Hi Zheka and Tagir,
@Override
public void forEach(final Consumer<? super E> action) {
Objects.requireNonNull(action);
for (int i = 0; i < this.n; i++) {
action.accept(this.element);
}
}
I think here we should extract this.element and this.n into a local vars, as
Consumer may have interaction with volatile field inside (e.g.
AtomicInteger::addAndGet) which would cause a load of consumed field at each
iteration. See original post by Nitsan Wakart
https://psy-lob-saw.blogspot.com/2014/08/the-volatile-read-suprise.html
Regards,
Sergey Tsypanov
07.12.2018, 15:22, "Zheka Kozlov" <orionllm...@gmail.com>:
> What about forEach()?
>
> @Override
> public void forEach(final Consumer<? super E> action) {
> Objects.requireNonNull(action);
> for (int i = 0; i < this.n; i++) {
> action.accept(this.element);
> }
> }
>
> I think this version has better chances to be faster than the default
> implementation (did not measure though).
>
> вт, 4 дек. 2018 г. в 14:40, Tagir Valeev <amae...@gmail.com>:
>
>> Hello!
>>
>> > In CopiesList.equals() please use eq() instead of Objects.equal() (see a
>> comment at the line 5345).
>>
>> Ok
>>
>> > I think you should use iterator() instead of listIterator(). See the
>> explanation here:
>> http://mail.openjdk.java.net/pipermail/core-libs-dev/2018-April/052472.html
>>
>> Ok. I wonder why this message received no attention.
>>
>> Here's updated webrev:
>> http://cr.openjdk.java.net/~tvaleev/webrev/8214687/r3/
>>
>> With best regards,
>> Tagir Valeev
>> On Tue, Dec 4, 2018 at 1:10 PM Zheka Kozlov <orionllm...@gmail.com> wrote:
>> >
>> > I think you should use iterator() instead of listIterator(). See the
>> explanation here:
>> http://mail.openjdk.java.net/pipermail/core-libs-dev/2018-April/052472.html
>> >
>> > вт, 4 дек. 2018 г. в 12:23, Tagir Valeev <amae...@gmail.com>:
>> >>
>> >> Hello!
>> >>
>> >> Thank you for your comments!
>> >>
>> >> Yes, deserialization will be broken if we assume that size is never 0.
>> >> Also we'll introduce referential identity Collections.nCopies(0, x) ==
>> >> Collections.nCopies(0, y) which might introduce slight semantics
>> >> change in existing programs. Once I suggested to wire Arrays.asList()
>> >> (with no args) to Collections.emptyList(), but it was rejected for the
>> >> same reason: no need to introduce a risk of possible semantics change.
>> >>
>> >> I updated webrev with equals implementation and test:
>> >> http://cr.openjdk.java.net/~tvaleev/webrev/8214687/r2/
>> >> Comparing two CopiesList is much faster now indeed. Also we can spare
>> >> an iterator in the common case and hoist the null-check out of the
>> >> loop. Not sure whether we can rely that JIT will always do this for
>> >> us, but if you think that it's unnecessary, I can merge the loops
>> >> back. Note that now copiesList.equals(arrayList) could be faster than
>> >> arrayList.equals(copiesList). I don't think it's an issue. On the
>> >> other hand we could keep simpler and delegate to super-implementation
>> >> if the other object is not a CopiesList (like it's implemented in
>> >> java.util.RegularEnumSet::equals for example). What do you think?
>> >>
>> >> With best regards,
>> >> Tagir Valeev.
>> >> On Tue, Dec 4, 2018 at 10:56 AM Stuart Marks <stuart.ma...@oracle.com>
>> wrote:
>> >> >
>> >> >
>> >> > >> I believe it makes sense to override CopiesList.equals()
>> >> > > Also: contains(), iterator(), listIterator()
>> >> >
>> >> > equals(): sure
>> >> >
>> >> > contains() is already overridden. Not sure there's much benefit to
>> overriding
>> >> > the iterators.
>> >> >
>> >> > s'marks
