Well it’s been an interesting (and tiring) week. Last week all the developers at JTeam attended the Javapolis conference in Antwerp, Belgium. The entire conference lasts for 5 days but we where there only for the 1 hour talks on Wednesday and Thursday. So unfortunately I didn’t get to see Alef and Arjen’s university session on spring 2. (Both used to work for JTeam) JTeam was represented by Uri and Bram who did 15 minute presentation (quicky) on facetsearch (facetsearch.org). Which seemed to draw in a small but very enthusiastic audience.
Anyway here is quick run down of the talks I found most interesting:
Pragmantic Clustering Guide – Mike Cannon Brooks
Mike is one of the founders of Atlassian, the company that among other things created Jira and Confluence. He talked about how the confluence team over the period of 4 or was 6? Months added clustering capabilities to Confluence. He concluded that there is very little to be found about the subject on the web, and that they where for the most part forced to invent the wheel themselves. He identified a number of problem areas, from the top of my head there where the quartz jobs, the Lucene indexes, the object caches, filesystem, and discussed how they solved the problems. For the largest part they basically use the database for a lot of things and assume it is infinitely scalable.
Mike is a good speaker (great aussie accent ?) and the presentation was definitely interesting. I would really like to see more of these “from the trenches” style presentations at conferences.
Web Continuations – Geert Bevin
I only went to this presentation because there was nothing that really stood out in this block. I had briefly looked at rife before and had been quick to dismiss it as yet another MVC framework that arrived 4 years too late. I still believe there is no room for rife in the framework arena, but continuations are definitely an interesting and novel idea that I would love to see implemented in more mainstream frameworks. Geert actually mentioned that Webwork now has alpha quality support for continuations, which I think is great. And he’s even working on a JSR to create a standardized API for doing continuations. Continuations are all about pausing the execution of a program and then being able to resume it at a later point, (using fancy classloading tricks) It seems to me that this is a great technique to programmatically create wizard style interfaces. (far easier than webflow!) All in all I was pleasantly surprised. Unlike most of the speakers at Javapolis, Geert isn’t a native English speaker but in his case it didn’t really bother me. He spoke slow but fluently Bonus points for playing doom on a 8 by 5 screen 😉
Spring OSGi – Costin Leau
Costin Leau is an interface 21 consultant from Romania who has been working on the Spring – OSGi integration, I have to confess that (like many other developers) I knew little to nothing about OSGi prior to this presentation. It turns out that OSGi has been around for many years and among other things serves as the foundation for the eclipse plugin system. From what I understand you basically have this server that holds all or some of your jars. These jars should be OSGi enabled. OSGi enabled seems like a complicated term but it essentially just means that you need to add some entries to your jar’s manifest file eg. specifying the name and version of this jar. In this same manifest file you can also specify what other libraries this jar depends on (transitive dependencies). OSGi then makes sure that this jar only sees those libraries. This is very powerful because say component X depends on library Z 1.0 and library Y depends on library Z 2.0 which is not backwards compatible. You can still use library X and Y in your application. (Nice!) It also allows you to hot swap components / libraries at runtime without bringing the server down and run multiple versions of a component. Spring 2.1 will be OSGi enabled and will come with namespaces for OSGi lookups. All in all an interesting and enlightening talk. Clearly Costin speaks in public a lot. He is an articulate and interesting speaker