Re: List or Iterator

Tom Anderson <>
Mon, 27 Jul 2009 14:11:54 +0100
On Sun, 26 Jul 2009, Mike Schilling wrote:

Andreas Leitgeb wrote:

Mike Schilling <> wrote:

Lew wrote:

Andreas Leitgeb wrote:

In Java, the solution to this usually boils down to anonymous
classes: Iterable<Node> getChildrenIterable() {
       final Iterator<Node> it= getChildrenIterator();
       return new Iterable<Node>() {
           public Iterator<Node> iterator() { return it; }

Naturally the anonymity is a tangential detail. It's trivial to
give such a class a name, just not usually necessary.


Speaking of which, a semi-tangential question: has anyone ever found
a use for a local class (i.e, a class defined inside a method, just
like an anonymous class, but given a name)? I never have.

I haven't yet had a use for it myself, but I could think of a few:

1) An aesthetic tradeoff: you give that class a name, and in return
  you avoid having a line without the "class" keyword but followed
  a class-body.
2) with a named class you can also have your own constructor with
  parameters, while still sugar'ing away the need to pass finals
explicitly. 3) One may instantiate the same class at multiple places
  within the same method. (e.g. for a couple of switch-cases.)

All good points. Of course, when any of them apply, you've also got to
consider "Might I want to use this class in another method? If so, I
might as well make it a full-fledged nested class." Anyway, had local
classes never been invented, I doubt we'd miss them.

I didn't realise we did have them! When were they added?


I know thats not really relevant but I've just typed the words and my
backspace key doesn't work. -- phorenzik

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