Remove cumulate from Stream interface

[Joe Bowbeer]

I think I agree with Rémi.

Programmers should not have to think twice (and will not) about converting
their for-loops into forEach forms.

However, they should think twice before adding "parallel()".


On Wed, Dec 5, 2012 at 3:05 PM, Remi Forax <forax at univ-mlv.fr> wrote:

> On 12/05/2012 07:55 PM, Brian Goetz wrote:
>
>> Plus, your Mapper will violate the to-be-written specs about
>>>> statefulness/side-effects in lambdas passed to functional stream
>>>> methods.
>>>>
>>>
>>> Do you really want this overly restrictive wording for streams that are
>>> sequential ?
>>> I find this unrealistic, even if you try to specify this in the doc,
>>> nobody read the doc if not forced.
>>> Given that will not be enforced in the code, it will be only true on the
>>> paper.
>>>
>>
>> It may be unrealistic, but we have to do it anyway.  If someone passes a
>> Function to map() that mutates the collection source, all bets are going to
>> be off, and we have to say this.
>>
>
> yes, but mutating the collection source is not the same as saying no side
> effect.
> Moreover, i have trouble to understand why the old rules can't be applied
> for serial stream. If the collection is a concurrent collection, there is
> no problem, . If the collection is not concurrent, it will fail-fast.
>
> For parallel stream, if the lambda have side effects, i agree that there
> is no guarantee.
>
>
>    The spec can characterize when things are guaranteed to work; if people
>> do things that accidentally work because they are operating in a
>> restrictive environment, that's their concern.
>>
>>
> that why I think that sequential stream should always work or get a
> fail-fast exception and parallel stream should only work for lambda with no
> side effect.
>
> Rémi
>
>