looking for FAQ on interconversion of IntFoo and Foo<Integer>

[Ali Ebrahimi]

Hi,
does not IntSupplier  specialize Supplier? if yes, should not IntSupplier
wins over Supplier. what is most specific candidate?

Ali Ebrahimi


On Tue, Apr 16, 2013 at 12:57 PM, Remi Forax <forax at univ-mlv.fr> wrote:

> On 04/16/2013 09:01 AM, John Rose wrote:
> > Where is the standard place to find the design discussion for
> primitive-type specializations of the new interfaces (functions, producers,
> consumers, optionals...)?
> >
> > In particular, will users be able to ignore higher-order functions of
> unboxed values and later adjust code locally for efficiency?
> >
> > If so, are there conversion operators that correspond to auto-box and
> auto-unbox of non-functional, which can be used to make adjustments at the
> boundaries?
>
>  From the compiler point of view, in a lambda conversion Integer as is
> not a boxed int,
> so there is no such auto-boxing. Said differently a Stream of Integers
> and a Stream of ints are not the same object.
>
> >
> > Finally (and this is what prompted me to ask) why not make IntSupplier
> or OptionalInt be sub-interfaces of the reference-bearing ones, with
> autoboxing around the edges (see below)?
>
> At some point in the past, IntSupplier was a subtype of Supplier but it
> doesn't play well with type inference
> and method resolution in the compiler
> Supplier or IntSupplier because they are functional interface are seen
> by the compiler as structural types
> and mixing structural types and classical subtyping relationship has
> some hairy interactions.
>
> >
> > Since this is probably a rehash of past discussions, I'm looking to be
> pointed at some sort of Email thread or even (!) a wiki page.
> >
> > Best,
> > — John
>
> cheers,
> Rémi
>
> >
> > P.S. It looks like this sort of stuff was in the repo at first and then
> was yanked recently.
> >
> > diff --git a/src/share/classes/java/util/function/IntSupplier.java
> b/src/share/classes/java/util/function/IntSupplier.java
> > --- a/src/share/classes/java/util/function/IntSupplier.java
> > +++ b/src/share/classes/java/util/function/IntSupplier.java
> > @@ -32,7 +32,12 @@
> >   * @since 1.8
> >   */
> > @FunctionalInterface
> > -public interface IntSupplier {
> > +public interface IntSupplier
> > +    extends Supplier<Integer>
> > +{
> > +    /** Returns the result of {@code getAsInt}, boxed. */
> > +    // in my dreams, this would allows IntSupplier to convert to
> Supplier<Integer>
> > +    public default Integer get() { return getAsInt(); }
> >
> >      /**
> >       * Returns an {@code int} value.
> >
> >
>
>
>