RFR: 8356255: Add Stable Field Updaters to allow efficient lazy field evaluations [v6]

[ExE Boss]

On Wed, 7 May 2025 14:58:33 GMT, Per Minborg <pminborg at openjdk.org> wrote:

>> This sketch shows how "Stable Updaters" can be used to create stable computations of `@Stable` fields. Only one updater is needed per class, similar to `AtomicIntegerFieldUpdater`.
>
> Per Minborg has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Add convenience methods and documentations

src/java.base/share/classes/jdk/internal/lang/stable/StableFieldUpdater.java line 257:

> 255:         check(accessor, int.class);
> 256:         Objects.requireNonNull(underlying);
> 257:         var adaptedUnderlying = checkAndAdapt(underlying, int.class);

Suggestion:

        // Implicit null checks:
        check(accessor, int.class);
        var adaptedUnderlying = checkAndAdapt(underlying, int.class);

src/java.base/share/classes/jdk/internal/lang/stable/StableFieldUpdater.java line 311:

> 309:         check(accessor, long.class);
> 310:         Objects.requireNonNull(underlying);
> 311:         var adaptedUnderlying = checkAndAdapt(underlying, long.class);

Suggestion:

        // Implicit null checks:
        check(accessor, long.class);
        var adaptedUnderlying = checkAndAdapt(underlying, long.class);

src/java.base/share/classes/jdk/internal/lang/stable/StableFieldUpdater.java line 588:

> 586: 
> 587:     private static MethodHandle checkAndAdapt(MethodHandle underlying, Class<?> returnType) {
> 588:         final var underlyingType = underlying.type();

Suggestion:

        // Implicit null check
        final var underlyingType = underlying.type();

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

PR Review Comment: https://git.openjdk.org/jdk/pull/25040#discussion_r2077860284
PR Review Comment: https://git.openjdk.org/jdk/pull/25040#discussion_r2077860770
PR Review Comment: https://git.openjdk.org/jdk/pull/25040#discussion_r2077861275