Paul Sandoz paul.sandoz at
Wed Jun 5 09:50:45 PDT 2013

On Jun 5, 2013, at 6:31 PM, Michael Nascimento <misterm at> wrote:

> Hi folks,
> Is there any good reason I cannot see for Collectors.sumBy, giving one
> could use mapToLong().sum() and avoid the costs of boxing?

Such Collector can be used with mapping, groupingBy and partitioningBy, e.g.

 Stream<Foo> s = ...
 Map<Foo, Long> m = s.collect(groupingBy(Function::identity, sumBy(this::mapFooToLong)));


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