Qcon in Review: November 7th

Summarizing November 7th, for those not following my tumbl'd thoughts.

Kent Beck's opening keynote was well-presented, but I didn't take much away from it other than the reason behind his shaved head.

A panel discussion on Architecting for Performance and Scalability was good, but it's hard to cover that kind of topic in an hour, particularly with a panel. Of particular note was Ari Zilka arguing that scaleout for relatively small scale should focus on load-balancing rather than partitioning.

After lunch, I attended Designing for Testability, with Cedric Beust and Alexandru Popescu. This was perhaps a mistake for me, having done a lot of pervasive testing and having used TestNG, I didn't really learn very much. This was the second time I felt that way, so I realized I was going to have to watch which topics I attend -- the ones I'm most interested in are often the ones I know the most about, and am least likely to learn something from an hour-long primer. TestNG contributed a great deal to the world of Java testing, but I feel like JUnit has been revitalized by that competition and the choice between the two is less clear than it was between TestNG and JUnit 3.8.1. Cedric also showed his usual bias against agile and TDD: which is fine, as far as I'm concerned, you use the process that works for you.

Next up was Eric Evans on Strategic Design. This was a good talk, although he's a measured speaker rather than overflowing with energy. Still, he's a clear communicator, and there were some interesting points. I particularly liked the metaphor of maps as models. His anecdote about pudding, which relies on the language context (american pudding: goey custard-like dessert; british pudding: any dessert) was also entertaining. Some of the detailed elements seemed vague, but it was still enjoyable.

I followed that up with Cameron Purdy's Java Scalability and Reliability. I'd seen this presentation (or a heavily related one) before, but he's such an entertaining speaker, I didn't mind seeing it again. He's also not afraid to stir up a little humorous controversy: taking a shot at Bob Lee and calling FTP the precursor to SOAP.

Finally, a panel discussion on What will the future of Java be? was really great. There was a lot of hunger in the room to see Java evolve in some fashion, whether or not it's part of its current platform, or in the shape of a new platform on the JVM. The panel was well-comprised with different viewpoints, and there were some pithy comments and good debates.

Joshua Bloch opined that Java is mature, and shouldn't go around in a pink miniskirt and pierced navel, but rather continue to evolve in a very measured fashion, making room for a new platform on the JVM, one that solves some of the existing fundamental problems. This was an interesting perspective, but I wish I could see evidence that there was serious effort being put into this concept (sorry, Charles Nutter, I don't think JRuby's that solution, as interesting as it is). A fair amount of time was spent talking about static/dynamic languages and backwards compatibility and the size of the Java download. Erik Meijer concluded with an interesting statement about DSLs: a disaster waiting to happen. This was probably my favorite session so far, both the topic and the speakers were great. Well worth watching when InfoQ puts it up.

QCon November 6th: DSL Tutorial

For those not following my more stream-of-consciousness reporting on QCon via Tumblr, I thought I'd summarize on a daily basis here.

On November 6th, I attended the Domain Specific Languages tutorial put on by Martin Fowler and Kent Beck. They started the presentation by letting us know they were only prepared for a half-day tutorial and had only recently realized they were scheduled for a full day. They then proceeded to get through the first 'hour' of material by lunch, and took the afternoon for the rest, so all in all it seems like the content was well-suited to the timeframe.

They did a good job of describing the kinds of domain specific languages (they used the terms internal and external, rather than the 'embedded' term that's been used elsewhere), showed some good examples of DSLs in Java and Ruby as well as completely custom DSLs, the tiny languages that the Pragmatic Programmers talk about. They also spent some time describing the boundaries of DSLs: What's a DSL vs. an API; a DSL is usually a thin veneer over a framework; the hardest part in writing a DSL is writing the framework beneath it.

The last portion focused on those external DSLs, using Antlr as an example on how you might build and use a parser for a domain-specific language. This was the most interesting to me, because although I've read a little on the subject, including some of Martin Fowler's exploration of Antlr already, it's the area that I knew the least about (having used jMock's Java DSL for years, and having done a few months of Ruby in anger).

There were a few interesting moments:

• Charlie Poole indicated that some domain specific languages make it harder for non-english speakers to use the API, because they lack the common use of the idioms of the language. For instance, is "2.days.from.tomorrow" easier than Calendar.getInstance().add(Calendar.DAY,2).getTime() for a german speaker? (I dunno, I'm not German).
• Neal Ford, describing the muddy boundary between an API and a DSL, said, "DSLs are like pornography: Hard to define, but I know it when I see it."
• Martin Fowler and Neal Ford have slightly different takes on open classes, the ability to add methods and behavior to classes you don't control, easy to do in Ruby. Martin argued that it was reasonable within the context of an application you control, but riskier in a library that will be integrated with someone else's application (and other libraries). Neal Ford argued that experienced Rubyists find this conflict arises very rarely, and that the benefits outweigh the risks.
  

In the end, I don't know that I actually learned that much, but that's to be expected when you already know a fair bit about the area. I expect that when they release a book on the subject, it'll be a good one, with the kind of detail you can't stuff into a day-long presentation, and particularly valuable to those of you who are interested in, but have little experience with, DSLs.

I ended the day by having some Mexican food from Mijita Cocina Mexicana, possibly the food highlight of my trip (so far).

Toronto: High-Turnout for Tech Events?

I was interested to learn that both Joel Spolsky, on the FogBugz World Tour and Mike Chambers at Adobe's On AIR Bus Tour said that their Toronto stops had one of the highest (if not, in fact, the highest) turnouts.

To be fair, Mike Chambers did check the numbers and said that Toronto wasn't the highest turnout, just close.

Still -- this is good news. It means that Toronto's a good place to have technology events, conferences, and the like. If we're willing to turn out en masse to hear vendors pitch their products, imagine how many people would show up for something actually interesting. Although we've got Agile 2007 headed our way next year, I'd like to see more conferences make a showing here.

And, no, NFJS, out by the airport doesn't really count.