On Thu, 30 Nov 2023 23:02:10 GMT, John Hendrikx <jhendr...@openjdk.org> wrote:
>> Andy Goryachev has updated the pull request incrementally with one
>> additional commit since the last revision:
>>
>> save 8 bytes
>
> modules/javafx.graphics/src/main/java/com/sun/javafx/css/CssUtil.java line 75:
>
>> 73:
>> 74: /** immutable list with random access backed by an array */
>> 75: private static class ImmutableArrayList<T> extends AbstractList<T>
>> implements RandomAccess {
>
> I'd like to point that a skeletal implementation of `AbstractList` will
> perform worse than `ArrayList` for any method that needs to walk the list, as
> the `AbstractList` will use iterators for methods like `indexOf`, `hashCode`
> and `equals`. Now that will probably be irrelevant, but as this seems to be
> a micro optimization, you should be aware of all the trade offs.
Good point, thanks!
This also applies to UnmodifiableArrayList.
For completeness sake, I wanted to mention a few issues (not in scope for this
PR) that came out of the code review:
- could use `UnmodifiableArrayList` but it stores extra int size. perhaps a
factory method can be added to it for when `size != elements.length`.
- could improve UnmodifiableArrayList with fast(er) `indexOf`, `hashCode`,
`equals` per @hjohn 's comment earlier
- `Control.getCssMetaData()` can be improved to skip merging of two lists if
skinBase is null
- the same immutable list should be used in `Control.getCssMetaData()` instead
of `ArrayList()`
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PR Review Comment: https://git.openjdk.org/jfx/pull/1293#discussion_r1411406802
