RFR: 8001647: In-place methods on Collection/List

Akhil Arora akhil.arora at oracle.com
Fri Apr 19 19:17:37 PDT 2013

On 04/19/2013 05:42 AM, David Holmes wrote:
> On 19/04/2013 10:14 PM, Paul Sandoz wrote:
>> On Apr 19, 2013, at 1:15 PM, Alan Bateman <Alan.Bateman at oracle.com>
>> wrote:
>>> On 18/04/2013 19:49, Akhil Arora wrote:
>>>> Looks like the stars are aligning on getting on this into TL... the
>>>> refreshed webrev is -
>>>> http://cr.openjdk.java.net/~akhil/8001647.8/webrev/
>>> A minor comment on Collection.removeIf is "that satisifies the given
>>> predicate" might be better than "which matches the provided
>>> predicate". Also for completeness, you could say "RuntimeExceptions
>>> and Errors thrown by the predicate are propagated ...".
>>> In List.replaceAll then @throws NullPointerException is listed twice,
>>> which is okay, but might be better to combine them. A typo in the
>>> second NPE description "if the an element".
>>> In the implementation then the only thing that puzzled me is checking
>>> the modification count in legacy Vector, that seems unnecessary.
>> The function value could structurally modify the Vector instance.
> So this came through while I was writing my similar comments ...
> My reaction to this is simply "well don't do that". If the
> function/predicate/comparator is mutating the Vector then the user gets
> what they deserve in my opinion. Trying to account for that is somewhat
> futile. As per my other email the loop check for
> modCount==expectedModCount will get hoisted from the loop. Further in
> removeIf you need to be a lot more defensive during the first iteration
> as you haven't kept a reference to the original size and array. That
> aside the second part of removeIf (the actual removal) doesn't invoke
> any external code so no concurrent modification is possible then.
> This seems like overkill to me.

removed the in-loop modCount checks in the second part of removeIf for 
ArrayList and Vector

There are some tests that verify that a CME is thrown when a lambda 
modifies the collection it is operating upon. I added a count of how 
many times a lambda is called, and except for sort (which calls through 
to Arrays.sort), all such attempts are detected at the very first 
attempt (at index 0) so the checks seem to be working (and are not 
getting hoisted).

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