When expectations are high, you’re invariably up for some disappointment. Charles and Tom were unable to demo Rails-in-a-war-on-Glassfish; but at least they gave a warning in advance. But I definitely expected something more–or rather something else–from Eric Evans’ university session on domain-driven design (ddd).

The afternoon session on scripting languages went well enough anyway–or at least, the JRuby part did. The session took off with a theoretical explanation of JSR-2something (the support for scripting languages in Java SE). After that, Charles and Tom got their chance to warm up the Java-minded public for all goodness of Ruby. It took a little while for them to get comfortable, but then Tom was at the keyboard showing the simplicity of building a small Rails app from scratch; and Charles got the flow of the presentation going, explaining what Tom was doing and going into JRuby details. The hour flew by for most of the audience. When I got back after the half our break, Charles and Tom were still answering questions.

Charles and Tom showing some well-known faces

Now you have to believe me, in the 90 minutes of Groovy that followed, I did keep an open mind. I tried to look at the code samples objectively. I tried to admire the work that has gone into creating a dynamic variant of Java. I really tried hard to imagine a scenario where I would be tempted to remotely consider using Groovy in a real-world app. Okay, and I was also just a little bit busy trying to get my laptop to talk to the JavaPolis wireless network, which wasn’t easy either. But at least that one I finally succeeded at. The Groovy thing–I’m afraid it’s not for me. It gives me the worst of both worlds: no sweet Ruby syntax, and on top of that uglified Java syntax as well. Maybe next time I’ll see the light. I promise to keep an open mind.

The thing that most disappointed me however, was Eric Evans’ morning session on domain-driven design. Not that it was a bad presentation, not at all. Maybe it’s all about expectations. I expected an introduction into ddd. What is it, what’s so great about it, why should we use it, what lessons have been learned, what tips can a ddd guru give us? Instead we got a session about domain modeling: how do we get from use case to domain model. And also, if we have multiple models within our application/organization, what patterns can we discern regarding the interfacing between those models and the teams that design them? Interesting enough, no problem there; but what does this have to do with ddd? Domain modeling like this can well be done without any domain-drivenness. Or can it? I’ll know more in a week or two, when Evans’ book that I ordered will arrive.

Just arrived in Antwerp, Belgium, for the JavaPolis 2006 conference which starts tomorrow morning. Same venue (Metropolis, where I stopped on the way to pick up this year’s goodies bag), same hotel (Astrid–yeah I know it has a tacky name but it’s really not that cheap). Fortunately, the state of Antwerp’s wireless networking has advanced in a year’s time; I now have free wifi in my hotel room as well as at the JavaPolis venue. Allowing me to write this short blog entry.
And so I won’t be accused of blogging just for the sake of it, just because I can blog, I will list the university sessions that I’ll be attending tomorrow.

• First off is Eric Evans, talking about domain-driven design. This promises to be not only a theoretical introduction to the subject, but also an interactive domain modeling session. I’ve been looking forward to hear more about ddd since visiting Sogyo’s evening session two weeks ago. Especially as that session has left me confused whether Rails might be seen as a domain-driven development framework. I’m still not convinced; maybe tomorrow’s session will bring some clarification–and new arguments!
• In the afternoon, I’ll be at room 4 for the Dynamic Languages session. More in particular, for the JRuby part of that one. Originally, this session was scheduled as an all-JRuby university session; but somehow, the Groovy guys have managed to squeeze their way in as well. I really don’t see the point of Groovy, other than proving that Java can be as cool as Ruby if only we mutilate the language enough and make it dynamic. I promise I’ll keep an open mind during their session tomorrow, though I don’t think I’ll be able to take in anything after seeing Charles and Tom perform the miracle of Rails-in-a-war-on-Glassfish.

The all new JavaPolis 2006 bag

So much to do in this hot and cold summer (July: 36 degrees, August: 16 degrees) and so little to blog about. In case anybody wonders, this is what I’ve been up to lately.

Gone back two years in time: After I finally left the WebLogic project in May, a little later than planned, I was re-assigned to the organization I worked at two years ago. It was as if time had stood still when I got back there. Not only because there were many familiar faces to welcome me, but also because the entire development environment was pretty much as I’d left it. So it’s back to Java 1.4, back to Struts, back to EJB’s, back to this pre-SOA SOA architecture… Then again, as someone asked me: what would I use instead of Struts? What indeed, if not Ruby and Rails? Does it really matter which XML-infested Java framework you use? Would Shale or Spring MVC make so much of a difference? I get by because there’s a lot of code and XML to copy/paste from, but the amount of code that is the result is frightening.

Trying to keep up with the insane tempo of the JRuby guys: After trying to get Rails on JRuby to work for my NLJUG presentation in May, with help from Charles Nutter and Tom Enebo, the JRuby protagonists, I kind of stuck around on the JRuby mailing list, which reads like a Dan Brown novel (well it does if you like coding). I even got a small job, rewriting Mongrel’s HTTP/1.1 Ragel parser to a JavaCC grammar (Why is there no Ragel-to-Java translator? I wish I’d had the time to write one. Now I had to use JavaCC, which was rather frustrating, either because of the limitations of JavaCC, especially in its idea of regular expressions, or because of my own limited knowledge of parsing–but it’s here, checked in in a fresh new RubyForge project, ) and it seems to be working. Mongrel will work completely with JRuby if Ola gets his JRuby extension framework going, allowing you to extend the Ruby language with Java libraries as easily as you can now with C libraries.

Organizing the Java Summer Camp 2006: After last year’s success with Simon Ritter‘s presentation of Java 5’s new features (fortunately no-one seems to remember the train mixup that got Simon 50km away from the venue and cause Rietje (office Mom) and me to pick him up there and drive back at questionable speed), Profict decided to do another Java Summer Camp this year. Like RubyEnRails before, this turns out to be very time-consuming. Finding a theme (Java & Ajax), speakers (Greg Murray! Bram Smeets!), visitors (90+, we’re fully booked!), a venue (another castle!), seats, food, sound system, camera, parking space…

Got my first production-worthy Rails application live: as a side note to the Java Summer Camp, I rewrote the small Rails app that I used to keep track of the RubyEnRails visitors. It can now handle multiple events, multiple users, it sends bulk email to visitors, it exports visitor data to Excel to keep the managers happy and it has a new and improved gui (which took me longer to design then it did to code the application itself).

Busy finding new colleagues: Yes I know, I should be proclaiming the wonders of Ruby and Rails at all times–but the truth is, I don’t hate Java, I don’t mind (that much) doing Java as a day job, and I don’t mind working for a Java shop. Although I’ll never quit dreaming of my own world empire, someday, somehow–in the meantime I’m very happy to be working for Profict. In spite of its focus on doing application integration projects (some people love diving in at the deep end, writing code that never sees the light of day; but I prefer staying near the surface, where the code reaches the user’s screens); but there’s enough work to do at the edges of integration: portals for one; and there are always the external assignments that I’ve been on for the last couple of years (what’s English for detacheren??). But what I really like about Profict is the fact that it’s small enough to know everybody (no huge consulting firm for me, thank you). It is a close group of mostly very experienced people, formed over the years only ‘by invitation’ (employers asking those people around them to join that they themselves would like to have as colleagues). So maybe I shouldn’t advertise the fact that we’re looking for still more people on my blog, for everyone to read–on the other hand, if you’re persistent enough to read this blog entry, you’re welcome to come talk (well, if you live in Holland anyway)! Okay, end of shameless commercial intermezzo…

Done a Grey’s Anatomy and The O.C. marathon: If you hate The O.C., you have got to at least love its theme song: California by Phantom Planet. That alone makes me want to go there (or at least as soon as flying to the US becomes a little more relaxed again). And Grey’s, what can I say: it’s little more than the 835th romance-in-a-hospital show (St. Elsewhere, Chicago Hope, ER, Medisch Centrum West) but there’s something that makes me want to keep watching–maybe Izzie? (A supporting character is usually my favorite: Summer in The O.C., Chloe in 24, Paris in Gilmore Girls, Starbuck in Battlestar and of course Locke in Lost; the exception is Prison Break).

Making the switch to Linux: Somewhere in the process of getting Subversion with SSH to work under Windows XP, which proved a hopeless case, either with or without Cygwin or VMWare, I decided to to finally make the switch. I shrinked my XP partition (I’ll still need it for graphics and photography work, as I just can’t get the Gimp to do what I want just as easily) and installed Ubuntu Dapper Drake. It feels like coming home (I worked with VMS and Unix long ago). It’s still not MacOS yet, but at least my 3GHz Dual Core cost just a third of Apple’s new beast…

Twice a year the Dutch Java User Group organizes a mini conference with sessions about Java, JEE, and everything related. In spring this day is called J-Spring (which has nothing to do with the Spring framework), in fall it’s called J-Fall. While preparing for RubyEnRails 2006 I thought it would be a good idea to enter a paper for the J-Spring, for an introductory session called Is Ruby The New Java?. I was a bit surprised when my paper was accepted, and even more surprised last Thursday (J-Spring day) about how many Java people showed an interest for my session: I got the big conference hall (and it really does look big when you climb the stage), filled with maybe some 200 people. Even though I got the usual nervous questions about things like duck typing and performance, I had the impression that overall, people really liked what they saw. Apparently Ruby and Rails are hot in Java land.

And likewise, Java is hot in Ruby and Rails land; allbeit with a slightly different angle. I’m talking about the JRuby project, an interface to Java allowing Ruby code to run under a Java Virtual Machine. JRuby’s ‘holy grail’ being to be able to run Rails applications in a Java application server. At this year’s JavaOne, JRuby lead developers Charles Nutter and Tom Enebo were able to show a working Rails application running under Tomcat. In spite of their help and a lot of emails, I did not manage to reproduce their setup for a demo at J-Spring. Instead, I showed how easy it is to call an EJB from Ruby, as well as a Rails application based not on a database but on a Java web service.

You might wonder what’s the use of such an interface to Java. Like I said in my J-Spring presentation, I believe it offers some great possibilities for the future of Ruby and Rails. Once Rails runs on the JVM, it becomes that much easier to use Rails within established enterprisey Java environments. For that to happen, Java developers working within those environments need to be convinced of Ruby and Rails’ added value. And so I hope that my presentation has helped to convert some of those Java developers to Java developers-who-want-to-develop-with-Rails.

If you’re interested you can download my presentation here.

After installing and playing with JRuby a few days ago, I started wondering if it would be possible to access an EJB from a JRuby script. After all, the Java code to call an EJB is purely client code, only communicating with an application server over an HTTP-like protocol (HTTP-like in BEA’s case, anyway). At my current project, the OptimalJ team generates all their domain code and delivers business services around that in the form of session EJBs to us, the web frontend team. We’re using BEA WebLogic Portal to code the frontend. Now if we’d have EJB access from JRuby, and Rails on JRuby (which seems to be only a matter of time), I guess we would be able to build a frontend like this in Rails. There’s just the tiny matter of convincing the company’s enterprise architect, who’s already sick of hearing me talk about Ruby and Rails.

Anyway, to the code! To my surprise (after 6 years of experience with EJBs, anything EJB-related working instantly comes as a great surprise) it was just a matter of JRubyfying the Java code that you would write to use an EJB. It just works, there’s nothing more to it. Here’s an example of the magic code:

require 'java'
 
include_class 'java.util.Properties'
include_class 'javax.naming.Context'
include_class 'javax.naming.InitialContext'
 
properties = Properties.new
properties.put(Context::INITIAL_CONTEXT_FACTORY,
    "weblogic.jndi.WLInitialContextFactory")
properties.put(Context::PROVIDER_URL, "t3://localhost:7001")
context = InitialContext.new(properties)
home = context.lookup("business-ejb-jndi-name")
business_ejb = home.create
result = business_ejb.someBusinessMethod(parameters)

Okay, here’s some small print. The example works on a BEA WebLogic application server. For another JEE application server you’ll need to fill in the correct InitialContextFactory class name. Fill in the JNDI name for the EJB after the lookup call. Also, before running the script, you’ll have to put the right libraries in the CLASSPATH environment variable. For example, for the BEA server I had to include weblogic.jar and the EJB client jar containing the home interface to the EJB. But once you’ve figured that out, it should work; I got it to work on JBoss as well as BEA. Consult your local Java guru if necessary.

I’ve put all this in a JRuby module (to be downloaded here), which enables you to write just this to call your favourite EJB:

require 'rejb'
business_ejb = Rejb::ejb("business-ejb-jndi-name")
result = business_ejb.someBusinessMethod(parameters)

I’ve been feeling very happy over the last few days, even though there’s no Spring in sight. Must be the summer of Ruby that’s coming…