Hans Muller's Blog: November 2005 Archive

It's my fault. The fact that adding a component to a JFrame required one to explicitly add it to the JFrame's "contentPane" is my fault. Early on in Swing's evolution we added a runtime exception that warned developers not to write JFrame.add(myComponent) and it has been raising hackles ever since. Graham Hamilton covered my transgression in his My Favorite (Dead) Java Boilerplate blog and I thought I'd explain the rationale behind it's birth and eventual demise.

It turns out that I did not create this trip-wire to incite violence or to "educate developers about the choices" within the JFrame container. JFrame's automatically created rootPane, layeredPane, and contentPane substructure was designed to enable popup effects that appear on top of the main GUI. The original motivation for JFrame's substructure was we to support lightweight menus and tooltips and even dialogs that appeared within a top level window. It's also possible to use the substructure to produce novel GUI effects, like translucent full-window progress monitors. So why did JFrame.add() generate an exceptional slap in the face for the developer who's not schooled in all of this?

The 1.0 and 1.1 releases of Swing were delivered on the original Java 1.x platform. Our audience was AWT developers who typically wrote small apps by subclassing java.awt.Frame and overriding paint() or setting its layout manager and adding children. When we decided to create JFrame's substructure there was a debate about the wisdom of automatically mapping JFrame.add() to JFrame.getContentPane().add(). The reason I rejected that approach is that this "convenience" is a shallow illusion. To complete the illusion one would have to redirect get/setLayout(), and addComponentListener(), and getComponent() and getChildren() and so on. In addition to making it tough to actually get inside the JFrame itself, the complete illusion would be asymmetrical since the source of events or a layout manager's container wouldn't match what a developer would expect. So in the interest of consistency, not education, we did not automatically redirect JFrame.add() to the content pane.

Time has passed and the number of AWT developers who's expectations might have been violated by making JFrame.add() convenient has become pretty small. It's also true that the merits of providing a simple trouble-free out of the box experience, even if it depends on an imperfect illusion, are increasingly important. So, in Tiger, JFrame's add and setLayout (and addLayout) methods have changed to "do what you [probably] mean". The other JFrame methods, like getComponent(), do not redirect, so if you use them, be careful. And if you don't use them, well, ignorance is bliss.

Now that we've got that out of the way, anyone have a nomination for a new Swing boilerplate hall of shame candidate? As far as I know, the rest of the API is perfect.

A Brief Report from JavaOne Japan

Posted by hansmuller on November 09, 2005 at 07:32 AM | Permalink | Comments (5)

Big JavaOne Tokyo Sign

This year, JavaOne Japan is during the week of November 7th in a jaw dropping venue called Tokyo International Forum. On Tuesday Scott Violet, Josh Marianacci, and I made two presentations based on Desktop Java talks from the San Francisco JavaOne: Extreme GUI Makeover, Episode 1: Lookin' Good, and Extreme GUI Makeover, Episode 2: Runnin' Fast.

Sessions at JavaOne Japan are shorter, just 45 minutes, and the presentations are translated into Japanese in real-time. Before each session we met with the translators to go over technical terms and other jargon. The translators work in pairs because the job is a bit of a mental sprint, so they shift the work back and forth. They always advise us to follow two simple rules: speak slowly, pausing between slides to allow them catch up, and don't tell jokes. Not being funny just comes naturally, however it's tough to speak slowly when you're trying to cram 60 minutes of material into a 45 minute session. We tended to start out at a sensible pace and then gradually accelerate to the point where the last slide sounded like it was delivered by Alvin and the Chipmunks. After the first talk we met the translators in the corridor. The culture here is polite and friendly and I think they abhor violence. Still, I was glad that the translators didn't have a club handy.

Here are the important sites and documents we referred to during the talk. The San Francisco versions of both talks are available online at developers.sun.com:

Romain Guy developed some of the special effects shown in the "Lookin' Good" presentation and he's been writing about them in his jroller blog as well as his blog on java.net. The code for some of the special effects is available now from the SwingFX project . The animation framework used to animate the button and window backgrounds was written by Chet Haase and is the basis of an open source project at timingframework.dev.java.net

The Mustang splash screen API is documented in this java.sun.com tutorial And you can download an early access build of Mustang from mustang.dev.java.net.

Scott Violet's in-depth article about performance tuning applications with large JTables is available on java.sun.com: Christmas Tree Applications

The SwingWorker API, for moving work from the event dispatching thread to a worker thread, has been extensively documented. The latest documents and downloads can be found at swingworker.dev.java.net

The latest beta release of NetBeans includes support for performance tuning and the new Matisse Swing GUI designer. You can download NetBeans from netbeans.org. Information about configuring the GC, for example to reduce startup time by making the heap big enough, can be also found on the netbeans site: performance.netbeans.org/howto/jvmswitches/

Three other bloggers have covered the Extreme GUI talks at JavaOne Japan: Charles Ditzel: Live From Tokyo: Extreme UI Makeover - A Great Talk on Developing Powerful Desktop Apps and John O'Conner: JavaOne Tokyo '05: Extreme GUI Makeover and Greg Sporar from the NetBeans team: JavaOne Tokyo, Day One. Scott, Josh and I appreciate the coverage and the photos (thanks John)!

Powered by
Movable Type 3.01D

java.net RSS Feeds