RFC: draft API for JEP 269 Convenience Collection Factories

[Louis Wasserman]

I'm unclear on whether the question is where Guava stopped, or why we
included the fixed-args versions as well as the varargs versions?

Part of the answer, of course, is that those factories predate
@SafeVarargs, and frankly even now Guava doesn't really depend on Java 7.

If you're asking about why we stopped where we did, we collected actually
rather a lot of data on the size of static collection constants using
immutable collections, both with builder syntax and without.
https://github.com/google/guava/issues/2071#issuecomment-126468933 has the
statistics (in terms of ratios, not absolute numbers), but we found that
there was right about an exponential trend: static collection constants of
size n+1 were ~half as common as collection constants of size n.

On Sat, Oct 10, 2015 at 6:56 AM Remi Forax <forax at univ-mlv.fr> wrote:

> ----- Mail original -----
> > De: "Stephen Colebourne" <scolebourne at joda.org>
> > À: "core-libs-dev" <core-libs-dev at openjdk.java.net>
> > Envoyé: Vendredi 9 Octobre 2015 15:11:47
> > Objet: Re: RFC: draft API for JEP 269 Convenience Collection Factories
> >
> > On 9 October 2015 at 00:39, Stuart Marks <stuart.marks at oracle.com>
> wrote:
>
> [...]
>
> > > 2. Other concrete collection factories.
> > >
> > > I've chosen to provide factories for the concrete collections
> ArrayList,
> > > HashSet, and HashMap, since those seem to be the most commonly used. Is
> > > there a need to provide factories for other concrete collections, such
> as
> > > LinkedHashMap?
> >
> > LinkedHashMap definitely
> > LinkedList definitely not (as its very slow and use should not be
> > encouraged).
> > TreeSet/TreeMap, maybe, they'd need an extra parameter though.
>
> There is an issue with LinkedHashMap (resp LinkedHashSet),
> it inherits from HashMap /facepalm/, and static methods are accessible
> through class inheritance /facepalm/.
> So if LinkedHashMap doesn't declare some methods of(),
>   LinkedHashMap.of("foo")
> will return a HashMap :(
>
> cheers,
> Rémi
>