On Tue, 21 Feb 2023 03:39:46 GMT, Tingjun Yuan <[email protected]> wrote:
>> Currently, the two subclasses of `java.util.EnumSet` optimize bulk
>> operations when the argument is also a `EnumSet`, but there is no such
>> optimization for wrapper sets (returned by `Collections.unmodifiableSet`,
>> `Collections.synchronizedSet`, etc.) and immutable sets (returned by
>> `Set.of` methods) of `Enum`s.
>>
>> This PR introduces optimization classes for these situations. No public
>> APIs are changed.
>
> Tingjun Yuan has updated the pull request incrementally with one additional
> commit since the last revision:
>
> Set.copyOf: need defensive copy
The `RandomAccess` `SortedSet` `NaviagableSet` implementations are public to
users while `RegularEnumSetCompatible` and `JumboEnumSetCompatible` aren't. So
I guess we can implement another interface for these wrappers to retrieve their
backing instances, like:
interface WrapperCollection {
Collection<?> getBacking();
}
and thus:
interface RegularEnumSetCompatible {
static RegularEnumSetCompatible tryConvert(Collection<?> coll) {
if (coll instanceof RegularEnumSetCompatible compat) return compat;
if (coll instanceof WrapperCollection wrap) return
tryConvert(wrap.getBacking());
return null;
}
}
Adding extra `getClass() == UnmodifiableRegularEnumSet.class` indeed will
affect most users, which rarely are enum set compatibles.
-------------
PR Comment: https://git.openjdk.org/jdk/pull/12498#issuecomment-1478689026
