RFR: JDK-8322964 Optimize performance of CSS selector matching [v2]

[John Hendrikx]

On Mon, 8 Jan 2024 16:01:01 GMT, Andy Goryachev <angorya at openjdk.org> wrote:

>> John Hendrikx has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains eight additional commits since the last revision:
>> 
>>  - Merge branch 'master' into feature/selector-performance-improvement
>>  - Add since tag to new API
>>  - Add deprecated annotation and fixed deprecation descriptions
>>  - Use copyOf instead of Collections.unmodifiableList(new ArrayList<>(x))
>>  - Pull up frozen field to abstract FixedCapacitySet class
>>  - Add copyright header
>>  - Deprecate StyleClass and remove StyleClassSet for faster solution
>>  - Fix regression
>
> modules/javafx.graphics/src/main/java/javafx/css/SimpleSelector.java line 382:
> 
>> 380:         hash = 31 * (hash + name.hashCode());
>> 381:         hash = 31 * (hash + selectorStyleClassNames.hashCode());
>> 382:         hash = 31 * (hash + selectorStyleClassNames.hashCode());
> 
> this pattern destroys some information that otherwise should be used to produce a better hash code.
> instead of 
> `hash = 31 * (hash + newPart);`
> it should be
> `hash = 31 * hash + newPart;`
> 
> (also in CompoundSelector)

I agree that it is not nice :)  However, changing this seems out of scope for this PR as my changes are unrelated to this, and I didn't even touch `CompoundSelector`.  As selectors are never stored in sets/maps, it is hard to justify changing this as part of this PR as it would not be related to improving performance.

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

PR Review Comment: https://git.openjdk.org/jfx/pull/1316#discussion_r1444941427