RFR: JDK-8319123 : Implementation of JEP-461: Stream Gatherers (Preview) [v2]

[Per Minborg]

On Thu, 9 Nov 2023 09:33:54 GMT, Viktor Klang <vklang at openjdk.org> wrote:

>> src/java.base/share/classes/java/util/stream/Gatherer.java line 261:
>> 
>>> 259:     /**
>>> 260:      * Returns an initializer which is the default initializer of a Gatherer.
>>> 261:      * The returned initializer identifies that the owner Gatherer is stateless.
>> 
>> I know the text is logically correct but is there a way to be more intuitively correct? I mean, there are other initializers that could also mean the Gather is stateless.
>
> @minborg Not really, from an evaluation-perspective only this specific initializer indicates true statelessness (other instances will signal that it is stateful even if it happens to use `null` as its state). True statelessness means that the initializer doesn't need to be invoked, and that any state does not need to be tracked.

Then it should read something that "if, and only if"

>> src/java.base/share/classes/java/util/stream/Gatherer.java line 419:
>> 
>>> 417:      * @return the new {@code Gatherer}
>>> 418:      */
>>> 419:     static <T, R> Gatherer<T, Void, R> of(
>> 
>> Nit: In `Collector` the parameters are formatted in a different way. Should we be consistent with that existing formatting?
>
> Which parameters? The type parameters or the method parameters?

Here is an example:


    static<T, A, R> Collector<T, A, R> of(Supplier<A> supplier,
                                          BiConsumer<A, T> accumulator,
                                          BinaryOperator<A> combiner,
                                          Function<A, R> finisher,
                                          Characteristics... characteristics) {

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PR Review Comment: https://git.openjdk.org/jdk/pull/16420#discussion_r1387941646
PR Review Comment: https://git.openjdk.org/jdk/pull/16420#discussion_r1387942446