Thursday, May 08, 2008

Complexity Budget

Are you a human? If not, then this is probably not for you.

If you are, then you have a "complexity budget". I define it a little bit differently than the author of the article. My definition is that you can spend only so much on understanding something. Example. What does this little C program do?


It prints the primes below 100. And it blows the complexity budget. C++ also often blows the complexity budget. A friend of mine once said: "To understand C++, you have to be a C++ compiler."

Java once was a simple language but the wise guys with a sun-burn (from being exposed too long to the sun, get it?) decided to do something about it and came up with Generics. And since they weren't sure that this would indeed make the language too complex, they added annotations on top of that. Excellent move!

But it didn't work. There are still too many people who use and understand Java. So they came up with JSR 308 which allows you to use annotations in even more places to write code like this (from this article):

@NotEmpty List<@NonNull String> strings
        = new ArrayList<@NonNull String>();

If that doesn't do it, nothing will.

On a positive side note, in Groovy, I can not only register an annotation processor (AP) in the compiler, I can even manipulate the AST from the AP, allowing to create code like this:

def load(long id) {
    return """select * from demo_table where id = ${id}""";

That doesn't return a string but an object of type DemoType filled with the data from the database. Life can be so simple.

And to the guys from Sun: Thanks a lot! We really appreciate your help! :-)

Links: Article by Michael Nygard about JSR 308

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