Very interesting post. I read a little bit about wrapping all primitives and removing getters and setters in this article: http://www.javaworld.com/javaworld/jw-01-2004/jw-0102-toolbox.html It’s a good read; check it out.

-Steve

Interesting, and cool to see that you actually took the time to try this experiment. But, one thing I would say is that it’s not really possible for you to judge the value of these constraints on your own. My main complaint about the “object calisthenics” exercise was that the guidelines favoured “proper OO” and conciseness over readability and simplicity.

For you, the “one level of identation per method” and “wrap all primitives” guidelines might seem like good constraints, it’s hard for you to judge because you don’t have to experience reading the code without understanding it. Someone not familiar with the code might have to spend more time exploring the code to figure it out.

On the other hand, there is no clear-cut answer to these things. Some people prefer nice abstractions, other people just want to see what the code is actually doing. I don’t mind the abstractions when I know I can trust them (e.g. the Python standard library) but am less comfortable with code that hasn’t been as thoroughly tested. YMMV.

Anyways, great article. Good point about the advantage of wrapping primitives when you’re using a language with explicit types — I hadn’t thought about that.

I certainly agree with your “good.” As to the “bad,” I think limiting a class to no more than two instance variables is a salutary exercise, as it tends to force reconsideration of whether an object really shows cohesion or whether it’s doing several things that should be broken out separately.

Cheers!

you might want to check out how your setup handles code. This is a prototype as I see it:
RatingPrediction SVDApproximation::prediction(const CustomerID&, const MovieID&);

Something’s escaping things when they don’t need to be escaped. I suspect that the tag has something to do with it, but I’m not sure.