This Saturday we’ve (the Software Craftsmanship in Cracow guys) organized a Code Retreat, right after AgileCE. We’ve invited Corey Haines to join us and facilitate this meetup, and later on even Alexandru Bolboaca AND Maria Diaconu joined us in facilitating the event and so it got even better :-)

Corey doing the introductional Keynote

Before we start, just a quick reminder what a CodeRetreat actually is (for the sake of everyone reading this blog not knowing what the hell I’m so excited about ;-)). The rules are really easy, take a bynch of passionate programmers, put them in a room for 1 whole day and tell them to code the game of life. There are about 6 sessions, where each time you’d pair up with another person and code away. After 45 minutes you have to delete the code you’ve written, then after a 15m pause to talk about your results you find a new pair and code it again from scratch. It’s important to embrace the code deleting part – it’s somewhat like catharsis… :-) No matter how bad (or great) the code you’ve written was, on average in 22.5 minutes it will go away :-)  The idea is to embrace that you most probably won’t finish the problem in time, so you can just focus on honing your skills in TDD, pairing, IDE usage and generale code style and skillz. There’s no better way to learn these skills than to confront them with someone else’s – that way you both can learn new tricks or find out why some ol tricks you used actually suck :-) In the end of the day, you’ve become a better programmer… and will hopefully take these new skills into your workplace and improve the code quality there :-)

Happy hacking!

The response to our CR was really amazing. We’ve had quite a few sponsors – LunarLogic, AppliCake, ABB, Sii… and the PolishJUG helped out as well as it could with organizing the whole thing :-) Oh, and I hope you’ve seen our nice website created by Olga from LLP? The interest from participants was equally big – all places where “sold out” in just about 3 hours… ;-) We where around 50 people in total and I think that’s a perfect number of coders for such an event. Some coded in Java, some in .NET and others in Ruby or Python, oh and there was an Objective-C and Scala team too. One of the nive things during a CR is being able to try out a new language, so the Ruby guys where really overflown by people wanting to try Ryby for example ;-) I’ve spent the rest of my sessions (4/5) coding in Java and just once had to lay hands on Eclipse… ;-) During one session I tried out ruby (ルビ) with Adam from SCKRK, which was fun as I did read some books/articles about it and really enjoyed the BDD that rspec uses. I also noticed that scala test seems to have derrived from it (or the other way arround :p)… :-)

The 2nd room was also full

After two sessions we had nice long lunch, to relinquish our coding skills and ideas (we’ve ordered from thaisty). And then a next set of 3 sessions followed. This time more focused on experimentation etc. For example one session we managed to not use if’s and for’s at all (sigh, upto one place but the time ran out then..). Google Guava was a great help there :-) On another sessions we’ve focused on Mockito and the more advanced mocking techniques such as parameter catching etc… In the end we really knew how much over engeenired it was but nevertheless it was really interesting to learn and play with these thoughts – that’s what CR is about.

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Final Wrap Up

Later on we’ve sent out a questionary on how much you enjoyed the CR and the response was also really positive. We’ll think about coffee next time – promissed. :-)

Stanley just pulled in my quick gallery commit to our website git repo a moment ago, so you can now visit coderetreat.sckrk.com/gallery and look for yourself on the pics :-) They’re fetched from my picasa so if you’d rather download them all from there, please do so :-)

Group Photo

All in all… I’m really happy and proud to have been part of this event. It’s really been one of a kind and I hope all of you feel the same way about it. Well, it would certainly seem so after the opinions on the final wrap up and questionary later on. :-) So, once again, thank you for participating and see you soon on most major coding events :-) (ps: GeeCON is one of them).

http://github.com/barthez/mysql.integra.dbfiller – an simple Python app that is able to generate SQL code with inserts that we need to fill up our database for load testing. It’s doing an simple simulation of people checking in and out from various activities at some job and calculates when who should cone and do their shift… My friend Bartek is by far more into python, and has coded most of this app (just check the impact charts ;-)), so much of the kudos for this goes to him.

Noticed an gigantic hardware problem our student groups server… Some didn’t believe me in the beginning… This week we went to see how much of the harddrives “went bye bye” in real life, as there was nothing that could be done remotely. I’ve been battling with the read-only / filesystem some evenings before, and concluded that it’s not just a small hdd failure – it had to be something BIG… And boy, BIG it was… Something between all the drives and the rest of the server seems to have died. My best guess is the SCSI controller… It’s not really worth it to replace the parts as the server was very very old, well, let’s hope we get some (anything) machine to finally run our tests on. SCSI Controllers on fire…

netbeans.edu.pl – was written by me in Grails. I have yet to release the sources, but will do so for sure – after I polish them a little, because they’ve been written under immense time pressure etc. It’s a quite nice framework, but obviously it’s an overkill for such an simple site as netbeans.edu.pl… It was quite fun to write my own taglib for the twitter integration and also I’ve also used the GoogleData API to serve images directly from Picasa Web Albums… Of course there are PHP lib’s that could do this, but it just seemed “nicer” to me to write this in Groovy…

After the NBPTraining me and two friends started developing an simple Traveling Salesman Visualization using the NetBeans Platform – solving the problem with Genetic Algorithms. We’ve decided to use prefuse for the graph visualization stuff… Let’s hope it was a good decision – of course I know that it’s not being developed since a long time, and the API isn’t even Generic, but it looks quite nice and the workflow with grapghs is really neat – the “actions” stuff… I’ll be trying to write our own renderer for this program so keep your fingers crossed – hope it’s turn out well. Sadly, were presenting an pre-alpha of this program on Wednesday and I won’t be able to come to the uni as at that time I’ll be taking the Gradle Training at GeeCON. :-)

Inspired by both koziołek’s post about vaadin + spring and the nice tutorial that Darek Zoń has been writing lately I decided to take another look at Vaadin. I’d describe it best as… “GWT that looks and feels good right from the start”… ;-) The sources of what might become an simple rss reader app can be found on github: RssR – vaadin rss reader. I’ve had some experience with GWT while trying to create an online crossword solving system, but I have to admit – it’s not really near it’s final stages… And I somehow dont have the willpower to go back to it at this moment – while starting out with it I hoped that I could easily just drop my existing crossword stuff into GWT and add some simple frontend – turned out that this isn’t so easy. Ah well. Vaadin on the other side looks much nicer for some “real, even if generic, webapp”, so I chose to try implementing an simple rssreader based on it. Loging in and basic hibernate setup (not finished yet) is already in place. Oh, and I’m also using maven on this one. If you’re interested in it, or are just abour ti start an Vaadin project, check out the sources and maby they’ll help you out figuring out what all this is about :-) It’s able to run on jetty by calling mvn jetty:run-war :-) (lol just found an google code project about exactly the same stuff only written in pure spring http://code.google.com/p/rsser Kudos to the coder! :-))

Oh and just an minor mention about Google Guava, I’ve been looking at it’s API lately and it’s quite nice I think. It’s not as magic filled as op4j, but this might be just the good thing about it. As I had to do an presentation to pass an class about presentations at school, I’ve done this super simple presentation about a very basic subset of Guava’s features. While doing it I’ve learned how to use the LaTeX Beamer class, and yup, it’s really very nice indeed! Notice the coloured Java syntax? Nice trick, ain’t it :-)

Oh, and while doing all this I also created an very simple website www.kemerling.pl. The graphics where done by another friend of mine. It was quite hell to get all this to display properly (the while part, with bazylion transparent layers… ;-)), but I hope it looks all right :-)

Hmm… back to coding! Gotta improve the NBP Traveling Salesman now :-)

PS: It seems that this blog has been added to www.dworld.pl/blogEntry/blog/113! Whoa that’s really really awesome and I’m really really grateful to be aggregated together with Poland’s most active Java bloggers :-) I don’t know whom I should thank for adding me there, so I’ll thank that the whole community and Grzegorz Duda as dworlds author :-)

Our server “Kopiec” is somewhat online (running CentOS off course) – we’re able to start/stop if thanks to a tool that’s called “remote insight”, and I’ve put 3 databases on there. MariaDB, InfiniDB and a clean MySQL instalation. We’re somewhat having problems with TokuDB, but that’s going to be our 4th database of interest. If you want to keep track of our test’s you can take a look at: http://mysqlintegra.project13.pl/.

The first step in getting things tested is filling those db’s with some data, and I mean a LOT of data. So we hacked up a more or less quick and dirty python script called dbfiller (source code avaiable on github) that would simulate a very simple table generation scheme (people working on shifts and checking in when they’re finished or start some activity). If you’re interested, our task is specyfied in the /doc/Opis.pdf file (sorry, only in polish). After a few days it’s up and running and we’re moving on to filling up those databases with some gigabytes of data.

Next we’re going to write some SQL Views/Procedures and then we’ll use Apache JMeter to run some performance benchmarks of some interesting data storage engines.

PS: If you’re wondering about my GWT-Crossword project – yeah, it’s still actual, and I’ll get right on it when done with some of the stuff here.
PPS: Yes, an Linux powered phone AT LAST in my hands! The HTC HERO is comming to me really soon – never again shall I use a ShitOS like WindowsMobile 6.5.

Python Web Development with Django (in polish “Python i Django. Programowanie aplikacji webowych“) by Jeff Forcier, Paul Bissex, Wesley Chun. This book is clearly aimed at beginners, not only in Python or Django but in WedDevelopment as such. Thanks to this, it’s really easy to read and understand. Well, Django itself is quite easy to understand as are most of trendy frameworks out there.

As for what it is, a beginner book, aimed at introducing people to both Python and Django, it does it’s job very well. We get to know all the basic stuff Django offers, the CRUD generator, ORM framework and template system. There are also 3 more or less real life applications written and described in the book – a photo upload service, an ajax chat (jQuery with JSON) and a simple CMS website.

All in all, it does go over all the major features of Django, the main problem (for me) with it is that it doesn’t go any deeper into any of Djangos potential, sometimes even directly stating that something won’t be covered here and sending us straight to the Official Django Documentation. I know that it’s the best place for up to date infos, but that’s not why I pay for a book about some technology, right? ;-) That said, let’s sum up what I think about this book:

Pros:

• Nice intro into Django and Python
• Sample apps are fun and quite “real”
• Easy to read, doesn’t make your head boil from millions of hacks per line ;-)

Cons:

• Doesn’t cover anything more advanced, like more examples on custom tag creation and “best practices“
• Everything covered in this book could be easily looked up online (documentation + “django book”), it doesn’t add much more to the topic…
• It didn’t convert me into a django fan ;-)