kotlinx.coroutines.experimental

Class Deferred.DefaultImpls

kotlinx.coroutines.experimental.Deferred.DefaultImpls

Enclosing interface:

Deferred<T>

public static class Deferred.DefaultImpls

Deferred value is a non-blocking cancellable future — it is a interface Job that has a result.

It is created with BuildersKt.async coroutine builder or via constructor of interface CompletableDeferred class. It is in Job.isActive state while the value is being computed.

Deferred value has the same state machine as the interface Job with additional convenience methods to retrieve successful or failed result of the computation that was carried out. The result of the deferred is available when it is Job.isCompleted and can be retrieved by Deferred.await method, which throws exception if the deferred had failed. Note, that a cancelled deferred is also considered to be completed. The corresponding exception can be retrieved via Deferred.getCompletionExceptionOrNull from a completed instance of deferred.

Usually, a deferred value is created in active state (it is created and started). However, BuildersKt.async coroutine builder has an optional start parameter that creates a deferred value in new state when this parameter is set to CoroutineStart.LAZY. Such a deferred can be be made active by invoking Job.start, Job.join, or Deferred.await.

A deferred value is a interface Job. A job in the coroutineContext of BuildersKt.async builder represents the coroutine itself.

All functions on this interface and on all interfaces derived from it are thread-safe and can be safely invoked from concurrent coroutines without external synchronization.

See Also:

interface Job, BuildersKt.async, interface CompletableDeferred, Job.isActive, interface Job, Job.isCompleted, Deferred.await, Deferred.getCompletionExceptionOrNull, BuildersKt.async, Job.start, Job.join, Deferred.await, interface Job, coroutineContext, BuildersKt.async

Method Summary

Modifier and Type	Method and Description
static <T,R> R	fold(Deferred<? extends T> $this, R initial, kotlin.jvm.functions.Function2<? super R,? super kotlin.coroutines.experimental.CoroutineContext.Element,? extends R> operation)
static <T,E extends Element> E	get(Deferred<? extends T> $this, kotlin.coroutines.experimental.CoroutineContext.Key<E> key)
static <T> java.lang.Throwable	getCompletionException(Deferred<? extends T> $this) Deprecated.
static <T> kotlin.coroutines.experimental.CoroutineContext	minusKey(Deferred<? extends T> $this, kotlin.coroutines.experimental.CoroutineContext.Key<?> key)
static <T> Job	plus(Deferred<? extends T> $this, Job other) Deprecated.
static <T> kotlin.coroutines.experimental.CoroutineContext	plus(Deferred<? extends T> $this, kotlin.coroutines.experimental.CoroutineContext context)

Method Detail

getCompletionException

public static <T> java.lang.Throwable getCompletionException(Deferred<? extends T> $this)

Deprecated.

plus

public static <T> Job plus(Deferred<? extends T> $this,
                           Job other)

Deprecated.

plus

public static <T> kotlin.coroutines.experimental.CoroutineContext plus(Deferred<? extends T> $this,
                                                                       kotlin.coroutines.experimental.CoroutineContext context)

fold

public static <T,R> R fold(Deferred<? extends T> $this,
                           R initial,
                           kotlin.jvm.functions.Function2<? super R,? super kotlin.coroutines.experimental.CoroutineContext.Element,? extends R> operation)

get

public static <T,E extends Element> E get(Deferred<? extends T> $this,
                                          kotlin.coroutines.experimental.CoroutineContext.Key<E> key)

minusKey

public static <T> kotlin.coroutines.experimental.CoroutineContext minusKey(Deferred<? extends T> $this,
                                                                           kotlin.coroutines.experimental.CoroutineContext.Key<?> key)