RFR: jsr166 jdk9 integration wave 12

[Doug Lea]

On 11/18/2016 02:28 AM, Remi Forax wrote:
> Martin,
> for ArrayDeque, when you start to have methods like
>   @SuppressWarnings("unchecked")
>    static final <E> E elementAt(Object[] es, int i) {
>        return (E) es[i];
>    }
>
> I think it's a better idea to type the field elements as a E[] instead of Object[].
> Historically, using Object(] instead of E[] was preferred because it's a kind of 'more true' at runtime,
> but it will be less true with anyfied generics and as we can see if it leads to introduce method like elementAt, using E[] will make the code more readable.
>

We always use Object[] in cases where anyfication isn't possible
(without further code rework) because we rely on null as a distinct
value. Elsewhere we do use E[].

-Doug


> so the constructors should be:
>   @SuppressWarnings("unchecked")
>   public ArrayDeque() {
>     elements = (E[])new Object[16];
>   }
>
> (same transformation for ArrayDeque(int)).
>
> And you can remove all the casts to E and the corresponnding SuppressWarnings and remove the method elementAt.
>
> Rémi
>
> ----- Mail original -----
>> De: "Martin Buchholz" <martinrb at google.com>
>> À: "core-libs-dev" <core-libs-dev at openjdk.java.net>, "Doug Lea" <dl at cs.oswego.edu>, "Stuart Marks"
>> <stuart.marks at oracle.com>, "Paul Sandoz" <paul.sandoz at oracle.com>
>> Envoyé: Mardi 18 Octobre 2016 03:34:34
>> Objet: RFR: jsr166 jdk9 integration wave 12
>
>> Most of this is for Stuart - very collection-y.
>>
>> http://cr.openjdk.java.net/~martin/webrevs/openjdk9/jsr166-jdk9-integration/
>>
>> This includes a rewrite of ArrayDeque to bring it to parity with ArrayList
>> (except for List features).
>> The patch includes public methods ensureCapacity, trimToSize, replaceAll as
>> in ArrayList, but we can defer making them public to a later change (or a
>> later release), since new public methods are always controversial.  But I'd
>> really like to get the performance/scalability changes in for jdk 9.
>>
>> It also includes a redo of ArrayList#removeIf to make it more efficient and
>> consistent with behavior of other implementations, including ArrayDeque.
>>
>> The patches are a little tangled because they step on each other's toes.
>> File CollectionTest is in "miscellaneous", but it tests both the ArrayDeque
>> and ArrayList changes.
>