Tuesday July 24, 2007

(See intro for a background and caveats on these coding advice blog entries.)

It's been a while since I've posted Java-coding opinions. But I couldn't resist on this one. The tip itself is straightforward:

A getter method's name should not sound like an action method.
Getter methods and setter methods should not have the same name.

I'm speaking from bitter experience since I just fixed a bug where my code had accidentally been calling a getter method, when I thought I was calling a setter method. The method in question is java.lang.ProcessBuilder#redirectErrorStream. If you're launching a process, and you want to read its output, you may want to redirect its error output to its standard output such that you only have to read the input from a single source (assuming you don't care to distinguish between output and error.)

Well, my code was initializing the ProcessBuilder:

        ProcessBuilder pb = new ProcessBuilder(args);
        pb.directory(pwd);
        pb.redirectErrorStream();

The problem here is that redirectErrorStream() does NOT redirect the error stream! It just returns false to tell me that it's not yet planning to redirect the error stream. The correct way to do this is

        ProcessBuilder pb = new ProcessBuilder(args);
        pb.directory(pwd);
        pb.redirectErrorStream(true);

This is the kind of thing a bug detection tool like findbugs could detect. It already warns if it sees you doing something similar, like calling String.trim() without storing the return value. Unfortunately, it didn't warn me about this case - so I filed a request. But this was a great reminder to run findbugs on my code again, which turned up some other interesting things to look at...

Roman and Gregg interviewed me in the latest episode of the NetBeans podcast.

Here are the shownotes from Roman's blog:

• 0:00 Introduction and Tor's podcasting, he's also a podcaster at the Javaposse
• 2:30 What Tor has worked on at Sun: Java Studio Creator, Project Semplice, and the Ruby tools
• 5:00 Overview of Ruby features in the NetBeans IDE
• 7:25 Debugging Ruby
• 9:50 Rails support
• 10:51 Switching between Ruby implementations
• 11:49 Implementation of the type inference and code completion logic
• 17:10 Implementation of refactoring features
• 18:54 Features Tor wants to implement next
• 21:33 Community feedback
• 23:17 Why should Java developers look at Ruby?
• 26:38 Other Ruby development tools
• 29:49 A version of NetBeans IDE that just has Ruby support? Check out this page on deadlock
• 32:16 Opportunities for contributors and cool features; check out the wiki page.
• 34:55 Support for other dynamic languages. Erlang IDE based on Tor's code.

The episode is here, subscription is here.