Sorry if I might be teaching people to suck eggs, but you can discover the
functional method of a functional interface through reflection. It’s a bit of a
lookup but presumably in groovy the results of such lookups do get cached...
I use (reassembled from something that’s a bit more broken up than this):
Optional.of(Function.class)
.filter(Class::isInterface)
.filter(c -> c.isAnnotationPresent(FunctionalInterface.class))
.stream()
.flatMap(c -> Arrays.stream(c.getMethods()))
.filter(Predicate.not(Method::isDefault)
.and(m -> !Modifier.isStatic(m.getModifiers())))
.findFirst()
.map(Method::getName);
<< Optional[public abstract java.lang.Object
java.util.function.Function.apply(java.lang.Object)]
Modify to allow any interface as long as it has only one abstract method by,
instead of the .findFirst(), go to a list or array and only use it if it’s
exactly one entry long.
--
Rachel Greenham
rac...@merus.eu
> On 29 Apr 2021, at 12:46, Christopher Smith <chry...@gmail.com> wrote:
>
> That option is not available when using, for example,
> java.util.function.Function.
>
> On Thu, Apr 29, 2021, 03:34 Angelo Schneider <angelo.schnei...@oomentor.de>
> wrote:
> Is that not already covered by the call() - method?
> I mean the option to declare a method called `Object call(args)´
> Best Regards
> Angelo
>
> ---
> Angelo Schneider
> angelo.schnei...@oomentor.de
> +49 172 9873893
>
> > Am 29.04.2021 um 02:47 schrieb Christopher Smith <chrylis+gro...@gmail.com>:
> >
> > It would be convenient to be able to use the convention of "use
> > parentheses on a function-like object" with functional interfaces; for
> > example, if a variable is declared as type Function, to have
> > `myVar(3)` run `myVar.apply(3)`. Is there any chance this would be
> > practical, or would its semantics be limited sufficiently by the
> > default-dynamic nature of Groovy to not add value?
> >
> > (I have in mind Groovy's tendency to do runtime switcheroos with
> > anything that implements Map as a counterexample, but that may be
> > beside the point.)
>
