raboof/pekko
1
0
Fork 0
Code Issues Pull requests Projects Releases 6 Packages Wiki Activity Actions 10

Add basic documentation to Futures.{sequence,traverse}

Browse source
This commit is contained in:
Derek Williams 2011-04-03 10:40:06 -06:00
parent 1d69665bb8
commit 27009707d9
1 changed files with 8 additions and 2 deletions
Download patch file Download diff file Expand all files Collapse all files

10
akka-actor/src/main/scala/akka/dispatch/Future.scala
View file

@ -156,13 +156,19 @@ object Futures {
import scala.collection.generic.CanBuildFrom
/**
* FIXME document Futures.sequence
* Simple version of Futures.traverse. Transforms a Traversable[Future[A]] into a Future[Traversable[A]].
* Useful for reducing many Futures into a single Future.
*/
def sequence[A, M[_] <: Traversable[_]](in: M[Future[A]], timeout: Long = Actor.TIMEOUT)(implicit cbf: CanBuildFrom[M[Future[A]], A, M[A]]): Future[M[A]] =
in.foldLeft(new DefaultCompletableFuture[Builder[A, M[A]]](timeout).completeWithResult(cbf(in)): Future[Builder[A, M[A]]])((fr, fa) => for (r <- fr; a <- fa.asInstanceOf[Future[A]]) yield (r += a)).map(_.result)
/**
* FIXME document Futures.traverse
* Transforms a Traversable[A] into a Future[Traversable[B]] using the provided Function A => Future[B].
* This is useful for performing a parallel map. For example, to apply a function to all items of a list
* in parallel:
* <pre>
* val myFutureList = Futures.traverse(myList)(x => Future(myFunc(x)))
* </pre>
*/
def traverse[A, B, M[_] <: Traversable[_]](in: M[A], timeout: Long = Actor.TIMEOUT)(fn: A => Future[B])(implicit cbf: CanBuildFrom[M[A], B, M[B]]): Future[M[B]] =
in.foldLeft(new DefaultCompletableFuture[Builder[B, M[B]]](timeout).completeWithResult(cbf(in)): Future[Builder[B, M[B]]]) { (fr, a) =>