Thursday July 07, 2005

Somebody asked how to find out more about the new "ui" tags in Creator 2. This seems like a good opportunity to point out that we have code completion, and popup javadoc, for JSP tags as well. In particular, if you switch to the JSP view of your source files, put the caret over a tag like <ui:button>, and hit Ctrl-Space or Ctrl-\, you get a completion popup listing possible alternatives. As you walk around in the list with the arrow keys, the TLD doc for the tag is listed in the popup (which for java files show javadoc documentation for the methods). There's quite a bit of documentation for all the new components - look at the size of the scrollbar to get a sense of the size of the button help. Or better yet, go try this yourself!

Of course, you don't have to go to the JSP view and read tag documentation to learn about the components. In the Early Access version we don't have all the help for the new components written, but if you for example select the Button in the JSF Standard palette, you'll see that the dynamic help window begins with a help topic for the Button component. Double click on it and you can read component-oriented documentation on the button component. We'll be filling this out as we finish Creator 2.

(As always in this blog, click on the thumbnail to see the full picture.)

I just came across this blog entry by Ken Arnold (who's writing a book on the Java language) where the author argues that generics should not have been included in JDK 5.0:

I don't know how to ease into this gently. So I'll just spit it out.

Generics are a mistake.

This is not a problem based on technical disagreements. It's a fundamental language design problem.

... it feels like the JSR process ran far ahead, without a step back to ask “Is this feature really necessary”. It seemed to just be understood that it was necessary.

It was understood wrong.

I disagree with Ken. The big point of adding generics is allowing people to use type checked collections and so on. Nearly all Java programmers use the Collections API. Using the genericized collections in JDK 5.0 is not hard - it's really easy, makes the code cleaner, and detects programmer errors. The fact that creating generic collections classes is hard is besides the point - most programmers don't have to. Yes, there's a price for having more flexible libraries: they're harder to write. That is nothing new. Developers can continue to write JDK 1.4-style APIs and libraries if they want to.

Perhaps the comparison is a bit unfair, but take EJBs. Prior to EJB3, developers had to work really hard to write an EJB. With EJB3, all they have to do is add some metadata annotations to their simple Java code, and everything else is handled automatically. Did this make writing an app server harder? You bet. But that's a fair trade-off - there will be a lot more programmers using EJBs than programmers writing app servers. While not a perfect analogy, I think the same principles apply here. For a few library designers, who now want to create generic types (they still have the option of creating old style types), life just got more complicated. However, for all their clients, life got easier. Easier is good.