Simon Zambrovski

Yesterday, the OSGi session took place in Hotel East in Hamburg. Peter Kriens, the OSGi evangelist showed a wonderful Zen Presentation on OSGi. I wrote a lot during his talk which happens to me very seldom. Here are the core statements I understood:

• The core difference between usual plugin architectures and OSGi is that OSGi concentrates on collaboration of the components.
• OSGi delivers a controlled environment, in which the question if a component runs or not can be answered in beforehand.
• OSGi bundles use metadata (about versions, dependencies, etc) to predict an error, not discover it in runtime.
• OSGi has a very narrow API containing the minimal common part.
• OSGi consists of module, life cycle and services layers. The initially developed services layer required smart class loading mechanisms (module layer).

1. The module layer is desigend to control the class loading machanisms (e.G. structureal class loader hierarchies instead of a linear classpath)
2. Life cycle layer adds a management API (e.G. inform the others about installation event)
3. Separation of concerns is promoted by definition of services for different tasks.

• Services are used for decoupling of system parts (This is a standard application of service-orientation).
• OSGI makes dependencies explicit (private, import, export)
• OSGI tries to make the system managable, taking dynamics and lifecycle as fisrst-class citizens
• OSGI will be extended to support distribution: the team works on policies, SLAs, etc…

I liked the talk and the way how Peter Kriens addressed the problems of OO in big systems. I was confirmed in some ideas about coupling that will be layed out in my thesis. After the presentation we had a delicious meal and wraped up the evening with interesting discussion about pros and contras of OSGi. Peter Friese showed me some remote OSGi staff, he was playing with. The lack of documentation in this area makes it a little difficult, but I hope he will post some news on it. As usual, you can find other pictures in my FlickR gallery.

Yesterday, the second Eclipse Stammtisch Hamburg took place. It was nice to see the Hamburger community again. I had the opportunity to speak with Ralph about the activities in consortium and about the innovation netoworks, about German education system and other subjects. It was a very interesting discussion, even it was a non-technical one.  Later, we discussed the xText development with Peter.

As usually the rest of pictures can be found in my flickr gallery.

The first “Eclipse Stammtisch Hamburg” took place in Bolero in Ottensen. It was a full success, about 50 people were there. Peter and Stefan seemed to like it too. I was glad to see people I met on Eclipse Democamp again. I liked the location, having a separated room, big enough for another 50 people. I spoke with Ralph on the intended frequency of the event - it could be good to have it once in a quater. Some pictures can be seen in my FlickR gallery.

During the ongoing work on development of a language for enterprise modeling it seems reasonable to develop a prototype modeling tool. Especially in case of enterprise models, which tend to become huge very quickly, it is important to have a possibility to define views on the models, and store them persistently. Eclipse ecosystem offers a bunch of frameworks for creation of DSLs, but these only support certain types of mapping between model elements and notations.

Helge concentrated during the work on his Master Thesis on development of that prototype tooling.

Our talk concentrated on building a repository for GMF-based diagram editor models. Due to the limitation in resources, the goal was to minimize the adoptions and changes of GMF/EMF generators and create a prototype model repository.

Thanks to Marco Kuznik from Loroma for providing the video of the talk. It is pretty dark, but you can hear our voices and it is in German.