zippedFiles =
Dir.new(dir).entries.sort.reverse.delete_if { |x| ! (x =~ /gz$/) }

’nuff said.

Okay, there is more to say.

First of all, what does this line of code do? It goes through every file in the given directory, sort them in reverse order while excluding any file that doesn’t end in “.gz”.

This code ported to Java is quite intimidating:

List<String> result = new ArrayList<String>();
File f = new File(directory);
for (String fileName : f.list()) {
if (fileName.endsWith(".gz")) {
result.add(fileName);
}
}
Collections.sort(result, new Comparator<String>() {
public int compare(String o1, String o2) {
return o2.compareTo(o1);
}
public boolean equals(Object o) {
return super.equals(o);
}
});
This code comes from a log analyzer utility that I wrote some time ago.  It goes through the Apache log of my Web server and allows me to easily plug-in listeners to collect various kinds of statistics.  This utility has provided me with a flexible log analyzer framework into which I have plugged various additional loggers these past months.
 Since I hadn’t taken a look at this code in a few months, I was quite happy to realize that it passes the “six-month readability test”.  A language that has never passed this test for me is Perl.  Perl might be a powerful language but if you stop using it for six months, you will need a book to reread your own code and a personal trainer just to modify it.
 So I was quite happy to understand my old Ruby code right away, even in the most idiomatic sections such as the one I pasted above.  The code carries its intent clearly thanks to aptly-name methods and closures are, as usual, as pleasant to use as they are powerful.
 There is a problem with my log analyzer, though, which is the reason why I am revisiting it today:  it’s pretty slow.  It takes about five minutes to run through a month of logs, which I find unacceptable. Therefore, I want to port it to a different language.
 While I love Ruby, I have to say I like Groovy even more, because it gives me the same flexibility as Ruby with the familiar Java syntax on top of it.  However, I have had some bad experiences with the current versions of Groovy and as far as I can tell from the mailing-list, the stability of the compiler still leaves a lot to be desired.
 Exit Groovy (for now).  So it will probably be Java or C#.  I am hoping the poor performance comes from the Ruby interpreter and not from my code, but I will find out soon enough.