I’m helping out with a study group for "Head First Design Patterns," which just finished chapter 6. On the whole, it’s a pretty good introduction to software design patterns – way more accessible than the seminal work by the Gang of Four; however, the examples sometimes make my head hurt. I can’t imagine what they’re doing to the heads of the beginners in the group. Coming up with decent examples is the hardest thing to do in expository writing, and I certainly give the authors an E for effort in creativity, but I wish they had been a little less concerned with making their examples "hip" and a little more concerned with making them appropriate.To wit, the whole pizza store analogy in chapter 4 (to illustrate factory method and abstract factory) is flawed. For one thing, that’s just not the way you’d model a pizza business in any actual software that I can imagine. For another, the differences between a New York pizza factory and a Chicago pizza factory are too subtle/trivial to make for an effective illustration of why you would need to subclass anything (much less use a factory to manage the subclasses). A much better example, as everyone in my group agreed, would have been an application that needs to offer up a consistent set of functionality to users who are accessing it in wildly different ways: one’s in a web browser on a desktop, another is running a cell phone app, another is using a touch-tone phone, and yet another is using a voice-activated headset. All the client code knows is that, for example, it needs to ask a multiple-choice question and obtain the answer. It’s up to an abstract factory to provide the client with a set of classes that can do that, in the context of the selected user-interface, in whatever way is necessary.
To a lesser degree, the Starbucks coffee example at the beginning of the book suffers from the same too-hip-to-be-effective syndrome, although I do think that the remote-control example for the Command pattern in chapter six is dead on.
For any novice who is reading this book without the benefit of a study group, I highly suggest that you find at least one other programmer who is experienced in design patterns to explain why/if/how the examples are lacking.
TDD has become as automatic for me as breathing. It’s a beautiful thing when you get to start a new project from scratch and can write every line of code test-first. These days, however, I’m working on a legacy app with very little in the way of unit tests, and it feels as if I’m working at 5,000 meters above sea level and struggling for every breath of rarified atmosphere.
I discovered a neat trick for copying a record, or set of records, within the same SQL table today. For example, say you have 20 employees listed in department A, and you want to clone all 20 records to also be listed under department B.
This blog is back. It's been offline for far too long -- a case of me being so busy working on software projects for other people that I haven't been able to keep my own stuff going. Anywho... Things are starting to settle down, so you can look forward to more of my endearing, but not necessarily enduring, wisdom to come.
My business partner, Vladimir Drndarski, will be speaking on Tuesday, Feb 22 at 7pm in the city of Orange on the topic of Building WebApps with Tapestry. This will be at a meeting of the 
The "Great Moments with Mr. Lincoln" attraction on Disneyland's Main Street is going away on Februrary 22 (the day after President's Day) to make room for a special exhibit celebrating Disneyland's 50th anniversary, and our favorite audio-animatronic won't be giving his rendition of the Gettysburg Address again until Autumn 2006. So, if you haven't seen Great Moments lately, be sure and catch it this month -- especially if you haven't seen it since 2001 when the 3D audio effects were added and the whole tie-in with Mathew Brady's glass plate photography was included in the story. This is a great attraction to catch on your way out of the park. They always run it one last time after the official park closing. So, put on your headphones, have a seat, enjoy the show, and wait for the exiting crowd to die down. Who knows? You and your kids may even learn a thing or three about US history in the process.
Happy New Year. One of my New Year's resolutions is to play more poker, and to that end I would encourage any and all poker players here in Orange County, CA to attend the Poker Meetups every third Tuesday. We don't actually play at these. We just meet and talk, and arrange for games at other times. I usually bring whatever poker books I've been reading to pass around and we always have some terrific discussions. So, get yourself registered on meetup.com and then RSVP for the next poker meetup.
