Constructing parallel streams

[Joe Bowbeer]

I can easily imagine a pipeline that has alternating
sequential/parallel/sequential segments.  Is there any reason to discourage
a programmer from using the parallel/sequential methods to express this?
On Dec 10, 2012 7:50 AM, "Brian Goetz" <brian.goetz at oracle.com> wrote:

> I don't like users being able to call parallel in the middle of the
>> stream construction.
>>
>
> I don't love it either.  The semantics are perfectly tractible, and the
> implementation is perfectly straightforward, but the performance is
> unlikely to be a win in most cases.  (I mentioned earlier we would doc that
> this really should only be done at the head of the pipeline.)
>
>  I propose to have an interface ParallelizableStream that allows to
>> choose if the user want the sequential or the parallel stream upfront.
>>
>
> Yeah, we investigated this direction first.  Combinatorial explosion:
> IntParallelizableStream, etc.
>
> However, this could trivially become a dynamic property of streams (fits
> easily into the existing stream flags mechanism).  Then only the head
> streams would have the property, and if you tried to do parallel() farther
> down the stream, we could ignore it or even throw ISE.
>
>