scaladsl
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 one in port and 2 or more out 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 all downstreams cancel
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
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 one first port, one second port and one out 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
A Flow is a set of stream processing steps that has one open input and one open output.
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 Akka code base!
Binary compatibility is only maintained for callers of this trait’s interface.
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 Akka 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 Akka code base!
Binary compatibility is only maintained for callers of this trait’s interface.
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
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
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 one out port, one preferred input port and 1 or more secondary in 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
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 one out 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
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
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
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 when all downstreams cancel
Flow with attached input and output, can be executed.
Allows access to an SSLSession with Scala types
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 a Subscriber
Trait allows to have the queue as a sink for some stream.
Trait allows to have the queue as a sink for some stream. "SinkQueue" pulls data from stream with backpressure mechanism.
This trait adds cancel support to SinkQueue.
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 Streams Publisher (at least conceptually).
This trait allows to have the queue as a data source for some stream.
This trait adds completion support to SourceQueue.
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.
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 one in port and one left and one right 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
UnzipWith specialized for 10 outputs
UnzipWith specialized for 11 outputs
UnzipWith specialized for 12 outputs
UnzipWith specialized for 13 outputs
UnzipWith specialized for 14 outputs
UnzipWith specialized for 15 outputs
UnzipWith specialized for 16 outputs
UnzipWith specialized for 17 outputs
UnzipWith specialized for 18 outputs
UnzipWith specialized for 19 outputs
UnzipWith specialized for 2 outputs
UnzipWith specialized for 20 outputs
UnzipWith specialized for 3 outputs
UnzipWith specialized for 4 outputs
UnzipWith specialized for 5 outputs
UnzipWith specialized for 6 outputs
UnzipWith specialized for 7 outputs
UnzipWith specialized for 8 outputs
UnzipWith specialized for 9 outputs
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 a left and a right input port and one out port
Emits when all of the inputs has an element available
Backpressures when downstream backpressures
Completes when any upstream completes
Cancels when downstream cancels
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 a n input ports and one out port
Emits when all of the inputs has an element available
Backpressures when downstream backpressures
Completes when any upstream completes
Cancels when downstream cancels
ZipWith specialized for 10 inputs
ZipWith specialized for 11 inputs
ZipWith specialized for 12 inputs
ZipWith specialized for 13 inputs
ZipWith specialized for 14 inputs
ZipWith specialized for 15 inputs
ZipWith specialized for 16 inputs
ZipWith specialized for 17 inputs
ZipWith specialized for 18 inputs
ZipWith specialized for 19 inputs
ZipWith specialized for 2 inputs
ZipWith specialized for 20 inputs
ZipWith specialized for 3 inputs
ZipWith specialized for 4 inputs
ZipWith specialized for 5 inputs
ZipWith specialized for 6 inputs
ZipWith specialized for 7 inputs
ZipWith specialized for 8 inputs
ZipWith specialized for 9 inputs
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 a n input ports and one out port
Emits when all of the inputs has an element available
Backpressures when downstream backpressures
Completes when any upstream completes
Cancels when downstream cancels
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.
Allows coupling termination (cancellation, completion, erroring) of Sinks and Sources while creating a Flow them them.
Allows coupling termination (cancellation, completion, erroring) of Sinks and Sources while creating a Flow them them.
Similar to Flow.fromSinkAndSource however that API does not connect the completion signals of the wrapped stages.
Java API: Factories to create sinks and sources from files
For use only with JDK 9+.
For use only with JDK 9+.
Provides support for java.util.concurrent.Flow.* interfaces which mirror the Reactive Streams
interfaces from org.reactivestreams. See: [http://www.reactive-streams.org/](reactive-streams.org).
Provides JSON framing stages that can separate valid JSON objects from incoming ByteString objects.
Convenience functions for often-encountered purposes like keeping only the left (first) or only the right (second) of two input values.
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.
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.
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.
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.
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.
Converters for interacting with the blocking java.io streams APIs and Java 8 Streams
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 akka.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 Akka 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 SSLContext from which the SSLEngine is then created. Handshake parameters are set using NegotiateNewSession messages, the settings for the initial handshake need to be provided up front using the same class; please refer to the method documentation below.
IMPORTANT NOTE
The TLS specification does 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 stage 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 stage 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 stage will shut down once both events have been received. See also TLSClosing.
This object holds simple wrapping akka.stream.scaladsl.BidiFlow implementations that can be used instead of TLS when no encryption is desired.
This object holds simple wrapping akka.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.
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 one in port and one left and one right 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
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
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
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
Flowcan be connected to theSourcelater by using Source#via with the flow as argument, and it remains a Source.Transformations can be appended to
SourceandFlowwith 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
Futureor 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,FlowandSinkin 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 combinator.
By default every operation is executed within its own akka.actor.Actor to enable full pipelining of the chained set of computations. This behavior is determined by the akka.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.