Good idea to look into alternatives to blueprint.
The big advantage I see for DS is that it is very light weight. I am not
so sure about its long term future though.
I personally think the future of OSGi dependency injection is CDI like
pax-cdi + weld or openwebbeans.
Of course this is not really near term and far from being a sure bet.
Still I think if we switch the DI framework we should
also at least experiment with CDI. I am currently working on a karaf
tutorial for CDI. The service injections already work very well.
I am now looking into jpa support.
In any case I think switching the DI framework should be considered for
karaf 4. So in this case we have a bit of time to experiment.
Christian
On 04.12.2013 21:41, Ioannis Canellos wrote:
For anyone curious on how Karaf without Blueprint would look like,
here is a karaf branch that is free of blueprint:
https://github.com/iocanel/karaf/tree/karaf-light (it's a fork of the
karat-2.3.x branch).
It is actually a refactored karaf 2.3.x that removes blueprint from
all modules (yet still provides blueprint as feaures). Karaf specific
blueprint namespace handlers have moved to optional bundles so that
they can still be used if needed.
Blueprint has been replaced with Felix SCR (including the shell
commands). Moreover, misc refactorings on features and startup bundles
have been performed in order to reduce the size and the amount of
bundles in the minimal distro.
The result is a minimal distribution that starts 12 bundles [1] (out
of 37 which were part of karaf 2.3.3 minimal distro). 10 of those
bundle were blueprint bundles and the rest are extra noise.
My motivation behind this refactoring was:
i) I like declarative services more than blueprint.
ii) I've been working on projects that are packaged inside the karaf
minimal distro which would benefit from a smaller size (e.g.
jclouds-cli).
iii) I wanted to make a karaf distro as flexible as possible.
Please note that my main focus was the minimal distribution and also
this is not 100% polished.
Enjoy!
[1]: The bundle list of the minimal distro:
ID State Level Name
[ 0] [Active ] [ 0] System Bundle (4.0.3)
[ 1] [Active ] [ 5] OPS4J Pax Url - mvn: (1.3.6)
[ 2] [Active ] [ 5] OPS4J Pax Url - wrap: (1.3.6)
[ 3] [Active ] [ 8] OPS4J Pax Logging - API (1.7.1)
[ 4] [Active ] [ 8] OPS4J Pax Logging - Service (1.7.1)
[ 5] [Active ] [ 10] Apache Felix Configuration Admin Service (1.6.0)
[ 6] [Active ] [ 11] Apache Felix File Install (3.2.6)
[ 7] [Active ] [ 13] Apache Felix Declarative Services (1.6.2)
[ 8] [Active ] [ 25] Apache Karaf :: Shell :: Console (2.3.4.SNAPSHOT)
[ 9] [Active ] [ 30] Apache Karaf :: Features :: Core (2.3.4.SNAPSHOT)
[ 10] [Active ] [ 30] Apache Karaf :: Features :: Command
(2.3.4.SNAPSHOT)
[ 11] [Active ] [ 30] Apache Karaf :: Shell :: Log Commands
(2.3.4.SNAPSHOT)
[ 12] [Active ] [ 30] Apache Karaf :: Shell :: OSGi Commands
(2.3.4.SNAPSHOT)
--
Christian Schneider
http://www.liquid-reality.de
Open Source Architect
http://www.talend.com
