On Jun 13, 2013, at 4:06 PM, Remi Forax <fo...@univ-mlv.fr> wrote: >> >>> There is a difference between an Iterator/forEach and a spliterator/stream, >>> with a stream you know that the called lambdas will not interfere and >>> mutate the source collection. >>> >> You do? I don't think there is any conceptual difference between the >> following w.r.t. interference: >> >> ArrayList l = ... >> l.stream().filter(...).forEach(e -> l.add(e)); >> l.spliterator().forEachRemaining(e -> l.add(e)); >> >> and: >> >> ArrayList l = ... >> l.forEach(e -> l.add(e)); >> l.iterator().forEachRemaining(e -> l.add(e)); >> >> Of course we have (or will have) strong wording saying don't implement >> interfering lambdas, but we still have to check for co-modification in the >> traversal methods of ArrayList spliterator. > > Isn't it because if you remove an element from an ArrayList while iterating > you can see a stale value ? > While with a HashMap, if you have only one thread, you can not see a stale > entry ?
Assuming just one thread do you agree that in all of the above examples the only way the list can be interfered with is by the Consumer instance e -> l.add(s) ? > So a spliterator on HashMap can only check the modCount at the end unlike the > one on ArrayList that need to check at each step. > The ArrayList.spliterator.forEachRemaining implementation also checks at the end. Paul.
