The for (T x: array) ... use case is precisely what's motivating me, yes; I
don't have any intention of e.g. implementing Iterator.remove(). We allow
that syntax on "real" Java arrays, but not on JsArrays.
Does returning T[] actually avoid creating an Iterator object, or does it
just create an Iterator of different type?
I'm not sure I understand Ray's concern... JSO wouldn't implement iterable,
so another subclass of JSO would do whatever the author made it do. Most of
the methods on JsArray<T> and e.g. JsArrayString[1] are final, but we
wouldn't *have* to do that for iterator(), so a subclass could still
override.
[1] why don't we just use JsArray<String> instead of JsArrayString?
Pre-generics compatibility? If so, should we re-implement JsArrayString as
a trivial extension of JsArray<String>?
On Wed, Apr 1, 2009 at 9:22 AM, Thomas Broyer <t.bro...@gmail.com> wrote:
>
>
>
> On 31 mar, 22:29, Ray Cromwell <cromwell...@gmail.com> wrote:
> > Wouldn't this cause a problem when you want more than one JSO to
> implement
> > Iterable? I wouldn't make the class itself implement Iterable, I'd add a
> > helper method to return an Iterable, e.g.
> > public class JsArray<T> extends JavaScriptObject {
> >
> > public Iterable<T> iterable() { ... }
> >
> > }
> >
> > for(T foo : someJsArray.iterable()) {
> >
> > }
> >
> > The risk of adding it to the class type itself is that you potentially
> block
> > anyone else from making a JSO that implements Iterable.
>
> For better performance in web mode, returning a T[] would be
> preferable (as it would just return the JsArray unchanged, without
> wrapping class).
> See
> http://code.google.com/p/gwt-in-the-air/source/browse/trunk/src/net/ltgt/gwt/jscollections/client/JsArrays.java#124
> (that's something we discussed already a few months ago and I believe
> that's what you're using in GQuery too; the array should be considered
> read-only, the main use case is iterating using a for(:) loop)
>
> Or maybe, i don't if it would work: can a super-source class
> implementation return a different type as a "normal" source class?
> i.e. in src/com/google/gwt/core/client/JsArray<T>: Iterable<T> iterable
> ()
> while in super/com/google/gwt/core/client/JsArray<T>: T[] iterable()
> though it can break at compile time if not used in a for(:) loop (e.g.
> assigned to an intermediate Iterable<T> variable and/or explicitly
> calling Iterable<T> methods)
> >
>
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