One thing that would make this info more readily useful (and in fact I’ve done this on my paper copy of this site) is to emphasize (bold or underline) the key part of the Scala code that gives you the effect you are demonstrating. So, for example, in part one “val bar:Bar” is emphasized, in part two “private”, in part three “extends SuperFoo(bar)”, in part four the second line, and in part 5 “@BeanProperty var”. The value in doing this is that you immediately know that no changes were required anywhere else.

Oh, and Paul’s comment on how to make a constructor private has been very helpful; since constructors are chained, that’s what you have to do if you are going to store the data in a different form from what the user hands you to create it. Would it make sense to add that tip to your collection?

One last note is that the rules are somewhat modified for case classes.

Thanks very much for taking the time to write this down, Stephan; you materially contributed to my success with Scala!

Yeah… I know ;D

class Foo private (x: Int) { }

For the setter to work I think you should define bar as a var, not val?

private var bar = aBar

class Foo(private val bar: Bar)

or just

class Foo(bar: Bar)

more concisely:

class Foo(private val bar: Bar) {
…
}