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Tuesday, May 16, 2006

Tapestry: Duke's Choice!

In something that was a bit of a surprise, even to me, Tapestry won a Duke's Choice award for innovation at this years JavaOne.

They gave me a big, wacky Duke statuette (photos to follow). I mean, I'm going to have to hire a pack mule to get it back to Portland. I also had a chance to chat with James Gosling about Java. I complimented him on the language and told him how much fun I'm having with it, which he seemed to like. On the other hand ... when I mentioned wanting "all the goodness of Java, but a little less typing", ala Ruby, he went a little cold. I didn't realize until this moment that he might have thought I was referring to object typing (an issue for another day) when I was, in fact, talking about keystrokes!

Meanwhile, I had to drop off the statuette in the room, so I've probably missed the Java bloggers meetup at the Thirsty Bear. We'll see if I can catch the end of that.

Been having a lot of fun so far ... maybe tomorrow, I'll even make it to a session!

Monday, May 08, 2006

NFJS Meltdown

I had a "perfect storm" of technical problems at yesterday's No Fluff Just Stuff which, sadly, scared away part of the audience. I had just re-installed Eclipse on my laptop, reorganizing my plugins into multiple extension folders (so make my eventual upgrade to Eclipse 3.2 easier) and I inadventently installed a new version of the Eclipse Jetty Launcher plugin, version 1.4, that is not compatible with Eclipse 3.1, just with 3.2. Ouch!

So, a lot of fumbling there that got in the way, took up time, and put me off my game. But people were still very interested and involved, with good questions. I have to think about the JavaScript stuff though ... it may just be too much for people who haven't seen Tapestry before.

See folks at JavaOne!

Tuesday, May 02, 2006


So I find myself with a crowded desk: one laptop, a mouse for the laptop, a keyboard, mouse, and two LCDs for my desktop. It's getting crowded, and it gets annoying to switch between different keyboards.

Worse, I do all my Thunderbird email just off the laptop (though I use GMail on either or both). That's a problem when I need to copy text from the desktop to the laptop so I can mail it.

Solution: Synergy -- an open source tool that links my computers together.

Synergy allows me to use my desktop keyboard and mouse on both systems. The mouse travels off the left side of my desktop screen onto the right side of my laptop screen. Focus follows mouse, at least in terms of system-to-system, so I can type on one system (say, the desktop), move the cursor over to the laptop, and type into the active window there (without clicking). Synergy even updates window decorations.

Better yet ... Synergy supports cut-and-paste of text between the two systems. So I can copy text out of my browser on the desktop and paste it into compose window on the laptop. I had thought about using a KVM switch at one time, and this kicks its ass! In fact, had I discovered this a few weeks ago, I might not have bought a mouse for the laptop.

Not an issue for me, but it's also cross-platform. It supports Windows, Linux and (with some problems) Mac OS X.

Monday, May 01, 2006

Tapestry 5 Class Reloading

One of the big advantages of the scripting approaches to Web development (including JavaServer Pages at one extreme, and Ruby on Rails at the other) is the velocity of change: you can change a source file (a JSP, a Rails template, or even a Rails class) and see the change immediately.

Tapestry has traditionally been more aggressive at caching. Once a template or a XML file has been loaded into memory, it's stuck there. During development, you can use the -Dorg.apache.tapestry.disable-caching=true trick to turn caching off, but this not only slows down every request, but includes a memory leak that will eventually tank the application. It also does not reload classes the way it reloads templates and XML files.

In my quest to create a Java web development environment as compelling as Rails, one of the first things to tackle is this aspect of development: effective and efficient reloading of component classes.

The first pass at that code is now in the repository. Component classes are loaded in their own class loader (this is also necessary for the Tapestry AOP code that transforms classes as they are loaded into memory). When any transformed classes are changed externally, the class loader, as well as all instances derived from those classes, are discarded and a new class loader is created.

This will work quite well, far better than Tapestry 4's development mode. In production, you'll just throttle down how often Tapestry checks to see if underlying files have changed.

What's interesting is that I've been working, off and on, on this code base since mid-February. This compares to how long I spent on the initial prototype of Tapestry way back in January 2000, where I spent a couple of weeks of furious coding just to get to a simple "Hello World". In those couple of weeks, I "invested" Tapestry with many of the features that would grow with it, and support that growth, over the intervening years: the component hiearchy, the original and primitive form of templates, component parameter bindings, page loading, external XML page and component specifications, and other things long forgotten. To me, it was like winding up a spring ... all that upfront effort paid off with a basic design that was "right enough" to keep Tapestry innovative for many years.

The reason I'm starting with a new code base for Tapestry 5 is that it's time to wind up that spring again. The couple of design errors, only apparent after the fact, in Tapestry 4 are all but insurmountable without a fresh start (this primarily includes the requirement to extend base classes, but there are many more subtle things that need addressing). Further, the fact that I've spent a chunk of time getting the basic class loading and AOP support in place, the fact that anything web application is still weeks or months off, is actually a Good Thing. The spring is going to be wound nice and tight, full of energy for years to come.