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/*
 * Copyright (C) 2014-2020 Lightbend Inc. 
 */

package akka.stream.javadsl

import java.util.concurrent.CompletionStage
import java.util.function.BiFunction
import java.util.function.Supplier
import java.util.Comparator
import java.util.Optional
import java.util.concurrent.CompletableFuture

import akka.actor.ActorRef
import akka.actor.ClassicActorSystemProvider
import akka.dispatch.ExecutionContexts
import akka.event.LoggingAdapter
import akka.japi.Pair
import akka.japi.Util
import akka.japi.function
import akka.stream._
import akka.stream.impl.fusing.LazyFlow
import akka.util.JavaDurationConverters._
import akka.util.unused
import akka.util.ConstantFun
import akka.util.Timeout
import akka.Done
import akka.NotUsed
import akka.japi.function.Creator
import com.github.ghik.silencer.silent
import org.reactivestreams.Processor

import scala.annotation.unchecked.uncheckedVariance
import scala.compat.java8.FutureConverters._
import scala.concurrent.duration.FiniteDuration
import scala.reflect.ClassTag

object Flow {

  /** Create a `Flow` which can process elements of type `T`. */
  def create[T](): javadsl.Flow[T, T, NotUsed] = fromGraph(scaladsl.Flow[T])

  def fromProcessor[I, O](processorFactory: function.Creator[Processor[I, O]]): javadsl.Flow[I, O, NotUsed] =
    new Flow(scaladsl.Flow.fromProcessor(() => processorFactory.create()))

  def fromProcessorMat[I, O, Mat](
      processorFactory: function.Creator[Pair[Processor[I, O], Mat]]): javadsl.Flow[I, O, Mat] =
    new Flow(scaladsl.Flow.fromProcessorMat { () =>
      val javaPair = processorFactory.create()
      (javaPair.first, javaPair.second)
    })

  /**
   * Creates a [Flow] which will use the given function to transform its inputs to outputs. It is equivalent
   * to `Flow.create[T].map(f)`
   */
  def fromFunction[I, O](f: function.Function[I, O]): javadsl.Flow[I, O, NotUsed] =
    Flow.create[I]().map(f)

  /** Create a `Flow` which can process elements of type `T`. */
  def of[T](@unused clazz: Class[T]): javadsl.Flow[T, T, NotUsed] = create[T]()

  /**
   * A graph with the shape of a flow logically is a flow, this method makes it so also in type.
   */
  def fromGraph[I, O, M](g: Graph[FlowShape[I, O], M]): Flow[I, O, M] =
    g match {
      case f: Flow[I, O, M] => f
      case other            => new Flow(scaladsl.Flow.fromGraph(other))
    }

  /**
   * Defers the creation of a [[Flow]] until materialization. The `factory` function
   * exposes [[Materializer]] which is going to be used during materialization and
   * [[Attributes]] of the [[Flow]] returned by this method.
   */
  def fromMaterializer[I, O, M](
      factory: BiFunction[Materializer, Attributes, Flow[I, O, M]]): Flow[I, O, CompletionStage[M]] =
    scaladsl.Flow.fromMaterializer((mat, attr) => factory(mat, attr).asScala).mapMaterializedValue(_.toJava).asJava

  /**
   * Defers the creation of a [[Flow]] until materialization. The `factory` function
   * exposes [[ActorMaterializer]] which is going to be used during materialization and
   * [[Attributes]] of the [[Flow]] returned by this method.
   */
  @deprecated("Use 'fromMaterializer' instead", "2.6.0")
  def setup[I, O, M](
      factory: BiFunction[ActorMaterializer, Attributes, Flow[I, O, M]]): Flow[I, O, CompletionStage[M]] =
    scaladsl.Flow.setup((mat, attr) => factory(mat, attr).asScala).mapMaterializedValue(_.toJava).asJava

  /**
   * Creates a `Flow` from a `Sink` and a `Source` where the Flow's input
   * will be sent to the Sink and the Flow's output will come from the Source.
   *
   * The resulting flow can be visualized as:
   * {{{
   *     +----------------------------------------------+
   *     | Resulting Flow[I, O, NotUsed]                |
   *     |                                              |
   *     |  +---------+                  +-----------+  |
   *     |  |         |                  |           |  |
   * I  ~~> | Sink[I] | [no-connection!] | Source[O] | ~~> O
   *     |  |         |                  |           |  |
   *     |  +---------+                  +-----------+  |
   *     +----------------------------------------------+
   * }}}
   *
   * The completion of the Sink and Source sides of a Flow constructed using
   * this method are independent. So if the Sink receives a completion signal,
   * the Source side will remain unaware of that. If you are looking to couple
   * the termination signals of the two sides use `Flow.fromSinkAndSourceCoupled` instead.
   *
   * See also [[fromSinkAndSourceMat]] when access to materialized values of the parameters is needed.
   */
  def fromSinkAndSource[I, O](sink: Graph[SinkShape[I], _], source: Graph[SourceShape[O], _]): Flow[I, O, NotUsed] =
    new Flow(scaladsl.Flow.fromSinkAndSourceMat(sink, source)(scaladsl.Keep.none))

  /**
   * Creates a `Flow` from a `Sink` and a `Source` where the Flow's input
   * will be sent to the Sink and the Flow's output will come from the Source.
   *
   * The resulting flow can be visualized as:
   * {{{
   *     +-------------------------------------------------------+
   *     | Resulting Flow[I, O, M]                              |
   *     |                                                      |
   *     |  +-------------+                  +---------------+  |
   *     |  |             |                  |               |  |
   * I  ~~> | Sink[I, M1] | [no-connection!] | Source[O, M2] | ~~> O
   *     |  |             |                  |               |  |
   *     |  +-------------+                  +---------------+  |
   *     +------------------------------------------------------+
   * }}}
   *
   * The completion of the Sink and Source sides of a Flow constructed using
   * this method are independent. So if the Sink receives a completion signal,
   * the Source side will remain unaware of that. If you are looking to couple
   * the termination signals of the two sides use `Flow.fromSinkAndSourceCoupledMat` instead.
   *
   * The `combine` function is used to compose the materialized values of the `sink` and `source`
   * into the materialized value of the resulting [[Flow]].
   */
  def fromSinkAndSourceMat[I, O, M1, M2, M](
      sink: Graph[SinkShape[I], M1],
      source: Graph[SourceShape[O], M2],
      combine: function.Function2[M1, M2, M]): Flow[I, O, M] =
    new Flow(scaladsl.Flow.fromSinkAndSourceMat(sink, source)(combinerToScala(combine)))

  /**
   * Allows coupling termination (cancellation, completion, erroring) of Sinks and Sources while creating a Flow from them.
   * Similar to [[Flow.fromSinkAndSource]] however couples the termination of these two operators.
   *
   * The resulting flow can be visualized as:
   * {{{
   *     +---------------------------------------------+
   *     | Resulting Flow[I, O, NotUsed]               |
   *     |                                             |
   *     |  +---------+                 +-----------+  |
   *     |  |         |                 |           |  |
   * I  ~~> | Sink[I] | ~~~(coupled)~~~ | Source[O] | ~~> O
   *     |  |         |                 |           |  |
   *     |  +---------+                 +-----------+  |
   *     +---------------------------------------------+
   * }}}
   *
   * E.g. if the emitted [[Flow]] gets a cancellation, the [[Source]] of course is cancelled,
   * however the Sink will also be completed. The table below illustrates the effects in detail:
   *
   * 
   *   
   *     
   *     
   *     
   *   
   *   
   *     
   *     
   *     
   *   
   *   
   *     
   *     
   *     
   *   
   *   
   *     
   *     
   *     
   *   
   *   
   *     
   *     
   *     
   *   
   *   
   *     
   *     
   *     
   *   
   *   
   *     
   *     
   *     
   *   
   * 
Returned FlowSink (in)Source (out)
cause: upstream (sink-side) receives completioneffect: receives completioneffect: receives cancel
cause: upstream (sink-side) receives erroreffect: receives erroreffect: receives cancel
cause: downstream (source-side) receives canceleffect: completeseffect: receives cancel
effect: cancels upstream, completes downstreameffect: completescause: signals complete
effect: cancels upstream, errors downstreameffect: receives errorcause: signals error or throws
effect: cancels upstream, completes downstreamcause: cancelseffect: receives cancel
* * See also [[fromSinkAndSourceCoupledMat]] when access to materialized values of the parameters is needed. */ def fromSinkAndSourceCoupled[I, O]( sink: Graph[SinkShape[I], _], source: Graph[SourceShape[O], _]): Flow[I, O, NotUsed] = new Flow(scaladsl.Flow.fromSinkAndSourceCoupled(sink, source)) /** * Allows coupling termination (cancellation, completion, erroring) of Sinks and Sources while creating a Flow from them. * Similar to [[Flow.fromSinkAndSource]] however couples the termination of these two operators. * * The resulting flow can be visualized as: * {{{ * +-----------------------------------------------------+ * | Resulting Flow[I, O, M] | * | | * | +-------------+ +---------------+ | * | | | | | | * I ~~> | Sink[I, M1] | ~~~(coupled)~~~ | Source[O, M2] | ~~> O * | | | | | | * | +-------------+ +---------------+ | * +-----------------------------------------------------+ * }}} * * E.g. if the emitted [[Flow]] gets a cancellation, the [[Source]] of course is cancelled, * however the Sink will also be completed. The table on [[Flow.fromSinkAndSourceCoupled]] * illustrates the effects in detail. * * The `combine` function is used to compose the materialized values of the `sink` and `source` * into the materialized value of the resulting [[Flow]]. */ def fromSinkAndSourceCoupledMat[I, O, M1, M2, M]( sink: Graph[SinkShape[I], M1], source: Graph[SourceShape[O], M2], combine: function.Function2[M1, M2, M]): Flow[I, O, M] = new Flow(scaladsl.Flow.fromSinkAndSourceCoupledMat(sink, source)(combinerToScala(combine))) /** * Creates a real `Flow` upon receiving the first element. Internal `Flow` will not be created * if there are no elements, because of completion, cancellation, or error. * * The materialized value of the `Flow` is the value that is created by the `fallback` function. * * '''Emits when''' the internal flow is successfully created and it emits * * '''Backpressures when''' the internal flow is successfully created and it backpressures * * '''Completes when''' upstream completes and all elements have been emitted from the internal flow * * '''Cancels when''' downstream cancels */ @deprecated( "Use 'Flow.completionStageFlow' in combination with prefixAndTail(1) instead, see `completionStageFlow` operator docs for details", "2.6.0") def lazyInit[I, O, M]( flowFactory: function.Function[I, CompletionStage[Flow[I, O, M]]], fallback: function.Creator[M]): Flow[I, O, M] = { import scala.compat.java8.FutureConverters._ val sflow = scaladsl.Flow .fromGraph(new LazyFlow[I, O, M](t => flowFactory.apply(t).toScala.map(_.asScala)(ExecutionContexts.sameThreadExecutionContext))) .mapMaterializedValue(_ => fallback.create()) new Flow(sflow) } /** * Creates a real `Flow` upon receiving the first element. Internal `Flow` will not be created * if there are no elements, because of completion, cancellation, or error. * * The materialized value of the `Flow` is a `Future[Option[M]]` that is completed with `Some(mat)` when the internal * flow gets materialized or with `None` when there where no elements. If the flow materialization (including * the call of the `flowFactory`) fails then the future is completed with a failure. * * '''Emits when''' the internal flow is successfully created and it emits * * '''Backpressures when''' the internal flow is successfully created and it backpressures * * '''Completes when''' upstream completes and all elements have been emitted from the internal flow * * '''Cancels when''' downstream cancels */ @deprecated("Use 'Flow.lazyCompletionStageFlow' instead", "2.6.0") def lazyInitAsync[I, O, M]( flowFactory: function.Creator[CompletionStage[Flow[I, O, M]]]): Flow[I, O, CompletionStage[Optional[M]]] = { import scala.compat.java8.FutureConverters._ val sflow = scaladsl.Flow .lazyInitAsync(() => flowFactory.create().toScala.map(_.asScala)(ExecutionContexts.sameThreadExecutionContext)) .mapMaterializedValue( fut => fut .map(_.fold[Optional[M]](Optional.empty())(m => Optional.ofNullable(m)))( ExecutionContexts.sameThreadExecutionContext) .toJava) new Flow(sflow) } /** * Turn a `CompletionStage` into a flow that will consume the values of the source when the future completes successfully. * If the `Future` is completed with a failure the stream is failed. * * The materialized completion stage value is completed with the materialized value of the future flow or failed with a * [[NeverMaterializedException]] if upstream fails or downstream cancels before the completion stage has completed. */ def completionStageFlow[I, O, M](flow: CompletionStage[Flow[I, O, M]]): Flow[I, O, CompletionStage[M]] = lazyCompletionStageFlow(() => flow) /** * Defers invoking the `create` function to create a future flow until there is downstream demand and passing * that downstream demand upstream triggers the first element. * * Note that asynchronous boundaries (and other operators) in the stream may do pre-fetching which counter acts * the laziness and can trigger the factory earlier than expected. * * '''Emits when''' the internal flow is successfully created and it emits * * '''Backpressures when''' the internal flow is successfully created and it backpressures or downstream backpressures * * '''Completes when''' upstream completes and all elements have been emitted from the internal flow * * '''Cancels when''' downstream cancels */ def lazyFlow[I, O, M](create: Creator[Flow[I, O, M]]): Flow[I, O, CompletionStage[M]] = lazyCompletionStageFlow(() => CompletableFuture.completedFuture(create.create())) /** * Defers invoking the `create` function to create a future flow until there downstream demand has caused upstream * to send a first element. * * The materialized future value is completed with the materialized value of the created flow when that has successfully * been materialized. * * If the `create` function throws or returns a future that fails the stream is failed, in this case the materialized * future value is failed with a [[NeverMaterializedException]]. * * Note that asynchronous boundaries (and other operators) in the stream may do pre-fetching which counter acts * the laziness and can trigger the factory earlier than expected. * * '''Emits when''' the internal flow is successfully created and it emits * * '''Backpressures when''' the internal flow is successfully created and it backpressures or downstream backpressures * * '''Completes when''' upstream completes and all elements have been emitted from the internal flow * * '''Cancels when''' downstream cancels */ def lazyCompletionStageFlow[I, O, M]( create: Creator[CompletionStage[Flow[I, O, M]]]): Flow[I, O, CompletionStage[M]] = scaladsl.Flow .lazyFutureFlow[I, O, M](() => create.create().toScala.map(_.asScala)(ExecutionContexts.sameThreadExecutionContext)) .mapMaterializedValue(_.toJava) .asJava /** * Upcast a stream of elements to a stream of supertypes of that element. Useful in combination with * fan-in operators where you do not want to pay the cost of casting each element in a `map`. * * @tparam SuperOut a supertype to the type of element flowing out of the flow * @return A flow that accepts `In` and outputs elements of the super type */ def upcast[In, SuperOut, Out <: SuperOut, M](flow: Flow[In, Out, M]): Flow[In, SuperOut, M] = flow.asInstanceOf[Flow[In, SuperOut, M]] } /** Create a `Flow` which can process elements of type `T`. */ final class Flow[In, Out, Mat](delegate: scaladsl.Flow[In, Out, Mat]) extends Graph[FlowShape[In, Out], Mat] { import akka.util.ccompat.JavaConverters._ override def shape: FlowShape[In, Out] = delegate.shape override def traversalBuilder = delegate.traversalBuilder override def toString: String = delegate.toString /** Converts this Flow to its Scala DSL counterpart */ def asScala: scaladsl.Flow[In, Out, Mat] = delegate /** * Transform only the materialized value of this Flow, leaving all other properties as they were. */ def mapMaterializedValue[Mat2](f: function.Function[Mat, Mat2]): Flow[In, Out, Mat2] = new Flow(delegate.mapMaterializedValue(f.apply _)) /** * Transform this [[Flow]] by appending the given processing steps. * {{{ * +---------------------------------+ * | Resulting Flow[In, T, Mat] | * | | * | +------+ +------+ | * | | | | | | * In ~~> | this | ~~Out~~> | flow | ~~> T * | | Mat| | M| | * | +------+ +------+ | * +---------------------------------+ * }}} * The materialized value of the combined [[Flow]] will be the materialized * value of the current flow (ignoring the other Flow’s value), use * `viaMat` if a different strategy is needed. * * See also [[viaMat]] when access to materialized values of the parameter is needed. */ def via[T, M](flow: Graph[FlowShape[Out, T], M]): javadsl.Flow[In, T, Mat] = new Flow(delegate.via(flow)) /** * Transform this [[Flow]] by appending the given processing steps. * {{{ * +---------------------------------+ * | Resulting Flow[In, T, M2] | * | | * | +------+ +------+ | * | | | | | | * In ~~> | this | ~~Out~~> | flow | ~~> T * | | Mat| | M| | * | +------+ +------+ | * +---------------------------------+ * }}} * The `combine` function is used to compose the materialized values of this flow and that * flow into the materialized value of the resulting Flow. * * It is recommended to use the internally optimized `Keep.left` and `Keep.right` combiners * where appropriate instead of manually writing functions that pass through one of the values. */ def viaMat[T, M, M2]( flow: Graph[FlowShape[Out, T], M], combine: function.Function2[Mat, M, M2]): javadsl.Flow[In, T, M2] = new Flow(delegate.viaMat(flow)(combinerToScala(combine))) /** * Connect this [[Flow]] to a [[Sink]], concatenating the processing steps of both. * {{{ * +------------------------------+ * | Resulting Sink[In, Mat] | * | | * | +------+ +------+ | * | | | | | | * In ~~> | flow | ~~Out~~> | sink | | * | | Mat| | M| | * | +------+ +------+ | * +------------------------------+ * }}} * The materialized value of the combined [[Sink]] will be the materialized * value of the current flow (ignoring the given Sink’s value), use * `toMat` if a different strategy is needed. * * See also [[toMat]] when access to materialized values of the parameter is needed. */ def to(sink: Graph[SinkShape[Out], _]): javadsl.Sink[In, Mat] = new Sink(delegate.to(sink)) /** * Connect this [[Flow]] to a [[Sink]], concatenating the processing steps of both. * {{{ * +----------------------------+ * | Resulting Sink[In, M2] | * | | * | +------+ +------+ | * | | | | | | * In ~~> | flow | ~Out~> | sink | | * | | Mat| | M| | * | +------+ +------+ | * +----------------------------+ * }}} * The `combine` function is used to compose the materialized values of this flow and that * Sink into the materialized value of the resulting Sink. * * It is recommended to use the internally optimized `Keep.left` and `Keep.right` combiners * where appropriate instead of manually writing functions that pass through one of the values. */ def toMat[M, M2](sink: Graph[SinkShape[Out], M], combine: function.Function2[Mat, M, M2]): javadsl.Sink[In, M2] = new Sink(delegate.toMat(sink)(combinerToScala(combine))) /** * Join this [[Flow]] to another [[Flow]], by cross connecting the inputs and outputs, creating a [[RunnableGraph]]. * {{{ * +------+ +-------+ * | | ~Out~> | | * | this | | other | * | | <~In~ | | * +------+ +-------+ * }}} * The materialized value of the combined [[Flow]] will be the materialized * value of the current flow (ignoring the other Flow’s value), use * `joinMat` if a different strategy is needed. * * See also [[joinMat]] when access to materialized values of the parameter is needed. */ def join[M](flow: Graph[FlowShape[Out, In], M]): javadsl.RunnableGraph[Mat] = RunnableGraph.fromGraph(delegate.join(flow)) /** * Join this [[Flow]] to another [[Flow]], by cross connecting the inputs and outputs, creating a [[RunnableGraph]] * {{{ * +------+ +-------+ * | | ~Out~> | | * | this | | other | * | | <~In~ | | * +------+ +-------+ * }}} * The `combine` function is used to compose the materialized values of this flow and that * Flow into the materialized value of the resulting Flow. * * It is recommended to use the internally optimized `Keep.left` and `Keep.right` combiners * where appropriate instead of manually writing functions that pass through one of the values. */ def joinMat[M, M2]( flow: Graph[FlowShape[Out, In], M], combine: function.Function2[Mat, M, M2]): javadsl.RunnableGraph[M2] = RunnableGraph.fromGraph(delegate.joinMat(flow)(combinerToScala(combine))) /** * Join this [[Flow]] to a [[BidiFlow]] to close off the “top” of the protocol stack: * {{{ * +---------------------------+ * | Resulting Flow | * | | * | +------+ +------+ | * | | | ~Out~> | | ~~> O1 * | | flow | | bidi | | * | | | <~In~ | | <~~ I2 * | +------+ +------+ | * +---------------------------+ * }}} * The materialized value of the combined [[Flow]] will be the materialized * value of the current flow (ignoring the [[BidiFlow]]’s value), use * [[Flow#joinMat[I2* joinMat]] if a different strategy is needed. */ def join[I2, O1, Mat2](bidi: Graph[BidiShape[Out, O1, I2, In], Mat2]): Flow[I2, O1, Mat] = new Flow(delegate.join(bidi)) /** * Join this [[Flow]] to a [[BidiFlow]] to close off the “top” of the protocol stack: * {{{ * +---------------------------+ * | Resulting Flow | * | | * | +------+ +------+ | * | | | ~Out~> | | ~~> O1 * | | flow | | bidi | | * | | | <~In~ | | <~~ I2 * | +------+ +------+ | * +---------------------------+ * }}} * The `combine` function is used to compose the materialized values of this flow and that * [[BidiFlow]] into the materialized value of the resulting [[Flow]]. * * It is recommended to use the internally optimized `Keep.left` and `Keep.right` combiners * where appropriate instead of manually writing functions that pass through one of the values. * * See also [[viaMat]] when access to materialized values of the parameter is needed. */ def joinMat[I2, O1, Mat2, M]( bidi: Graph[BidiShape[Out, O1, I2, In], Mat2], combine: function.Function2[Mat, Mat2, M]): Flow[I2, O1, M] = new Flow(delegate.joinMat(bidi)(combinerToScala(combine))) /** * Connect the `Source` to this `Flow` and then connect it to the `Sink` and run it. * * The returned tuple contains the materialized values of the `Source` and `Sink`, * e.g. the `Subscriber` of a `Source.asSubscriber` and `Publisher` of a `Sink.asPublisher`. * * @tparam T materialized type of given Source * @tparam U materialized type of given Sink */ def runWith[T, U]( source: Graph[SourceShape[In], T], sink: Graph[SinkShape[Out], U], systemProvider: ClassicActorSystemProvider): akka.japi.Pair[T, U] = { val (som, sim) = delegate.runWith(source, sink)(SystemMaterializer(systemProvider.classicSystem).materializer) akka.japi.Pair(som, sim) } /** * Connect the `Source` to this `Flow` and then connect it to the `Sink` and run it. * * The returned tuple contains the materialized values of the `Source` and `Sink`, * e.g. the `Subscriber` of a `Source.asSubscriber` and `Publisher` of a `Sink.asPublisher`. * * Prefer the method taking an ActorSystem unless you have special requirements. * * @tparam T materialized type of given Source * @tparam U materialized type of given Sink */ def runWith[T, U]( source: Graph[SourceShape[In], T], sink: Graph[SinkShape[Out], U], materializer: Materializer): akka.japi.Pair[T, U] = { val (som, sim) = delegate.runWith(source, sink)(materializer) akka.japi.Pair(som, sim) } /** * Transform this stream by applying the given function to each of the elements * as they pass through this processing step. * * Adheres to the [[ActorAttributes.SupervisionStrategy]] attribute. * * '''Emits when''' the mapping function returns an element * * '''Backpressures when''' downstream backpressures * * '''Completes when''' upstream completes * * '''Cancels when''' downstream cancels */ def map[T](f: function.Function[Out, T]): javadsl.Flow[In, T, Mat] = new Flow(delegate.map(f.apply)) /** * This is a simplified version of `wireTap(Sink)` that takes only a simple procedure. * Elements will be passed into this "side channel" function, and any of its results will be ignored. * * If the wire-tap operation is slow (it backpressures), elements that would've been sent to it will be dropped instead. * It is similar to [[#alsoTo]] but will not affect (i.e. backpressure) the flow tapped into. * * This operation is useful for inspecting the passed through element, usually by means of side-effecting * operations (such as `println`, or emitting metrics), for each element without having to modify it. * * For logging signals (elements, completion, error) consider using the [[log]] operator instead, * along with appropriate `ActorAttributes.logLevels`. * * '''Emits when''' upstream emits an element; the same element will be passed to the attached function, * as well as to the downstream operator * * '''Backpressures when''' downstream backpressures * * '''Completes when''' upstream completes * * '''Cancels when''' downstream cancels * */ def wireTap(f: function.Procedure[Out]): javadsl.Flow[In, Out, Mat] = new Flow(delegate.wireTap(f(_))) /** * Transform each input element into an `Iterable` of output elements that is * then flattened into the output stream. * * Make sure that the `Iterable` is immutable or at least not modified after * being used as an output sequence. Otherwise the stream may fail with * `ConcurrentModificationException` or other more subtle errors may occur. * * The returned `Iterable` MUST NOT contain `null` values, * as they are illegal as stream elements - according to the Reactive Streams specification. * * '''Emits when''' the mapping function returns an element or there are still remaining elements * from the previously calculated collection * * '''Backpressures when''' downstream backpressures or there are still remaining elements from the * previously calculated collection * * '''Completes when''' upstream completes and all remaining elements have been emitted * * '''Cancels when''' downstream cancels */ def mapConcat[T](f: function.Function[Out, java.lang.Iterable[T]]): javadsl.Flow[In, T, Mat] = new Flow(delegate.mapConcat { elem => Util.immutableSeq(f(elem)) }) /** * Transform each input element into an `Iterable` of output elements that is * then flattened into the output stream. The transformation is meant to be stateful, * which is enabled by creating the transformation function anew for every materialization — * the returned function will typically close over mutable objects to store state between * invocations. For the stateless variant see [[#mapConcat]]. * * Make sure that the `Iterable` is immutable or at least not modified after * being used as an output sequence. Otherwise the stream may fail with * `ConcurrentModificationException` or other more subtle errors may occur. * * The returned `Iterable` MUST NOT contain `null` values, * as they are illegal as stream elements - according to the Reactive Streams specification. * * Adheres to the [[ActorAttributes.SupervisionStrategy]] attribute. * * '''Emits when''' the mapping function returns an element or there are still remaining elements * from the previously calculated collection * * '''Backpressures when''' downstream backpressures or there are still remaining elements from the * previously calculated collection * * '''Completes when''' upstream completes and all remaining elements has been emitted * * '''Cancels when''' downstream cancels */ def statefulMapConcat[T]( f: function.Creator[function.Function[Out, java.lang.Iterable[T]]]): javadsl.Flow[In, T, Mat] = new Flow(delegate.statefulMapConcat { () => val fun = f.create() elem => Util.immutableSeq(fun(elem)) }) /** * Transform this stream by applying the given function to each of the elements * as they pass through this processing step. The function returns a `CompletionStage` and the * value of that future will be emitted downstream. The number of CompletionStages * that shall run in parallel is given as the first argument to ``mapAsync``. * These CompletionStages may complete in any order, but the elements that * are emitted downstream are in the same order as received from upstream. * * If the function `f` throws an exception or if the `CompletionStage` is completed * with failure and the supervision decision is [[akka.stream.Supervision#stop]] * the stream will be completed with failure. * * If the function `f` throws an exception or if the `CompletionStage` is completed * with failure and the supervision decision is [[akka.stream.Supervision#resume]] or * [[akka.stream.Supervision#restart]] the element is dropped and the stream continues. * * The function `f` is always invoked on the elements in the order they arrive. * * '''Emits when''' the CompletionStage returned by the provided function finishes for the next element in sequence * * '''Backpressures when''' the number of CompletionStages reaches the configured parallelism and the downstream * backpressures or the first future is not completed * * '''Completes when''' upstream completes and all CompletionStages have been completed and all elements have been emitted * * '''Cancels when''' downstream cancels * * @see [[#mapAsyncUnordered]] */ def mapAsync[T](parallelism: Int, f: function.Function[Out, CompletionStage[T]]): javadsl.Flow[In, T, Mat] = new Flow(delegate.mapAsync(parallelism)(x => f(x).toScala)) /** * Transform this stream by applying the given function to each of the elements * as they pass through this processing step. The function returns a `CompletionStage` and the * value of that future will be emitted downstream. The number of CompletionStages * that shall run in parallel is given as the first argument to ``mapAsyncUnordered``. * Each processed element will be emitted downstream as soon as it is ready, i.e. it is possible * that the elements are not emitted downstream in the same order as received from upstream. * * If the function `f` throws an exception or if the `CompletionStage` is completed * with failure and the supervision decision is [[akka.stream.Supervision#stop]] * the stream will be completed with failure. * * If the function `f` throws an exception or if the `CompletionStage` is completed * with failure and the supervision decision is [[akka.stream.Supervision#resume]] or * [[akka.stream.Supervision#restart]] the element is dropped and the stream continues. * * The function `f` is always invoked on the elements in the order they arrive (even though the result of the futures * returned by `f` might be emitted in a different order). * * Adheres to the [[ActorAttributes.SupervisionStrategy]] attribute. * * '''Emits when''' any of the CompletionStages returned by the provided function complete * * '''Backpressures when''' the number of CompletionStages reaches the configured parallelism and the downstream backpressures * * '''Completes when''' upstream completes and all CompletionStages have been completed and all elements have been emitted * * '''Cancels when''' downstream cancels * * @see [[#mapAsync]] */ def mapAsyncUnordered[T](parallelism: Int, f: function.Function[Out, CompletionStage[T]]): javadsl.Flow[In, T, Mat] = new Flow(delegate.mapAsyncUnordered(parallelism)(x => f(x).toScala)) /** * Use the `ask` pattern to send a request-reply message to the target `ref` actor. * If any of the asks times out it will fail the stream with a [[akka.pattern.AskTimeoutException]]. * * The `mapTo` class parameter is used to cast the incoming responses to the expected response type. * * Similar to the plain ask pattern, the target actor is allowed to reply with `akka.util.Status`. * An `akka.util.Status#Failure` will cause the operator to fail with the cause carried in the `Failure` message. * * Defaults to parallelism of 2 messages in flight, since while one ask message may be being worked on, the second one * still be in the mailbox, so defaulting to sending the second one a bit earlier than when first ask has replied maintains * a slightly healthier throughput. * * The operator fails with an [[akka.stream.WatchedActorTerminatedException]] if the target actor is terminated. * * Adheres to the [[ActorAttributes.SupervisionStrategy]] attribute. * * '''Emits when''' any of the CompletionStages returned by the provided function complete * * '''Backpressures when''' the number of futures reaches the configured parallelism and the downstream backpressures * * '''Completes when''' upstream completes and all futures have been completed and all elements have been emitted * * '''Fails when''' the passed in actor terminates, or a timeout is exceeded in any of the asks performed * * '''Cancels when''' downstream cancels */ def ask[S](ref: ActorRef, mapTo: Class[S], timeout: Timeout): javadsl.Flow[In, S, Mat] = ask(2, ref, mapTo, timeout) /** * Use the `ask` pattern to send a request-reply message to the target `ref` actor. * If any of the asks times out it will fail the stream with a [[akka.pattern.AskTimeoutException]]. * * The `mapTo` class parameter is used to cast the incoming responses to the expected response type. * * Similar to the plain ask pattern, the target actor is allowed to reply with `akka.util.Status`. * An `akka.util.Status#Failure` will cause the operator to fail with the cause carried in the `Failure` message. * * Parallelism limits the number of how many asks can be "in flight" at the same time. * Please note that the elements emitted by this operator are in-order with regards to the asks being issued * (i.e. same behaviour as mapAsync). * * The operator fails with an [[akka.stream.WatchedActorTerminatedException]] if the target actor is terminated. * * Adheres to the [[ActorAttributes.SupervisionStrategy]] attribute. * * '''Emits when''' any of the CompletionStages returned by the provided function complete * * '''Backpressures when''' the number of futures reaches the configured parallelism and the downstream backpressures * * '''Completes when''' upstream completes and all futures have been completed and all elements have been emitted * * '''Fails when''' the passed in actor terminates, or a timeout is exceeded in any of the asks performed * * '''Cancels when''' downstream cancels */ def ask[S](parallelism: Int, ref: ActorRef, mapTo: Class[S], timeout: Timeout): javadsl.Flow[In, S, Mat] = new Flow(delegate.ask[S](parallelism)(ref)(timeout, ClassTag(mapTo))) /** * The operator fails with an [[akka.stream.WatchedActorTerminatedException]] if the target actor is terminated. * * '''Emits when''' upstream emits * * '''Backpressures when''' downstream backpressures * * '''Completes when''' upstream completes * * '''Fails when''' the watched actor terminates * * '''Cancels when''' downstream cancels */ def watch(ref: ActorRef): javadsl.Flow[In, Out, Mat] = new Flow(delegate.watch(ref)) /** * Only pass on those elements that satisfy the given predicate. * * Adheres to the [[ActorAttributes.SupervisionStrategy]] attribute. * * '''Emits when''' the given predicate returns true for the element * * '''Backpressures when''' the given predicate returns true for the element and downstream backpressures * * '''Completes when''' upstream completes * * '''Cancels when''' downstream cancels * */ def filter(p: function.Predicate[Out]): javadsl.Flow[In, Out, Mat] = new Flow(delegate.filter(p.test)) /** * Only pass on those elements that NOT satisfy the given predicate. * * Adheres to the [[ActorAttributes.SupervisionStrategy]] attribute. * * '''Emits when''' the given predicate returns false for the element * * '''Backpressures when''' the given predicate returns false for the element and downstream backpressures * * '''Completes when''' upstream completes * * '''Cancels when''' downstream cancels */ def filterNot(p: function.Predicate[Out]): javadsl.Flow[In, Out, Mat] = new Flow(delegate.filterNot(p.test)) /** * Transform this stream by applying the given partial function to each of the elements * on which the function is defined as they pass through this processing step. * Non-matching elements are filtered out. * * Adheres to the [[ActorAttributes.SupervisionStrategy]] attribute. * * '''Emits when''' the provided partial function is defined for the element * * '''Backpressures when''' the partial function is defined for the element and downstream backpressures * * '''Completes when''' upstream completes * * '''Cancels when''' downstream cancels */ def collect[T](pf: PartialFunction[Out, T]): javadsl.Flow[In, T, Mat] = new Flow(delegate.collect(pf)) /** * Transform this stream by testing the type of each of the elements * on which the element is an instance of the provided type as they pass through this processing step. * Non-matching elements are filtered out. * * Adheres to the [[ActorAttributes.SupervisionStrategy]] attribute. * * '''Emits when''' the element is an instance of the provided type * * '''Backpressures when''' the element is an instance of the provided type and downstream backpressures * * '''Completes when''' upstream completes * * '''Cancels when''' downstream cancels */ def collectType[T](clazz: Class[T]): javadsl.Flow[In, T, Mat] = new Flow(delegate.collectType[T](ClassTag[T](clazz))) /** * Chunk up this stream into groups of the given size, with the last group * possibly smaller than requested due to end-of-stream. * * `n` must be positive, otherwise IllegalArgumentException is thrown. * * '''Emits when''' the specified number of elements has been accumulated or upstream completed * * '''Backpressures when''' a group has been assembled and downstream backpressures * * '''Completes when''' upstream completes * * '''Cancels when''' downstream cancels */ def grouped(n: Int): javadsl.Flow[In, java.util.List[Out], Mat] = new Flow(delegate.grouped(n).map(_.asJava)) // TODO optimize to one step /** * Ensure stream boundedness by limiting the number of elements from upstream. * If the number of incoming elements exceeds max, it will signal * upstream failure `StreamLimitException` downstream. * * Due to input buffering some elements may have been * requested from upstream publishers that will then not be processed downstream * of this step. * * The stream will be completed without producing any elements if `n` is zero * or negative. * * '''Emits when''' the specified number of elements to take has not yet been reached * * '''Backpressures when''' downstream backpressures * * '''Completes when''' the defined number of elements has been taken or upstream completes * * '''Errors when''' the total number of incoming element exceeds max * * '''Cancels when''' the defined number of elements has been taken or downstream cancels * * See also [[Flow.take]], [[Flow.takeWithin]], [[Flow.takeWhile]] */ def limit(n: Long): javadsl.Flow[In, Out, Mat] = new Flow(delegate.limit(n)) /** * Ensure stream boundedness by evaluating the cost of incoming elements * using a cost function. Exactly how many elements will be allowed to travel downstream depends on the * evaluated cost of each element. If the accumulated cost exceeds max, it will signal * upstream failure `StreamLimitException` downstream. * * Due to input buffering some elements may have been * requested from upstream publishers that will then not be processed downstream * of this step. * * The stream will be completed without producing any elements if `n` is zero * or negative. * * Adheres to the [[ActorAttributes.SupervisionStrategy]] attribute. * * '''Emits when''' the specified number of elements to take has not yet been reached * * '''Backpressures when''' downstream backpressures * * '''Completes when''' the defined number of elements has been taken or upstream completes * * '''Errors when''' when the accumulated cost exceeds max * * '''Cancels when''' the defined number of elements has been taken or downstream cancels * * See also [[Flow.take]], [[Flow.takeWithin]], [[Flow.takeWhile]] */ def limitWeighted(n: Long)(costFn: function.Function[Out, java.lang.Long]): javadsl.Flow[In, Out, Mat] = { new Flow(delegate.limitWeighted(n)(costFn.apply)) } /** * Apply a sliding window over the stream and return the windows as groups of elements, with the last group * possibly smaller than requested due to end-of-stream. * * `n` must be positive, otherwise IllegalArgumentException is thrown. * `step` must be positive, otherwise IllegalArgumentException is thrown. * * '''Emits when''' enough elements have been collected within the window or upstream completed * * '''Backpressures when''' a window has been assembled and downstream backpressures * * '''Completes when''' upstream completes * * '''Cancels when''' downstream cancels */ def sliding(n: Int, step: Int = 1): javadsl.Flow[In, java.util.List[Out], Mat] = new Flow(delegate.sliding(n, step).map(_.asJava)) // TODO optimize to one step /** * Similar to `fold` but is not a terminal operation, * emits its current value which starts at `zero` and then * applies the current and next value to the given function `f`, * emitting the next current value. * * If the function `f` throws an exception and the supervision decision is * [[akka.stream.Supervision#restart]] current value starts at `zero` again * the stream will continue. * * Adheres to the [[ActorAttributes.SupervisionStrategy]] attribute. * * Note that the `zero` value must be immutable. * * '''Emits when''' the function scanning the element returns a new element * * '''Backpressures when''' downstream backpressures * * '''Completes when''' upstream completes * * '''Cancels when''' downstream cancels */ def scan[T](zero: T)(f: function.Function2[T, Out, T]): javadsl.Flow[In, T, Mat] = new Flow(delegate.scan(zero)(f.apply)) /** * Similar to `scan` but with a asynchronous function, * emits its current value which starts at `zero` and then * applies the current and next value to the given function `f`, * emitting a `Future` that resolves to the next current value. * * If the function `f` throws an exception and the supervision decision is * [[akka.stream.Supervision.Restart]] current value starts at `zero` again * the stream will continue. * * If the function `f` throws an exception and the supervision decision is * [[akka.stream.Supervision.Resume]] current value starts at the previous * current value, or zero when it doesn't have one, and the stream will continue. * * Adheres to the [[ActorAttributes.SupervisionStrategy]] attribute. * * Note that the `zero` value must be immutable. * * '''Emits when''' the future returned by f` completes * * '''Backpressures when''' downstream backpressures * * '''Completes when''' upstream completes and the last future returned by `f` completes * * '''Cancels when''' downstream cancels * * See also [[FlowOps.scan]] */ def scanAsync[T](zero: T)(f: function.Function2[T, Out, CompletionStage[T]]): javadsl.Flow[In, T, Mat] = new Flow(delegate.scanAsync(zero) { (out, in) => f(out, in).toScala }) /** * Similar to `scan` but only emits its result when the upstream completes, * after which it also completes. Applies the given function `f` towards its current and next value, * yielding the next current value. * * Adheres to the [[ActorAttributes.SupervisionStrategy]] attribute. * * If the function `f` throws an exception and the supervision decision is * [[akka.stream.Supervision#restart]] current value starts at `zero` again * the stream will continue. * * Note that the `zero` value must be immutable. * * '''Emits when''' upstream completes * * '''Backpressures when''' downstream backpressures * * '''Completes when''' upstream completes * * '''Cancels when''' downstream cancels */ def fold[T](zero: T)(f: function.Function2[T, Out, T]): javadsl.Flow[In, T, Mat] = new Flow(delegate.fold(zero)(f.apply)) /** * Similar to `fold` but with an asynchronous function. * Applies the given function towards its current and next value, * yielding the next current value. * * Adheres to the [[ActorAttributes.SupervisionStrategy]] attribute. * * If the function `f` returns a failure and the supervision decision is * [[akka.stream.Supervision.Restart]] current value starts at `zero` again * the stream will continue. * * Note that the `zero` value must be immutable. * * '''Emits when''' upstream completes * * '''Backpressures when''' downstream backpressures * * '''Completes when''' upstream completes * * '''Cancels when''' downstream cancels */ def foldAsync[T](zero: T)(f: function.Function2[T, Out, CompletionStage[T]]): javadsl.Flow[In, T, Mat] = new Flow(delegate.foldAsync(zero) { (out, in) => f(out, in).toScala }) /** * Similar to `fold` but uses first element as zero element. * Applies the given function towards its current and next value, * yielding the next current value. * * If the stream is empty (i.e. completes before signalling any elements), * the reduce operator will fail its downstream with a [[NoSuchElementException]], * which is semantically in-line with that Scala's standard library collections * do in such situations. * * Adheres to the [[ActorAttributes.SupervisionStrategy]] attribute. * * '''Emits when''' upstream completes * * '''Backpressures when''' downstream backpressures * * '''Completes when''' upstream completes * * '''Cancels when''' downstream cancels */ def reduce(f: function.Function2[Out, Out, Out]): javadsl.Flow[In, Out, Mat] = new Flow(delegate.reduce(f.apply)) /** * Intersperses stream with provided element, similar to how [[scala.collection.immutable.List.mkString]] * injects a separator between a List's elements. * * Additionally can inject start and end marker elements to stream. * * Examples: * * {{{ * Source nums = Source.from(Arrays.asList(0, 1, 2, 3)); * nums.intersperse(","); // 1 , 2 , 3 * nums.intersperse("[", ",", "]"); // [ 1 , 2 , 3 ] * }}} * * In case you want to only prepend or only append an element (yet still use the `intercept` feature * to inject a separator between elements, you may want to use the following pattern instead of the 3-argument * version of intersperse (See [[Source.concat]] for semantics details): * * {{{ * Source.single(">> ").concat(flow.intersperse(",")) * flow.intersperse(",").concat(Source.single("END")) * }}} * * '''Emits when''' upstream emits (or before with the `start` element if provided) * * '''Backpressures when''' downstream backpressures * * '''Completes when''' upstream completes * * '''Cancels when''' downstream cancels */ def intersperse(start: Out, inject: Out, end: Out): javadsl.Flow[In, Out, Mat] = new Flow(delegate.intersperse(start, inject, end)) /** * Intersperses stream with provided element, similar to how [[scala.collection.immutable.List.mkString]] * injects a separator between a List's elements. * * Additionally can inject start and end marker elements to stream. * * Examples: * * {{{ * Source nums = Source.from(Arrays.asList(0, 1, 2, 3)); * nums.intersperse(","); // 1 , 2 , 3 * nums.intersperse("[", ",", "]"); // [ 1 , 2 , 3 ] * }}} * * '''Emits when''' upstream emits (or before with the `start` element if provided) * * '''Backpressures when''' downstream backpressures * * '''Completes when''' upstream completes * * '''Cancels when''' downstream cancels */ def intersperse(inject: Out): javadsl.Flow[In, Out, Mat] = new Flow(delegate.intersperse(inject)) /** * Chunk up this stream into groups of elements received within a time window, * or limited by the given number of elements, whatever happens first. * Empty groups will not be emitted if no elements are received from upstream. * The last group before end-of-stream will contain the buffered elements * since the previously emitted group. * * '''Emits when''' the configured time elapses since the last group has been emitted or `n` elements is buffered * * '''Backpressures when''' downstream backpressures, and there are `n+1` buffered elements * * '''Completes when''' upstream completes (emits last group) * * '''Cancels when''' downstream completes * * `n` must be positive, and `d` must be greater than 0 seconds, otherwise * IllegalArgumentException is thrown. */ @Deprecated @deprecated("Use the overloaded one which accepts java.time.Duration instead.", since = "2.5.12") def groupedWithin(n: Int, d: FiniteDuration): javadsl.Flow[In, java.util.List[Out], Mat] = new Flow(delegate.groupedWithin(n, d).map(_.asJava)) // TODO optimize to one step /** * Chunk up this stream into groups of elements received within a time window, * or limited by the given number of elements, whatever happens first. * Empty groups will not be emitted if no elements are received from upstream. * The last group before end-of-stream will contain the buffered elements * since the previously emitted group. * * '''Emits when''' the configured time elapses since the last group has been emitted or `n` elements is buffered * * '''Backpressures when''' downstream backpressures, and there are `n+1` buffered elements * * '''Completes when''' upstream completes (emits last group) * * '''Cancels when''' downstream completes * * `n` must be positive, and `d` must be greater than 0 seconds, otherwise * IllegalArgumentException is thrown. */ @silent("deprecated") def groupedWithin(n: Int, d: java.time.Duration): javadsl.Flow[In, java.util.List[Out], Mat] = groupedWithin(n, d.asScala) /** * Chunk up this stream into groups of elements received within a time window, * or limited by the weight of the elements, whatever happens first. * Empty groups will not be emitted if no elements are received from upstream. * The last group before end-of-stream will contain the buffered elements * since the previously emitted group. * * '''Emits when''' the configured time elapses since the last group has been emitted or weight limit reached * * '''Backpressures when''' downstream backpressures, and buffered group (+ pending element) weighs more than `maxWeight` * * '''Completes when''' upstream completes (emits last group) * * '''Cancels when''' downstream completes * * `maxWeight` must be positive, and `d` must be greater than 0 seconds, otherwise * IllegalArgumentException is thrown. */ @Deprecated @deprecated("Use the overloaded one which accepts java.time.Duration instead.", since = "2.5.12") def groupedWeightedWithin( maxWeight: Long, costFn: function.Function[Out, java.lang.Long], d: FiniteDuration): javadsl.Flow[In, java.util.List[Out], Mat] = new Flow(delegate.groupedWeightedWithin(maxWeight, d)(costFn.apply).map(_.asJava)) /** * Chunk up this stream into groups of elements received within a time window, * or limited by the weight of the elements, whatever happens first. * Empty groups will not be emitted if no elements are received from upstream. * The last group before end-of-stream will contain the buffered elements * since the previously emitted group. * * '''Emits when''' the configured time elapses since the last group has been emitted or weight limit reached * * '''Backpressures when''' downstream backpressures, and buffered group (+ pending element) weighs more than `maxWeight` * * '''Completes when''' upstream completes (emits last group) * * '''Cancels when''' downstream completes * * `maxWeight` must be positive, and `d` must be greater than 0 seconds, otherwise * IllegalArgumentException is thrown. */ @silent("deprecated") def groupedWeightedWithin( maxWeight: Long, costFn: function.Function[Out, java.lang.Long], d: java.time.Duration): javadsl.Flow[In, java.util.List[Out], Mat] = groupedWeightedWithin(maxWeight, costFn, d.asScala) /** * Shifts elements emission in time by a specified amount. It allows to store elements * in internal buffer while waiting for next element to be emitted. Depending on the defined * [[akka.stream.DelayOverflowStrategy]] it might drop elements or backpressure the upstream if * there is no space available in the buffer. * * Delay precision is 10ms to avoid unnecessary timer scheduling cycles * * Internal buffer has default capacity 16. You can set buffer size by calling `addAttributes(inputBuffer)` * * '''Emits when''' there is a pending element in the buffer and configured time for this element elapsed * * EmitEarly - strategy do not wait to emit element if buffer is full * * '''Backpressures when''' depending on OverflowStrategy * * Backpressure - backpressures when buffer is full * * DropHead, DropTail, DropBuffer - never backpressures * * Fail - fails the stream if buffer gets full * * '''Completes when''' upstream completes and buffered elements have been drained * * '''Cancels when''' downstream cancels * * @param of time to shift all messages * @param strategy Strategy that is used when incoming elements cannot fit inside the buffer */ @Deprecated @deprecated("Use the overloaded one which accepts java.time.Duration instead.", since = "2.5.12") def delay(of: FiniteDuration, strategy: DelayOverflowStrategy): Flow[In, Out, Mat] = new Flow(delegate.delay(of, strategy)) /** * Shifts elements emission in time by a specified amount. It allows to store elements * in internal buffer while waiting for next element to be emitted. Depending on the defined * [[akka.stream.DelayOverflowStrategy]] it might drop elements or backpressure the upstream if * there is no space available in the buffer. * * Delay precision is 10ms to avoid unnecessary timer scheduling cycles * * Internal buffer has default capacity 16. You can set buffer size by calling `addAttributes(inputBuffer)` * * '''Emits when''' there is a pending element in the buffer and configured time for this element elapsed * * EmitEarly - strategy do not wait to emit element if buffer is full * * '''Backpressures when''' depending on OverflowStrategy * * Backpressure - backpressures when buffer is full * * DropHead, DropTail, DropBuffer - never backpressures * * Fail - fails the stream if buffer gets full * * '''Completes when''' upstream completes and buffered elements have been drained * * '''Cancels when''' downstream cancels * * @param of time to shift all messages * @param strategy Strategy that is used when incoming elements cannot fit inside the buffer */ @silent("deprecated") def delay(of: java.time.Duration, strategy: DelayOverflowStrategy): Flow[In, Out, Mat] = delay(of.asScala, strategy) /** * Shifts elements emission in time by an amount individually determined through delay strategy a specified amount. * It allows to store elements in internal buffer while waiting for next element to be emitted. Depending on the defined * [[akka.stream.DelayOverflowStrategy]] it might drop elements or backpressure the upstream if * there is no space available in the buffer. * * It determines delay for each ongoing element invoking `DelayStrategy.nextDelay(elem: T): FiniteDuration`. * * Note that elements are not re-ordered: if an element is given a delay much shorter than its predecessor, * it will still have to wait for the preceding element before being emitted. * It is also important to notice that [[DelayStrategy]] can be stateful. * * Delay precision is 10ms to avoid unnecessary timer scheduling cycles. * * Internal buffer has default capacity 16. You can set buffer size by calling `addAttributes(inputBuffer)` * * '''Emits when''' there is a pending element in the buffer and configured time for this element elapsed * * EmitEarly - strategy do not wait to emit element if buffer is full * * '''Backpressures when''' depending on OverflowStrategy * * Backpressure - backpressures when buffer is full * * DropHead, DropTail, DropBuffer - never backpressures * * Fail - fails the stream if buffer gets full * * '''Completes when''' upstream completes and buffered elements have been drained * * '''Cancels when''' downstream cancels * * @param delayStrategySupplier creates new [[DelayStrategy]] object for each materialization * @param overFlowStrategy Strategy that is used when incoming elements cannot fit inside the buffer */ def delayWith( delayStrategySupplier: Supplier[DelayStrategy[Out]], overFlowStrategy: DelayOverflowStrategy): Flow[In, Out, Mat] = new Flow(delegate.delayWith(() => DelayStrategy.asScala(delayStrategySupplier.get), overFlowStrategy)) /** * Discard the given number of elements at the beginning of the stream. * No elements will be dropped if `n` is zero or negative. * * '''Emits when''' the specified number of elements has been dropped already * * '''Backpressures when''' the specified number of elements has been dropped and downstream backpressures * * '''Completes when''' upstream completes * * '''Cancels when''' downstream cancels */ def drop(n: Long): javadsl.Flow[In, Out, Mat] = new Flow(delegate.drop(n)) /** * Discard the elements received within the given duration at beginning of the stream. * * '''Emits when''' the specified time elapsed and a new upstream element arrives * * '''Backpressures when''' downstream backpressures * * '''Completes when''' upstream completes * * '''Cancels when''' downstream cancels */ @Deprecated @deprecated("Use the overloaded one which accepts java.time.Duration instead.", since = "2.5.12") def dropWithin(d: FiniteDuration): javadsl.Flow[In, Out, Mat] = new Flow(delegate.dropWithin(d)) /** * Discard the elements received within the given duration at beginning of the stream. * * '''Emits when''' the specified time elapsed and a new upstream element arrives * * '''Backpressures when''' downstream backpressures * * '''Completes when''' upstream completes * * '''Cancels when''' downstream cancels */ @silent("deprecated") def dropWithin(d: java.time.Duration): javadsl.Flow[In, Out, Mat] = dropWithin(d.asScala) /** * Terminate processing (and cancel the upstream publisher) after predicate * returns false for the first time. When inclusive is `true`, include the element * for which the predicate returned `false`. * Due to input buffering some elements may have been requested from upstream publishers * that will then not be processed downstream of this step. * * The stream will be completed without producing any elements if predicate is false for * the first stream element. * * Adheres to the [[ActorAttributes.SupervisionStrategy]] attribute. * * '''Emits when''' the predicate is true * * '''Backpressures when''' downstream backpressures * * '''Completes when''' predicate returned false (or 1 after predicate returns false if `inclusive` or upstream completes * * '''Cancels when''' predicate returned false or downstream cancels * * See also [[Flow.limit]], [[Flow.limitWeighted]] */ def takeWhile(p: function.Predicate[Out], inclusive: Boolean): javadsl.Flow[In, Out, Mat] = new Flow(delegate.takeWhile(p.test, inclusive)) /** * Terminate processing (and cancel the upstream publisher) after predicate * returns false for the first time. When inclusive is `true`, include the element * for which the predicate returned `false`. * Due to input buffering some elements may have been requested from upstream publishers * that will then not be processed downstream of this step. * * The stream will be completed without producing any elements if predicate is false for * the first stream element. * * '''Emits when''' the predicate is true * * '''Backpressures when''' downstream backpressures * * '''Completes when''' predicate returned false (or 1 after predicate returns false if `inclusive` or upstream completes * * '''Cancels when''' predicate returned false or downstream cancels * * See also [[Flow.limit]], [[Flow.limitWeighted]] */ def takeWhile(p: function.Predicate[Out]): javadsl.Flow[In, Out, Mat] = takeWhile(p, false) /** * Discard elements at the beginning of the stream while predicate is true. * All elements will be taken after predicate returns false first time. * * Adheres to the [[ActorAttributes.SupervisionStrategy]] attribute. * * '''Emits when''' predicate returned false and for all following stream elements * * '''Backpressures when''' predicate returned false and downstream backpressures * * '''Completes when''' upstream completes * * '''Cancels when''' downstream cancels */ def dropWhile(p: function.Predicate[Out]): javadsl.Flow[In, Out, Mat] = new Flow(delegate.dropWhile(p.test)) /** * Recover allows to send last element on failure and gracefully complete the stream * Since the underlying failure signal onError arrives out-of-band, it might jump over existing elements. * This operator can recover the failure signal, but not the skipped elements, which will be dropped. * * Throwing an exception inside `recover` _will_ be logged on ERROR level automatically. * * '''Emits when''' element is available from the upstream or upstream is failed and pf returns an element * * '''Backpressures when''' downstream backpressures * * '''Completes when''' upstream completes or upstream failed with exception pf can handle * * '''Cancels when''' downstream cancels */ @deprecated("Use recoverWithRetries instead.", "2.4.4") def recover(pf: PartialFunction[Throwable, Out]): javadsl.Flow[In, Out, Mat] = new Flow(delegate.recover(pf)) /** * Recover allows to send last element on failure and gracefully complete the stream * Since the underlying failure signal onError arrives out-of-band, it might jump over existing elements. * This operator can recover the failure signal, but not the skipped elements, which will be dropped. * * Throwing an exception inside `recover` _will_ be logged on ERROR level automatically. * * '''Emits when''' element is available from the upstream or upstream is failed and pf returns an element * * '''Backpressures when''' downstream backpressures * * '''Completes when''' upstream completes or upstream failed with exception pf can handle * * '''Cancels when''' downstream cancels */ @deprecated("Use recoverWithRetries instead.", "2.4.4") def recover(clazz: Class[_ <: Throwable], supplier: Supplier[Out]): javadsl.Flow[In, Out, Mat] = recover { case elem if clazz.isInstance(elem) => supplier.get() } /** * While similar to [[recover]] this operator can be used to transform an error signal to a different one *without* logging * it as an error in the process. So in that sense it is NOT exactly equivalent to `recover(t => throw t2)` since recover * would log the `t2` error. * * Since the underlying failure signal onError arrives out-of-band, it might jump over existing elements. * This operator can recover the failure signal, but not the skipped elements, which will be dropped. * * Similarly to [[recover]] throwing an exception inside `mapError` _will_ be logged. * * '''Emits when''' element is available from the upstream or upstream is failed and pf returns an element * * '''Backpressures when''' downstream backpressures * * '''Completes when''' upstream completes or upstream failed with exception pf can handle * * '''Cancels when''' downstream cancels * */ def mapError(pf: PartialFunction[Throwable, Throwable]): javadsl.Flow[In, Out, Mat] = new Flow(delegate.mapError(pf)) /** * While similar to [[recover]] this operator can be used to transform an error signal to a different one *without* logging * it as an error in the process. So in that sense it is NOT exactly equivalent to `recover(t => throw t2)` since recover * would log the `t2` error. * * Since the underlying failure signal onError arrives out-of-band, it might jump over existing elements. * This operator can recover the failure signal, but not the skipped elements, which will be dropped. * * Similarly to [[recover]] throwing an exception inside `mapError` _will_ be logged. * * '''Emits when''' element is available from the upstream or upstream is failed and pf returns an element * * '''Backpressures when''' downstream backpressures * * '''Completes when''' upstream completes or upstream failed with exception pf can handle * * '''Cancels when''' downstream cancels * */ def mapError[E <: Throwable](clazz: Class[E], f: function.Function[E, Throwable]): javadsl.Flow[In, Out, Mat] = mapError { case err if clazz.isInstance(err) => f(clazz.cast(err)) } /** * RecoverWith allows to switch to alternative Source on flow failure. It will stay in effect after * a failure has been recovered so that each time there is a failure it is fed into the `pf` and a new * Source may be materialized. * * Since the underlying failure signal onError arrives out-of-band, it might jump over existing elements. * This operator can recover the failure signal, but not the skipped elements, which will be dropped. * * Throwing an exception inside `recoverWith` _will_ be logged on ERROR level automatically. * * '''Emits when''' element is available from the upstream or upstream is failed and element is available * from alternative Source * * '''Backpressures when''' downstream backpressures * * '''Completes when''' upstream completes or upstream failed with exception pf can handle * * '''Cancels when''' downstream cancels * */ @silent("deprecated") def recoverWith(pf: PartialFunction[Throwable, _ <: Graph[SourceShape[Out], NotUsed]]): javadsl.Flow[In, Out, Mat] = new Flow(delegate.recoverWith(pf)) /** * RecoverWith allows to switch to alternative Source on flow failure. It will stay in effect after * a failure has been recovered so that each time there is a failure it is fed into the `pf` and a new * Source may be materialized. * * Since the underlying failure signal onError arrives out-of-band, it might jump over existing elements. * This operator can recover the failure signal, but not the skipped elements, which will be dropped. * * Throwing an exception inside `recoverWith` _will_ be logged on ERROR level automatically. * * '''Emits when''' element is available from the upstream or upstream is failed and element is available * from alternative Source * * '''Backpressures when''' downstream backpressures * * '''Completes when''' upstream completes or upstream failed with exception pf can handle * * '''Cancels when''' downstream cancels * */ def recoverWith( clazz: Class[_ <: Throwable], supplier: Supplier[Graph[SourceShape[Out], NotUsed]]): javadsl.Flow[In, Out, Mat] = recoverWith { case elem if clazz.isInstance(elem) => supplier.get() } /** * RecoverWithRetries allows to switch to alternative Source on flow failure. It will stay in effect after * a failure has been recovered up to `attempts` number of times so that each time there is a failure * it is fed into the `pf` and a new Source may be materialized. Note that if you pass in 0, this won't * attempt to recover at all. * * A negative `attempts` number is interpreted as "infinite", which results in the exact same behavior as `recoverWith`. * * Since the underlying failure signal onError arrives out-of-band, it might jump over existing elements. * This operator can recover the failure signal, but not the skipped elements, which will be dropped. * * Throwing an exception inside `recoverWithRetries` _will_ be logged on ERROR level automatically. * * '''Emits when''' element is available from the upstream or upstream is failed and element is available * from alternative Source * * '''Backpressures when''' downstream backpressures * * '''Completes when''' upstream completes or upstream failed with exception pf can handle * * '''Cancels when''' downstream cancels * * @param attempts Maximum number of retries or -1 to retry indefinitely * @param pf Receives the failure cause and returns the new Source to be materialized if any */ def recoverWithRetries( attempts: Int, pf: PartialFunction[Throwable, Graph[SourceShape[Out], NotUsed]]): javadsl.Flow[In, Out, Mat] = new Flow(delegate.recoverWithRetries(attempts, pf)) /** * RecoverWithRetries allows to switch to alternative Source on flow failure. It will stay in effect after * a failure has been recovered up to `attempts` number of times so that each time there is a failure * it is fed into the `pf` and a new Source may be materialized. Note that if you pass in 0, this won't * attempt to recover at all. * * A negative `attempts` number is interpreted as "infinite", which results in the exact same behavior as `recoverWith`. * * Since the underlying failure signal onError arrives out-of-band, it might jump over existing elements. * This operator can recover the failure signal, but not the skipped elements, which will be dropped. * * Throwing an exception inside `recoverWithRetries` _will_ be logged on ERROR level automatically. * * '''Emits when''' element is available from the upstream or upstream is failed and element is available * from alternative Source * * '''Backpressures when''' downstream backpressures * * '''Completes when''' upstream completes or upstream failed with exception pf can handle * * '''Cancels when''' downstream cancels * * @param attempts Maximum number of retries or -1 to retry indefinitely * @param clazz the class object of the failure cause * @param supplier supply the new Source to be materialized */ def recoverWithRetries( attempts: Int, clazz: Class[_ <: Throwable], supplier: Supplier[Graph[SourceShape[Out], NotUsed]]): javadsl.Flow[In, Out, Mat] = recoverWithRetries(attempts, { case elem if clazz.isInstance(elem) => supplier.get() }) /** * Terminate processing (and cancel the upstream publisher) after the given * number of elements. Due to input buffering some elements may have been * requested from upstream publishers that will then not be processed downstream * of this step. * * The stream will be completed without producing any elements if `n` is zero * or negative. * * '''Emits when''' the specified number of elements to take has not yet been reached * * '''Backpressures when''' downstream backpressures * * '''Completes when''' the defined number of elements has been taken or upstream completes * * '''Cancels when''' the defined number of elements has been taken or downstream cancels * * See also [[Flow.limit]], [[Flow.limitWeighted]] */ def take(n: Long): javadsl.Flow[In, Out, Mat] = new Flow(delegate.take(n)) /** * Terminate processing (and cancel the upstream publisher) after the given * duration. Due to input buffering some elements may have been * requested from upstream publishers that will then not be processed downstream * of this step. * * Note that this can be combined with [[#take]] to limit the number of elements * within the duration. * * '''Emits when''' an upstream element arrives * * '''Backpressures when''' downstream backpressures * * '''Completes when''' upstream completes or timer fires * * '''Cancels when''' downstream cancels or timer fires * * See also [[Flow.limit]], [[Flow.limitWeighted]] */ @Deprecated @deprecated("Use the overloaded one which accepts java.time.Duration instead.", since = "2.5.12") def takeWithin(d: FiniteDuration): javadsl.Flow[In, Out, Mat] = new Flow(delegate.takeWithin(d)) /** * Terminate processing (and cancel the upstream publisher) after the given * duration. Due to input buffering some elements may have been * requested from upstream publishers that will then not be processed downstream * of this step. * * Note that this can be combined with [[#take]] to limit the number of elements * within the duration. * * '''Emits when''' an upstream element arrives * * '''Backpressures when''' downstream backpressures * * '''Completes when''' upstream completes or timer fires * * '''Cancels when''' downstream cancels or timer fires * * See also [[Flow.limit]], [[Flow.limitWeighted]] */ @silent("deprecated") def takeWithin(d: java.time.Duration): javadsl.Flow[In, Out, Mat] = takeWithin(d.asScala) /** * Allows a faster upstream to progress independently of a slower subscriber by conflating elements into a summary * until the subscriber is ready to accept them. For example a conflate step might average incoming numbers if the * upstream publisher is faster. * * This version of conflate allows to derive a seed from the first element and change the aggregated type to be * different than the input type. See [[Flow.conflate]] for a simpler version that does not change types. * * This element only rolls up elements if the upstream is faster, but if the downstream is faster it will not * duplicate elements. * * Adheres to the [[ActorAttributes.SupervisionStrategy]] attribute. * * '''Emits when''' downstream stops backpressuring and there is a conflated element available * * '''Backpressures when''' never * * '''Completes when''' upstream completes * * '''Cancels when''' downstream cancels * * see also [[Flow.conflate]] [[Flow.batch]] [[Flow.batchWeighted]] * * @param seed Provides the first state for a conflated value using the first unconsumed element as a start * @param aggregate Takes the currently aggregated value and the current pending element to produce a new aggregate * */ def conflateWithSeed[S]( seed: function.Function[Out, S], aggregate: function.Function2[S, Out, S]): javadsl.Flow[In, S, Mat] = new Flow(delegate.conflateWithSeed(seed.apply)(aggregate.apply)) /** * Allows a faster upstream to progress independently of a slower subscriber by conflating elements into a summary * until the subscriber is ready to accept them. For example a conflate step might average incoming numbers if the * upstream publisher is faster. * * This version of conflate does not change the output type of the stream. See [[Flow.conflateWithSeed]] for a * more flexible version that can take a seed function and transform elements while rolling up. * * This element only rolls up elements if the upstream is faster, but if the downstream is faster it will not * duplicate elements. * * Adheres to the [[ActorAttributes.SupervisionStrategy]] attribute. * * '''Emits when''' downstream stops backpressuring and there is a conflated element available * * '''Backpressures when''' never * * '''Completes when''' upstream completes * * '''Cancels when''' downstream cancels * * see also [[Flow.conflateWithSeed]] [[Flow.batch]] [[Flow.batchWeighted]] * * @param aggregate Takes the currently aggregated value and the current pending element to produce a new aggregate * */ def conflate(aggregate: function.Function2[Out, Out, Out]): javadsl.Flow[In, Out, Mat] = new Flow(delegate.conflate(aggregate.apply)) /** * Allows a faster upstream to progress independently of a slower subscriber by aggregating elements into batches * until the subscriber is ready to accept them. For example a batch step might store received elements in * an array up to the allowed max limit if the upstream publisher is faster. * * This element only rolls up elements if the upstream is faster, but if the downstream is faster it will not * duplicate elements. * * Adheres to the [[ActorAttributes.SupervisionStrategy]] attribute. * * '''Emits when''' downstream stops backpressuring and there is an aggregated element available * * '''Backpressures when''' there are `max` batched elements and 1 pending element and downstream backpressures * * '''Completes when''' upstream completes and there is no batched/pending element waiting * * '''Cancels when''' downstream cancels * * See also [[Flow.conflate]], [[Flow.batchWeighted]] * * @param max maximum number of elements to batch before backpressuring upstream (must be positive non-zero) * @param seed Provides the first state for a batched value using the first unconsumed element as a start * @param aggregate Takes the currently batched value and the current pending element to produce a new aggregate */ def batch[S]( max: Long, seed: function.Function[Out, S], aggregate: function.Function2[S, Out, S]): javadsl.Flow[In, S, Mat] = new Flow(delegate.batch(max, seed.apply)(aggregate.apply)) /** * Allows a faster upstream to progress independently of a slower subscriber by aggregating elements into batches * until the subscriber is ready to accept them. For example a batch step might concatenate `ByteString` * elements up to the allowed max limit if the upstream publisher is faster. * * This element only rolls up elements if the upstream is faster, but if the downstream is faster it will not * duplicate elements. * * Batching will apply for all elements, even if a single element cost is greater than the total allowed limit. * In this case, previous batched elements will be emitted, then the "heavy" element will be emitted (after * being applied with the `seed` function) without batching further elements with it, and then the rest of the * incoming elements are batched. * * '''Emits when''' downstream stops backpressuring and there is a batched element available * * '''Backpressures when''' there are `max` weighted batched elements + 1 pending element and downstream backpressures * * '''Completes when''' upstream completes and there is no batched/pending element waiting * * '''Cancels when''' downstream cancels * * See also [[Flow.conflate]], [[Flow.batch]] * * @param max maximum weight of elements to batch before backpressuring upstream (must be positive non-zero) * @param costFn a function to compute a single element weight * @param seed Provides the first state for a batched value using the first unconsumed element as a start * @param aggregate Takes the currently batched value and the current pending element to produce a new batch */ def batchWeighted[S]( max: Long, costFn: function.Function[Out, java.lang.Long], seed: function.Function[Out, S], aggregate: function.Function2[S, Out, S]): javadsl.Flow[In, S, Mat] = new Flow(delegate.batchWeighted(max, costFn.apply, seed.apply)(aggregate.apply)) /** * Allows a faster downstream to progress independently of a slower upstream by extrapolating elements from an older * element until new element comes from the upstream. For example an expand step might repeat the last element for * the subscriber until it receives an update from upstream. * * This element will never "drop" upstream elements as all elements go through at least one extrapolation step. * This means that if the upstream is actually faster than the upstream it will be backpressured by the downstream * subscriber. * * Expand does not support [[akka.stream.Supervision#restart]] and [[akka.stream.Supervision#resume]]. * Exceptions from the `expander` function will complete the stream with failure. * * See also [[#extrapolate]] for a version that always preserves the original element and allows for an initial "startup" element. * * '''Emits when''' downstream stops backpressuring * * '''Backpressures when''' downstream backpressures or iterator runs empty * * '''Completes when''' upstream completes * * '''Cancels when''' downstream cancels * * @param expander Takes the current extrapolation state to produce an output element and the next extrapolation * state. * @see [[#extrapolate]] */ def expand[U](expander: function.Function[Out, java.util.Iterator[U]]): javadsl.Flow[In, U, Mat] = new Flow(delegate.expand(in => expander(in).asScala)) /** * Allows a faster downstream to progress independent of a slower upstream. * * This is achieved by introducing "extrapolated" elements - based on those from upstream - whenever downstream * signals demand. * * Extrapolate does not support [[akka.stream.Supervision#restart]] and [[akka.stream.Supervision#resume]]. * Exceptions from the `extrapolate` function will complete the stream with failure. * * See also [[#expand]] for a version that can overwrite the original element. * * '''Emits when''' downstream stops backpressuring, AND EITHER upstream emits OR initial element is present OR * `extrapolate` is non-empty and applicable * * '''Backpressures when''' downstream backpressures or current `extrapolate` runs empty * * '''Completes when''' upstream completes and current `extrapolate` runs empty * * '''Cancels when''' downstream cancels * * @param extrapolator Takes the current upstream element and provides a sequence of "extrapolated" elements based * on the original, to be emitted in case downstream signals demand. * @see [[#expand]] */ def extrapolate(extrapolator: function.Function[Out @uncheckedVariance, java.util.Iterator[Out @uncheckedVariance]]) : javadsl.Flow[In, Out, Mat] = new Flow(delegate.extrapolate(in => extrapolator(in).asScala)) /** * Allows a faster downstream to progress independent of a slower upstream. * * This is achieved by introducing "extrapolated" elements - based on those from upstream - whenever downstream * signals demand. * * Extrapolate does not support [[akka.stream.Supervision#restart]] and [[akka.stream.Supervision#resume]]. * Exceptions from the `extrapolate` function will complete the stream with failure. * * See also [[#expand]] for a version that can overwrite the original element. * * '''Emits when''' downstream stops backpressuring, AND EITHER upstream emits OR initial element is present OR * `extrapolate` is non-empty and applicable * * '''Backpressures when''' downstream backpressures or current `extrapolate` runs empty * * '''Completes when''' upstream completes and current `extrapolate` runs empty * * '''Cancels when''' downstream cancels * * @param extrapolator Takes the current upstream element and provides a sequence of "extrapolated" elements based * on the original, to be emitted in case downstream signals demand. * @param initial The initial element to be emitted, in case upstream is able to stall the entire stream. * @see [[#expand]] */ def extrapolate( extrapolator: function.Function[Out @uncheckedVariance, java.util.Iterator[Out @uncheckedVariance]], initial: Out @uncheckedVariance): javadsl.Flow[In, Out, Mat] = new Flow(delegate.extrapolate(in => extrapolator(in).asScala, Some(initial))) /** * Adds a fixed size buffer in the flow that allows to store elements from a faster upstream until it becomes full. * Depending on the defined [[akka.stream.OverflowStrategy]] it might drop elements or backpressure the upstream if * there is no space available * * '''Emits when''' downstream stops backpressuring and there is a pending element in the buffer * * '''Backpressures when''' downstream backpressures or depending on OverflowStrategy: *
    *
  • Backpressure - backpressures when buffer is full
  • *
  • DropHead, DropTail, DropBuffer - never backpressures
  • *
  • Fail - fails the stream if buffer gets full
  • *
* * '''Completes when''' upstream completes and buffered elements have been drained * * '''Cancels when''' downstream cancels * * @param size The size of the buffer in element count * @param overflowStrategy Strategy that is used when incoming elements cannot fit inside the buffer */ def buffer(size: Int, overflowStrategy: OverflowStrategy): javadsl.Flow[In, Out, Mat] = new Flow(delegate.buffer(size, overflowStrategy)) /** * Takes up to `n` elements from the stream (less than `n` if the upstream completes before emitting `n` elements) * and returns a pair containing a strict sequence of the taken element * and a stream representing the remaining elements. If ''n'' is zero or negative, then this will return a pair * of an empty collection and a stream containing the whole upstream unchanged. * * In case of an upstream error, depending on the current state * - the master stream signals the error if less than `n` elements have been seen, and therefore the substream * has not yet been emitted * - the tail substream signals the error after the prefix and tail has been emitted by the main stream * (at that point the main stream has already completed) * * '''Emits when''' the configured number of prefix elements are available. Emits this prefix, and the rest * as a substream * * '''Backpressures when''' downstream backpressures or substream backpressures * * '''Completes when''' prefix elements have been consumed and substream has been consumed * * '''Cancels when''' downstream cancels or substream cancels */ def prefixAndTail(n: Int): javadsl.Flow[In, akka.japi.Pair[java.util.List[Out], javadsl.Source[Out, NotUsed]], Mat] = new Flow(delegate.prefixAndTail(n).map { case (taken, tail) => akka.japi.Pair(taken.asJava, tail.asJava) }) /** * This operation demultiplexes the incoming stream into separate output * streams, one for each element key. The key is computed for each element * using the given function. When a new key is encountered for the first time * a new substream is opened and subsequently fed with all elements belonging to * that key. * * WARNING: If `allowClosedSubstreamRecreation` is set to `false` (default behavior) the operator * keeps track of all keys of streams that have already been closed. If you expect an infinite * number of keys this can cause memory issues. Elements belonging to those keys are drained * directly and not send to the substream. * * Note: If `allowClosedSubstreamRecreation` is set to `true` substream completion and incoming * elements are subject to race-conditions. If elements arrive for a stream that is in the process * of closing these elements might get lost. * * The object returned from this method is not a normal [[Flow]], * it is a [[SubFlow]]. This means that after this operator all transformations * are applied to all encountered substreams in the same fashion. Substream mode * is exited either by closing the substream (i.e. connecting it to a [[Sink]]) * or by merging the substreams back together; see the `to` and `mergeBack` methods * on [[SubFlow]] for more information. * * It is important to note that the substreams also propagate back-pressure as * any other stream, which means that blocking one substream will block the `groupBy` * operator itself—and thereby all substreams—once all internal or * explicit buffers are filled. * * If the group by function `f` throws an exception and the supervision decision * is [[akka.stream.Supervision#stop]] the stream and substreams will be completed * with failure. * * If the group by function `f` throws an exception and the supervision decision * is [[akka.stream.Supervision#resume]] or [[akka.stream.Supervision#restart]] * the element is dropped and the stream and substreams continue. * * Function `f` MUST NOT return `null`. This will throw exception and trigger supervision decision mechanism. * * '''Emits when''' an element for which the grouping function returns a group that has not yet been created. * Emits the new group * * '''Backpressures when''' there is an element pending for a group whose substream backpressures * * '''Completes when''' upstream completes * * '''Cancels when''' downstream cancels and all substreams cancel * * @param maxSubstreams configures the maximum number of substreams (keys) * that are supported; if more distinct keys are encountered then the stream fails * @param f computes the key for each element * @param allowClosedSubstreamRecreation enables recreation of already closed substreams if elements with their * corresponding keys arrive after completion */ def groupBy[K]( maxSubstreams: Int, f: function.Function[Out, K], allowClosedSubstreamRecreation: Boolean): SubFlow[In, Out, Mat] = new SubFlow(delegate.groupBy(maxSubstreams, f.apply, allowClosedSubstreamRecreation)) /** * This operation demultiplexes the incoming stream into separate output * streams, one for each element key. The key is computed for each element * using the given function. When a new key is encountered for the first time * a new substream is opened and subsequently fed with all elements belonging to * that key. * * WARNING: The operator keeps track of all keys of streams that have already been closed. * If you expect an infinite number of keys this can cause memory issues. Elements belonging * to those keys are drained directly and not send to the substream. * * @see [[#groupBy]] */ def groupBy[K](maxSubstreams: Int, f: function.Function[Out, K]): SubFlow[In, Out, Mat] = new SubFlow(delegate.groupBy(maxSubstreams, f.apply, false)) /** * This operation applies the given predicate to all incoming elements and * emits them to a stream of output streams, always beginning a new one with * the current element if the given predicate returns true for it. This means * that for the following series of predicate values, three substreams will * be produced with lengths 1, 2, and 3: * * {{{ * false, // element goes into first substream * true, false, // elements go into second substream * true, false, false // elements go into third substream * }}} * * In case the *first* element of the stream matches the predicate, the first * substream emitted by splitWhen will start from that element. For example: * * {{{ * true, false, false // first substream starts from the split-by element * true, false // subsequent substreams operate the same way * }}} * * The object returned from this method is not a normal [[Flow]], * it is a [[SubFlow]]. This means that after this operator all transformations * are applied to all encountered substreams in the same fashion. Substream mode * is exited either by closing the substream (i.e. connecting it to a [[Sink]]) * or by merging the substreams back together; see the `to` and `mergeBack` methods * on [[SubFlow]] for more information. * * It is important to note that the substreams also propagate back-pressure as * any other stream, which means that blocking one substream will block the `splitWhen` * operator itself—and thereby all substreams—once all internal or * explicit buffers are filled. * * If the split predicate `p` throws an exception and the supervision decision * is [[akka.stream.Supervision#stop]] the stream and substreams will be completed * with failure. * * If the split predicate `p` throws an exception and the supervision decision * is [[akka.stream.Supervision#resume]] or [[akka.stream.Supervision#restart]] * the element is dropped and the stream and substreams continue. * * '''Emits when''' an element for which the provided predicate is true, opening and emitting * a new substream for subsequent element * * '''Backpressures when''' there is an element pending for the next substream, but the previous * is not fully consumed yet, or the substream backpressures * * '''Completes when''' upstream completes * * '''Cancels when''' downstream cancels and substreams cancel on `SubstreamCancelStrategy.drain()`, downstream * cancels or any substream cancels on `SubstreamCancelStrategy.propagate()` * * See also [[Flow.splitAfter]]. */ def splitWhen(p: function.Predicate[Out]): SubFlow[In, Out, Mat] = new SubFlow(delegate.splitWhen(p.test)) /** * This operation applies the given predicate to all incoming elements and * emits them to a stream of output streams, always beginning a new one with * the current element if the given predicate returns true for it. * * @see [[#splitWhen]] */ def splitWhen(substreamCancelStrategy: SubstreamCancelStrategy)(p: function.Predicate[Out]): SubFlow[In, Out, Mat] = new SubFlow(delegate.splitWhen(substreamCancelStrategy)(p.test)) /** * This operation applies the given predicate to all incoming elements and * emits them to a stream of output streams. It *ends* the current substream when the * predicate is true. This means that for the following series of predicate values, * three substreams will be produced with lengths 2, 2, and 3: * * {{{ * false, true, // elements go into first substream * false, true, // elements go into second substream * false, false, true // elements go into third substream * }}} * * The object returned from this method is not a normal [[Flow]], * it is a [[SubFlow]]. This means that after this operator all transformations * are applied to all encountered substreams in the same fashion. Substream mode * is exited either by closing the substream (i.e. connecting it to a [[Sink]]) * or by merging the substreams back together; see the `to` and `mergeBack` methods * on [[SubFlow]] for more information. * * It is important to note that the substreams also propagate back-pressure as * any other stream, which means that blocking one substream will block the `splitAfter` * operator itself—and thereby all substreams—once all internal or * explicit buffers are filled. * * If the split predicate `p` throws an exception and the supervision decision * is [[akka.stream.Supervision.Stop]] the stream and substreams will be completed * with failure. * * If the split predicate `p` throws an exception and the supervision decision * is [[akka.stream.Supervision.Resume]] or [[akka.stream.Supervision.Restart]] * the element is dropped and the stream and substreams continue. * * '''Emits when''' an element passes through. When the provided predicate is true it emits the element * and opens a new substream for subsequent element * * '''Backpressures when''' there is an element pending for the next substream, but the previous * is not fully consumed yet, or the substream backpressures * * '''Completes when''' upstream completes * * '''Cancels when''' downstream cancels and substreams cancel on `SubstreamCancelStrategy.drain`, downstream * cancels or any substream cancels on `SubstreamCancelStrategy.propagate` * * See also [[Flow.splitWhen]]. */ def splitAfter(p: function.Predicate[Out]): SubFlow[In, Out, Mat] = new SubFlow(delegate.splitAfter(p.test)) /** * This operation applies the given predicate to all incoming elements and * emits them to a stream of output streams. It *ends* the current substream when the * predicate is true. * * @see [[#splitAfter]] */ def splitAfter(substreamCancelStrategy: SubstreamCancelStrategy)(p: function.Predicate[Out]): SubFlow[In, Out, Mat] = new SubFlow(delegate.splitAfter(substreamCancelStrategy)(p.test)) /** * Transform each input element into a `Source` of output elements that is * then flattened into the output stream by concatenation, * fully consuming one Source after the other. * * '''Emits when''' a currently consumed substream has an element available * * '''Backpressures when''' downstream backpressures * * '''Completes when''' upstream completes and all consumed substreams complete * * '''Cancels when''' downstream cancels */ def flatMapConcat[T, M](f: function.Function[Out, _ <: Graph[SourceShape[T], M]]): Flow[In, T, Mat] = new Flow(delegate.flatMapConcat[T, M](x => f(x))) /** * Transform each input element into a `Source` of output elements that is * then flattened into the output stream by merging, where at most `breadth` * substreams are being consumed at any given time. * * '''Emits when''' a currently consumed substream has an element available * * '''Backpressures when''' downstream backpressures * * '''Completes when''' upstream completes and all consumed substreams complete * * '''Cancels when''' downstream cancels */ def flatMapMerge[T, M](breadth: Int, f: function.Function[Out, _ <: Graph[SourceShape[T], M]]): Flow[In, T, Mat] = new Flow(delegate.flatMapMerge(breadth, o => f(o))) /** * Concatenate the given [[Source]] to this [[Flow]], meaning that once this * Flow’s input is exhausted and all result elements have been generated, * the Source’s elements will be produced. * * Note that the [[Source]] is materialized together with this Flow and just kept * from producing elements by asserting back-pressure until its time comes. * * If this [[Flow]] gets upstream error - no elements from the given [[Source]] will be pulled. * * '''Emits when''' element is available from current stream or from the given [[Source]] when current is completed * * '''Backpressures when''' downstream backpressures * * '''Completes when''' given [[Source]] completes * * '''Cancels when''' downstream cancels */ def concat[M](that: Graph[SourceShape[Out], M]): javadsl.Flow[In, Out, Mat] = new Flow(delegate.concat(that)) /** * Concatenate the given [[Source]] to this [[Flow]], meaning that once this * Flow’s input is exhausted and all result elements have been generated, * the Source’s elements will be produced. * * Note that the [[Source]] is materialized together with this Flow and just kept * from producing elements by asserting back-pressure until its time comes. * * If this [[Flow]] gets upstream error - no elements from the given [[Source]] will be pulled. * * It is recommended to use the internally optimized `Keep.left` and `Keep.right` combiners * where appropriate instead of manually writing functions that pass through one of the values. * * @see [[#concat]] */ def concatMat[M, M2]( that: Graph[SourceShape[Out], M], matF: function.Function2[Mat, M, M2]): javadsl.Flow[In, Out, M2] = new Flow(delegate.concatMat(that)(combinerToScala(matF))) /** * Prepend the given [[Source]] to this [[Flow]], meaning that before elements * are generated from this Flow, the Source's elements will be produced until it * is exhausted, at which point Flow elements will start being produced. * * Note that this Flow will be materialized together with the [[Source]] and just kept * from producing elements by asserting back-pressure until its time comes. * * If the given [[Source]] gets upstream error - no elements from this [[Flow]] will be pulled. * * '''Emits when''' element is available from the given [[Source]] or from current stream when the [[Source]] is completed * * '''Backpressures when''' downstream backpressures * * '''Completes when''' this [[Flow]] completes * * '''Cancels when''' downstream cancels */ def prepend[M](that: Graph[SourceShape[Out], M]): javadsl.Flow[In, Out, Mat] = new Flow(delegate.prepend(that)) /** * Prepend the given [[Source]] to this [[Flow]], meaning that before elements * are generated from this Flow, the Source's elements will be produced until it * is exhausted, at which point Flow elements will start being produced. * * Note that this Flow will be materialized together with the [[Source]] and just kept * from producing elements by asserting back-pressure until its time comes. * * If the given [[Source]] gets upstream error - no elements from this [[Flow]] will be pulled. * * It is recommended to use the internally optimized `Keep.left` and `Keep.right` combiners * where appropriate instead of manually writing functions that pass through one of the values. * * @see [[#prepend]] */ def prependMat[M, M2]( that: Graph[SourceShape[Out], M], matF: function.Function2[Mat, M, M2]): javadsl.Flow[In, Out, M2] = new Flow(delegate.prependMat(that)(combinerToScala(matF))) /** * Provides a secondary source that will be consumed if this source completes without any * elements passing by. As soon as the first element comes through this stream, the alternative * will be cancelled. * * Note that this Flow will be materialized together with the [[Source]] and just kept * from producing elements by asserting back-pressure until its time comes or it gets * cancelled. * * On errors the operator is failed regardless of source of the error. * * '''Emits when''' element is available from first stream or first stream closed without emitting any elements and an element * is available from the second stream * * '''Backpressures when''' downstream backpressures * * '''Completes when''' the primary stream completes after emitting at least one element, when the primary stream completes * without emitting and the secondary stream already has completed or when the secondary stream completes * * '''Cancels when''' downstream cancels and additionally the alternative is cancelled as soon as an element passes * by from this stream. */ def orElse[M](secondary: Graph[SourceShape[Out], M]): javadsl.Flow[In, Out, Mat] = new Flow(delegate.orElse(secondary)) /** * Provides a secondary source that will be consumed if this source completes without any * elements passing by. As soon as the first element comes through this stream, the alternative * will be cancelled. * * It is recommended to use the internally optimized `Keep.left` and `Keep.right` combiners * where appropriate instead of manually writing functions that pass through one of the values. * * @see [[#orElse]] */ def orElseMat[M2, M3]( secondary: Graph[SourceShape[Out], M2], matF: function.Function2[Mat, M2, M3]): javadsl.Flow[In, Out, M3] = new Flow(delegate.orElseMat(secondary)(combinerToScala(matF))) /** * Attaches the given [[Sink]] to this [[Flow]], meaning that elements that passes * through will also be sent to the [[Sink]]. * * It is similar to [[#wireTap]] but will backpressure instead of dropping elements when the given [[Sink]] is not ready. * * '''Emits when''' element is available and demand exists both from the Sink and the downstream. * * '''Backpressures when''' downstream or Sink backpressures * * '''Completes when''' upstream completes * * '''Cancels when''' downstream or Sink cancels */ def alsoTo(that: Graph[SinkShape[Out], _]): javadsl.Flow[In, Out, Mat] = new Flow(delegate.alsoTo(that)) /** * Attaches the given [[Sink]] to this [[Flow]], meaning that elements that passes * through will also be sent to the [[Sink]]. * * It is similar to [[#wireTapMat]] but will backpressure instead of dropping elements when the given [[Sink]] is not ready. * * It is recommended to use the internally optimized `Keep.left` and `Keep.right` combiners * where appropriate instead of manually writing functions that pass through one of the values. * * @see [[#alsoTo]] */ def alsoToMat[M2, M3]( that: Graph[SinkShape[Out], M2], matF: function.Function2[Mat, M2, M3]): javadsl.Flow[In, Out, M3] = new Flow(delegate.alsoToMat(that)(combinerToScala(matF))) /** * Attaches the given [[Sink]] to this [[Flow]], meaning that elements will be sent to the [[Sink]] * instead of being passed through if the predicate `when` returns `true`. * * '''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''' any of the downstreams cancel */ def divertTo(that: Graph[SinkShape[Out], _], when: function.Predicate[Out]): javadsl.Flow[In, Out, Mat] = new Flow(delegate.divertTo(that, when.test)) /** * Attaches the given [[Sink]] to this [[Flow]], meaning that elements will be sent to the [[Sink]] * instead of being passed through if the predicate `when` returns `true`. * * @see [[#divertTo]] * * It is recommended to use the internally optimized `Keep.left` and `Keep.right` combiners * where appropriate instead of manually writing functions that pass through one of the values. */ def divertToMat[M2, M3]( that: Graph[SinkShape[Out], M2], when: function.Predicate[Out], matF: function.Function2[Mat, M2, M3]): javadsl.Flow[In, Out, M3] = new Flow(delegate.divertToMat(that, when.test)(combinerToScala(matF))) /** * Attaches the given [[Sink]] to this [[Flow]] as a wire tap, meaning that elements that pass * through will also be sent to the wire-tap Sink, without the latter affecting the mainline flow. * If the wire-tap Sink backpressures, elements that would've been sent to it will be dropped instead. * * It is similar to [[#alsoTo]] which does backpressure instead of dropping elements. * * '''Emits when''' element is available and demand exists from the downstream; the element will * also be sent to the wire-tap Sink if there is demand. * * '''Backpressures when''' downstream backpressures * * '''Completes when''' upstream completes * * '''Cancels when''' downstream cancels */ def wireTap(that: Graph[SinkShape[Out], _]): javadsl.Flow[In, Out, Mat] = new Flow(delegate.wireTap(that)) /** * Attaches the given [[Sink]] to this [[Flow]] as a wire tap, meaning that elements that pass * through will also be sent to the wire-tap Sink, without the latter affecting the mainline flow. * If the wire-tap Sink backpressures, elements that would've been sent to it will be dropped instead. * * It is similar to [[#alsoToMat]] which does backpressure instead of dropping elements. * * It is recommended to use the internally optimized `Keep.left` and `Keep.right` combiners * where appropriate instead of manually writing functions that pass through one of the values. * * @see [[#wireTap]] */ def wireTapMat[M2, M3]( that: Graph[SinkShape[Out], M2], matF: function.Function2[Mat, M2, M3]): javadsl.Flow[In, Out, M3] = new Flow(delegate.wireTapMat(that)(combinerToScala(matF))) /** * Interleave is a deterministic merge of the given [[Source]] with elements of this [[Flow]]. * It first emits `segmentSize` number of elements from this flow to downstream, then - same amount for `that` source, * then repeat process. * * Example: * {{{ * Source src = Source.from(Arrays.asList(1, 2, 3)) * Flow flow = flow.interleave(Source.from(Arrays.asList(4, 5, 6, 7)), 2) * src.via(flow) // 1, 2, 4, 5, 3, 6, 7 * }}} * * After one of upstreams is complete than all the rest elements will be emitted from the second one * * If this [[Flow]] or [[Source]] gets upstream error - stream completes with failure. * * '''Emits when''' element is available from the currently consumed upstream * * '''Backpressures when''' downstream backpressures. Signal to current * upstream, switch to next upstream when received `segmentSize` elements * * '''Completes when''' the [[Flow]] and given [[Source]] completes * * '''Cancels when''' downstream cancels */ def interleave(that: Graph[SourceShape[Out], _], segmentSize: Int): javadsl.Flow[In, Out, Mat] = interleave(that, segmentSize, eagerClose = false) /** * Interleave is a deterministic merge of the given [[Source]] with elements of this [[Flow]]. * It first emits `segmentSize` number of elements from this flow to downstream, then - same amount for `that` source, * then repeat process. * * If eagerClose is false and one of the upstreams complete the elements from the other upstream will continue passing * through the interleave operator. If eagerClose is true and one of the upstream complete interleave will cancel the * other upstream and complete itself. * * If this [[Flow]] or [[Source]] gets upstream error - stream completes with failure. * * '''Emits when''' element is available from the currently consumed upstream * * '''Backpressures when''' downstream backpressures. Signal to current * upstream, switch to next upstream when received `segmentSize` elements * * '''Completes when''' the [[Flow]] and given [[Source]] completes * * '''Cancels when''' downstream cancels */ def interleave(that: Graph[SourceShape[Out], _], segmentSize: Int, eagerClose: Boolean): javadsl.Flow[In, Out, Mat] = new Flow(delegate.interleave(that, segmentSize, eagerClose)) /** * Interleave is a deterministic merge of the given [[Source]] with elements of this [[Flow]]. * It first emits `segmentSize` number of elements from this flow to downstream, then - same amount for `that` source, * then repeat process. * * After one of upstreams is complete than all the rest elements will be emitted from the second one * * If this [[Flow]] or [[Source]] gets upstream error - stream completes with failure. * * It is recommended to use the internally optimized `Keep.left` and `Keep.right` combiners * where appropriate instead of manually writing functions that pass through one of the values. * * @see [[#interleave]] */ def interleaveMat[M, M2]( that: Graph[SourceShape[Out], M], segmentSize: Int, matF: function.Function2[Mat, M, M2]): javadsl.Flow[In, Out, M2] = interleaveMat(that, segmentSize, eagerClose = false, matF) /** * Interleave is a deterministic merge of the given [[Source]] with elements of this [[Flow]]. * It first emits `segmentSize` number of elements from this flow to downstream, then - same amount for `that` source, * then repeat process. * * If eagerClose is false and one of the upstreams complete the elements from the other upstream will continue passing * through the interleave operator. If eagerClose is true and one of the upstream complete interleave will cancel the * other upstream and complete itself. * * If this [[Flow]] or [[Source]] gets upstream error - stream completes with failure. * * It is recommended to use the internally optimized `Keep.left` and `Keep.right` combiners * where appropriate instead of manually writing functions that pass through one of the values. * * @see [[#interleave]] */ def interleaveMat[M, M2]( that: Graph[SourceShape[Out], M], segmentSize: Int, eagerClose: Boolean, matF: function.Function2[Mat, M, M2]): javadsl.Flow[In, Out, M2] = new Flow(delegate.interleaveMat(that, segmentSize, eagerClose)(combinerToScala(matF))) /** * Merge the given [[Source]] to this [[Flow]], taking elements as they arrive from input streams, * picking randomly when several elements ready. * * '''Emits when''' one of the inputs has an element available * * '''Backpressures when''' downstream backpressures * * '''Completes when''' all upstreams complete * * '''Cancels when''' downstream cancels */ def merge(that: Graph[SourceShape[Out], _]): javadsl.Flow[In, Out, Mat] = merge(that, eagerComplete = false) /** * Merge the given [[Source]] to this [[Flow]], taking elements as they arrive from input streams, * picking randomly when several 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 */ def merge(that: Graph[SourceShape[Out], _], eagerComplete: Boolean): javadsl.Flow[In, Out, Mat] = new Flow(delegate.merge(that, eagerComplete)) /** * Merge the given [[Source]] to this [[Flow]], taking elements as they arrive from input streams, * picking randomly when several elements ready. * * It is recommended to use the internally optimized `Keep.left` and `Keep.right` combiners * where appropriate instead of manually writing functions that pass through one of the values. * * @see [[#merge]] */ def mergeMat[M, M2]( that: Graph[SourceShape[Out], M], matF: function.Function2[Mat, M, M2]): javadsl.Flow[In, Out, M2] = mergeMat(that, matF, eagerComplete = false) /** * Merge the given [[Source]] to this [[Flow]], taking elements as they arrive from input streams, * picking randomly when several elements ready. * * It is recommended to use the internally optimized `Keep.left` and `Keep.right` combiners * where appropriate instead of manually writing functions that pass through one of the values. * * @see [[#merge]] */ def mergeMat[M, M2]( that: Graph[SourceShape[Out], M], matF: function.Function2[Mat, M, M2], eagerComplete: Boolean): javadsl.Flow[In, Out, M2] = new Flow(delegate.mergeMat(that, eagerComplete)(combinerToScala(matF))) /** * 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 input stream emitted at least one element. * * '''Emits when''' an 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) */ def mergeLatest( that: Graph[SourceShape[Out], _], eagerComplete: Boolean): javadsl.Flow[In, java.util.List[Out], Mat] = new Flow(delegate.mergeLatest(that, eagerComplete).map(_.asJava)) /** * 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 input stream emitted at least one element. * * It is recommended to use the internally optimized `Keep.left` and `Keep.right` combiners * where appropriate instead of manually writing functions that pass through one of the values. */ def mergeLatestMat[Mat2, Mat3]( that: Graph[SourceShape[Out], Mat2], eagerComplete: Boolean, matF: function.Function2[Mat, Mat2, Mat3]): javadsl.Flow[In, java.util.List[Out], Mat3] = new Flow(delegate.mergeLatestMat(that, eagerComplete)(combinerToScala(matF))).map(_.asJava) /** * Merge two sources. Prefer one source if both sources have elements ready. * * '''emits''' when one of the inputs has an element available. If multiple have elements available, prefer the 'right' one when 'preferred' is 'true', or the 'left' one when 'preferred' is 'false'. * * '''backpressures''' when downstream backpressures * * '''completes''' when all upstreams complete (This behavior is changeable to completing when any upstream completes by setting `eagerComplete=true`.) */ def mergePreferred( that: Graph[SourceShape[Out], _], preferred: Boolean, eagerComplete: Boolean): javadsl.Flow[In, Out, Mat] = new Flow(delegate.mergePreferred(that, preferred, eagerComplete)) /** * Merge two sources. Prefer one source if both sources have elements ready. * * It is recommended to use the internally optimized `Keep.left` and `Keep.right` combiners * where appropriate instead of manually writing functions that pass through one of the values. */ def mergePreferredMat[Mat2, Mat3]( that: Graph[SourceShape[Out], Mat2], preferred: Boolean, eagerComplete: Boolean, matF: function.Function2[Mat, Mat2, Mat3]): javadsl.Flow[In, Out, Mat3] = new Flow(delegate.mergePreferredMat(that, preferred, eagerComplete)(combinerToScala(matF))) /** * Merge two sources. Prefer the sources depending on the 'priority' parameters. * * '''emits''' when one of the inputs has an element available, preferring inputs based on the 'priority' parameters if both have elements available * * '''backpressures''' when downstream backpressures * * '''completes''' when both upstreams complete (This behavior is changeable to completing when any upstream completes by setting `eagerComplete=true`.) */ def mergePrioritized( that: Graph[SourceShape[Out], _], leftPriority: Int, rightPriority: Int, eagerComplete: Boolean): javadsl.Flow[In, Out, Mat] = new Flow(delegate.mergePrioritized(that, leftPriority, rightPriority, eagerComplete)) /** * Merge two sources. Prefer the sources depending on the 'priority' parameters. * * It is recommended to use the internally optimized `Keep.left` and `Keep.right` combiners * where appropriate instead of manually writing functions that pass through one of the values. */ def mergePrioritizedMat[Mat2, Mat3]( that: Graph[SourceShape[Out], Mat2], leftPriority: Int, rightPriority: Int, eagerComplete: Boolean, matF: function.Function2[Mat, Mat2, Mat3]): javadsl.Flow[In, Out, Mat3] = new Flow(delegate.mergePrioritizedMat(that, leftPriority, rightPriority, eagerComplete)(combinerToScala(matF))) /** * Merge the given [[Source]] to this [[Flow]], taking elements as they arrive from input streams, * picking always the smallest of the available elements (waiting for one element from each side * to be available). This means that possible contiguity of the input streams is not exploited to avoid * waiting for elements, this merge will block when one of the inputs does not have more elements (and * does not complete). * * '''Emits when''' all of the inputs have an element available * * '''Backpressures when''' downstream backpressures * * '''Completes when''' all upstreams complete * * '''Cancels when''' downstream cancels */ def mergeSorted[M](that: Graph[SourceShape[Out], M], comp: Comparator[Out]): javadsl.Flow[In, Out, Mat] = new Flow(delegate.mergeSorted(that)(Ordering.comparatorToOrdering(comp))) /** * Merge the given [[Source]] to this [[Flow]], taking elements as they arrive from input streams, * picking always the smallest of the available elements (waiting for one element from each side * to be available). This means that possible contiguity of the input streams is not exploited to avoid * waiting for elements, this merge will block when one of the inputs does not have more elements (and * does not complete). * * It is recommended to use the internally optimized `Keep.left` and `Keep.right` combiners * where appropriate instead of manually writing functions that pass through one of the values. * * @see [[#mergeSorted]]. */ def mergeSortedMat[Mat2, Mat3]( that: Graph[SourceShape[Out], Mat2], comp: Comparator[Out], matF: function.Function2[Mat, Mat2, Mat3]): javadsl.Flow[In, Out, Mat3] = new Flow(delegate.mergeSortedMat(that)(combinerToScala(matF))(Ordering.comparatorToOrdering(comp))) /** * Combine the elements of current [[Flow]] and the given [[Source]] into a stream of tuples. * * '''Emits when''' all of the inputs have an element available * * '''Backpressures when''' downstream backpressures * * '''Completes when''' any upstream completes * * '''Cancels when''' downstream cancels */ def zip[T](source: Graph[SourceShape[T], _]): javadsl.Flow[In, Out Pair T, Mat] = zipMat(source, Keep.left) /** * Combine the elements of current [[Flow]] and the given [[Source]] into a stream of tuples. * * It is recommended to use the internally optimized `Keep.left` and `Keep.right` combiners * where appropriate instead of manually writing functions that pass through one of the values. * * @see [[#zip]] */ def zipMat[T, M, M2]( that: Graph[SourceShape[T], M], matF: function.Function2[Mat, M, M2]): javadsl.Flow[In, Out Pair T, M2] = this.viaMat( Flow.fromGraph( GraphDSL.create(that, new function.Function2[GraphDSL.Builder[M], SourceShape[T], FlowShape[Out, Out Pair T]] { def apply(b: GraphDSL.Builder[M], s: SourceShape[T]): FlowShape[Out, Out Pair T] = { val zip: FanInShape2[Out, T, Out Pair T] = b.add(Zip.create[Out, T]) b.from(s).toInlet(zip.in1) FlowShape(zip.in0, zip.out) } })), matF) /** * Combine the elements of current flow and the given [[Source]] into a stream of tuples. * * '''Emits when''' at first emits when both inputs emit, and then as long as any input emits (coupled to the default value of the completed input). * * '''Backpressures when''' downstream backpressures * * '''Completes when''' all upstream completes * * '''Cancels when''' downstream cancels */ def zipAll[U, A >: Out](that: Graph[SourceShape[U], _], thisElem: A, thatElem: U): Flow[In, Pair[A, U], Mat] = new Flow(delegate.zipAll(that, thisElem, thatElem).map { case (a, u) => Pair.create(a, u) }) /** * Combine the elements of current flow and the given [[Source]] into a stream of tuples. * * @see [[#zipAll]] * * '''Emits when''' at first emits when both inputs emit, and then as long as any input emits (coupled to the default value of the completed input). * * '''Backpressures when''' downstream backpressures * * '''Completes when''' all upstream completes * * '''Cancels when''' downstream cancels */ def zipAllMat[U, Mat2, Mat3, A >: Out](that: Graph[SourceShape[U], Mat2], thisElem: A, thatElem: U)( matF: (Mat, Mat2) => Mat3): Flow[In, Pair[A, U], Mat3] = new Flow(delegate.zipAllMat(that, thisElem, thatElem)(matF).map { case (a, u) => Pair.create(a, u) }) /** * Combine the elements of 2 streams into a stream of tuples, picking always the latest element of each. * * A `ZipLatest` has a `left` and a `right` input port and one `out` 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 * * '''Cancels when''' downstream cancels */ def zipLatest[T](source: Graph[SourceShape[T], _]): javadsl.Flow[In, Out Pair T, Mat] = zipLatestMat(source, Keep.left) /** * Combine the elements of current [[Flow]] and the given [[Source]] into a stream of tuples, picking always the latest element of each. * * It is recommended to use the internally optimized `Keep.left` and `Keep.right` combiners * where appropriate instead of manually writing functions that pass through one of the values. * * @see [[#zipLatest]] */ def zipLatestMat[T, M, M2]( that: Graph[SourceShape[T], M], matF: function.Function2[Mat, M, M2]): javadsl.Flow[In, Out Pair T, M2] = this.viaMat( Flow.fromGraph( GraphDSL.create(that, new function.Function2[GraphDSL.Builder[M], SourceShape[T], FlowShape[Out, Out Pair T]] { def apply(b: GraphDSL.Builder[M], s: SourceShape[T]): FlowShape[Out, Out Pair T] = { val zip: FanInShape2[Out, T, Out Pair T] = b.add(ZipLatest.create[Out, T]) b.from(s).toInlet(zip.in1) FlowShape(zip.in0, zip.out) } })), matF) /** * Put together the elements of current [[Flow]] and the given [[Source]] * into a stream of combined elements using a combiner function. * * '''Emits when''' all of the inputs have an element available * * '''Backpressures when''' downstream backpressures * * '''Completes when''' any upstream completes * * '''Cancels when''' downstream cancels */ def zipWith[Out2, Out3]( that: Graph[SourceShape[Out2], _], combine: function.Function2[Out, Out2, Out3]): javadsl.Flow[In, Out3, Mat] = new Flow(delegate.zipWith[Out2, Out3](that)(combinerToScala(combine))) /** * Put together the elements of current [[Flow]] and the given [[Source]] * into a stream of combined elements using a combiner function. * * It is recommended to use the internally optimized `Keep.left` and `Keep.right` combiners * where appropriate instead of manually writing functions that pass through one of the values. * * @see [[#zipWith]] */ def zipWithMat[Out2, Out3, M, M2]( that: Graph[SourceShape[Out2], M], combine: function.Function2[Out, Out2, Out3], matF: function.Function2[Mat, M, M2]): javadsl.Flow[In, Out3, M2] = new Flow(delegate.zipWithMat[Out2, Out3, M, M2](that)(combinerToScala(combine))(combinerToScala(matF))) /** * 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. * * 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 */ def zipLatestWith[Out2, Out3]( that: Graph[SourceShape[Out2], _], combine: function.Function2[Out, Out2, Out3]): javadsl.Flow[In, Out3, Mat] = new Flow(delegate.zipLatestWith[Out2, Out3](that)(combinerToScala(combine))) /** * Put together the elements of current [[Flow]] and the given [[Source]] * into a stream of combined elements using a combiner function, picking always the latest element of each. * * It is recommended to use the internally optimized `Keep.left` and `Keep.right` combiners * where appropriate instead of manually writing functions that pass through one of the values. * * @see [[#zipLatestWith]] */ def zipLatestWithMat[Out2, Out3, M, M2]( that: Graph[SourceShape[Out2], M], combine: function.Function2[Out, Out2, Out3], matF: function.Function2[Mat, M, M2]): javadsl.Flow[In, Out3, M2] = new Flow(delegate.zipLatestWithMat[Out2, Out3, M, M2](that)(combinerToScala(combine))(combinerToScala(matF))) /** * Combine the elements of current flow into a stream of tuples consisting * of all elements paired with their index. Indices start at 0. * * '''Emits when''' upstream emits an element and is paired with their index * * '''Backpressures when''' downstream backpressures * * '''Completes when''' upstream completes * * '''Cancels when''' downstream cancels */ def zipWithIndex: Flow[In, Pair[Out, java.lang.Long], Mat] = new Flow(delegate.zipWithIndex.map { case (elem, index) => Pair[Out, java.lang.Long](elem, index) }) /** * If the first element has not passed through this operator before the provided timeout, the stream is failed * with a [[java.util.concurrent.TimeoutException]]. * * '''Emits when''' upstream emits an element * * '''Backpressures when''' downstream backpressures * * '''Completes when''' upstream completes or fails if timeout elapses before first element arrives * * '''Cancels when''' downstream cancels */ @Deprecated @deprecated("Use the overloaded one which accepts java.time.Duration instead.", since = "2.5.12") def initialTimeout(timeout: FiniteDuration): javadsl.Flow[In, Out, Mat] = new Flow(delegate.initialTimeout(timeout)) /** * If the first element has not passed through this operator before the provided timeout, the stream is failed * with a [[java.util.concurrent.TimeoutException]]. * * '''Emits when''' upstream emits an element * * '''Backpressures when''' downstream backpressures * * '''Completes when''' upstream completes or fails if timeout elapses before first element arrives * * '''Cancels when''' downstream cancels */ @silent("deprecated") def initialTimeout(timeout: java.time.Duration): javadsl.Flow[In, Out, Mat] = initialTimeout(timeout.asScala) /** * If the completion of the stream does not happen until the provided timeout, the stream is failed * with a [[java.util.concurrent.TimeoutException]]. * * '''Emits when''' upstream emits an element * * '''Backpressures when''' downstream backpressures * * '''Completes when''' upstream completes or fails if timeout elapses before upstream completes * * '''Cancels when''' downstream cancels */ @Deprecated @deprecated("Use the overloaded one which accepts java.time.Duration instead.", since = "2.5.12") def completionTimeout(timeout: FiniteDuration): javadsl.Flow[In, Out, Mat] = new Flow(delegate.completionTimeout(timeout)) /** * If the completion of the stream does not happen until the provided timeout, the stream is failed * with a [[java.util.concurrent.TimeoutException]]. * * '''Emits when''' upstream emits an element * * '''Backpressures when''' downstream backpressures * * '''Completes when''' upstream completes or fails if timeout elapses before upstream completes * * '''Cancels when''' downstream cancels */ @silent("deprecated") def completionTimeout(timeout: java.time.Duration): javadsl.Flow[In, Out, Mat] = completionTimeout(timeout.asScala) /** * If the time between two processed elements exceeds the provided timeout, the stream is failed * with a [[java.util.concurrent.TimeoutException]]. The timeout is checked periodically, * so the resolution of the check is one period (equals to timeout value). * * '''Emits when''' upstream emits an element * * '''Backpressures when''' downstream backpressures * * '''Completes when''' upstream completes or fails if timeout elapses between two emitted elements * * '''Cancels when''' downstream cancels */ @Deprecated @deprecated("Use the overloaded one which accepts java.time.Duration instead.", since = "2.5.12") def idleTimeout(timeout: FiniteDuration): javadsl.Flow[In, Out, Mat] = new Flow(delegate.idleTimeout(timeout)) /** * If the time between two processed elements exceeds the provided timeout, the stream is failed * with a [[java.util.concurrent.TimeoutException]]. The timeout is checked periodically, * so the resolution of the check is one period (equals to timeout value). * * '''Emits when''' upstream emits an element * * '''Backpressures when''' downstream backpressures * * '''Completes when''' upstream completes or fails if timeout elapses between two emitted elements * * '''Cancels when''' downstream cancels */ @silent("deprecated") def idleTimeout(timeout: java.time.Duration): javadsl.Flow[In, Out, Mat] = idleTimeout(timeout.asScala) /** * If the time between the emission of an element and the following downstream demand exceeds the provided timeout, * the stream is failed with a [[java.util.concurrent.TimeoutException]]. The timeout is checked periodically, * so the resolution of the check is one period (equals to timeout value). * * '''Emits when''' upstream emits an element * * '''Backpressures when''' downstream backpressures * * '''Completes when''' upstream completes or fails if timeout elapses between element emission and downstream demand. * * '''Cancels when''' downstream cancels */ @Deprecated @deprecated("Use the overloaded one which accepts java.time.Duration instead.", since = "2.5.12") def backpressureTimeout(timeout: FiniteDuration): javadsl.Flow[In, Out, Mat] = new Flow(delegate.backpressureTimeout(timeout)) /** * If the time between the emission of an element and the following downstream demand exceeds the provided timeout, * the stream is failed with a [[java.util.concurrent.TimeoutException]]. The timeout is checked periodically, * so the resolution of the check is one period (equals to timeout value). * * '''Emits when''' upstream emits an element * * '''Backpressures when''' downstream backpressures * * '''Completes when''' upstream completes or fails if timeout elapses between element emission and downstream demand. * * '''Cancels when''' downstream cancels */ @silent("deprecated") def backpressureTimeout(timeout: java.time.Duration): javadsl.Flow[In, Out, Mat] = backpressureTimeout(timeout.asScala) /** * Injects additional elements if upstream does not emit for a configured amount of time. In other words, this * operator attempts to maintains a base rate of emitted elements towards the downstream. * * If the downstream backpressures then no element is injected until downstream demand arrives. Injected elements * do not accumulate during this period. * * Upstream elements are always preferred over injected elements. * * '''Emits when''' upstream emits an element or if the upstream was idle for the configured period * * '''Backpressures when''' downstream backpressures * * '''Completes when''' upstream completes * * '''Cancels when''' downstream cancels */ @Deprecated @deprecated("Use the overloaded one which accepts java.time.Duration instead.", since = "2.5.12") def keepAlive(maxIdle: FiniteDuration, injectedElem: function.Creator[Out]): javadsl.Flow[In, Out, Mat] = new Flow(delegate.keepAlive(maxIdle, () => injectedElem.create())) /** * Injects additional elements if upstream does not emit for a configured amount of time. In other words, this * operator attempts to maintains a base rate of emitted elements towards the downstream. * * If the downstream backpressures then no element is injected until downstream demand arrives. Injected elements * do not accumulate during this period. * * Upstream elements are always preferred over injected elements. * * '''Emits when''' upstream emits an element or if the upstream was idle for the configured period * * '''Backpressures when''' downstream backpressures * * '''Completes when''' upstream completes * * '''Cancels when''' downstream cancels */ @silent("deprecated") def keepAlive(maxIdle: java.time.Duration, injectedElem: function.Creator[Out]): javadsl.Flow[In, Out, Mat] = keepAlive(maxIdle.asScala, injectedElem) /** * Sends elements downstream with speed limited to `elements/per`. In other words, this operator set the maximum rate * for emitting messages. This operator works for streams where all elements have the same cost or length. * * Throttle implements the token bucket model. There is a bucket with a given token capacity (burst size). * Tokens drops into the bucket at a given rate and can be `spared` for later use up to bucket capacity * to allow some burstiness. Whenever stream wants to send an element, it takes as many * tokens from the bucket as element costs. If there isn't any, throttle waits until the * bucket accumulates enough tokens. Elements that costs more than the allowed burst will be delayed proportionally * to their cost minus available tokens, meeting the target rate. Bucket is full when stream just materialized and * started. * * The burst size is calculated based on the given rate (`cost/per`) as 0.1 * rate, for example: * - rate < 20/second => burst size 1 * - rate 20/second => burst size 2 * - rate 100/second => burst size 10 * - rate 200/second => burst size 20 * * The throttle `mode` is [[akka.stream.ThrottleMode.Shaping]], which makes pauses before emitting messages to * meet throttle rate. * * '''Emits when''' upstream emits an element and configured time per each element elapsed * * '''Backpressures when''' downstream backpressures or the incoming rate is higher than the speed limit * * '''Completes when''' upstream completes * * '''Cancels when''' downstream cancels * */ def throttle(elements: Int, per: java.time.Duration): javadsl.Flow[In, Out, Mat] = new Flow(delegate.throttle(elements, per.asScala)) /** * Sends elements downstream with speed limited to `elements/per`. In other words, this operator set the maximum rate * for emitting messages. This operator works for streams where all elements have the same cost or length. * * Throttle implements the token bucket model. There is a bucket with a given token capacity (burst size or maximumBurst). * Tokens drops into the bucket at a given rate and can be `spared` for later use up to bucket capacity * to allow some burstiness. Whenever stream wants to send an element, it takes as many * tokens from the bucket as element costs. If there isn't any, throttle waits until the * bucket accumulates enough tokens. Elements that costs more than the allowed burst will be delayed proportionally * to their cost minus available tokens, meeting the target rate. Bucket is full when stream just materialized and started. * * Parameter `mode` manages behavior when upstream is faster than throttle rate: * - [[akka.stream.ThrottleMode.Shaping]] makes pauses before emitting messages to meet throttle rate * - [[akka.stream.ThrottleMode.Enforcing]] fails with exception when upstream is faster than throttle rate * * It is recommended to use non-zero burst sizes as they improve both performance and throttling precision by allowing * the implementation to avoid using the scheduler when input rates fall below the enforced limit and to reduce * most of the inaccuracy caused by the scheduler resolution (which is in the range of milliseconds). * * WARNING: Be aware that throttle is using scheduler to slow down the stream. This scheduler has minimal time of triggering * next push. Consequently it will slow down the stream as it has minimal pause for emitting. This can happen in * case burst is 0 and speed is higher than 30 events per second. You need to increase the `maximumBurst` if * elements arrive with small interval (30 milliseconds or less). Use the overloaded `throttle` method without * `maximumBurst` parameter to automatically calculate the `maximumBurst` based on the given rate (`cost/per`). * In other words the throttler always enforces the rate limit when `maximumBurst` parameter is given, but in * certain cases (mostly due to limited scheduler resolution) it enforces a tighter bound than what was prescribed. * * '''Emits when''' upstream emits an element and configured time per each element elapsed * * '''Backpressures when''' downstream backpressures or the incoming rate is higher than the speed limit * * '''Completes when''' upstream completes * * '''Cancels when''' downstream cancels * */ @Deprecated @deprecated("Use the overloaded one which accepts java.time.Duration instead.", since = "2.5.12") def throttle(elements: Int, per: FiniteDuration, maximumBurst: Int, mode: ThrottleMode): javadsl.Flow[In, Out, Mat] = new Flow(delegate.throttle(elements, per, maximumBurst, mode)) /** * Sends elements downstream with speed limited to `elements/per`. In other words, this operator set the maximum rate * for emitting messages. This operator works for streams where all elements have the same cost or length. * * Throttle implements the token bucket model. There is a bucket with a given token capacity (burst size or maximumBurst). * Tokens drops into the bucket at a given rate and can be `spared` for later use up to bucket capacity * to allow some burstiness. Whenever stream wants to send an element, it takes as many * tokens from the bucket as element costs. If there isn't any, throttle waits until the * bucket accumulates enough tokens. Elements that costs more than the allowed burst will be delayed proportionally * to their cost minus available tokens, meeting the target rate. Bucket is full when stream just materialized and started. * * Parameter `mode` manages behavior when upstream is faster than throttle rate: * - [[akka.stream.ThrottleMode.Shaping]] makes pauses before emitting messages to meet throttle rate * - [[akka.stream.ThrottleMode.Enforcing]] fails with exception when upstream is faster than throttle rate * * It is recommended to use non-zero burst sizes as they improve both performance and throttling precision by allowing * the implementation to avoid using the scheduler when input rates fall below the enforced limit and to reduce * most of the inaccuracy caused by the scheduler resolution (which is in the range of milliseconds). * * WARNING: Be aware that throttle is using scheduler to slow down the stream. This scheduler has minimal time of triggering * next push. Consequently it will slow down the stream as it has minimal pause for emitting. This can happen in * case burst is 0 and speed is higher than 30 events per second. You need to increase the `maximumBurst` if * elements arrive with small interval (30 milliseconds or less). Use the overloaded `throttle` method without * `maximumBurst` parameter to automatically calculate the `maximumBurst` based on the given rate (`cost/per`). * In other words the throttler always enforces the rate limit when `maximumBurst` parameter is given, but in * certain cases (mostly due to limited scheduler resolution) it enforces a tighter bound than what was prescribed. * * '''Emits when''' upstream emits an element and configured time per each element elapsed * * '''Backpressures when''' downstream backpressures or the incoming rate is higher than the speed limit * * '''Completes when''' upstream completes * * '''Cancels when''' downstream cancels * */ def throttle( elements: Int, per: java.time.Duration, maximumBurst: Int, mode: ThrottleMode): javadsl.Flow[In, Out, Mat] = new Flow(delegate.throttle(elements, per.asScala, maximumBurst, mode)) /** * Sends elements downstream with speed limited to `cost/per`. Cost is * calculating for each element individually by calling `calculateCost` function. * This operator works for streams when elements have different cost(length). * Streams of `ByteString` for example. * * Throttle implements the token bucket model. There is a bucket with a given token capacity (burst size or maximumBurst). * Tokens drops into the bucket at a given rate and can be `spared` for later use up to bucket capacity * to allow some burstiness. Whenever stream wants to send an element, it takes as many * tokens from the bucket as element costs. If there isn't any, throttle waits until the * bucket accumulates enough tokens. Elements that costs more than the allowed burst will be delayed proportionally * to their cost minus available tokens, meeting the target rate. Bucket is full when stream just materialized and started. * * Parameter `mode` manages behavior when upstream is faster than throttle rate: * - [[akka.stream.ThrottleMode.Shaping]] makes pauses before emitting messages to meet throttle rate * - [[akka.stream.ThrottleMode.Enforcing]] fails with exception when upstream is faster than throttle rate. Enforcing * cannot emit elements that cost more than the maximumBurst * * It is recommended to use non-zero burst sizes as they improve both performance and throttling precision by allowing * the implementation to avoid using the scheduler when input rates fall below the enforced limit and to reduce * most of the inaccuracy caused by the scheduler resolution (which is in the range of milliseconds). * * WARNING: Be aware that throttle is using scheduler to slow down the stream. This scheduler has minimal time of triggering * next push. Consequently it will slow down the stream as it has minimal pause for emitting. This can happen in * case burst is 0 and speed is higher than 30 events per second. You need to increase the `maximumBurst` if * elements arrive with small interval (30 milliseconds or less). Use the overloaded `throttle` method without * `maximumBurst` parameter to automatically calculate the `maximumBurst` based on the given rate (`cost/per`). * In other words the throttler always enforces the rate limit when `maximumBurst` parameter is given, but in * certain cases (mostly due to limited scheduler resolution) it enforces a tighter bound than what was prescribed. * * '''Emits when''' upstream emits an element and configured time per each element elapsed * * '''Backpressures when''' downstream backpressures or the incoming rate is higher than the speed limit * * '''Completes when''' upstream completes * * '''Cancels when''' downstream cancels * */ @Deprecated @deprecated("Use the overloaded one which accepts java.time.Duration instead.", since = "2.5.12") def throttle( cost: Int, per: FiniteDuration, maximumBurst: Int, costCalculation: function.Function[Out, Integer], mode: ThrottleMode): javadsl.Flow[In, Out, Mat] = new Flow(delegate.throttle(cost, per, maximumBurst, costCalculation.apply, mode)) /** * Sends elements downstream with speed limited to `cost/per`. Cost is * calculating for each element individually by calling `calculateCost` function. * This operator works for streams when elements have different cost(length). * Streams of `ByteString` for example. * * Throttle implements the token bucket model. There is a bucket with a given token capacity (burst size). * Tokens drops into the bucket at a given rate and can be `spared` for later use up to bucket capacity * to allow some burstiness. Whenever stream wants to send an element, it takes as many * tokens from the bucket as element costs. If there isn't any, throttle waits until the * bucket accumulates enough tokens. Elements that costs more than the allowed burst will be delayed proportionally * to their cost minus available tokens, meeting the target rate. Bucket is full when stream just materialized and * started. * * The burst size is calculated based on the given rate (`cost/per`) as 0.1 * rate, for example: * - rate < 20/second => burst size 1 * - rate 20/second => burst size 2 * - rate 100/second => burst size 10 * - rate 200/second => burst size 20 * * The throttle `mode` is [[akka.stream.ThrottleMode.Shaping]], which makes pauses before emitting messages to * meet throttle rate. * * '''Emits when''' upstream emits an element and configured time per each element elapsed * * '''Backpressures when''' downstream backpressures or the incoming rate is higher than the speed limit * * '''Completes when''' upstream completes * * '''Cancels when''' downstream cancels * */ def throttle( cost: Int, per: java.time.Duration, costCalculation: function.Function[Out, Integer]): javadsl.Flow[In, Out, Mat] = new Flow(delegate.throttle(cost, per.asScala, costCalculation.apply)) /** * Sends elements downstream with speed limited to `cost/per`. Cost is * calculating for each element individually by calling `calculateCost` function. * This operator works for streams when elements have different cost(length). * Streams of `ByteString` for example. * * Throttle implements the token bucket model. There is a bucket with a given token capacity (burst size or maximumBurst). * Tokens drops into the bucket at a given rate and can be `spared` for later use up to bucket capacity * to allow some burstiness. Whenever stream wants to send an element, it takes as many * tokens from the bucket as element costs. If there isn't any, throttle waits until the * bucket accumulates enough tokens. Elements that costs more than the allowed burst will be delayed proportionally * to their cost minus available tokens, meeting the target rate. Bucket is full when stream just materialized and started. * * Parameter `mode` manages behavior when upstream is faster than throttle rate: * - [[akka.stream.ThrottleMode.Shaping]] makes pauses before emitting messages to meet throttle rate * - [[akka.stream.ThrottleMode.Enforcing]] fails with exception when upstream is faster than throttle rate. Enforcing * cannot emit elements that cost more than the maximumBurst * * It is recommended to use non-zero burst sizes as they improve both performance and throttling precision by allowing * the implementation to avoid using the scheduler when input rates fall below the enforced limit and to reduce * most of the inaccuracy caused by the scheduler resolution (which is in the range of milliseconds). * * WARNING: Be aware that throttle is using scheduler to slow down the stream. This scheduler has minimal time of triggering * next push. Consequently it will slow down the stream as it has minimal pause for emitting. This can happen in * case burst is 0 and speed is higher than 30 events per second. You need to increase the `maximumBurst` if * elements arrive with small interval (30 milliseconds or less). Use the overloaded `throttle` method without * `maximumBurst` parameter to automatically calculate the `maximumBurst` based on the given rate (`cost/per`). * In other words the throttler always enforces the rate limit when `maximumBurst` parameter is given, but in * certain cases (mostly due to limited scheduler resolution) it enforces a tighter bound than what was prescribed. * * '''Emits when''' upstream emits an element and configured time per each element elapsed * * '''Backpressures when''' downstream backpressures or the incoming rate is higher than the speed limit * * '''Completes when''' upstream completes * * '''Cancels when''' downstream cancels * */ def throttle( cost: Int, per: java.time.Duration, maximumBurst: Int, costCalculation: function.Function[Out, Integer], mode: ThrottleMode): javadsl.Flow[In, Out, Mat] = new Flow(delegate.throttle(cost, per.asScala, maximumBurst, costCalculation.apply, mode)) /** * This is a simplified version of throttle that spreads events evenly across the given time interval. * * Use this operator when you need just slow down a stream without worrying about exact amount * of time between events. * * If you want to be sure that no time interval has no more than specified number of events you need to use * [[throttle]] with maximumBurst attribute. * @see [[#throttle]] */ @Deprecated @deprecated("Use the overloaded one which accepts java.time.Duration instead.", since = "2.5.12") def throttleEven(elements: Int, per: FiniteDuration, mode: ThrottleMode): javadsl.Flow[In, Out, Mat] = new Flow(delegate.throttleEven(elements, per, mode)) /** * This is a simplified version of throttle that spreads events evenly across the given time interval. * * Use this operator when you need just slow down a stream without worrying about exact amount * of time between events. * * If you want to be sure that no time interval has no more than specified number of events you need to use * [[throttle]] with maximumBurst attribute. * @see [[#throttle]] */ @Deprecated @deprecated("Use throttle without `maximumBurst` parameter instead.", "2.5.12") def throttleEven(elements: Int, per: java.time.Duration, mode: ThrottleMode): javadsl.Flow[In, Out, Mat] = throttleEven(elements, per.asScala, mode) /** * This is a simplified version of throttle that spreads events evenly across the given time interval. * * Use this operator when you need just slow down a stream without worrying about exact amount * of time between events. * * If you want to be sure that no time interval has no more than specified number of events you need to use * [[throttle]] with maximumBurst attribute. * @see [[#throttle]] */ @Deprecated @deprecated("Use throttle without `maximumBurst` parameter instead.", "2.5.12") def throttleEven( cost: Int, per: FiniteDuration, costCalculation: function.Function[Out, Integer], mode: ThrottleMode): javadsl.Flow[In, Out, Mat] = new Flow(delegate.throttleEven(cost, per, costCalculation.apply, mode)) /** * This is a simplified version of throttle that spreads events evenly across the given time interval. * * Use this operator when you need just slow down a stream without worrying about exact amount * of time between events. * * If you want to be sure that no time interval has no more than specified number of events you need to use * [[throttle]] with maximumBurst attribute. * @see [[#throttle]] */ @Deprecated @deprecated("Use throttle without `maximumBurst` parameter instead.", "2.5.12") def throttleEven( cost: Int, per: java.time.Duration, costCalculation: function.Function[Out, Integer], mode: ThrottleMode): javadsl.Flow[In, Out, Mat] = throttleEven(cost, per.asScala, costCalculation, mode) /** * Detaches upstream demand from downstream demand without detaching the * stream rates; in other words acts like a buffer of size 1. * * '''Emits when''' upstream emits an element * * '''Backpressures when''' downstream backpressures * * '''Completes when''' upstream completes * * '''Cancels when''' downstream cancels */ def detach: javadsl.Flow[In, Out, Mat] = new Flow(delegate.detach) /** * Materializes to `CompletionStage` that completes on getting termination message. * The future completes with success when received complete message from upstream or cancel * from downstream. It fails with the same error when received error message from * downstream. */ def watchTermination[M]()(matF: function.Function2[Mat, CompletionStage[Done], M]): javadsl.Flow[In, Out, M] = new Flow(delegate.watchTermination()((left, right) => matF(left, right.toJava))) /** * Materializes to `FlowMonitor[Out]` that allows monitoring of the current flow. All events are propagated * by the monitor unchanged. Note that the monitor inserts a memory barrier every time it processes an * event, and may therefor affect performance. * * The `combine` function is used to combine the `FlowMonitor` with this flow's materialized value. */ @Deprecated @deprecated("Use monitor() or monitorMat(combine) instead", "2.5.17") def monitor[M]()(combine: function.Function2[Mat, FlowMonitor[Out], M]): javadsl.Flow[In, Out, M] = new Flow(delegate.monitorMat(combinerToScala(combine))) /** * Materializes to `FlowMonitor[Out]` that allows monitoring of the current flow. All events are propagated * by the monitor unchanged. Note that the monitor inserts a memory barrier every time it processes an * event, and may therefor affect performance. * * The `combine` function is used to combine the `FlowMonitor` with this flow's materialized value. */ def monitorMat[M](combine: function.Function2[Mat, FlowMonitor[Out], M]): javadsl.Flow[In, Out, M] = new Flow(delegate.monitorMat(combinerToScala(combine))) /** * Materializes to `Pair>`, which is unlike most other operators (!), * in which usually the default materialized value keeping semantics is to keep the left value * (by passing `Keep.left()` to a `*Mat` version of a method). This operator is an exception from * that rule and keeps both values since dropping its sole purpose is to introduce that materialized value. * * The `FlowMonitor[Out]` allows monitoring of the current flow. All events are propagated * by the monitor unchanged. Note that the monitor inserts a memory barrier every time it processes an * event, and may therefor affect performance. */ def monitor(): Flow[In, Out, Pair[Mat, FlowMonitor[Out]]] = monitorMat(Keep.both) /** * Delays the initial element by the specified duration. * * '''Emits when''' upstream emits an element if the initial delay is already elapsed * * '''Backpressures when''' downstream backpressures or initial delay is not yet elapsed * * '''Completes when''' upstream completes * * '''Cancels when''' downstream cancels */ @Deprecated @deprecated("Use the overloaded one which accepts java.time.Duration instead.", since = "2.5.12") def initialDelay(delay: FiniteDuration): javadsl.Flow[In, Out, Mat] = new Flow(delegate.initialDelay(delay)) /** * Delays the initial element by the specified duration. * * '''Emits when''' upstream emits an element if the initial delay is already elapsed * * '''Backpressures when''' downstream backpressures or initial delay is not yet elapsed * * '''Completes when''' upstream completes * * '''Cancels when''' downstream cancels */ @silent("deprecated") def initialDelay(delay: java.time.Duration): javadsl.Flow[In, Out, Mat] = initialDelay(delay.asScala) /** * Replace the attributes of this [[Flow]] with the given ones. If this Flow is a composite * of multiple graphs, new attributes on the composite will be less specific than attributes * set directly on the individual graphs of the composite. * * Note that this operation has no effect on an empty Flow (because the attributes apply * only to the contained processing operators). */ override def withAttributes(attr: Attributes): javadsl.Flow[In, Out, Mat] = new Flow(delegate.withAttributes(attr)) /** * Add the given attributes to this [[Flow]]. If the specific attribute was already present * on this graph this means the added attribute will be more specific than the existing one. * If this Flow is a composite of multiple graphs, new attributes on the composite will be * less specific than attributes set directly on the individual graphs of the composite. */ override def addAttributes(attr: Attributes): javadsl.Flow[In, Out, Mat] = new Flow(delegate.addAttributes(attr)) /** * Add a ``name`` attribute to this Flow. */ override def named(name: String): javadsl.Flow[In, Out, Mat] = new Flow(delegate.named(name)) /** * Put an asynchronous boundary around this `Flow` */ override def async: javadsl.Flow[In, Out, Mat] = new Flow(delegate.async) /** * Put an asynchronous boundary around this `Flow` * * @param dispatcher Run the graph on this dispatcher */ override def async(dispatcher: String): javadsl.Flow[In, Out, Mat] = new Flow(delegate.async(dispatcher)) /** * Put an asynchronous boundary around this `Flow` * * @param dispatcher Run the graph on this dispatcher * @param inputBufferSize Set the input buffer to this size for the graph */ override def async(dispatcher: String, inputBufferSize: Int): javadsl.Flow[In, Out, Mat] = new Flow(delegate.async(dispatcher, inputBufferSize)) /** * Logs elements flowing through the stream as well as completion and erroring. * * By default element and completion signals are logged on debug level, and errors are logged on Error level. * This can be adjusted according to your needs by providing a custom [[Attributes.LogLevels]] attribute on the given Flow: * * The `extract` function will be applied to each element before logging, so it is possible to log only those fields * of a complex object flowing through this element. * * Uses the given [[LoggingAdapter]] for logging. * * Adheres to the [[ActorAttributes.SupervisionStrategy]] attribute. * * '''Emits when''' the mapping function returns an element * * '''Backpressures when''' downstream backpressures * * '''Completes when''' upstream completes * * '''Cancels when''' downstream cancels */ def log(name: String, extract: function.Function[Out, Any], log: LoggingAdapter): javadsl.Flow[In, Out, Mat] = new Flow(delegate.log(name, e => extract.apply(e))(log)) /** * Logs elements flowing through the stream as well as completion and erroring. * * By default element and completion signals are logged on debug level, and errors are logged on Error level. * This can be adjusted according to your needs by providing a custom [[Attributes.LogLevels]] attribute on the given Flow: * * The `extract` function will be applied to each element before logging, so it is possible to log only those fields * of a complex object flowing through this element. * * Uses an internally created [[LoggingAdapter]] which uses `akka.stream.Log` as it's source (use this class to configure slf4j loggers). * * '''Emits when''' the mapping function returns an element * * '''Backpressures when''' downstream backpressures * * '''Completes when''' upstream completes * * '''Cancels when''' downstream cancels */ def log(name: String, extract: function.Function[Out, Any]): javadsl.Flow[In, Out, Mat] = this.log(name, extract, null) /** * Logs elements flowing through the stream as well as completion and erroring. * * By default element and completion signals are logged on debug level, and errors are logged on Error level. * This can be adjusted according to your needs by providing a custom [[Attributes.LogLevels]] attribute on the given Flow: * * Uses the given [[LoggingAdapter]] for logging. * * '''Emits when''' the mapping function returns an element * * '''Backpressures when''' downstream backpressures * * '''Completes when''' upstream completes * * '''Cancels when''' downstream cancels */ def log(name: String, log: LoggingAdapter): javadsl.Flow[In, Out, Mat] = this.log(name, ConstantFun.javaIdentityFunction[Out], log) /** * Logs elements flowing through the stream as well as completion and erroring. * * By default element and completion signals are logged on debug level, and errors are logged on Error level. * This can be adjusted according to your needs by providing a custom [[Attributes.LogLevels]] attribute on the given Flow. * * Uses an internally created [[LoggingAdapter]] which uses `akka.stream.Log` as it's source (use this class to configure slf4j loggers). * * '''Emits when''' the mapping function returns an element * * '''Backpressures when''' downstream backpressures * * '''Completes when''' upstream completes * * '''Cancels when''' downstream cancels */ def log(name: String): javadsl.Flow[In, Out, Mat] = this.log(name, ConstantFun.javaIdentityFunction[Out], null) /** * Converts this Flow to a [[RunnableGraph]] that materializes to a Reactive Streams [[org.reactivestreams.Processor]] * which implements the operations encapsulated by this Flow. Every materialization results in a new Processor * instance, i.e. the returned [[RunnableGraph]] is reusable. * * @return A [[RunnableGraph]] that materializes to a Processor when run() is called on it. */ def toProcessor: RunnableGraph[Processor[In, Out]] = { RunnableGraph.fromGraph(delegate.toProcessor) } /** * Turns a Flow into a FlowWithContext which manages a context per element along a stream. * * @param collapseContext turn each incoming pair of element and context value into an element of this Flow * @param extractContext turn each outgoing element of this Flow into an outgoing context value * */ def asFlowWithContext[U, CtxU, CtxOut]( collapseContext: function.Function2[U, CtxU, In], extractContext: function.Function[Out, CtxOut]): FlowWithContext[U, CtxU, Out, CtxOut, Mat] = this.asScala.asFlowWithContext((x: U, c: CtxU) => collapseContext.apply(x, c))(x => extractContext.apply(x)).asJava } object RunnableGraph { /** * A graph with a closed shape is logically a runnable graph, this method makes * it so also in type. */ def fromGraph[Mat](graph: Graph[ClosedShape, Mat]): RunnableGraph[Mat] = graph match { case r: RunnableGraph[Mat] => r case _ => new RunnableGraphAdapter[Mat](scaladsl.RunnableGraph.fromGraph(graph)) } /** INTERNAL API */ private final class RunnableGraphAdapter[Mat](runnable: scaladsl.RunnableGraph[Mat]) extends RunnableGraph[Mat] { override def shape = ClosedShape override def traversalBuilder = runnable.traversalBuilder override def toString: String = runnable.toString override def mapMaterializedValue[Mat2](f: function.Function[Mat, Mat2]): RunnableGraphAdapter[Mat2] = new RunnableGraphAdapter(runnable.mapMaterializedValue(f.apply _)) override def run(materializer: Materializer): Mat = runnable.run()(materializer) override def withAttributes(attr: Attributes): RunnableGraphAdapter[Mat] = { val newRunnable = runnable.withAttributes(attr) if (newRunnable eq runnable) this else new RunnableGraphAdapter(newRunnable) } override def asScala: scaladsl.RunnableGraph[Mat] = runnable } } /** * Java API * * Flow with attached input and output, can be executed. */ abstract class RunnableGraph[+Mat] extends Graph[ClosedShape, Mat] { /** * Run this flow and return the materialized values of the flow. * * Uses the system materializer. */ def run(systemProvider: ClassicActorSystemProvider): Mat = { run(SystemMaterializer(systemProvider.classicSystem).materializer) } /** * Run this flow using a special materializer and return the materialized values of the flow. * * Prefer the method taking an ActorSystem unless you have special requirements. */ def run(materializer: Materializer): Mat /** * Transform only the materialized value of this RunnableGraph, leaving all other properties as they were. */ def mapMaterializedValue[Mat2](f: function.Function[Mat, Mat2]): RunnableGraph[Mat2] override def withAttributes(attr: Attributes): RunnableGraph[Mat] override def addAttributes(attr: Attributes): RunnableGraph[Mat] = withAttributes(traversalBuilder.attributes and attr) override def named(name: String): RunnableGraph[Mat] = withAttributes(Attributes.name(name)) /** * Converts this Java DSL element to its Scala DSL counterpart. */ def asScala: scaladsl.RunnableGraph[Mat] }




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