RFR: 8342486: Implement JEP 505: Structured Concurrency (Fifth Preview) [v11]

[Alan Bateman]

On Wed, 7 May 2025 07:14:58 GMT, Shaojin Wen <swen at openjdk.org> wrote:

>> Alan Bateman has updated the pull request with a new target base due to a merge or a rebase. The pull request now contains 20 commits:
>> 
>>  - Merge branch 'master' into JDK-8342486
>>  - Merge branch 'master' into JDK-8342486
>>  - Merge branch 'master' into JDK-8342486
>>  - Sync up from loom repo
>>  - Merge branch 'master' into JDK-8342486
>>  - Add JEP number, update copyright headers
>>  - Merge branch 'master' into JDK-8342486
>>  - Sync up from loom repo
>>  - Merge branch 'master' into JDK-8342486
>>  - Sync up from loom repo
>>  - ... and 10 more: https://git.openjdk.org/jdk/compare/0eb680ca...5fec717f
>
> src/java.base/share/classes/java/util/concurrent/Joiners.java line 84:
> 
>> 82:             @SuppressWarnings("unchecked")
>> 83:             var s = (Subtask<T>) subtask;
>> 84:             subtasks.add(s);
> 
> Suggestion:
> 
>             subtasks.add((Subtask<T>) subtask);
> 
> The local variable s is only used once and can be simplified

No, it has to be a local to avoid broadening the use of SW.

> src/java.base/share/classes/java/util/concurrent/Joiners.java line 155:
> 
>> 153:                 case FAILED -> throw subtask.exception();
>> 154:                 default -> throw new InternalError();
>> 155:             };
> 
> Suggestion:
> 
>             return switch (subtask.state()) {
>                 case SUCCESS -> subtask.get();
>                 case FAILED  -> throw subtask.exception();
>                 default      -> throw new InternalError();
>             };
> 
> The switch of the stateToInt method is aligned, so it should also be aligned here to keep the style consistent

I'll look to re-align these in the loom repo for the next refresh.

> src/java.base/share/classes/java/util/concurrent/StructuredTaskScope.java line 820:
> 
>> 818:     @PreviewFeature(feature = PreviewFeature.Feature.STRUCTURED_CONCURRENCY)
>> 819:     final class TimeoutException extends RuntimeException {
>> 820:         @java.io.Serial
> 
> Use import without full path

I think `@java.io.Serial` is okay here, you'll see the same in many other areas.

-------------

PR Review Comment: https://git.openjdk.org/jdk/pull/21934#discussion_r2077217919
PR Review Comment: https://git.openjdk.org/jdk/pull/21934#discussion_r2077215677
PR Review Comment: https://git.openjdk.org/jdk/pull/21934#discussion_r2077222469