending on 
the same artifact but in two incompatible versions (e.g. a version 1.x and a 
version 2.x). Can e.g. Apache Karaf automatically generate proper versions even 
if the JAR dropped into the folder does not contain any version information at 
all, so that one is wired to A and the other to B?

I like in Maven that it automatically materializes all dependencies on my 
machine and I do not have to do anything. When I install an OSGi-bundled 
annotator, the same thing should be the case. It come with all dependencies 
that are not readily available on Eclipse Update Sites - it may depend on stuff 
that's available out there and that Eclipse can automatically resolve and 
download. Unfortunately, I believe that the Eclipse Update Site ecosystem is 
much smaller than that of Maven. Something that might help here is the 
Springsource Enterprise Bundle Repository 
(http://ebr.springsource.com/repository/app/), but lots of stuff is also not 
covered there (e.g. Tika).

While I agree that it's better to depend on libraries, for the most part, I 
think adding bundling dependencies is more practical for the end user. The 
alternative would be that the UIMA project offers an Update Site with 
OSGi-ified versions of the dependencies required by the annotators. I 
personally would not go down that road though, as I believe it causes lots of 
work regarding maintenance of such bundles.

So far my thoughts.

Best,

-- Richard

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