Package org.apache.pekko.dispatch

Class CompletionStages

java.lang.Object

org.apache.pekko.dispatch.CompletionStages

public class CompletionStages
extends Object

CompletionStages provides utilities for working with CompletionStages.

Constructor Summary

Constructors

Constructor	Description
CompletionStages()

Method Summary

Modifier and Type	Method	Description
static <T> scala.concurrent.Future<T>	asScala(CompletionStage<T> stage)	Convert a CompletionStage to a Scala Future.
static <T> CompletionStage<Optional<T>>	find(Iterable<? extends CompletionStage<? extends T>> stages, Function<T,Boolean> predicate)	Return the first CompletionStage in the given Iterable that matches the given predicate.
static <T> CompletionStage<T>	firstCompletedOf(Iterable<? extends CompletionStage<? extends T>> stages)	Returns a new CompletionStage that, when completed, will contain the result of the first of the given stages to complete, with the same value or exception.
static <T, R> CompletionStage<R>	fold(R zero, Iterable<? extends CompletionStage<? extends T>> stages, Function2<R,T,R> function)	Aggregate the results of the given stages using the given associative function and a zero value.
static <T, R> CompletionStage<R>	reduce(Iterable<? extends CompletionStage<? extends T>> stages, Function2<R,T,R> function)	Reduce the results of the given stages using the given associative function.
static <T> CompletionStage<List<T>>	sequence(Iterable<? extends CompletionStage<? extends T>> stages, Executor executor)	Transform a java.lang.Iterable of CompletionStages into a single CompletionStage with a java.util.List of all the results.
static <T, R> CompletionStage<List<R>>	traverse(Iterable<T> input, Function<T,CompletionStage<R>> function, Executor executor)	Transform a java.lang.Iterable of CompletionStages into a single CompletionStage with a java.util.List of all the results.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Details

CompletionStages

public CompletionStages()

Method Details

asScala

public static <T> scala.concurrent.Future<T> asScala(CompletionStage<T> stage)

Convert a CompletionStage to a Scala Future.

find

public static <T> CompletionStage<Optional<T>> find(Iterable<? extends CompletionStage<? extends T>> stages,
 Function<T,Boolean> predicate)

Return the first CompletionStage in the given Iterable that matches the given predicate. If no stage matches the predicate, an empty Optional is returned.

Parameters:

stages - the stages to search through

predicate - the predicate to apply to each completed stage

Returns:

a CompletionStage that, when completed, will contain an Optional with the first matching element, or an empty Optional if none matched

Since:

1.2.0

firstCompletedOf

public static <T> CompletionStage<T> firstCompletedOf(Iterable<? extends CompletionStage<? extends T>> stages)

Returns a new CompletionStage that, when completed, will contain the result of the first of the given stages to complete, with the same value or exception.

If the given iterable is empty, the returned stage never completes.

Parameters:

stages - the stages

Returns:

a CompletionStage that, when completed, will contain the result of the first stage to complete with the same value or exception.

Since:

1.2.0

fold

public static <T,
R> CompletionStage<R> fold(R zero,
 Iterable<? extends CompletionStage<? extends T>> stages,
 Function2<R,T,R> function)

Aggregate the results of the given stages using the given associative function and a zero value. The stages are processed in the order they are given.

Parameters:

zero - the zero value

stages - the stages to aggregate

function - the associative function to use for aggregation

Returns:

a CompletionStage that, when completed, will contain the aggregated result

Since:

1.2.0

reduce

public static <T,
R> CompletionStage<R> reduce(Iterable<? extends CompletionStage<? extends T>> stages,
 Function2<R,T,R> function)

Reduce the results of the given stages using the given associative function. The stages are processed in the order they are given. If the given iterable is empty, the returned stage is completed with a NoSuchElementException.

Parameters:

stages - the stages to reduce

function - the associative function to use for reduction

Returns:

a CompletionStage that, when completed, will contain the reduced result of the stages or a NoSuchElementException if the given iterable is empty

Since:

1.2.0

sequence

public static <T> CompletionStage<List<T>> sequence(Iterable<? extends CompletionStage<? extends T>> stages,
 Executor executor)

Transform a java.lang.Iterable of CompletionStages into a single CompletionStage with a java.util.List of all the results. The stages are processed in the order they are given.

Parameters:

stages - the stages to sequence

executor - the executor to use for asynchronous execution, or null to use synchronous execution

Returns:

a CompletionStage that, when completed, will contain a java.util.List with all the results

Since:

1.2.0

traverse

public static <T,
R> CompletionStage<List<R>> traverse(Iterable<T> input,
 Function<T,CompletionStage<R>> function,
 Executor executor)

Transform a java.lang.Iterable of CompletionStages into a single CompletionStage with a java.util.List of all the results. The stages are processed in the order they are given.

Parameters:

input - the input iterable

function - the function to apply to each element

executor - the executor to use for asynchronous execution, or null to use synchronous execution

Returns:

a CompletionStage that, when completed, will contain a java.util.List with all the results

Since:

1.2.0