And they did. Went to see We Will Rock You – the musical by Queen and Ben Elton last night and it was sensational. The songs fit into the story line brilliantly and the story itself was interesting and not just an excuse for singing the songs. The constant use of song references as bad puns just added to the experience for me and it was particularly impressive to see the customization for the Australian audience. The lead bohemian was titled after the great rock singer from the past “John Farnam” and when captured he was told – “This really is the last time”. That’s the kind of joke that flowed through the night and all of them went down extremely well. The music itself was very loud and very energetic. Unless you are an absolute die-hard, noone can match Freddy Mercury type of person you’ll appreciate the vocal talent that performed the extremely difficult songs Queen put together. Definitely worth seeing.

Just when you thought it was safe to turn the TV on again, Young Talent Time makes a come back. The worst part is that the Minogue sisters have promised to appear on the show – any hope that some actual talent may be found is lost…

I have slightly obscure tastes in music – particularly, I like musicals, not the highlights CDs the full recording of the original cast. It’s certainly not the most obscure taste in music but it does lead to an awful lot of trouble tracking down what I want and worse still I know what I want ahead of time unlike most people with really obscure tastes who just stumble across things they like. Coming back to the point though, you can’t just walk into HMV or pretty much any music store that I’ve found and pick up a copy of the original 1986 cast recording of The Phantom of The Opera or Miss Saigon or Les Miserables. However with this new fangled technology intarweb thingy I can head on over to Amazon and order it from there. There’s a bunch of other online stores around that may or may not have what I want for prices roughly equal to Amazon but what I love about Amazon is watching it try to predict my buying habits. I know most people freak out about privacy violations when computer systems start gathering data about them but with Amazon it’s like a fun game. It managed to pick that I was looking to purchase Miss Saigon and The Phantom Of The Opera the last time I went there and offered a package deal on them. It’s recommendations are also really quite good – including detecting that I tend to buy the versions that Lea Salonga is in (she tends to be part of the original cast of a lot of big musicals). Sadly, it doesn’t seem to have worked out that I only buy CDs from them as it keeps offering books and sheet music. While I do tend to buy a fair bit of sheet music of musicals I won’t purchase it without first flicking through it to make sure I have a chance of being able to play it. The big downside of buying from Amazon though is I have to wait two and a half weeks for things to arrive (that or pay an extra arm for postage).

Tor Norbye politely requests that the caps lock key be removed and the control key put there instead. There’s one very good reason why that shouldn’t be done: Everyone (except old school UNIX geeks) is used to the control key being where it is. Moving the control key would seriously annoy people. If you’re one of the people who are used to control being next to ‘a’ then imagine the whole world being as annoyed as you every time they use a computer and find that control is in the “wrong” place. More importantly though, putting control beside ‘a’ isn’t a good place anyway. The little finger is the most difficult finger to control on the human hand and is used least commonly. In touch typing, currently the left little finger is positioned over ‘a’ and moves up for ‘q’ and ‘z’. If you’re British or Australian, ‘q’ and ‘z’ are incredibly uncommon letters (American’s customi_z_ed their language by putting a bunch of Zs in). Now think of the most common keyboard shortcuts used on computers these days (think Windows users, not emacs users):

There seems to be a growing trend for projects to use XML configuration files – fine. There seems to be a growing trend for those projects to provide a schema for those files – good. There seems to be a growing trend for those projects never to validate their configuration files against the schema – bad. As I’ve previously mentioned, my job involves creating an XML forms editor and it turns out that this forms editor is really quite good at editing configuration files (see our very own configuration tool). We thought it might be nice to create a simple editor for Maven POM files. Sadly, it seems that the schema for a POM file doesn’t come anywhere near close to describing what should actually be in a POM. Maven has support for inheriting a POM and using the information in it, thus allowing that information to be omitted from the POM itself. Now admittedly, it’s not possible to specifically describe this in XML schema (the POM being inherited from can omit any information it likes as well assuming that it will be filled in by the extending POM), but the current schema insists that everything be specified in every POM file which makes validation completely useless. The POM files from the plugins don’t validate against the schema for a number of reasons as well. JDNC is even worse – Xerces finds errors in the schema itself (and I’m fairly sure Xerces is correct). This, combined with fairly poor documentation, makes it extremely difficult to implement tool support. It’s a shame, I’d probably use Maven if it wasn’t such a pain in the neck to create the POM file correctly (that and dependency management which is wonderfully simple for things in the public repository and annoyingly difficult for things that aren’t). Maybe I’ll come back and create a more useful schema for Maven at some point, but updating the schema doesn’t really help me identify the areas of our product that need improving.

Anton Tagunov added an excellent comment to yesterday’s entry:

The one thing that has always stopped me from doing this was: interning must use some global lock. So, while interning would cause little to no harm for desktop application it is likely to introduce extra synchronization bottleneck for server applications. Thus potentially degrading perfromance on some multi-cpu beast. Would you agree with this, Adrian? Firstly, let me make something very clear: string interning will cause bugs in your code and they will be hard to track down – they will however be easy to fix once found. At some point, someone, somewhere will forget to intern a string and let it pass into your code that assumes strings are interned. Also, string interning is an extremely situational optimization. In most cases, it will worsen performance because the overhead of interning the strings will not be made up for by the reduced complexity of comparisons. Even of the cases where it does help, most of the time the difference will not be noticeable. As always, don’t bother optimizing until you know that you need to and that it will help – this is an optimization that causes the code to become less maintainable. Having said that, lets go back to the original question. Firstly, does string interning require synchronization? Probably, but not in terms of Java. The String.intern() method is a native method and works via JNI. It would be difficult to imagine a way of achieving the behavior without at least some synchronization though. The synchronized block however would be very small, and very rarely encountered. There are two situations to consider, either the string is already in the interned list or the string is not. If it is, then no synchronization needs to occur because the list is only being read. So multiple strings can be interned at once so long as all of them are already in the interned list. Synchronization will be needed however whenever a string is interned for the first time (ie: it doesn’t match any String constant that has been loaded or any previously interned string). So on a multiple CPU system, it would be very bad to intern a lot of strings that are only ever used once or twice as they would require a lot of synchronization for no benefit. Of course on a single CPU system, doing this would be a bad thing anyway because it would incur the extra cost of comparing strings to check if they match an interned string without gaining any real benefit. My theory would then be (and only real world application profiling will confirm this in any particular situation) that the string interning technique is slightly less likely to pay off on multiple CPU systems, however because the situations in which string interning is useful require that the vast majority of String.intern() calls match something already in the cache (most likely one of the string constants they’re to be compared against) the question of how many CPUs will be in use isn’t going to have any significant impact. I can’t stress enough though that if you don’t have specific profiling data that shows String comparisons as the biggest bottle neck in your application, you shouldn’t apply this optimization. Great question. UPDATE: Here’s an interesting discussion of interning relating specifically to this question. The automatic google search on the side (if you actually click through to this blog entry) is very handy at times.

Elan Meng investigates the behaviours of string constants, interning and == compared to .equals. Very informative. The question remaining is, why would anyone ever use == instead of .equals on a String considering how likely it is to cause confusion and the potential for disaster if one of the strings for some reason isn’t interned. The answer is performance. In the average case, the performance difference between == and .equals is pretty much non-existent. The first thing .equals does (like any good equals method) is check if the objects are == and returns true immediately if they are. The second thing .equals does is check that the strings have the same length (in Java the length of the string is a constant field and so requires no computation). If an answer still hasn’t been found, the characters of each String are iterated over and as soon as they differ, false is returned. Now, consider the possible cases:

Angel Studios is starting to plan a round of screen tests for the people interested in being a part of our films and stage productions. We’d essentially like a database of actors we can flick through and find a list of people who might be suitable for a given role. We also need to do a bunch of auditions for our upcoming short film which is just starting production. There are a few people I want to get back in touch with to particularly invite along to do a screen test but we need to sort out exactly how we want to do it yet. Even so, if anyone’s interested in getting involved in film or stage productions, no experience is necessary, give me a yell (adrian at intencha dot com) and I’ll let you know when we’re actually ready to start doing some. It’s a lot of fun.

This is a great example of getting stuck in a mindset. A piece of very poorly written Java code is presented followed by a much shorter piece of Groovy code and Groovy is declared the winner.

The original Groovy:

list = ["Rod", "James", "Chris"]
shorts = list.findAll { it.size() <= 4 }
shorts.each { println it }

Java:

for ( String item : new String[] {"Rod", "James", "Chris" } )  if ( item.length() <= 4 ) System.out.println(item);

oooo, one line! It must be good… Of course if I were actually going to write that, I’d write it as:

Continuing my journey of learning regarding scripting languages (starting here):

I like it because it saves typing. There was a good example of a 20-line Java program that was reduced to 3 lines in Groovy. I’ve lost the link though. Posted by: Jonathan Aquino I like readability. Java can definitely be overly verbose at times, particularly with IO:

BufferedInputStream in = new BufferedInputStream(new InputStreamReader(System.in()); however, number of lines required to do something isn't something that I really consider when choosing a language. Obviously if it's at either extreme it matters, but few languages are either so short or so long that it really impacts readability. I'm also far more concerned with maintenance time than with development time because maintenance time almost always outweighs development time. Having said that, many people do like really compact languages and some scripting languages provide that (HyperTalk certainly doesn't). Greg Black adds some 

interesting comments as well. I certainly see the benefits of scripting for quick and dirty solutions or small programs as I tried to point out. Greg also quotes me as saying:

As much as the title seems to suggest one of my rants, this is actually a valid question along with a bit of my own pondering. Scripting languages seem to be the flavor of the month these days and I’m not really sure why. I’ve got nothing against scripting languages but I don’t see why they should be considered the be all and end all solution that people seem to think they are. Interestingly, when I first seriously got into programming, it was using HyperCard and there was a constant barrage of insults coming from the “real programmers” about these hobbyists using scripting languages. More than ten years later and all of a sudden you’re just not groovy (pardon the pun) if you’re not using a scripting language. I love being able to write a quick perl script to munge a text file in an odd format or to run through the Xalan codebase and change the package so that it doesn’t conflict with the version in the JRE. Our support auto-responder at work is a cool little perl script that I wrote to take the incoming (evil MS HTML formatted email) that comes from the web form, parse it, log the details in our tracking system and fire back an email to the user with the tracking number. Works a charm. It would be a real pain to write that stuff in anything but perl because of perl’s awesome support for text parsing and abundant if unwieldy and occasionally unreliable libraries in CPAN. I’ve also written a major business system in perl with database interaction, workflow and all that jazz. It worked well but it was certainly no easier to do it in perl than Java or most likely C given appropriate libraries. I wouldn’t consider C an option unless performance was absolutely critical for server systems however because it leaves open the risk of buffer overruns and similar security holes that can be completely eliminated automatically by most other languages. Even if speed were critical I’d recommend buying faster hardware or using a distributed system before writing a server in C. I’ve also written little scripts and smallish sites in PHP. It’s a nice language that I enjoy using but again I don’t see anything hugely wonderful about it. Everyone seems to be very python oriented these days and I must admit to having almost no knowledge of the language but from the code I have tried to modify in python I really don’t see any reason to be overly excited about it. Again, there doesn’t seem to be anything particularly wrong with it, but I don’t see why it would be so much better than C, Java, Visual Basic, C# etc. I also use JavaScript a lot at work and use it as a full programming language, not just to do roll over graphics. It can do some cool things but the resulting code is far from easily maintainable and again, I don’t see the advantage other than it’s the only option for code-in-a-browser when working cross-browser. The most common reason I hear people giving for why they like scripting languages is because they “just flow better”. I just don’t buy that. I grew up on scripting languages and I just don’t find that they flow any better than any other languages. They do tend to be easier to learn because you get to ignore most of the rules of good programming while you learn (think perl without the use strict directive). If you want to write good code though, you should put that use strict line back in and pay attention to all those little details that make initial coding harder but maintainability easier. Once you’re thinking about all those little things I find scripting has the same feel as “programming”. So am I abnormal or am I just missing something? Maybe it’s both….

A while back Kyle Rankin questioned why people would use InstallShield under Linux. He suggests people use the standard package management schemes that the various distributions provide and he’s dead right. You should make things consistent for the user because it’s consistency that makes a user interface easy to learn and makes it more productive (once you’ve learnt it once you can use it in a whole heap of places at once without taking the time to think of the right way to do it). There is however a problem with this. There are just way too many linux distributions. Even taking into account the fact that there’s a lot of overlap in package management tools, it’s a big ask to expect a company to provide different packages for all of the different systems. Given that, they now have two choices: