Archive for the ‘Nice stuff’ Category

software design

Software design is so complex that there is evidently no failure,
or it is so simple that there is no evident failure.

(Translated from German)

Softwaredesign ist so komplex, dass es keinen offensichtlichen Fehler gibt,
oder so einfach, dass es offensichtlich keinen Fehler gibt.

Found in a mail footer.

six degrees of facebook

After six degrees of separation, six degrees of wikipedia there is an project working on the relationships of facebook… guess it’s name … “six degrees of” … no – sorry – it is called The Anatomy of the Facebook Social Graph (see also here) – but the idea is the same. Interesting is that the hop distance tends to fall over the years as network grows.

Hop distance
(image captured / embedded from here)

Software engineers vs. the Universe

Programming today is a race between software engineers striving to build bigger and better idiot-proof programs, and the Universe trying to produce bigger and better idiots. So far, the Universe is winning.

Said by Rich Cook.

Eclipse DemoCamp Nov 2009 in Berlin

After the Eclipse DemoCamp in Leipzig a few days ago I went to the Berlin DemoCamp and presented emf.observables a second time. “Prezing” is fun! But step by step…

We arrived just early enough to get one seat of around 60 seats and see Ralph Müller with his key note. He incited us to become a Eclipse Foundation member and to visit the Eclipse Summit Europe 2010. He hadn’t any free tickets… :-(

Ralph Müller | Key note

Kristian Duske showed us a really cool use case for GEF3D. He used it to work with GMF mapping models (which can get really complex) in a very intuitive way. This is completly different way of handling GMF complexity in comparison to GenGMF.

Kristian Duske | GEF3D based GMFMap editor

Nothing is impossible! Arc lines between connections in a GMF based editor have been implemented! For a variability editor it is an essential feature and I know from my diploma thesis that such features are really hard to achieve with GMF.

Martin Esser | Variability Editor with GMF

Xtext is a project presented since the early days of Eclipse DemoCamps and this time done by Peter Friese. There are some new features on the roadmap for the next 0.8 release.

Peter Friese | Xtext

Break: During the breaks we talked about what we have seen and raided the delicious buffet.

Despite the original order we’ve got the one and only double feature now — two presenters using two beamers. Joachim Hänsel and Jaroslav Svacina made us aware of EVOTest a framework for evolutionary testing. It uses optimization search algorithms for finding problematic input parameter.

Joachim Hänsel and Jaroslav Svacina | EvoTest
(The second beamer was too dark for the picture.)

Do I have created a good model? How does it conform to the guidelines? Answers to such queries can give Metrino which has been presented by Marcus Engelhardt. There is also an adapter for the EMF validation framework so you could see the results in the problems view.

Marcus Engelhardt | Metrino

Matthias Köster created an IDE for Clojure and used the DLTK to do that. He showed us how easy it is to get fast results with the DLTK.

Matthias Köster | DLTK based IDE for Clojure

Break: Do I have said already that the food was delicious? Thanks to Tom for organizing the DemoCamp!

Stephan Herrmann showed ObjectTeams and a adapted version of EclipseLink to persist next to the objects the associated teams and roles.

I’m sorry, the is no picture available

SMILA is system for extracting semantic information from arbitrary media. It e.g. extracts images from PDF files and makes them searchable. You can also search for similar images like with google! Presented by Igor Novakovic.

Igor Novakovic | SMILA

Now it was my turn to present emf.observables. It is my last project and generates IObservable wrapper classes for EMF model classes. The wrappers provide an easy and type save access to the EMFObservables hierarchies.

Enrico Schnepel | emf.observables

I have used “prezi” instead of some slide based software and presenting it was much fun. Creating a prezi is relative easy and intuitive but the software to do that is very feature-limited.

All in all it was a very nice evening where I have seen many interesting projects and talked to many interesting people during the breaks.

Many thanks to Lars for giving me a lift to Berlin and to Martin for the short stay.

Check also Jevopi’s blog with his retrospective!

Eclipse DemoCamp Nov 2009 in Leipzig

Yesterday itemis had organized an Eclipse DemoCamp in Leipzig once again. Like in the many Eclipse DemoCamps I have seen before – it was once again a happening with many interesting projects.


The planned first presenter had some technical problems with the beamer so I filled in and showed my “prezi” instead. “emf.observables” is a new project of mine and can be used to aid in the programming of RCP applications. It generates type safe wrapper classes for IObservable Objects. It was the first time that I used Prezi for my presentation and I have to admit that presenting it was fun. From the questions I had to answer and the personal chats afterwards I got the impression that it was interesting to the audience.

“Und heute generier’ ich” by Alexander Nittka

Alex showed a nice demo from a RCP application he uses for his voluntary work at the Deutscher Go Bund. He uses a DSL developed with Xtext for entering and validating withdrawals and their rejects for all associated members. It was interesting to see Xtext in an application without the generation of source code.


During the break we had some time to chat to each other while eating delicious Soljanka as well as potato soup.

JPA (EclipseLink) in OSGI Anwendungen” by Karsten Voigt

Karsten got the beamer working and showed us how easy it is to use the Java Persistence API 2.0 reference implementation “EclipseLink” in an OSGI context. The Eclipse JPA tooling allows you to generate the complete JPA infrastructure from an existing SQL database and to administrate it. OSGI declarative services are used to wrap queries. It was quite interesting but I can’t use it in my current projects because they don’t use a database.

FeatureMapper by Florian Heidenreich

The FeatureMapper is a tooling to connect arbitrary existing EMF based models with features in a product line context. The existing EMF, GMF and EMFText editors are extended by the tooling and display which model objects a selected feature configuration covers. They also want to implement support for Xtext.

Konsistente Software-Dokumentation by Andreas Bartho

The DEFT (Development Environment For Tutorials) project is really interesting because it allows you to keep your documentation current as you change your code. Code snippets are copied into your documentation with code formatting. The Tuba project does the same but for models which is also very neat. They want to combine both projects and want to support screen shots from RCP applications running in a JUnit context.

I am looking forward to the next Eclipse DemoCamp in Berlin where I will talk about emf.observables too. See you there!

Eclipse DemoCamp Galileo Review

The DemoCamp which has been organized by b+m (my self) in cooperation with FOKUS (Tom Ritter) was a full success. We had seven talks – each about 20 minutes:

  1. Ralph Mueller gave us some infos about the Eclpse Foundation and the Eclipse eco system in Europe (PDF)
  2. Alex Koderman talked about the verinice project, an open source solution for Information Security Management (PDF)
  3. Tom Ritter spoke about Model Sharing in a Distributed Model-Driven Development (PDF)
  4. Martin Flügge showed us Dawn, a web-based collaborative extension for GMF editors (PDF)
  5. Eike Stepper gave us a talk about the Net4j signalling platform (PDF)
  6. My talk was about how to COPE with long term metamodel evolution (PDF) and
  7. Max Bureck spoke about a graphical QVT/R-Editor (PDF)

There was some kind of running gag due to the unawareness of the speakers to actually show a demo because of miscellaneous technical reasons.

In the beginning and during the breaks we had the opportunity to have nice chat and the advantage of a delicious buffet. Thanks to the sponsors.

After the camp some of us moved into a timeless restaurant for celebrating an Eclipse Stammtisch which was also very nice.

All together it was a long but very nice day.

Please note: There will be a second Eclipse Stammtisch on the 16th June where you will have the possibility to meet some members of the Eclipse Board of Directors. Please have a look at Eikes post announcing the Stammtisch. If you want to participate please enter your name into the Doodle poll.

The art of skew house building

It is quite impressive how people build houses in a big city in germany…

© by Google Maps

Eclipse DemoCamp Galileo

Like in the previos year I am one of the two organizers of the Eclipse DemoCamp Galileo 2009 in Berlin. It will take place on the 9th June here. I will give a talk about COPE and how to use it to evolute a meta model and migrate the corresponding instance models (as I have done it for GenGMF). If you don’t have the time to visit the Berlin DemoCamp you will get a second chance to hear my voice in Leipzig on the 23rd June. Sorry, I can’t be in Leipzig on this day because I will be in Kiel… But if you would like to chat with me and some members of the Eclipse Board of Directors at an Eclipse Stammtisch have a look at Eikes Post. See you there!

highly compressed irrelevance

A typical “tweet” is highly compressed irrelevance – 140 characters the world don’t need but served in real time.

(freely translated from German)
by Ulf J. Froitzheim in Technology Review, 3/2009, P. 86

Copying EMF objects accross namespaces

I am currently preparing a new release for my GenGMF project. Because the new meta model contains important but incompatible changes I have migrated the GenGMF tooling to a new name space and created a migration script for converting the specific editor models. The new meta model is much smaller than the old one which results in smaller models — I’ve eliminated the need for the mapping elements in the templates. To make the migration as easy as possible I’ve created some helper functions to move corresponding attributes and references. Only the “real” changes in the meta model are migrated using a Xtend script.

To demonstrate the facilities of the CrossNamespaceCopier I’ve created a small meta model…

Demo meta model

As you see the Class2 from the “http://source.namespace” has been eliminated in the “http://target.namespace” and both attributes have been moved – attribute2 to Class1 and attribute3 to Class3. In order to migrate a model instance one has to call the CrossNamespaceCopier which copies the objects while migrating the name spaces according to rules previously set. OtherClass objects from the “http://other.namespace” will be copied as they are. All references and attributes which could not be automatically migrated need to copied in a small script manually.

extension CrossNamespaceCopier;

namespace::target::Class1 migrate(namespace::source::Class1 sc1)
:   let tc1 =
    // initialization for the copier, but the
    // let statement needs to be in the beginning
    (   crossNsInitStaticInstance()
    ->  crossNsSetupNamespaceMapping(
    // the content for the tc1 variable
    ->  (   (namespace::target::Class1)
    // skipping Class2 in source
:   tc1.setClass3Reference(
    // pull up attribute2
->  tc1.setAttribute2(
    // pull down attribute3
->  tc1.class3Reference.setAttribute3(
    // uninitializing
->  crossNsReleaseStaticInstance()
->  tc1

You will find the CrossNamespaceCopier as well as the demo files contained in a zip file.