akka.stream.scaladsl

Interface SubFlow<Out,Mat,F,C>

All Superinterfaces:

FlowOps<Out,Mat>

All Known Implementing Classes:

SubFlowImpl

public interface SubFlow<Out,Mat,F,C>
extends FlowOps<Out,Mat>

A &ldquo;stream of streams&rdquo; sub-flow of data elements, e.g. produced by groupBy. SubFlows cannot contribute to the super-flow&rsquo;s materialized value since they are materialized later, during the runtime of the flow graph processing.

Method Summary

Modifier and Type	Method and Description
F	concatSubstreams() Flatten the sub-flows back into the super-flow by concatenating them.
F	mergeSubstreams() Flatten the sub-flows back into the super-flow by performing a merge without parallelism limit (i.e.
F	mergeSubstreamsWithParallelism(int parallelism) Flatten the sub-flows back into the super-flow by performing a merge with the given parallelism limit.
<M> C	to(Graph<SinkShape<Out>,M> sink) Attach a Sink to each sub-flow, closing the overall Graph that is being constructed.

Methods inherited from interface akka.stream.scaladsl.FlowOps

addAttributes, alsoTo, alsoToGraph, andThen, async, backpressureTimeout, batch, batchWeighted, buffer, collect, completionTimeout, concat, concatGraph, conflate, conflateWithSeed, delay, detach, drop, dropWhile, dropWithin, expand, filter, filterNot, flatMapConcat, flatMapMerge, fold, foldAsync, groupBy, grouped, groupedWithin, idleTimeout, initialDelay, initialTimeout, interleave, interleaveGraph, intersperse, intersperse, keepAlive, limit, limitWeighted, log, map, mapAsync, mapAsyncUnordered, mapConcat, mapError, merge, mergeGraph, mergeSorted, mergeSortedGraph, named, orElse, orElseGraph, prefixAndTail, prepend, prependGraph, recover, recoverWith, recoverWithRetries, reduce, scan, scanAsync, sliding, splitAfter, splitAfter, splitWhen, splitWhen, statefulMapConcat, take, takeWhile, takeWhile, takeWithin, throttle, throttle, transform, via, withAttributes, zip, zipGraph, zipWith, zipWithGraph, zipWithIndex

Method Detail

to

<M> C to(Graph<SinkShape<Out>,M> sink)

Attach a Sink to each sub-flow, closing the overall Graph that is being constructed.

Specified by:

to in interface FlowOps<Out,Mat>

Parameters:

sink - (undocumented)

Returns:

(undocumented)

mergeSubstreams

F mergeSubstreams()

Flatten the sub-flows back into the super-flow by performing a merge without parallelism limit (i.e. having an unbounded number of sub-flows active concurrently).

This is identical in effect to mergeSubstreamsWithParallelism(Integer.MAX_VALUE).

Returns:

(undocumented)

mergeSubstreamsWithParallelism

F mergeSubstreamsWithParallelism(int parallelism)

Flatten the sub-flows back into the super-flow by performing a merge with the given parallelism limit. This means that only up to parallelism substreams will be executed at any given time. Substreams that are not yet executed are also not materialized, meaning that back-pressure will be exerted at the operator that creates the substreams when the parallelism limit is reached.

Parameters:

parallelism - (undocumented)

Returns:

(undocumented)

concatSubstreams

F concatSubstreams()

Flatten the sub-flows back into the super-flow by concatenating them. This is usually a bad idea when combined with groupBy since it can easily lead to deadlock—the concatenation does not consume from the second substream until the first has finished and the groupBy stage will get back-pressure from the second stream.

This is identical in effect to mergeSubstreamsWithParallelism(1).

Returns:

(undocumented)