Package org.apache.pekko.stream

Class Attributes

java.lang.Object
org.apache.pekko.stream.Attributes
All Implemented Interfaces:
Serializable, scala.Equals, scala.Product
public final class Attributes extends Object implements scala.Product, Serializable
Holds attributes which can be used to alter pekko.stream.scaladsl.Flow / pekko.stream.javadsl.Flow or pekko.stream.scaladsl.GraphDSL / pekko.stream.javadsl.GraphDSL materialization.

Note that more attributes for the Materializer are defined in ActorAttributes.

The attributeList is ordered with the most specific attribute first, least specific last. Note that the order was the opposite in Akka 2.4.x.

Operators should in general not access the attributeList but instead use get to get the expected value of an attribute.

See Also:

  • Constructor Details

    • Attributes

      public Attributes(scala.collection.immutable.List<Attributes.Attribute> attributeList)

  • Method Details

    • $lessinit$greater$default$1

      public static scala.collection.immutable.List<Attributes.Attribute> $lessinit$greater$default$1()

    • cancellationStrategyCompleteState

      public static org.apache.pekko.stream.Attributes.CancellationStrategy.Strategy cancellationStrategyCompleteState()
      Java API

      Strategy that treats cancelStage the same as completeStage, i.e. all inlets are cancelled (propagating the cancellation cause) and all outlets are regularly completed.

      This used to be the default behavior before Akka 2.6.

      This behavior can be problematic in stacks of BidiFlows where different layers of the stack are both connected through inputs and outputs. In this case, an error in a doubly connected component triggers both a cancellation going upstream and an error going downstream. Since the stack might be connected to those components with inlets and outlets, a race starts whether the cancellation or the error arrives first. If the error arrives first, that's usually good because then the error can be propagated both on inlets and outlets. However, if the cancellation arrives first, the previous default behavior to complete the stage will lead other outputs to be completed regularly. The error which arrive late at the other hand will just be ignored (that connection will have been cancelled already and also the paths through which the error could propagates are already shut down).

    • cancellationStrategyFailStage

      public static org.apache.pekko.stream.Attributes.CancellationStrategy.Strategy cancellationStrategyFailStage()
      Java API

      Strategy that treats cancelStage the same as failStage, i.e. all inlets are cancelled (propagating the cancellation cause) and all outlets are failed propagating the cause from cancellation.

    • cancellationStrategyPropagateFailure

      public static org.apache.pekko.stream.Attributes.CancellationStrategy.Strategy cancellationStrategyPropagateFailure()
      Java API

      Strategy that treats cancelStage in different ways depending on the cause that was given to the cancellation.

      If the cause was a regular, active cancellation (SubscriptionWithCancelException.NoMoreElementsNeeded), the stage receiving this cancellation is completed regularly.

      If another cause was given, this is treated as an error and the behavior is the same as with failStage.

      This is a good default strategy.

    • cancellationStrategyAfterDelay

      public static org.apache.pekko.stream.Attributes.CancellationStrategy.Strategy cancellationStrategyAfterDelay(scala.concurrent.duration.FiniteDuration delay, org.apache.pekko.stream.Attributes.CancellationStrategy.Strategy strategy)
      Java API

      Strategy that allows to delay any action when cancelStage is invoked.

      The idea of this strategy is to delay any action on cancellation because it is expected that the stage is completed through another path in the meantime. The downside is that a stage and a stream may live longer than expected if no such signal is received and cancellation is invoked later on. In streams with many stages that all apply this strategy, this strategy might significantly delay the propagation of a cancellation signal because each upstream stage might impose such a delay. During this time, the stream will be mostly "silent", i.e. it cannot make progress because of backpressure, but you might still be able observe a long delay at the ultimate source.

    • nestedMaterializationCancellationPolicyEagerCancellation

      public static Attributes.NestedMaterializationCancellationPolicy nestedMaterializationCancellationPolicyEagerCancellation()
      JAVA API A Attributes.NestedMaterializationCancellationPolicy that configures graph stages delaying nested flow materialization to cancel immediately when downstream cancels before nested flow materialization. This applies to pekko.stream.scaladsl.FlowOps.flatMapPrefix, pekko.stream.scaladsl.Flow.futureFlow and derived operators.

    • nestedMaterializationCancellationPolicyPropagateToNested

      public static Attributes.NestedMaterializationCancellationPolicy nestedMaterializationCancellationPolicyPropagateToNested()
      JAVA API A Attributes.NestedMaterializationCancellationPolicy that configures graph stages delaying nested flow materialization to delay cancellation when downstream cancels before nested flow materialization. Once the nested flow is materialized it will be cancelled immediately. This applies to pekko.stream.scaladsl.FlowOps.flatMapPrefix, pekko.stream.scaladsl.Flow.futureFlow and derived operators.

    • nestedMaterializationCancellationPolicyDefault

      public static Attributes.NestedMaterializationCancellationPolicy nestedMaterializationCancellationPolicyDefault()
      Default Attributes.NestedMaterializationCancellationPolicy, please see pekko.stream.Attributes#nestedMaterializationCancellationPolicyEagerCancellation() for details.

    • logLevelOff

      public static Logging.LogLevel logLevelOff()
      Java API: Use to disable logging on certain operations when configuring createLogLevels(org.apache.pekko.event.Logging.LogLevel, org.apache.pekko.event.Logging.LogLevel, org.apache.pekko.event.Logging.LogLevel)

    • logLevelError

      public static Logging.LogLevel logLevelError()
      Java API: Use to enable logging at ERROR level for certain operations when configuring createLogLevels(org.apache.pekko.event.Logging.LogLevel, org.apache.pekko.event.Logging.LogLevel, org.apache.pekko.event.Logging.LogLevel)

    • logLevelWarning

      public static Logging.LogLevel logLevelWarning()
      Java API: Use to enable logging at WARNING level for certain operations when configuring createLogLevels(org.apache.pekko.event.Logging.LogLevel, org.apache.pekko.event.Logging.LogLevel, org.apache.pekko.event.Logging.LogLevel)

    • logLevelInfo

      public static Logging.LogLevel logLevelInfo()
      Java API: Use to enable logging at INFO level for certain operations when configuring createLogLevels(org.apache.pekko.event.Logging.LogLevel, org.apache.pekko.event.Logging.LogLevel, org.apache.pekko.event.Logging.LogLevel)

    • logLevelDebug

      public static Logging.LogLevel logLevelDebug()
      Java API: Use to enable logging at DEBUG level for certain operations when configuring createLogLevels(org.apache.pekko.event.Logging.LogLevel, org.apache.pekko.event.Logging.LogLevel, org.apache.pekko.event.Logging.LogLevel)

    • apply

      public static Attributes apply(Attributes.Attribute attribute)
      INTERNAL API

    • apply$default$1

      public static scala.collection.immutable.List<Attributes.Attribute> apply$default$1()

    • none

      public static Attributes none()
      INTERNAL API

    • asyncBoundary

      public static Attributes asyncBoundary()

    • name

      public static Attributes name(String name)
      Specifies the name of the operation. If the name is null or empty the name is ignored, i.e. none() is returned.

    • inputBuffer

      public static Attributes inputBuffer(int initial, int max)
      Each asynchronous piece of a materialized stream topology is executed by one Actor that manages an input buffer for all inlets of its shape. This attribute configures the initial and maximal input buffer in number of elements for each inlet.

    • createLogLevels

      public static Attributes createLogLevels(Logging.LogLevel onElement, Logging.LogLevel onFinish, Logging.LogLevel onFailure)
      Java API

      Configures log() operator log-levels to be used when logging. Logging a certain operation can be completely disabled by using logLevelOff().

    • createLogLevels

      public static Attributes createLogLevels(Logging.LogLevel onElement)
      Java API

      Configures log() operator log-levels to be used when logging onElement. Logging a certain operation can be completely disabled by using logLevelOff().

    • logLevels

      public static Attributes logLevels(Logging.LogLevel onElement, Logging.LogLevel onFinish, Logging.LogLevel onFailure)
      Configures log() operator log-levels to be used when logging. Logging a certain operation can be completely disabled by using LogLevels.Off.

      See Attributes.createLogLevels for Java API

    • logLevels$default$1

      public static Logging.LogLevel logLevels$default$1()

    • logLevels$default$2

      public static Logging.LogLevel logLevels$default$2()

    • logLevels$default$3

      public static Logging.LogLevel logLevels$default$3()

    • extractName

      public static String extractName(org.apache.pekko.stream.impl.TraversalBuilder builder, String default_)
      Compute a name by concatenating all Name attributes that the given module has, returning the given default value if none are found.

    • apply

      public static Attributes apply(scala.collection.immutable.List<Attributes.Attribute> attributeList)

    • unapply

      public static scala.Option<scala.collection.immutable.List<Attributes.Attribute>> unapply(Attributes x$0)

    • attributeList

      public scala.collection.immutable.List<Attributes.Attribute> attributeList()

    • getAttribute

      public <T extends Attributes.Attribute> T getAttribute(Class<T> c, T default_)
      Java API: Get the most specific attribute value for a given Attribute type or subclass thereof. If no such attribute exists, return a default value.

      The most specific value is the value that was added closest to the graph or operator itself or if the same attribute was added multiple times to the same graph, the last to be added.

      This is the expected way for operators to access attributes.

    • getAttribute

      public <T extends Attributes.Attribute> Optional<T> getAttribute(Class<T> c)
      Java API: Get the most specific attribute value for a given Attribute type or subclass thereof.

      The most specific value is the value that was added closest to the graph or operator itself or if the same attribute was added multiple times to the same graph, the last to be added.

      This is the expected way for operators to access attributes.

    • get

      public <T extends Attributes.Attribute> T get(T default_, scala.reflect.ClassTag<T> evidence$1)
      Scala API: Get the most specific attribute value for a given Attribute type or subclass thereof or if no such attribute exists, return a default value.

      The most specific value is the value that was added closest to the graph or operator itself or if the same attribute was added multiple times to the same graph, the last to be added.

      This is the expected way for operators to access attributes.

    • get

      public <T extends Attributes.Attribute> scala.Option<T> get(scala.reflect.ClassTag<T> evidence$2)
      Scala API: Get the most specific attribute value for a given Attribute type or subclass thereof.

      The most specific value is the value that was added closest to the graph or operator itself or if the same attribute was added multiple times to the same graph, the last to be added.

      This is the expected way for operators to access attributes.

    • mandatoryAttribute

      public <T extends Attributes.MandatoryAttribute> T mandatoryAttribute(scala.reflect.ClassTag<T> evidence$3)
      Scala API: Get the most specific of one of the mandatory attributes. Mandatory attributes are guaranteed to always be among the attributes when the attributes are coming from a materialization.

    • getMandatoryAttribute

      public <T extends Attributes.MandatoryAttribute> T getMandatoryAttribute(Class<T> c)
      Java API: Get the most specific of one of the mandatory attributes. Mandatory attributes are guaranteed to always be among the attributes when the attributes are coming from a materialization.

      Parameters:
      c - A class that is a subtype of Attributes.MandatoryAttribute

    • and

      public Attributes and(Attributes other)
      Adds given attributes. Added attributes are considered more specific than already existing attributes of the same type.

    • and

      public Attributes and(Attributes.Attribute other)
      Adds given attribute. Added attribute is considered more specific than already existing attributes of the same type.

    • nameLifted

      public scala.Option<String> nameLifted()
      Extracts Name attributes and concatenates them.

    • nameOrDefault

      public String nameOrDefault(String default_)

    • nameOrDefault$default$1

      public String nameOrDefault$default$1()

    • contains

      public boolean contains(Attributes.Attribute attr)
      Test whether the given attribute is contained within this attributes list.

      Note that operators in general should not inspect the whole hierarchy but instead use get to get the most specific attribute value.

    • getAttributeList

      public List<Attributes.Attribute> getAttributeList()
      Java API

      The list is ordered with the most specific attribute first, least specific last. Note that the order was the opposite in Akka 2.4.x.

      Note that operators in general should not inspect the whole hierarchy but instead use get to get the most specific attribute value.

    • getAttributeList

      public <T extends Attributes.Attribute> List<T> getAttributeList(Class<T> c)
      Java API: Get all attributes of a given Class or subclass thereof.

      The list is ordered with the most specific attribute first, least specific last. Note that the order was the opposite in Akka 2.4.x.

      Note that operators in general should not inspect the whole hierarchy but instead use get to get the most specific attribute value.

    • filtered

      public <T extends Attributes.Attribute> scala.collection.immutable.List<T> filtered(scala.reflect.ClassTag<T> evidence$4)
      Scala API: Get all attributes of a given type (or subtypes thereof).

      Note that operators in general should not inspect the whole hierarchy but instead use get to get the most specific attribute value.

      The list is ordered with the most specific attribute first, least specific last. Note that the order was the opposite in Akka 2.4.x.

    • getFirstAttribute

      public <T extends Attributes.Attribute> T getFirstAttribute(Class<T> c, T default_)
      Deprecated.
      Attributes should always be most specific, use getAttribute[T]. Since Akka 2.5.7.
      Java API: Get the least specific attribute (added first) of a given Class or subclass thereof. If no such attribute exists the default value is returned.

    • getFirstAttribute

      public <T extends Attributes.Attribute> Optional<T> getFirstAttribute(Class<T> c)
      Deprecated.
      Attributes should always be most specific, use get[T]. Since Akka 2.5.7.
      Java API: Get the least specific attribute (added first) of a given Class or subclass thereof.

    • getFirst

      public <T extends Attributes.Attribute> T getFirst(T default_, scala.reflect.ClassTag<T> evidence$5)
      Deprecated.
      Attributes should always be most specific, use get[T]. Since Akka 2.5.7.
      Scala API: Get the least specific attribute (added first) of a given type parameter T Class or subclass thereof. If no such attribute exists the default value is returned.

    • getFirst

      public <T extends Attributes.Attribute> scala.Option<T> getFirst(scala.reflect.ClassTag<T> evidence$6)
      Deprecated.
      Attributes should always be most specific, use get[T]. Since Akka 2.5.7.
      Scala API: Get the least specific attribute (added first) of a given type parameter T Class or subclass thereof.

    • copy

      public Attributes copy(scala.collection.immutable.List<Attributes.Attribute> attributeList)

    • copy$default$1

      public scala.collection.immutable.List<Attributes.Attribute> copy$default$1()

    • productPrefix

      public String productPrefix()
      Specified by:
      productPrefix in interface scala.Product

    • productArity

      public int productArity()
      Specified by:
      productArity in interface scala.Product

    • productElement

      public Object productElement(int x$1)
      Specified by:
      productElement in interface scala.Product

    • productIterator

      public scala.collection.Iterator<Object> productIterator()
      Specified by:
      productIterator in interface scala.Product

    • canEqual

      public boolean canEqual(Object x$1)
      Specified by:
      canEqual in interface scala.Equals

    • productElementName

      public String productElementName(int x$1)
      Specified by:
      productElementName in interface scala.Product

    • hashCode

      public int hashCode()
      Overrides:
      hashCode in class Object

    • toString

      public String toString()
      Overrides:
      toString in class Object

    • equals

      public boolean equals(Object x$1)
      Specified by:
      equals in interface scala.Equals
      Overrides:
      equals in class Object