Using Java 8’s Optional with Stream::flatMap

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The new Java 8 stream framework and friends make for some very concise Java code, but I have come across a seemingly-simple situation that is tricky to do concisely.

Consider a List<Thing> things and method Optional<Other> resolve(Thing thing). I want to map the Things to Optional<Other>s and get the first Other.

The obvious solution would be to use things.stream().flatMap(this::resolve).findFirst(), but flatMap requires that you return a stream, and Optional doesn’t have a stream() method (or is it a Collection or provide a method to convert it to or view it as a Collection).

The best I can come up with is this:

things.stream()
    .map(this::resolve)
    .filter(Optional::isPresent)
    .map(Optional::get)
    .findFirst();

But that seems awfully long-winded for what seems like a very common case.

Anyone have a better idea?

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