21381d5710
* Sink.seq (Scala DSL) now returns immutable.Seq rather than Seq * Sink.seq will not silently truncate when incoming elements is > Int.MAX_VALUE * minor doc fixes * replacing various grouped(n) / Sink.head with limit(n) / Sink.seq in various tests * fix inconsistent indentation in RequestParserSpec
59 lines
1.5 KiB
Scala
59 lines
1.5 KiB
Scala
package docs.stream.cookbook
|
|
|
|
import akka.NotUsed
|
|
import akka.stream.scaladsl.{ Sink, Source }
|
|
|
|
import scala.collection.immutable
|
|
import scala.concurrent.Await
|
|
import scala.concurrent.duration._
|
|
|
|
class RecipeMultiGroupBy extends RecipeSpec {
|
|
|
|
"Recipe for multi-groupBy" must {
|
|
|
|
"work" in {
|
|
|
|
case class Topic(name: String)
|
|
|
|
val elems = Source(List("1: a", "1: b", "all: c", "all: d", "1: e"))
|
|
val extractTopics = { msg: Message =>
|
|
if (msg.startsWith("1")) List(Topic("1"))
|
|
else List(Topic("1"), Topic("2"))
|
|
}
|
|
|
|
//#multi-groupby
|
|
val topicMapper: (Message) => immutable.Seq[Topic] = extractTopics
|
|
|
|
val messageAndTopic: Source[(Message, Topic), NotUsed] = elems.mapConcat { msg: Message =>
|
|
val topicsForMessage = topicMapper(msg)
|
|
// Create a (Msg, Topic) pair for each of the topics
|
|
// the message belongs to
|
|
topicsForMessage.map(msg -> _)
|
|
}
|
|
|
|
val multiGroups = messageAndTopic
|
|
.groupBy(2, _._2).map {
|
|
case (msg, topic) =>
|
|
// do what needs to be done
|
|
//#multi-groupby
|
|
(msg, topic)
|
|
//#multi-groupby
|
|
}
|
|
//#multi-groupby
|
|
|
|
val result = multiGroups
|
|
.grouped(10)
|
|
.mergeSubstreams
|
|
.map(g => g.head._2.name + g.map(_._1).mkString("[", ", ", "]"))
|
|
.limit(10)
|
|
.runWith(Sink.seq)
|
|
|
|
Await.result(result, 3.seconds).toSet should be(Set(
|
|
"1[1: a, 1: b, all: c, all: d, 1: e]",
|
|
"2[all: c, all: d]"))
|
|
|
|
}
|
|
|
|
}
|
|
|
|
}
|