unrdered()

[Joe Bowbeer]

Consider making forEach ordered by default, and relying on unordered() to
disable this.
On Apr 3, 2013 10:00 PM, "Brian Goetz" <brian.goetz at oracle.com> wrote:

> At one point, we had an unordered() op.  I think it may be time to bring
> it back.
>
> There are a growing number of ops that have optimized implementations for
> unordered streams:
>
>   - distinct can be implemented with concurrent insertion into a CHS
> instead of merging if we don't care about order.  Not only is this less
> work (merging is expensive), but it makes distinct lazy (elements can flow
> through immediately once they've not been found in the CHS, instead of
> waiting for all the elements to be seen.)
>
>   - sorted is non-stable in unordered streams.
>
>   - limit/subsequence are far lighter for unordered streams (and can
> similarly be made lazy)
>
> So a way of saying "I know you think this stream has ordering, but I don't
> care about it" is a way of opting into these optimizations.
>
> Implementation is trivial.
>
> Adding .unordered() could also enable us to get rid of
> .collectUnordered(), and allow more of the reduce-like ops to benefit from
> the embrace of "disorder" without API explosion.
>
>
>
>
>
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