mergePrioritized

Merge multiple sources.

Fan-in operators

Signature

Source.mergePrioritizedSource.mergePrioritized Flow.mergePrioritizedFlow.mergePrioritized

Description

Merge multiple sources. Prefer sources depending on priorities if all sources have elements ready. If a subset of all sources have elements ready the relative priorities for those sources are used to prioritize. For example, when used with only two sources, the left source has a probability of (leftPriority) / (leftPriority + rightPriority) of being prioritized and similarly for the right source. The priorities for each source must be positive integers.

Example

Scala

copysourceimport org.apache.pekko.stream.scaladsl.{ Sink, Source }

val sourceA = Source(List(1, 2, 3, 4))
val sourceB = Source(List(10, 20, 30, 40))

sourceA.mergePrioritized(sourceB, 99, 1).runWith(Sink.foreach(println))
// prints e.g. 1, 10, 2, 3, 4, 20, 30, 40 since both sources have their first element ready and the left source
// has higher priority – if both sources have elements ready, sourceA has a 99% chance of being picked next
// while sourceB has a 1% chance

Java

copysourceSource<Integer, NotUsed> sourceA = Source.from(Arrays.asList(1, 2, 3, 4));
Source<Integer, NotUsed> sourceB = Source.from(Arrays.asList(10, 20, 30, 40));

sourceA.mergePrioritized(sourceB, 99, 1, false).runForeach(System.out::println, system);
// prints e.g. 1, 10, 2, 3, 4, 20, 30, 40 since both sources have their first element ready and
// the left source has higher priority – if both sources have elements ready, sourceA has a
// 99% chance of being picked next while sourceB has a 1% chance

Reactive Streams semantics