On May 2, 2015, at 11:31 PM, Remi Forax <fo...@univ-mlv.fr> wrote:
> Hi all,
> today, I stubble on a variant of JDK-8050818 [1],
> trying to call negate() on a lambda which is not yet a Predicate (due to
> target typing) which requires either to cast the lambda to a Predicate and
> everybody knows that cast are evil or to add a local variable.
>
> I think there is a way to fix that, it's not very orthodox so I let you judge.
> The idea is to introduce a static method 'of' on Predicate,
> class Predicate<T> {
> ...
> public static <T> Predicate<T> of(Predicate<T> predicate) {
> return predicate;
> }
> }
>
> so one can write:
> stream.filter(Predicate.of(String::isEmpty).negate())
> compared to
> stream.filter(((Predicate<String>)String::isEmpty).negate())
>
> so the question is, does it it worth the cost to introduce a static method
> that basically do nothing on all functional interfaces of java.util.function.
>
That does have the virtue of not adding a static method per operation but i
still cannot bring myself to add such methods as a work around for seems like a
compiler inference problem (albeit one in which might be very tricky or not
possible to solve).
In some respects i wonder if the default methods on the functional interfaces
are an attractive nuisance.
Paul.
