Support for java.util.Optional

[buko]

Surprised that cqengine doesn't support java.util.Optional. Is the engine trying to maintain compatibility with pre-Java 1.8 code?

Would be great to see a Optional<T>:ResultSet.unique() IMO. Most Java code these days doesn't use Exceptions to indicate a missing value, java.util.Optional fills that role pretty well. As things are we spend a lot of time translating uniqueResult() into an Optional.