2013/12/5 Christian Schneider <ch...@die-schneider.net> > 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. >
I disagree. CDI will have the same problems as blueprint, it's an application level injection framework, not focused *primarily* on OSGi. The lifecycle of CDI beans has to be static, so you have to use proxies. Blueprint has the exact same problem where the beans lifecycle is bound to the lifecycle of the container. On the opposite, DS has a better lifecycle mechanism for beans which can naturally handle the OSGi dynamism. And CDI would be even more heavyweight than blueprint, so I'd rather stick with blueprint than switching to CDI, even if it were ready. The real benefit of DS is that it has been designed to handle the OSGi dynamism, so it does less, but it does it better. > > 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 > >
