hg: lambda/lambda/jdk: Streams cleanups; add optimized forEach implementations; include subList in tested lists

[Paul Sandoz]

On Nov 19, 2012, at 11:51 AM, Remi Forax <forax at univ-mlv.fr> wrote:

> On 11/19/2012 10:47 AM, Paul Sandoz wrote:
>> On Nov 18, 2012, at 9:28 PM, Brian Goetz <brian.goetz at Oracle.COM> wrote:
>> 
>>>> A code like this should throw a CME and not an AIOOBE
>>>> arraylist.forEach(e -> { arraylist.remove(e); })
>>> The current code won't do that, as it copies the array into a local var
>>> before the loop, so the indexes are always valid.
>>> 
>>> A reasonable middle ground is a comodification check after the loop
>>> terminates.
>>> 
>> Yes, that's what Mike did with the original array proxy stuff.
>> 
>> It's not a fail-fast solution thus risks "arbitrary, non-deterministic behavior at an undetermined time in the future", but i think it is within the scope of ConcurrentModificationException.
> 
> The question is why ArrayList.forEach should not be fail-fast ?

I think we have to consider the wider context of Iterable/Iterator/Spliterator.forEach when used for parallel evaluation. In such cases it is advantageous not to fail-fast.

So while there is a precedent for the Iterator impls to fail-fast it does not necessarily mean all forEach impls should by default do the same.

Paul.