JEP 473: Stream Gatherers (Second Preview)

[Holo The Sage Wolf]

Think about `flatMap` (which filter is a special case of), this is
one-to-many function that can also return 1 or 0 elements for each input.
So it makes sense to include 0 as "many".

Filter isn't many-to-... At all, at no point it collapses a subsequence of
elements, it only works on one element at a time

On Sun, 7 Apr 2024, 19:31 Ernie Rael, <errael at raelity.com> wrote:

> On 24/04/07 9:11 AM, Viktor Klang wrote:
>
> Hi Ernie,
>
> "Many" in this case refers to "N", which is "0 ... N",
>
> OK, I was wondering about "many" including "0".
>
> so I'd say while it is techincally correct as-is, perhaps more precise
> would be to say "1-to-0..1" gatherer, since for every element in, there is
> 0 or 1 element out.
>
> I see.
>
>
> Many-to-one would be 0..N -> 1, which means that an empty input would
>
> "could" not "would"?
>
> yield a single output.
>
> Out of curiosity, is either correct technically?
>
>
> Other than at  initialization or finish, is it possible to have an "empty"
> input?
>
>
> -ernie
>
>
> Cheers,
> √
>
>
> *Viktor Klang*
> Software Architect, Java Platform Group
> Oracle
> ------------------------------
> *From:* core-libs-dev <core-libs-dev-retn at openjdk.org>
> <core-libs-dev-retn at openjdk.org> on behalf of Ernie Rael
> <errael at raelity.com> <errael at raelity.com>
> *Sent:* Sunday, 7 April 2024 18:06
> *To:* core-libs-dev at openjdk.org <core-libs-dev at openjdk.org>
> <core-libs-dev at openjdk.org>
> *Subject:* JEP 473: Stream Gatherers (Second Preview)
>
>
> This is about what might be a minor doc issue.
>
> In https://openjdk.org/jeps/473 it says
>
> As another example, Stream::filter takes a predicate that determines
> whether an input element should be passed downstream; this is simply a
> stateless one-to-many gatherer.
>
> Shouldn't this be "many-to-one"?
>
> -ernie
>
>
>
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