package scaladsl
Scala API: The flow DSL allows the formulation of stream transformations based on some input. The starting point is called Source and can be a collection, an iterator, a block of code which is evaluated repeatedly or a org.reactivestreams.Publisher. A flow with an attached input and open output is also a Source.
A flow may also be defined without an attached input or output and that is then
a Flow. The Flow
can be connected to the Source
later by using Source#via with
the flow as argument, and it remains a Source.
Transformations can be appended to Source
and Flow
with the operations
defined in FlowOps. Each DSL element produces a new flow that can be further transformed,
building up a description of the complete transformation pipeline.
The termination point of a flow is called Sink and can for example be a Future
or
org.reactivestreams.Subscriber. A flow with an attached output and open input
is also a Sink.
If a flow has both an attached input and an attached output it becomes a RunnableGraph. In order to execute this pipeline the flow must be materialized by calling RunnableGraph#run on it.
You can create your Source
, Flow
and Sink
in any order and then wire them together before
they are materialized by connecting them using Flow#via and Flow#to, or connecting them into a
GraphDSL with fan-in and fan-out elements.
See Reactive Streams for details on org.reactivestreams.Publisher and org.reactivestreams.Subscriber.
It should be noted that the streams modeled by this library are “hot”, meaning that they asynchronously flow through a series of processors without detailed control by the user. In particular it is not predictable how many elements a given transformation step might buffer before handing elements downstream, which means that transformation functions may be invoked more often than for corresponding transformations on strict collections like List. *An important consequence* is that elements that were produced into a stream may be discarded by later processors, e.g. when using the #take operator.
By default every operation is executed within its own org.apache.pekko.actor.Actor to enable full pipelining of the chained set of computations. This behavior is determined by the org.apache.pekko.stream.Materializer which is required by those methods that materialize the Flow into a series of org.reactivestreams.Processor instances. The returned reactive stream is fully started and active.
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- final class Balance[T] extends GraphStage[UniformFanOutShape[T, T]]
Fan-out the stream to several streams.
Fan-out the stream to several streams. Each upstream element is emitted to the first available downstream consumer. It will not shut down until the subscriptions for at least two downstream subscribers have been established.
A
Balance
has onein
port and 2 or moreout
ports.Emits when any of the outputs stops backpressuring; emits the element to the first available output
Backpressures when all of the outputs backpressure
Completes when upstream completes
Cancels when If eagerCancel is enabled: when any downstream cancels; otherwise: when all downstreams cancel
- final class BidiFlow[-I1, +O1, -I2, +O2, +Mat] extends Graph[BidiShape[I1, O1, I2, O2], Mat]
- final class Broadcast[T] extends GraphStage[UniformFanOutShape[T, T]]
Fan-out the stream to several streams emitting each incoming upstream element to all downstream consumers.
Fan-out the stream to several streams emitting each incoming upstream element to all downstream consumers. It will not shut down until the subscriptions for at least two downstream subscribers have been established.
Emits when all of the outputs stops backpressuring and there is an input element available
Backpressures when any of the outputs backpressure
Completes when upstream completes
Cancels when If eagerCancel is enabled: when any downstream cancels; otherwise: when all downstreams cancel
- final class Concat[T] extends GraphStage[UniformFanInShape[T, T]]
Takes multiple streams and outputs one stream formed from the input streams by first emitting all of the elements from the first stream and then emitting all of the elements from the second stream, etc.
Takes multiple streams and outputs one stream formed from the input streams by first emitting all of the elements from the first stream and then emitting all of the elements from the second stream, etc.
A
Concat
has onefirst
port, onesecond
port and oneout
port.Emits when the current stream has an element available; if the current input completes, it tries the next one
Backpressures when downstream backpressures
Completes when all upstreams complete
Cancels when downstream cancels
- trait DelayStrategy[-T] extends AnyRef
Allows to manage delay.
Allows to manage delay. Can be stateful to compute delay for any sequence of elements, as instances are not shared among running streams and all elements go through nextDelay(), updating state and returning delay for that element.
- final class Flow[-In, +Out, +Mat] extends FlowOpsMat[Out, Mat] with Graph[FlowShape[In, Out], Mat]
A
Flow
is a set of stream processing steps that has one open input and one open output. - trait FlowOps[+Out, +Mat] extends AnyRef
Scala API: Operations offered by Sources and Flows with a free output side: the DSL flows left-to-right only.
Scala API: Operations offered by Sources and Flows with a free output side: the DSL flows left-to-right only.
INTERNAL API: this trait will be changed in binary-incompatible ways for classes that are derived from it! Do not implement this interface outside the Pekko code base!
Binary compatibility is only maintained for callers of this trait’s interface.
- Annotations
- @DoNotInherit() @ccompatUsedUntil213()
- trait FlowOpsMat[+Out, +Mat] extends FlowOps[Out, Mat]
INTERNAL API: this trait will be changed in binary-incompatible ways for classes that are derived from it! Do not implement this interface outside the Pekko code base!
INTERNAL API: this trait will be changed in binary-incompatible ways for classes that are derived from it! Do not implement this interface outside the Pekko code base!
Binary compatibility is only maintained for callers of this trait’s interface.
- final class FlowWithContext[-In, -CtxIn, +Out, +CtxOut, +Mat] extends GraphDelegate[FlowShape[(In, CtxIn), (Out, CtxOut)], Mat] with FlowWithContextOps[Out, CtxOut, Mat]
A flow that provides operations which automatically propagate the context of an element.
A flow that provides operations which automatically propagate the context of an element. Only a subset of common operations from FlowOps is supported. As an escape hatch you can use FlowWithContextOps.via to manually provide the context propagation for otherwise unsupported operations.
An "empty" flow can be created by calling
FlowWithContext[Ctx, T]
. - trait FlowWithContextOps[+Out, +Ctx, +Mat] extends AnyRef
Shared stream operations for FlowWithContext and SourceWithContext that automatically propagate a context element with each data element.
Shared stream operations for FlowWithContext and SourceWithContext that automatically propagate a context element with each data element.
- Annotations
- @ccompatUsedUntil213()
- trait GraphApply extends AnyRef
- final class Interleave[T] extends GraphStage[UniformFanInShape[T, T]]
Interleave represents deterministic merge which takes N elements per input stream, in-order of inputs, emits them downstream and then cycles/"wraps-around" the inputs.
Interleave represents deterministic merge which takes N elements per input stream, in-order of inputs, emits them downstream and then cycles/"wraps-around" the inputs.
Emits when element is available from current input (depending on phase)
Backpressures when downstream backpressures
Completes when all upstreams complete (eagerClose=false) or one upstream completes (eagerClose=true)
Cancels when downstream cancels
- final class Merge[T] extends GraphStage[UniformFanInShape[T, T]]
Merge several streams, taking elements as they arrive from input streams (picking randomly when several have elements ready).
Merge several streams, taking elements as they arrive from input streams (picking randomly when several have elements ready).
Emits when one of the inputs has an element available
Backpressures when downstream backpressures
Completes when all upstreams complete (eagerComplete=false) or one upstream completes (eagerComplete=true), default value is
false
Cancels when downstream cancels
- final class MergeLatest[T, M] extends GraphStage[UniformFanInShape[T, M]]
- final class MergePreferred[T] extends GraphStage[MergePreferredShape[T]]
Merge several streams, taking elements as they arrive from input streams (picking from preferred when several have elements ready).
Merge several streams, taking elements as they arrive from input streams (picking from preferred when several have elements ready).
A
MergePreferred
has oneout
port, onepreferred
input port and 1 or more secondaryin
ports.Emits when one of the inputs has an element available, preferring a specified input if multiple have elements available
Backpressures when downstream backpressures
Completes when all upstreams complete (eagerComplete=false) or one upstream completes (eagerComplete=true), default value is
false
Cancels when downstream cancels
- final class MergePrioritized[T] extends GraphStage[UniformFanInShape[T, T]]
Merge several streams, taking elements as they arrive from input streams (picking from prioritized once when several have elements ready).
Merge several streams, taking elements as they arrive from input streams (picking from prioritized once when several have elements ready).
A
MergePrioritized
has oneout
port, one or more input port with their priorities.Emits when one of the inputs has an element available, preferring a input based on its priority if multiple have elements available
Backpressures when downstream backpressures
Completes when all upstreams complete (eagerComplete=false) or one upstream completes (eagerComplete=true), default value is
false
Cancels when downstream cancels
- final class MergeSequence[T] extends GraphStage[UniformFanInShape[T, T]]
Takes multiple streams whose elements in aggregate have a defined linear sequence with difference 1, starting at 0, and outputs a single stream containing these elements, in order.
Takes multiple streams whose elements in aggregate have a defined linear sequence with difference 1, starting at 0, and outputs a single stream containing these elements, in order. That is, given a set of input streams with combined elements *ek*:
*e0*, *e1*, *e2*, ..., *en*
This will output a stream ordered by *k*.
The elements in the input streams must already be sorted according to the sequence. The input streams do not need to be linear, but the aggregate stream must be linear, no element *k* may be skipped or duplicated, either of these conditions will cause the stream to fail.
The typical use case for this is to merge a partitioned stream back together while maintaining order. This can be achieved by first using
zipWithIndex
on the input stream, then partitioning using a Partition fanout, and then maintaining the index through the processing of each partition before bringing together with this stage.Emits when one of the upstreams has the next expected element in the sequence available.
Backpressures when downstream backpressures
Completes when all upstreams complete
Cancels when downstream cancels
- final class MergeSorted[T] extends GraphStage[FanInShape2[T, T, T]]
Merge two pre-sorted streams such that the resulting stream is sorted.
Merge two pre-sorted streams such that the resulting stream is sorted.
Emits when both inputs have an element available
Backpressures when downstream backpressures
Completes when all upstreams complete
Cancels when downstream cancels
- final class Partition[T] extends GraphStage[UniformFanOutShape[T, T]]
Fan-out the stream to several streams.
Fan-out the stream to several streams. emitting an incoming upstream element to one downstream consumer according to the partitioner function applied to the element
Adheres to the ActorAttributes.SupervisionStrategy attribute.
Emits when emits when an element is available from the input and the chosen output has demand
Backpressures when the currently chosen output back-pressures
Completes when upstream completes and no output is pending
Cancels when all downstreams have cancelled (eagerCancel=false) or one downstream cancels (eagerCancel=true)
- final case class RunnableGraph[+Mat](traversalBuilder: TraversalBuilder) extends Graph[ClosedShape, Mat] with Product with Serializable
Flow with attached input and output, can be executed.
- trait ScalaSessionAPI extends AnyRef
Allows access to an SSLSession with Scala types
- final class Sink[-In, +Mat] extends Graph[SinkShape[In], Mat]
A
Sink
is a set of stream processing steps that has one open input.A
Sink
is a set of stream processing steps that has one open input. Can be used as aSubscriber
- trait SinkQueue[T] extends AnyRef
This trait allows to have a queue as a sink for a stream.
This trait allows to have a queue as a sink for a stream. A SinkQueue pulls data from a stream with a backpressure mechanism.
- trait SinkQueueWithCancel[T] extends SinkQueue[T]
This trait adds cancel support to SinkQueue.
- implicit final class SinkToCompletionStage[In, T] extends AnyVal
- final class Source[+Out, +Mat] extends FlowOpsMat[Out, Mat] with Graph[SourceShape[Out], Mat]
A
Source
is a set of stream processing steps that has one open output.A
Source
is a set of stream processing steps that has one open output. It can comprise any number of internal sources and transformations that are wired together, or it can be an “atomic” source, e.g. from a collection or a file. Materialization turns a Source into a Reactive StreamsPublisher
(at least conceptually). - trait SourceQueue[T] extends AnyRef
This trait allows to have a queue as a data source for some stream.
- trait SourceQueueWithComplete[T] extends SourceQueue[T]
This trait adds completion support to SourceQueue.
- implicit final class SourceToCompletionStage[Out, T] extends AnyVal
- final class SourceWithContext[+Out, +Ctx, +Mat] extends GraphDelegate[SourceShape[(Out, Ctx)], Mat] with FlowWithContextOps[Out, Ctx, Mat]
A source that provides operations which automatically propagate the context of an element.
A source that provides operations which automatically propagate the context of an element. Only a subset of common operations from FlowOps is supported. As an escape hatch you can use FlowWithContextOps.via to manually provide the context propagation for otherwise unsupported operations.
Can be created by calling Source.asSourceWithContext
- trait SubFlow[+Out, +Mat, +F[+_], C] extends FlowOps[Out, Mat]
A “stream of streams” sub-flow of data elements, e.g.
A “stream of streams” sub-flow of data elements, e.g. produced by
groupBy
. SubFlows cannot contribute to the super-flow’s materialized value since they are materialized later, during the runtime of the flow graph processing. - final class Tcp extends Extension
- final class TcpIdleTimeoutException extends TimeoutException with NoStackTrace
- final class Unzip[A, B] extends UnzipWith2[(A, B), A, B]
Takes a stream of pair elements and splits each pair to two output streams.
Takes a stream of pair elements and splits each pair to two output streams.
An
Unzip
has onein
port and oneleft
and oneright
output port.Emits when all of the outputs stop backpressuring and there is an input element available
Backpressures when any of the outputs backpressure
Completes when upstream completes
Cancels when any downstream cancels
- class UnzipWith10[In, A1, A2, A3, A4, A5, A6, A7, A8, A9, A10] extends GraphStage[FanOutShape10[In, A1, A2, A3, A4, A5, A6, A7, A8, A9, A10]]
UnzipWith
specialized for 10 outputs - class UnzipWith11[In, A1, A2, A3, A4, A5, A6, A7, A8, A9, A10, A11] extends GraphStage[FanOutShape11[In, A1, A2, A3, A4, A5, A6, A7, A8, A9, A10, A11]]
UnzipWith
specialized for 11 outputs - class UnzipWith12[In, A1, A2, A3, A4, A5, A6, A7, A8, A9, A10, A11, A12] extends GraphStage[FanOutShape12[In, A1, A2, A3, A4, A5, A6, A7, A8, A9, A10, A11, A12]]
UnzipWith
specialized for 12 outputs - class UnzipWith13[In, A1, A2, A3, A4, A5, A6, A7, A8, A9, A10, A11, A12, A13] extends GraphStage[FanOutShape13[In, A1, A2, A3, A4, A5, A6, A7, A8, A9, A10, A11, A12, A13]]
UnzipWith
specialized for 13 outputs - class UnzipWith14[In, A1, A2, A3, A4, A5, A6, A7, A8, A9, A10, A11, A12, A13, A14] extends GraphStage[FanOutShape14[In, A1, A2, A3, A4, A5, A6, A7, A8, A9, A10, A11, A12, A13, A14]]
UnzipWith
specialized for 14 outputs - class UnzipWith15[In, A1, A2, A3, A4, A5, A6, A7, A8, A9, A10, A11, A12, A13, A14, A15] extends GraphStage[FanOutShape15[In, A1, A2, A3, A4, A5, A6, A7, A8, A9, A10, A11, A12, A13, A14, A15]]
UnzipWith
specialized for 15 outputs - class UnzipWith16[In, A1, A2, A3, A4, A5, A6, A7, A8, A9, A10, A11, A12, A13, A14, A15, A16] extends GraphStage[FanOutShape16[In, A1, A2, A3, A4, A5, A6, A7, A8, A9, A10, A11, A12, A13, A14, A15, A16]]
UnzipWith
specialized for 16 outputs - class UnzipWith17[In, A1, A2, A3, A4, A5, A6, A7, A8, A9, A10, A11, A12, A13, A14, A15, A16, A17] extends GraphStage[FanOutShape17[In, A1, A2, A3, A4, A5, A6, A7, A8, A9, A10, A11, A12, A13, A14, A15, A16, A17]]
UnzipWith
specialized for 17 outputs - class UnzipWith18[In, A1, A2, A3, A4, A5, A6, A7, A8, A9, A10, A11, A12, A13, A14, A15, A16, A17, A18] extends GraphStage[FanOutShape18[In, A1, A2, A3, A4, A5, A6, A7, A8, A9, A10, A11, A12, A13, A14, A15, A16, A17, A18]]
UnzipWith
specialized for 18 outputs - class UnzipWith19[In, A1, A2, A3, A4, A5, A6, A7, A8, A9, A10, A11, A12, A13, A14, A15, A16, A17, A18, A19] extends GraphStage[FanOutShape19[In, A1, A2, A3, A4, A5, A6, A7, A8, A9, A10, A11, A12, A13, A14, A15, A16, A17, A18, A19]]
UnzipWith
specialized for 19 outputs - class UnzipWith2[In, A1, A2] extends GraphStage[FanOutShape2[In, A1, A2]]
UnzipWith
specialized for 2 outputs - class UnzipWith20[In, A1, A2, A3, A4, A5, A6, A7, A8, A9, A10, A11, A12, A13, A14, A15, A16, A17, A18, A19, A20] extends GraphStage[FanOutShape20[In, A1, A2, A3, A4, A5, A6, A7, A8, A9, A10, A11, A12, A13, A14, A15, A16, A17, A18, A19, A20]]
UnzipWith
specialized for 20 outputs - class UnzipWith21[In, A1, A2, A3, A4, A5, A6, A7, A8, A9, A10, A11, A12, A13, A14, A15, A16, A17, A18, A19, A20, A21] extends GraphStage[FanOutShape21[In, A1, A2, A3, A4, A5, A6, A7, A8, A9, A10, A11, A12, A13, A14, A15, A16, A17, A18, A19, A20, A21]]
UnzipWith
specialized for 21 outputs - class UnzipWith22[In, A1, A2, A3, A4, A5, A6, A7, A8, A9, A10, A11, A12, A13, A14, A15, A16, A17, A18, A19, A20, A21, A22] extends GraphStage[FanOutShape22[In, A1, A2, A3, A4, A5, A6, A7, A8, A9, A10, A11, A12, A13, A14, A15, A16, A17, A18, A19, A20, A21, A22]]
UnzipWith
specialized for 22 outputs - class UnzipWith3[In, A1, A2, A3] extends GraphStage[FanOutShape3[In, A1, A2, A3]]
UnzipWith
specialized for 3 outputs - class UnzipWith4[In, A1, A2, A3, A4] extends GraphStage[FanOutShape4[In, A1, A2, A3, A4]]
UnzipWith
specialized for 4 outputs - class UnzipWith5[In, A1, A2, A3, A4, A5] extends GraphStage[FanOutShape5[In, A1, A2, A3, A4, A5]]
UnzipWith
specialized for 5 outputs - class UnzipWith6[In, A1, A2, A3, A4, A5, A6] extends GraphStage[FanOutShape6[In, A1, A2, A3, A4, A5, A6]]
UnzipWith
specialized for 6 outputs - class UnzipWith7[In, A1, A2, A3, A4, A5, A6, A7] extends GraphStage[FanOutShape7[In, A1, A2, A3, A4, A5, A6, A7]]
UnzipWith
specialized for 7 outputs - class UnzipWith8[In, A1, A2, A3, A4, A5, A6, A7, A8] extends GraphStage[FanOutShape8[In, A1, A2, A3, A4, A5, A6, A7, A8]]
UnzipWith
specialized for 8 outputs - class UnzipWith9[In, A1, A2, A3, A4, A5, A6, A7, A8, A9] extends GraphStage[FanOutShape9[In, A1, A2, A3, A4, A5, A6, A7, A8, A9]]
UnzipWith
specialized for 9 outputs - trait UnzipWithApply extends AnyRef
- final class Zip[A, B] extends ZipWith2[A, B, (A, B)]
Combine the elements of 2 streams into a stream of tuples.
Combine the elements of 2 streams into a stream of tuples.
A
Zip
has aleft
and aright
input port and oneout
portEmits when all of the inputs has an element available
Backpressures when downstream backpressures
Completes when any upstream completes
Cancels when downstream cancels
- final class ZipLatest[A, B] extends ZipLatestWith2[A, B, (A, B)]
Combine the elements of 2 streams into a stream of tuples, picking always the latest element of each.
Combine the elements of 2 streams into a stream of tuples, picking always the latest element of each.
A
ZipLatest
has aleft
and aright
input port and oneout
port.No element is emitted until at least one element from each Source becomes available.
Emits when all of the inputs have at least an element available, and then each time an element becomes * available on either of the inputs
Backpressures when downstream backpressures
Completes when any upstream completes if
eagerComplete
is enabled or wait for all upstreams to completeCancels when downstream cancels
- class ZipLatestWith10[A1, A2, A3, A4, A5, A6, A7, A8, A9, A10, O] extends GraphStage[FanInShape10[A1, A2, A3, A4, A5, A6, A7, A8, A9, A10, O]]
ZipLatestWith
specialized for 10 inputs - class ZipLatestWith11[A1, A2, A3, A4, A5, A6, A7, A8, A9, A10, A11, O] extends GraphStage[FanInShape11[A1, A2, A3, A4, A5, A6, A7, A8, A9, A10, A11, O]]
ZipLatestWith
specialized for 11 inputs - class ZipLatestWith12[A1, A2, A3, A4, A5, A6, A7, A8, A9, A10, A11, A12, O] extends GraphStage[FanInShape12[A1, A2, A3, A4, A5, A6, A7, A8, A9, A10, A11, A12, O]]
ZipLatestWith
specialized for 12 inputs - class ZipLatestWith13[A1, A2, A3, A4, A5, A6, A7, A8, A9, A10, A11, A12, A13, O] extends GraphStage[FanInShape13[A1, A2, A3, A4, A5, A6, A7, A8, A9, A10, A11, A12, A13, O]]
ZipLatestWith
specialized for 13 inputs - class ZipLatestWith14[A1, A2, A3, A4, A5, A6, A7, A8, A9, A10, A11, A12, A13, A14, O] extends GraphStage[FanInShape14[A1, A2, A3, A4, A5, A6, A7, A8, A9, A10, A11, A12, A13, A14, O]]
ZipLatestWith
specialized for 14 inputs - class ZipLatestWith15[A1, A2, A3, A4, A5, A6, A7, A8, A9, A10, A11, A12, A13, A14, A15, O] extends GraphStage[FanInShape15[A1, A2, A3, A4, A5, A6, A7, A8, A9, A10, A11, A12, A13, A14, A15, O]]
ZipLatestWith
specialized for 15 inputs - class ZipLatestWith16[A1, A2, A3, A4, A5, A6, A7, A8, A9, A10, A11, A12, A13, A14, A15, A16, O] extends GraphStage[FanInShape16[A1, A2, A3, A4, A5, A6, A7, A8, A9, A10, A11, A12, A13, A14, A15, A16, O]]
ZipLatestWith
specialized for 16 inputs - class ZipLatestWith17[A1, A2, A3, A4, A5, A6, A7, A8, A9, A10, A11, A12, A13, A14, A15, A16, A17, O] extends GraphStage[FanInShape17[A1, A2, A3, A4, A5, A6, A7, A8, A9, A10, A11, A12, A13, A14, A15, A16, A17, O]]
ZipLatestWith
specialized for 17 inputs - class ZipLatestWith18[A1, A2, A3, A4, A5, A6, A7, A8, A9, A10, A11, A12, A13, A14, A15, A16, A17, A18, O] extends GraphStage[FanInShape18[A1, A2, A3, A4, A5, A6, A7, A8, A9, A10, A11, A12, A13, A14, A15, A16, A17, A18, O]]
ZipLatestWith
specialized for 18 inputs - class ZipLatestWith19[A1, A2, A3, A4, A5, A6, A7, A8, A9, A10, A11, A12, A13, A14, A15, A16, A17, A18, A19, O] extends GraphStage[FanInShape19[A1, A2, A3, A4, A5, A6, A7, A8, A9, A10, A11, A12, A13, A14, A15, A16, A17, A18, A19, O]]
ZipLatestWith
specialized for 19 inputs - class ZipLatestWith2[A1, A2, O] extends GraphStage[FanInShape2[A1, A2, O]]
ZipLatestWith
specialized for 2 inputs - class ZipLatestWith20[A1, A2, A3, A4, A5, A6, A7, A8, A9, A10, A11, A12, A13, A14, A15, A16, A17, A18, A19, A20, O] extends GraphStage[FanInShape20[A1, A2, A3, A4, A5, A6, A7, A8, A9, A10, A11, A12, A13, A14, A15, A16, A17, A18, A19, A20, O]]
ZipLatestWith
specialized for 20 inputs - class ZipLatestWith21[A1, A2, A3, A4, A5, A6, A7, A8, A9, A10, A11, A12, A13, A14, A15, A16, A17, A18, A19, A20, A21, O] extends GraphStage[FanInShape21[A1, A2, A3, A4, A5, A6, A7, A8, A9, A10, A11, A12, A13, A14, A15, A16, A17, A18, A19, A20, A21, O]]
ZipLatestWith
specialized for 21 inputs - class ZipLatestWith22[A1, A2, A3, A4, A5, A6, A7, A8, A9, A10, A11, A12, A13, A14, A15, A16, A17, A18, A19, A20, A21, A22, O] extends GraphStage[FanInShape22[A1, A2, A3, A4, A5, A6, A7, A8, A9, A10, A11, A12, A13, A14, A15, A16, A17, A18, A19, A20, A21, A22, O]]
ZipLatestWith
specialized for 22 inputs - class ZipLatestWith3[A1, A2, A3, O] extends GraphStage[FanInShape3[A1, A2, A3, O]]
ZipLatestWith
specialized for 3 inputs - class ZipLatestWith4[A1, A2, A3, A4, O] extends GraphStage[FanInShape4[A1, A2, A3, A4, O]]
ZipLatestWith
specialized for 4 inputs - class ZipLatestWith5[A1, A2, A3, A4, A5, O] extends GraphStage[FanInShape5[A1, A2, A3, A4, A5, O]]
ZipLatestWith
specialized for 5 inputs - class ZipLatestWith6[A1, A2, A3, A4, A5, A6, O] extends GraphStage[FanInShape6[A1, A2, A3, A4, A5, A6, O]]
ZipLatestWith
specialized for 6 inputs - class ZipLatestWith7[A1, A2, A3, A4, A5, A6, A7, O] extends GraphStage[FanInShape7[A1, A2, A3, A4, A5, A6, A7, O]]
ZipLatestWith
specialized for 7 inputs - class ZipLatestWith8[A1, A2, A3, A4, A5, A6, A7, A8, O] extends GraphStage[FanInShape8[A1, A2, A3, A4, A5, A6, A7, A8, O]]
ZipLatestWith
specialized for 8 inputs - class ZipLatestWith9[A1, A2, A3, A4, A5, A6, A7, A8, A9, O] extends GraphStage[FanInShape9[A1, A2, A3, A4, A5, A6, A7, A8, A9, O]]
ZipLatestWith
specialized for 9 inputs - trait ZipLatestWithApply extends AnyRef
- final class ZipN[A] extends ZipWithN[A, Seq[A]]
Combine the elements of multiple streams into a stream of sequences.
Combine the elements of multiple streams into a stream of sequences.
A
ZipN
has an
input ports and oneout
portEmits when all of the inputs has an element available
Backpressures when downstream backpressures
Completes when any upstream completes
Cancels when downstream cancels
- class ZipWith10[A1, A2, A3, A4, A5, A6, A7, A8, A9, A10, O] extends GraphStage[FanInShape10[A1, A2, A3, A4, A5, A6, A7, A8, A9, A10, O]]
ZipWith
specialized for 10 inputs - class ZipWith11[A1, A2, A3, A4, A5, A6, A7, A8, A9, A10, A11, O] extends GraphStage[FanInShape11[A1, A2, A3, A4, A5, A6, A7, A8, A9, A10, A11, O]]
ZipWith
specialized for 11 inputs - class ZipWith12[A1, A2, A3, A4, A5, A6, A7, A8, A9, A10, A11, A12, O] extends GraphStage[FanInShape12[A1, A2, A3, A4, A5, A6, A7, A8, A9, A10, A11, A12, O]]
ZipWith
specialized for 12 inputs - class ZipWith13[A1, A2, A3, A4, A5, A6, A7, A8, A9, A10, A11, A12, A13, O] extends GraphStage[FanInShape13[A1, A2, A3, A4, A5, A6, A7, A8, A9, A10, A11, A12, A13, O]]
ZipWith
specialized for 13 inputs - class ZipWith14[A1, A2, A3, A4, A5, A6, A7, A8, A9, A10, A11, A12, A13, A14, O] extends GraphStage[FanInShape14[A1, A2, A3, A4, A5, A6, A7, A8, A9, A10, A11, A12, A13, A14, O]]
ZipWith
specialized for 14 inputs - class ZipWith15[A1, A2, A3, A4, A5, A6, A7, A8, A9, A10, A11, A12, A13, A14, A15, O] extends GraphStage[FanInShape15[A1, A2, A3, A4, A5, A6, A7, A8, A9, A10, A11, A12, A13, A14, A15, O]]
ZipWith
specialized for 15 inputs - class ZipWith16[A1, A2, A3, A4, A5, A6, A7, A8, A9, A10, A11, A12, A13, A14, A15, A16, O] extends GraphStage[FanInShape16[A1, A2, A3, A4, A5, A6, A7, A8, A9, A10, A11, A12, A13, A14, A15, A16, O]]
ZipWith
specialized for 16 inputs - class ZipWith17[A1, A2, A3, A4, A5, A6, A7, A8, A9, A10, A11, A12, A13, A14, A15, A16, A17, O] extends GraphStage[FanInShape17[A1, A2, A3, A4, A5, A6, A7, A8, A9, A10, A11, A12, A13, A14, A15, A16, A17, O]]
ZipWith
specialized for 17 inputs - class ZipWith18[A1, A2, A3, A4, A5, A6, A7, A8, A9, A10, A11, A12, A13, A14, A15, A16, A17, A18, O] extends GraphStage[FanInShape18[A1, A2, A3, A4, A5, A6, A7, A8, A9, A10, A11, A12, A13, A14, A15, A16, A17, A18, O]]
ZipWith
specialized for 18 inputs - class ZipWith19[A1, A2, A3, A4, A5, A6, A7, A8, A9, A10, A11, A12, A13, A14, A15, A16, A17, A18, A19, O] extends GraphStage[FanInShape19[A1, A2, A3, A4, A5, A6, A7, A8, A9, A10, A11, A12, A13, A14, A15, A16, A17, A18, A19, O]]
ZipWith
specialized for 19 inputs - class ZipWith2[A1, A2, O] extends GraphStage[FanInShape2[A1, A2, O]]
ZipWith
specialized for 2 inputs - class ZipWith20[A1, A2, A3, A4, A5, A6, A7, A8, A9, A10, A11, A12, A13, A14, A15, A16, A17, A18, A19, A20, O] extends GraphStage[FanInShape20[A1, A2, A3, A4, A5, A6, A7, A8, A9, A10, A11, A12, A13, A14, A15, A16, A17, A18, A19, A20, O]]
ZipWith
specialized for 20 inputs - class ZipWith21[A1, A2, A3, A4, A5, A6, A7, A8, A9, A10, A11, A12, A13, A14, A15, A16, A17, A18, A19, A20, A21, O] extends GraphStage[FanInShape21[A1, A2, A3, A4, A5, A6, A7, A8, A9, A10, A11, A12, A13, A14, A15, A16, A17, A18, A19, A20, A21, O]]
ZipWith
specialized for 21 inputs - class ZipWith22[A1, A2, A3, A4, A5, A6, A7, A8, A9, A10, A11, A12, A13, A14, A15, A16, A17, A18, A19, A20, A21, A22, O] extends GraphStage[FanInShape22[A1, A2, A3, A4, A5, A6, A7, A8, A9, A10, A11, A12, A13, A14, A15, A16, A17, A18, A19, A20, A21, A22, O]]
ZipWith
specialized for 22 inputs - class ZipWith3[A1, A2, A3, O] extends GraphStage[FanInShape3[A1, A2, A3, O]]
ZipWith
specialized for 3 inputs - class ZipWith4[A1, A2, A3, A4, O] extends GraphStage[FanInShape4[A1, A2, A3, A4, O]]
ZipWith
specialized for 4 inputs - class ZipWith5[A1, A2, A3, A4, A5, O] extends GraphStage[FanInShape5[A1, A2, A3, A4, A5, O]]
ZipWith
specialized for 5 inputs - class ZipWith6[A1, A2, A3, A4, A5, A6, O] extends GraphStage[FanInShape6[A1, A2, A3, A4, A5, A6, O]]
ZipWith
specialized for 6 inputs - class ZipWith7[A1, A2, A3, A4, A5, A6, A7, O] extends GraphStage[FanInShape7[A1, A2, A3, A4, A5, A6, A7, O]]
ZipWith
specialized for 7 inputs - class ZipWith8[A1, A2, A3, A4, A5, A6, A7, A8, O] extends GraphStage[FanInShape8[A1, A2, A3, A4, A5, A6, A7, A8, O]]
ZipWith
specialized for 8 inputs - class ZipWith9[A1, A2, A3, A4, A5, A6, A7, A8, A9, O] extends GraphStage[FanInShape9[A1, A2, A3, A4, A5, A6, A7, A8, A9, O]]
ZipWith
specialized for 9 inputs - trait ZipWithApply extends AnyRef
- class ZipWithN[A, O] extends GraphStage[UniformFanInShape[A, O]]
Combine the elements of multiple streams into a stream of sequences using a combiner function.
Combine the elements of multiple streams into a stream of sequences using a combiner function.
A
ZipWithN
has an
input ports and oneout
portEmits when all of the inputs has an element available
Backpressures when downstream backpressures
Completes when any upstream completes
Cancels when downstream cancels
Value Members
- object Balance
- object BidiFlow
- object Broadcast
- object BroadcastHub
A BroadcastHub is a special streaming hub that is able to broadcast streamed elements to a dynamic set of consumers.
A BroadcastHub is a special streaming hub that is able to broadcast streamed elements to a dynamic set of consumers. It consists of two parts, a Sink and a Source. The Sink broadcasts elements from a producer to the actually live consumers it has. Once the producer has been materialized, the Sink it feeds into returns a materialized value which is the corresponding Source. This Source can be materialized an arbitrary number of times, where each of the new materializations will receive their elements from the original Sink.
- object Compression
- object Concat
- object CoupledTerminationFlow
Allows coupling termination (cancellation, completion, erroring) of Sinks and Sources while creating a Flow from them.
Allows coupling termination (cancellation, completion, erroring) of Sinks and Sources while creating a Flow from them. Similar to
Flow.fromSinkAndSource
however that API does not connect the completion signals of the wrapped operators. - object DelayStrategy
- object FileIO
Factories to create sinks and sources from files
- object Flow
- object FlowWithContext
- object Framing
- object GraphDSL extends GraphApply
- object Interleave
- object JsonFraming
Provides JSON framing operators that can separate valid JSON objects from incoming ByteString objects.
- object Keep
Convenience functions for often-encountered purposes like keeping only the left (first) or only the right (second) of two input values.
- object Merge
- object MergeHub
A MergeHub is a special streaming hub that is able to collect streamed elements from a dynamic set of producers.
A MergeHub is a special streaming hub that is able to collect streamed elements from a dynamic set of producers. It consists of two parts, a Source and a Sink. The Source streams the element to a consumer from its merged inputs. Once the consumer has been materialized, the Source returns a materialized value which is the corresponding Sink. This Sink can then be materialized arbitrary many times, where each of the new materializations will feed its consumed elements to the original Source.
- object MergeLatest
MergeLatest joins elements from N input streams into stream of lists of size N.
MergeLatest joins elements from N input streams into stream of lists of size N. i-th element in list is the latest emitted element from i-th input stream. MergeLatest emits list for each element emitted from some input stream, but only after each stream emitted at least one element
Emits when element is available from some input and each input emits at least one element from stream start
Completes when all upstreams complete (eagerClose=false) or one upstream completes (eagerClose=true)
Cancels when downstream cancels
- object MergePreferred
- object MergePrioritized
- object MergeSequence
- object OrElse
- object Partition
- object PartitionHub
A
PartitionHub
is a special streaming hub that is able to route streamed elements to a dynamic set of consumers.A
PartitionHub
is a special streaming hub that is able to route streamed elements to a dynamic set of consumers. It consists of two parts, a Sink and a Source. The Sink e elements from a producer to the actually live consumers it has. The selection of consumer is done with a function. Each element can be routed to only one consumer. Once the producer has been materialized, the Sink it feeds into returns a materialized value which is the corresponding Source. This Source can be materialized an arbitrary number of times, where each of the new materializations will receive their elements from the original Sink. - object RestartFlow
A RestartFlow wraps a Flow that gets restarted when it completes or fails.
A RestartFlow wraps a Flow that gets restarted when it completes or fails.
They are useful for graphs that need to run for longer than the Flow can necessarily guarantee it will, for example, for Flow streams that depend on a remote server that may crash or become partitioned. The RestartFlow ensures that the graph can continue running while the Flow restarts.
- object RestartSink
A RestartSink wraps a Sink that gets restarted when it completes or fails.
A RestartSink wraps a Sink that gets restarted when it completes or fails.
They are useful for graphs that need to run for longer than the Sink can necessarily guarantee it will, for example, for Sink streams that depend on a remote server that may crash or become partitioned. The RestartSink ensures that the graph can continue running while the Sink restarts.
- object RestartSource
A RestartSource wraps a Source that gets restarted when it completes or fails.
A RestartSource wraps a Source that gets restarted when it completes or fails.
They are useful for graphs that need to run for longer than the Source can necessarily guarantee it will, for example, for Source streams that depend on a remote server that may crash or become partitioned. The RestartSource ensures that the graph can continue running while the Source restarts.
- object RestartWithBackoffFlow
- object RetryFlow
- object RunnableGraph extends Serializable
- object ScalaSessionAPI
- object Sink
- object SinkQueueWithCancel
- object Source
- object SourceQueueWithComplete
- object SourceWithContext
- object StreamConverters
Converters for interacting with the blocking
java.io
streams APIs and Java 8 Streams - object StreamRefs
Factories for creating stream refs.
- object TLS
Stream cipher support based upon JSSE.
Stream cipher support based upon JSSE.
The underlying SSLEngine has four ports: plaintext input/output and ciphertext input/output. These are modeled as a pekko.stream.BidiShape element for use in stream topologies, where the plaintext ports are on the left hand side of the shape and the ciphertext ports on the right hand side.
Configuring JSSE is a rather complex topic, please refer to the JDK platform documentation or the excellent user guide that is part of the Play Framework documentation. The philosophy of this integration into Pekko Streams is to expose all knobs and dials to client code and therefore not limit the configuration possibilities. In particular the client code will have to provide the SSLEngine, which is typically created from a SSLContext. Handshake parameters and other parameters are defined when creating the SSLEngine.
IMPORTANT NOTE
The TLS specification until version 1.2 did not permit half-closing of the user data session that it transports—to be precise a half-close will always promptly lead to a full close. This means that canceling the plaintext output or completing the plaintext input of the SslTls operator will lead to full termination of the secure connection without regard to whether bytes are remaining to be sent or received, respectively. Especially for a client the common idiom of attaching a finite Source to the plaintext input and transforming the plaintext response bytes coming out will not work out of the box due to early termination of the connection. For this reason there is a parameter that determines whether the SslTls operator shall ignore completion and/or cancellation events, and the default is to ignore completion (in view of the client–server scenario). In order to terminate the connection the client will then need to cancel the plaintext output as soon as all expected bytes have been received. When ignoring both types of events the operator will shut down once both events have been received. See also TLSClosing. For now, half-closing is also not supported with TLS 1.3 where the spec allows it.
- object TLSPlacebo
This object holds simple wrapping pekko.stream.scaladsl.BidiFlow implementations that can be used instead of TLS when no encryption is desired.
This object holds simple wrapping pekko.stream.scaladsl.BidiFlow implementations that can be used instead of TLS when no encryption is desired. The flows will just adapt the message protocol by wrapping into SessionBytes and unwrapping SendBytes.
- object Tcp extends ExtensionId[Tcp] with ExtensionIdProvider
- object TcpAttributes
- object Unzip
Takes a stream of pair elements and splits each pair to two output streams.
Takes a stream of pair elements and splits each pair to two output streams.
An
Unzip
has onein
port and oneleft
and oneright
output port.Emits when all of the outputs stop backpressuring and there is an input element available
Backpressures when any of the outputs backpressure
Completes when upstream completes
Cancels when any downstream cancels
- object UnzipWith extends UnzipWithApply
Transforms each element of input stream into multiple streams using a splitter function.
Transforms each element of input stream into multiple streams using a splitter function.
Emits when all of the outputs stop backpressuring and there is an input element available
Backpressures when any of the outputs backpressure
Completes when upstream completes
Cancels when any downstream cancels
- object UnzipWithApply
- object WireTap
- object Zip
- object ZipLatest
- object ZipLatestWith extends ZipLatestWithApply
Combine the elements of multiple streams into a stream of combined elements using a combiner function, picking always the latest of the elements of each source.
Combine the elements of multiple streams into a stream of combined elements using a combiner function, picking always the latest of the elements of each source. The combined stream completes immediately if some upstreams have already completed while some upstreams did not emitted any value yet. If all upstreams produced some value and the optional parameter
eagerComplete
is true (default), the combined stream completes when any of the upstreams completes, otherwise, the combined stream will wait for all upstreams to complete.No element is emitted until at least one element from each Source becomes available. Whenever a new element appears, the zipping function is invoked with a tuple containing the new element and the other last seen elements.
Emits when all of the inputs have at least an element available, and then each time an element becomes available on either of the inputs
Backpressures when downstream backpressures
Completes when any of the upstreams completes
Cancels when downstream cancels
- object ZipN
- object ZipWith extends ZipWithApply
Combine the elements of multiple streams into a stream of combined elements using a combiner function.
Combine the elements of multiple streams into a stream of combined elements using a combiner function.
Emits when all of the inputs has an element available
Backpressures when downstream backpressures
Completes when any upstream completes
Cancels when downstream cancels
- object ZipWithN