Reputation: 3972
I do not understand why Scala's Future
is harder to use and has less functionality than Twitters, while the first has been created after the second. So, here are questions about scala.concurrent.Future
:
Future.onComplete
return Unit
instead of Future
? Composable methods are much more convenient.Future
not support cancellation?Upvotes: 3
Views: 169
Reputation: 2377
Future.onComplete
returns a unit, so the invocations cannot be chained. According to the scala docs, "note that this design is intentional, to avoid suggesting that chained invocations may imply an ordering on the execution of the registered callbacks (callbacks registered on the same future are unordered)."
To compose the future, use combinators like flatMap
, andThen
, and filter
, which all return a Future.
Check out http://docs.scala-lang.org/overviews/core/futures.html#functional-composition-and-for-comprehensions for more details
I think cancellation is quite nuanced. See this discussion for more details: How to cancel Future in Scala?
Upvotes: 6