concurrent sets

[Remi Forax]

On 01/12/2013 02:13 PM, Doug Lea wrote:
>
> I'm still working on lambda-related tie-ins for j.u.c stuff
> (mostly Spliterators).
>
> As mentioned before, we will supply two explicitly concurrent Sets,
> both via static factory methods:  ConcurrentHashMap.newKeySet, and
> ConcurrentSkipListMap.newKeySet. (The CSLM one gives Sorted/Navigable 
> Set)
>
> These are necessary when people need/want parallel collect-into
> operations for sets.
>
> But how will they know to do this?

they don't need if they use methods Collector.to*

the implicit way:
stream.parallel(). ... .collect(Collector.toSet());  // use a concurrent 
hash set
stream.parallell(). ... .collect(Collector.toSortedSet()); // use a 
concurrent skip list set

the explicit way:
Set<...> set = ConcurrentHashMap.newKeySet();
stream.parallel(). ... .forEach(set::add);
SortedSet<...> sortedSet = ConcurrentSkipListMap.newKeySet();
stream.parallell(). ... .forEach(sortedSet::add);

The explicit way can be written is the javadoc of newKeyset() as an 
example of use.

>
> -Doug
>
>
>

Rémi