RubyEnumerator implements java.util.Iterator

[kares]

feels like a good fit and this makes enumerator usable with Java 8 (with some boilerplate) :
java.util.Spliterators.spliterator(enum.to_java, enum.size || -1, charactestistics)

... ideally some more integration would be handy but JRuby would need compiling under Java 8 for easy : [1, 2, 3, 4, 5].each.to_java.stream or Enumerator.new { ... }.to_java.spliterator implementations.
esp. since the Enumeration's size and the spliterator characteristic are depend on internals. so this would like get revisited after a potential compilation switch in another release.

Ruby enumerator (and thus Ruby array) usability with 8 streaming is confirmed with test-cases.

[kares]

... ideally some more integration would be handy but JRuby would need compiling under Java 8 for easy : [1, 2, 3, 4, 5].each.to_java.stream or Enumerator.new { ... }.to_java.spliterator implementations.
esp. since the Enumeration's size and the spliterator characteristic are depend on internals. so this would like get revisited after a potential compilation switch in another release.

also possible by hooking up stream/spliterator on org.jruby.RubyEnumerator (in plain .rb for now)

// cc @headius @enebo let me know what do you think about getting this merged for 9.1.3

[headius]

@kares 👍 from me. @enebo?

[kares]

thanks for the review, have added the .rb part helpers (under Java 8) spliterator and stream since due compilation under Java 7 those can not be implemented in org.jruby.RubyEnumerator atm

[enebo]

@kares looks fine by me