ConcurrentHashMap/ConcurrentMap/Map.compute

[Brian Goetz]

>>>> We do not have explicit parallel versions of forEach for anything yet.
>>>> Existing
>>>> forEach methods are inherently sequential.
>>>
>>> But does any spec promise this?
>>
>> If you want parallel forEach you can do:
>>
>>    coll.parallel().forEach()
>
> But what's up with Maps?

There's always

   map.entrySet().parallel().forEach()

if this is the only case we're really worried about.

But, let's uplevel this.
  - What *other* operations do you want to expose in parallel other than 
forEach?
  - If you wanted to make the default of forEach parallel, how would the 
user ask for serial?  What about other operations?

The issue of "parallel collections" is one that we deliberately 
sidestepped as a simplifying scope-reduction choice.  Everything else 
we're doing here is either a simple serial extension to existing 
collection semantics (e.g., Collection.removeAll) or explicitly part of 
the Stream framework.  So, we don't have an answer; my preference would 
be to not invent one a month before feature-freeze if we don't have to.