60497f6561
Also-by: Johan Andrén <johan@markatta.com> Also-by: Roland Kuhn <rk@rkuhn.info> Also-by: Martynas Mickevičius <mmartynas@gmail.com>
59 lines
1.5 KiB
Scala
59 lines
1.5 KiB
Scala
package docs.stream.cookbook
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import akka.NotUsed
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import akka.stream.scaladsl.{ Sink, Source }
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import scala.collection.immutable
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import scala.concurrent.Await
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import scala.concurrent.duration._
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class RecipeMultiGroupBy extends RecipeSpec {
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"Recipe for multi-groupBy" must {
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"work" in {
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case class Topic(name: String)
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val elems = Source(List("1: a", "1: b", "all: c", "all: d", "1: e"))
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val extractTopics = { msg: Message =>
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if (msg.startsWith("1")) List(Topic("1"))
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else List(Topic("1"), Topic("2"))
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}
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//#multi-groupby
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val topicMapper: (Message) => immutable.Seq[Topic] = extractTopics
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val messageAndTopic: Source[(Message, Topic), NotUsed] = elems.mapConcat { msg: Message =>
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val topicsForMessage = topicMapper(msg)
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// Create a (Msg, Topic) pair for each of the topics
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// the message belongs to
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topicsForMessage.map(msg -> _)
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}
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val multiGroups = messageAndTopic
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.groupBy(2, _._2).map {
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case (msg, topic) =>
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// do what needs to be done
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//#multi-groupby
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(msg, topic)
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//#multi-groupby
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}
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//#multi-groupby
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val result = multiGroups
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.grouped(10)
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.mergeSubstreams
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.map(g => g.head._2.name + g.map(_._1).mkString("[", ", ", "]"))
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.grouped(10)
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.runWith(Sink.head)
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Await.result(result, 3.seconds).toSet should be(Set(
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"1[1: a, 1: b, all: c, all: d, 1: e]",
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"2[all: c, all: d]"))
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}
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}
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}
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