RFR: 8327858: Improve spliterator and forEach for single-element immutable collections [v2]

[Chen Liang]

On Tue, 12 Mar 2024 10:12:18 GMT, Viktor Klang <vklang at openjdk.org> wrote:

>> Chen Liang has updated the pull request with a new target base due to a merge or a rebase. The pull request now contains 13 commits:
>> 
>>  - Use the improved form in forEach
>>  - Merge branch 'master' of https://github.com/openjdk/jdk into feature/imm-coll-stream
>>  - Null checks should probably be in the beginning...
>>  - mark implicit null checks
>>  - Merge branch 'master' of https://github.com/openjdk/jdk into feature/imm-coll-stream
>>  - Copyright year, revert changes for non-few element collections
>>  - Merge branch 'master' of https://github.com/openjdk/jdk into feature/imm-coll-stream
>>  - Merge branch 'feature/imm-coll-stream' of https://github.com/liachmodded/jdk into feature/imm-coll-stream
>>  - Spliterator for 12, iterate/forEach benchmark
>>  - fix comments
>>  - ... and 3 more: https://git.openjdk.org/jdk/compare/d5b95a0e...69bd0e9c
>
> src/java.base/share/classes/java/util/ImmutableCollections.java line 926:
> 
>> 924:             if (!REVERSE && e1 != EMPTY) {
>> 925:                 action.accept((E) e1);
>> 926:             }
> 
> I'm curious to know how the following alternative would fare:
> 
> Suggestion:
> 
>             if (e1 != EMPTY) {
>                 action.accept(REVERSE ? (E)e1 : (E)e0); // implicit null check
>                 action.accept(REVERSE ? (E)e0 : (E)e1);
>             } else {
>                 action.accept(e0); // Implicit null check
>             }

@viktorklang-ora I've updated this piece of code, does it look better now?

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PR Review Comment: https://git.openjdk.org/jdk/pull/15834#discussion_r1534539452