CompletableFuture.anyOf metodu

Giriş
Açıklaması şöyle.

Completes when any of several CompletableFutures completes, with the same result.

Açıklaması şöyle

Waiting for any future to complete can be quickly done using  CompletableFuture#anyOf, and it handles exception propagation correctly out of the box.

However, there’s a slight complication.

If you look at the signature of  CompletableFuture#anyOf, you will see that it’s not very practical because it accepts multiple  CompletableFutures<?> and returns a single  CompletableFuture< Object> , but this is not the main issue here (just a slight inconvenience).

The real problem is that the  CompletableFuture<Object> returned by the method is not the future that completed first, but a new CompletableFuture instance that completes when any future completes.

This makes the whole idea of waiting for a future and then removing it from a list of remaining futures a bit complicated. We can’t rely on reference equality, so we can either do a linear scan after each signal from  CompletableFuture#anyOf, or try to come up with something better.