Package akka.dispatch

Class Futures

java.lang.Object

akka.dispatch.Futures

public class Futures
extends java.lang.Object

Futures is the Java API for Futures and Promises

Constructor Summary

Constructors

Constructor	Description
Futures()

Method Summary

Modifier and Type	Method	Description
static <T> scala.concurrent.Future<T>	failed(java.lang.Throwable exception)	creates an already completed Promise with the specified exception
static <T> java.util.concurrent.CompletionStage<T>	failedCompletionStage(java.lang.Throwable ex)	Creates an already completed CompletionStage with the specified exception
static <T> scala.concurrent.Future<Option<T>>	find(java.lang.Iterable<scala.concurrent.Future<T>> futures, Function<T,java.lang.Boolean> predicate, scala.concurrent.ExecutionContext executor)	Returns a Future that will hold the optional result of the first Future with a result that matches the predicate
static <T> scala.concurrent.Future<T>	firstCompletedOf(java.lang.Iterable<scala.concurrent.Future<T>> futures, scala.concurrent.ExecutionContext executor)	Returns a Future to the result of the first future in the list that is completed
static <T,R> scala.concurrent.Future<R>	fold(R zero, java.lang.Iterable<scala.concurrent.Future<T>> futures, Function2<R,T,R> fun, scala.concurrent.ExecutionContext executor)	A non-blocking fold over the specified futures, with the start value of the given zero.
static <T> scala.concurrent.Future<T>	future(java.util.concurrent.Callable<T> body, scala.concurrent.ExecutionContext executor)	Starts an asynchronous computation and returns a Future object with the result of that computation.
static <T> scala.concurrent.Promise<T>	promise()	Creates a promise object which can be completed with a value.
static <T,R> scala.concurrent.Future<R>	reduce(java.lang.Iterable<scala.concurrent.Future<T>> futures, Function2<R,T,R> fun, scala.concurrent.ExecutionContext executor)	Reduces the results of the supplied futures and binary function.
static <A> scala.concurrent.Future<java.lang.Iterable<A>>	sequence(java.lang.Iterable<scala.concurrent.Future<A>> in, scala.concurrent.ExecutionContext executor)	Simple version of traverse(java.lang.Iterable<A>, akka.japi.Function<A, scala.concurrent.Future<B>>, scala.concurrent.ExecutionContext).
static <T> scala.concurrent.Future<T>	successful(T result)	Creates an already completed Promise with the specified result
static <A,B> scala.concurrent.Future<java.lang.Iterable<B>>	traverse(java.lang.Iterable<A> in, Function<A,scala.concurrent.Future<B>> fn, scala.concurrent.ExecutionContext executor)	Transforms a JIterable[A] into a Future[JIterable[B} using the provided Function A => Future[B].

Methods inherited from class java.lang.Object

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

Constructor Detail

Futures

public Futures()

Method Detail

future

public static <T> scala.concurrent.Future<T> future(java.util.concurrent.Callable<T> body,
                                                    scala.concurrent.ExecutionContext executor)

Starts an asynchronous computation and returns a Future object with the result of that computation.

The result becomes available once the asynchronous computation is completed.

Parameters:

body - the asynchronous computation

executor - the execution context on which the future is run

Returns:

the Future holding the result of the computation

promise

public static <T> scala.concurrent.Promise<T> promise()

Creates a promise object which can be completed with a value.

Returns:

the newly created Promise object

failed

public static <T> scala.concurrent.Future<T> failed(java.lang.Throwable exception)

creates an already completed Promise with the specified exception

successful

public static <T> scala.concurrent.Future<T> successful(T result)

Creates an already completed Promise with the specified result

failedCompletionStage

public static <T> java.util.concurrent.CompletionStage<T> failedCompletionStage(java.lang.Throwable ex)

Creates an already completed CompletionStage with the specified exception

find

public static <T> scala.concurrent.Future<Option<T>> find(java.lang.Iterable<scala.concurrent.Future<T>> futures,
                                                          Function<T,java.lang.Boolean> predicate,
                                                          scala.concurrent.ExecutionContext executor)

Returns a Future that will hold the optional result of the first Future with a result that matches the predicate

firstCompletedOf

public static <T> scala.concurrent.Future<T> firstCompletedOf(java.lang.Iterable<scala.concurrent.Future<T>> futures,
                                                              scala.concurrent.ExecutionContext executor)

Returns a Future to the result of the first future in the list that is completed

fold

public static <T,R> scala.concurrent.Future<R> fold(R zero,
                                                          java.lang.Iterable<scala.concurrent.Future<T>> futures,
                                                          Function2<R,T,R> fun,
                                                          scala.concurrent.ExecutionContext executor)

A non-blocking fold over the specified futures, with the start value of the given zero. The fold is performed on the thread where the last future is completed, the result will be the first failure of any of the futures, or any failure in the actual fold, or the result of the fold.

reduce

public static <T,R> scala.concurrent.Future<R> reduce(java.lang.Iterable<scala.concurrent.Future<T>> futures,
                                                            Function2<R,T,R> fun,
                                                            scala.concurrent.ExecutionContext executor)

Reduces the results of the supplied futures and binary function.

sequence

public static <A> scala.concurrent.Future<java.lang.Iterable<A>> sequence(java.lang.Iterable<scala.concurrent.Future<A>> in,
                                                                          scala.concurrent.ExecutionContext executor)

Simple version of traverse(java.lang.Iterable<A>, akka.japi.Function<A, scala.concurrent.Future<B>>, scala.concurrent.ExecutionContext). Transforms a JIterable[Future[A} into a Future[JIterable[A}. Useful for reducing many Futures into a single Future.

traverse

public static <A,B> scala.concurrent.Future<java.lang.Iterable<B>> traverse(java.lang.Iterable<A> in,
                                                                                  Function<A,scala.concurrent.Future<B>> fn,
                                                                                  scala.concurrent.ExecutionContext executor)

Transforms a JIterable[A] into a Future[JIterable[B} using the provided Function A => Future[B]. This is useful for performing a parallel map. For example, to apply a function to all items of a list in parallel.