And i've forgotten to add that currently calling stream.iterator() is sloooow,
i don't know if it's just because the implementation of this method did not get
some love or it's a more fundamental issue because a spliterator is push while
an iterator is pull so the implementation needs an intermediary memory to store
the element in between.
Rémi
----- Mail original -----
> De: "Remi Forax" <fo...@univ-mlv.fr>
> À: "Peter Levart" <peter.lev...@gmail.com>
> Cc: "Rob Griffin, rgriffin" <rob.grif...@quest.com>, "core-libs-dev"
> <core-libs-dev@openjdk.java.net>
> Envoyé: Mardi 11 Décembre 2018 15:18:24
> Objet: Re: Add convenience collect methods to the Stream interface
> Hi Rob, Hi Petter,
> we (the lambda EG) have decided against implementing Iterable (see the answer
> of
> Brian), so for consistency we have also not enable the right hand side of a
> enhanced for loop to be a poly-expression (that enables the lambda
> conversion),
> hence the mandatory cast.
>
> Rémi
>
> ----- Mail original -----
>> De: "Peter Levart" <peter.lev...@gmail.com>
>> À: "Rob Griffin, rgriffin" <rob.grif...@quest.com>, "Remi Forax"
>> <fo...@univ-mlv.fr>
>> Cc: "core-libs-dev" <core-libs-dev@openjdk.java.net>
>> Envoyé: Mardi 11 Décembre 2018 14:42:51
>> Objet: Re: Add convenience collect methods to the Stream interface
>
>> Hi Rob,
>>
>> On 12/10/18 11:11 PM, Rob Griffin (rgriffin) wrote:
>>> Hi Remi,
>>>
>>> There are certainly places where we could do this when we are simply
>>> iterating
>>> over the results but that is not always the case. However I was
>>> disappointed to
>>> find that the enhanced for loop can't iterate over a stream so if callers of
>>> your example methods where doing something like this
>>>
>>> for (Employee emp : getAllEmployee()) {
>>> ...
>>> }
>>>
>>> then it would have to change to a forEach call if getAllEmployee returned a
>>> Stream.
>>
>> You can also get an Iterator from a Stream, so if you need external
>> iteration over elements of a Stream you don't have to collect it 1st to
>> some Collection:
>>
>> Stream<String> names() {
>> return Stream.of("John", "Jil", "Jack");
>> }
>>
>> ...and then...
>>
>> for (String name : (Iterable<String>) names()::iterator) {
>> System.out.println(name);
>> }
>>
>> This is hack-ish as it relies on the fact that enhanced for loop calls
>> Iterable.iterator() method only once, but is the only way to do it if
>> you already have a reference to Stream at hand. This would be more
>> correct way of doing it if you can call a factory for Stream:
>>
>> for (String name : (Iterable<String>) () -> names().iterator()) {
>> System.out.println(name);
>> }
>>
>> Regards, Peter
>>
>> P.S. I wonder why the enhanced for loop doesn't establish a context
>> where the type of expression after the colon could be inferred, so no
>> cast would be necessary. Perhaps because that type could either be an
> > Iterable<T> or a T[] ?
