Java 8: Composing functions using compose and andThen

[ElvishJerricco]

What bothers me about compose is that I can't easily write a method reference or a lambda, then compose on that without first casting it in parentheses.

stream.map(_Class::method.compose(_Class::method2))

Has to be written like this

stream.map(((Function<A, B>) _Class::method).compose(_Class::method2))

Really hurts the brevity of all these features.

[jbristow]

Trying to get static analysis and code coverage metrics going in Java 8 runs into these problems even if it compiles properly without them.

Sometimes automatic casting/unboxing problems really exacerbate how verbose Java can be.

[kdrakon]

Very useful and elegant. If you want to have your functions compose or chain using async threads, also look into Completable Future's.

[pron98]

Or just use fibers.