The Object Teams Blog

Adding team spirit to your objects.

Posts Tagged ‘slides

Using git for an interactive video – Replay the JDT tutorial

with 2 comments

When preparing the tutorial How to train the JDT dragon, Ayushman and me packed way more material than we could possible teach in 3 hours time.

Luckily, Ayush came up with an idea that enables all of you to go through the exercise all on your own: instead of creating zip files with various stages of the example projects, we pushed everything to github. I apologize to those who were overwhelmed by how we pushed git onto the tutorial participants in Reston.

Now, as EclipseCon is over, here’s what you can do:

  • Fetch the slides: PDF or slideshare
  • Clone the material for the plain JDT part (git: URL), containing two projects for the first two exercises.
    • org.eclipsecon2012.jdt.tutorial1: traverse the Java Model starting from the element selected in the UI
    • org.eclipsecon2012.jdt.quickFix1: implement a quickfix for adding a missing null check
  • Clone the misc repo (git: URL), containing
    • handouts: instructions for the exercises
    • org.eclipsecon2012.jdt.populator: plug-in that was used in the tutorial to create sample content in the runtime workbench; show cases how to programmatically create Java files from String content
  • Clone the OT repo (git: URL), containing
    • AntiDemo: the OT/Equinox hello-world: prohibition of class names starting with “Foo”.
    • Reachability: a full blown reachability analysis in < 300 LOC.

The last exercise, “Reachability”, we couldn’t even show in Reston, but luckily this is the most detailed repo: in 13+1 commits I recorded the individual steps of adding inter-procedural reachability analysis piggy-back on top of the JDT compiler. If you replay these commits from the git repo you can watch me creating this little plug-in from scratch. Starting from step 5 you’ll be able to see the results when you fire up a runtime workbench: the analysis will print to stdout what methods it found during each full build.

Look at the commit comments which summarize what I would have explained in demo mode. Still the material is pretty dense as it explains three technologies at the same time:

  1. How does this analysis work?
  2. What points in the JDT do we hook onto?
  3. How is the integration achieved using Object Teams.

Speaking of integration: using the “Binding Editor” you can see all bindings in a tabular view:

Bindings of the Reachability plug-in

The right hand side of the table give the full list of JDT elements we connect to:

  • classes that are extended using a role_obj role
  • methods/fields that are accessed externally via a callout binding callout binding
  • methods that are intercepted using a callin binding (after) callin binding.

As a special bonus, step 14 in the git repo shows how to add problem markers for each unreachable method, so that the JDT will actually offer its existing quickfix for removing:
Unreachable methods
(Yep, both methods are detected as unreachable: calling each other without being called from another reachable method doesn’t help).

I hope you enjoy playing with the examples. For questions please use one of the forums:

Written by Stephan Herrmann

April 7, 2012 at 15:20

Object Teams @ GeeCON 2010 in Poznań

with one comment

Last week I had the great opportunity to speak at GeeCON 2010.

Wow, that was a big screen in Multikino 51 to use for presentations!

I’ve uploaded my slides, so if you missed the presentation or want to recap some points, just grab the slides. Please post your feedback or questions to the Object Teams forum.

I very much enjoyed all those discussions at the conference and I’m very sorry I had to leave early. I was specifically happy to hear that quite a few people in the audience had actually experienced the exact problems that Object Teams addresses (erm, no, I’m not happy to see people suffering but about the chance to help ’em with our approach 🙂 ).

Another good thing about the conference was that I found some minutes to chat with one of the mentors of the Eclipse Object Teams Project, Chris Aniszczyk. He gave me some new ideas for our project plan, which I will update shortly.

Thanks for the warm welcome by the organizers and the audience!

Written by Stephan Herrmann

May 17, 2010 at 13:20

Posted in Eclipse, Object Teams

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