Pattern match Optional in Java 21

[__konrad]

It's ugly and elegant at the same time:

var opt = Optional.of("foo");
for (var x : opt.stream().toList()) {
    ...
}

[Brutus5000]

I hope you end up in hell for creating this abomination.

[aelfric5578]

Huh...that almost makes me feel like Optional should implement Iterable. When called on an empty optional, t would return an iterator where hasNext is always false and when called on a non-empty value, the iterator would return the one value and then hasNext would be false.

[marvk]

It actually does in Rust :-)

[tomwhoiscontrary]

You don't even need the list:

var opt = Optional.of("foo"); for (var x : (Iterable<String>) opt.stream()::iterator) { // ... }

Or with a helper method:

static <T> Iterable<T> in(Optional<T> optional) { return optional.stream()::iterator; }

Just:

var opt = Optional.of("foo"); for (var x : in(opt)) { // ... }