The final day of the conference, the last day I could go to informative and inspiring sessions. The whole day there will be parallel sessions, so here is a report of the sessions I have choosen to attend. We can also read the conference reports of day 1 and day 2.
Introducing GContracts presented by Andre Steingress was the first session of the day and it was great. GContracts is a cool product and can really improve the quality of your code. This is really something I want to use in my projects. With GContracts we can add annotation to our classes and method to ensure post-conditions, set required pre-conditions and class invariants. The syntax is simple so it easy to get started.
The next session was about myBalsamiq. This is project colaboration website to work on Balsamiq mockups that will be released later this year. And it is built using Grails! It is cool to see such a site with a lot of interaction and big user base is created with Grails. Also the architecture of the application was very intesting and looked really great. I wish them good luck with the launch of their product and it will be a great new testimonial for Grails applications.
Gaelyk was the subject of the following session presented by Guillaume Laforge the author of Gaelyk. Gaelyk allows us developers to use Groovy on the Google App Engine. First we learned about the way Google App Engine is positioned in the cloud and the payment model.
Also we took a good look at the services Google gives us developers to use, like datastore, memcache, image manipulation, email. Then it was time to see how we can use all this in a Groovy way. All Google services are directly usable in our Groovy code, because the services are added automatically through bindings. Also several DSLs are applied to make using the services easier. With a bit of live coding we could see this in action.
Gaelyk also has a plugin system, so we could write reusable parts as plugins and use them in our code. The presentation is available on SlideShare.
The session about Spock, my favorite test framework, was presented by Peter NiederWiesser who wrote Spock. The first part of the session was an introduction to Spock for those that didn't know Spock before. With small samples we could see how JUnit tests turned into beautiful Spock specifications. With a state machine and interaction sample this was very helpful.
The second half of the presentation was about the more advanced features in Spock for those that already knew Spock. Writing extensions for example is very easy in Spock and Peter showed this with a sample.
The code Peter used is available on GitHub.
Václav Pech gave a session about GPars. And because GPars is now part of Groovy 1.8 we can all use the very usable features of GPars to create concurrent and parallel running application code. Concurrency will play a big role in the future to create performant applications and with GPars we use Groovy to this. Multi-cores are already here and we will get more of them in the future in all our computers and appliances. And the good thing is, the implementation of the code is not difficult. For example to work with collections in parallel we only add two lines of code and we are done. The impact on the code is also small.
We can also choose to use the dataflow variable paradigm to create concurrent code, which will require a code rewrite, but the result is very elegant and will probably be worth it.
Finally Václav showed how actors can be used and how easy it to write the code. GPars is really something for me to get into in the near future and want to implement in my projects.
Testing is very important when we write code and the next session, Testing with Fitnesse, was just about that. Fitnesse is a framework that is used to write test scenarios in a Wiki with a very simple syntax. Erik Pragt and Marcin Erdmann have created a Grails plugin to use Fitnesse in Grails applications. First Erik gave a small introduction on how we can use Fitnesse and how the plugin uses Fitnesse to run tests. Fitnesse is best used for more complex business logic and is addition to unit tests written in for example Spock.
Then Marcin gave an impressive live coding demo to show TDD with Fitnesse and the plugin. Starting from scratch by writing the test scenarios and then implementing the logic in code.
The presentation was very good and gave a good idea about what Fitnesse is about and the power of it.
A very nice tip was to first test of a request is a AJAX request before applying a layout. This way the views can be reused in a AJAX and normal request without changing the view.
I had to leave for the airport before the panel discussion, which I couldn't attend unfortunately.
The overall feeling of this conference is that the Groovy community is very social, friendly and open. I learned a lot during these 3 days and just as last year my list-with-things-to-look-into-and-learn-more-about has grown again. Hopefully I will be able to cross most things off, before next year's Gr8Conf. Because Gr8Conf 2012 is already marked in my agenda.