Added in API level 24

CompletableFuture

open class CompletableFuture<T : Any!> : CompletionStage<T>, Future<T>

kotlin.Any
↳	java.util.concurrent.CompletableFuture

A Future that may be explicitly completed (setting its value and status), and may be used as a CompletionStage, supporting dependent functions and actions that trigger upon its completion.

When two or more threads attempt to complete, completeExceptionally, or cancel a CompletableFuture, only one of them succeeds.

In addition to these and related methods for directly manipulating status and results, CompletableFuture implements interface CompletionStage with the following policies:

• Actions supplied for dependent completions of non-async methods may be performed by the thread that completes the current CompletableFuture, or by any other caller of a completion method.
• All async methods without an explicit Executor argument are performed using the ForkJoinPool.commonPool() (unless it does not support a parallelism level of at least two, in which case, a new Thread is created to run each task). To simplify monitoring, debugging, and tracking, all generated asynchronous tasks are instances of the marker interface AsynchronousCompletionTask. Operations with time-delays can use adapter methods defined in this class, for example: supplyAsync(supplier, delayedExecutor(timeout, timeUnit)). To support methods with delays and timeouts, this class maintains at most one daemon thread for triggering and cancelling actions, not for running them.
• All CompletionStage methods are implemented independently of other public methods, so the behavior of one method is not impacted by overrides of others in subclasses.

CompletableFuture also implements Future with the following policies:

• Since (unlike FutureTask) this class has no direct control over the computation that causes it to be completed, cancellation is treated as just another form of exceptional completion. Method cancel has the same effect as completeExceptionally(new CancellationException()). Method isCompletedExceptionally can be used to determine if a CompletableFuture completed in any exceptional fashion.
• In case of exceptional completion with a CompletionException, methods get() and get(long,java.util.concurrent.TimeUnit) throw an ExecutionException with the same cause as held in the corresponding CompletionException. To simplify usage in most contexts, this class also defines methods join() and getNow that instead throw the CompletionException directly in these cases.

Arguments used to pass a completion result (that is, for parameters of type T) for methods accepting them may be null, but passing a null value for any other parameter will result in a NullPointerException being thrown.

Summary

Nested classes
abstract	AsynchronousCompletionTask A marker interface identifying asynchronous tasks produced by async methods.

Public constructors
CompletableFuture() Creates a new incomplete CompletableFuture.

Public methods
open CompletableFuture<Void!>!	acceptEither(other: CompletionStage<out T>!, action: Consumer<in T>!)
open CompletableFuture<Void!>!	acceptEitherAsync(other: CompletionStage<out T>!, action: Consumer<in T>!)
open CompletableFuture<Void!>!	acceptEitherAsync(other: CompletionStage<out T>!, action: Consumer<in T>!, executor: Executor!)
open static CompletableFuture<Void!>!	allOf(vararg cfs: CompletableFuture<*>!) Returns a new CompletableFuture that is completed when all of the given CompletableFutures complete.
open static CompletableFuture<Any!>!	anyOf(vararg cfs: CompletableFuture<*>!) Returns a new CompletableFuture that is completed when any of the given CompletableFutures complete, with the same result.
open CompletableFuture<U>!	applyToEither(other: CompletionStage<out T>!, fn: Function<in T, U>!)
open CompletableFuture<U>!	applyToEitherAsync(other: CompletionStage<out T>!, fn: Function<in T, U>!)
open CompletableFuture<U>!	applyToEitherAsync(other: CompletionStage<out T>!, fn: Function<in T, U>!, executor: Executor!)
open Boolean	cancel(mayInterruptIfRunning: Boolean) If not already completed, completes this CompletableFuture with a CancellationException.
open Boolean	complete(value: T) If not already completed, sets the value returned by get() and related methods to the given value.
open CompletableFuture<T>!	completeAsync(supplier: Supplier<out T>!) Completes this CompletableFuture with the result of the given Supplier function invoked from an asynchronous task using the default executor.
open CompletableFuture<T>!	completeAsync(supplier: Supplier<out T>!, executor: Executor!) Completes this CompletableFuture with the result of the given Supplier function invoked from an asynchronous task using the given executor.
open Boolean	completeExceptionally(ex: Throwable!) If not already completed, causes invocations of get() and related methods to throw the given exception.
open CompletableFuture<T>!	completeOnTimeout(value: T, timeout: Long, unit: TimeUnit!) Completes this CompletableFuture with the given value if not otherwise completed before the given timeout.
open static CompletableFuture<U>!	completedFuture(value: U) Returns a new CompletableFuture that is already completed with the given value.
open static CompletionStage<U>!	completedStage(value: U) Returns a new CompletionStage that is already completed with the given value and supports only those methods in interface CompletionStage.
open CompletableFuture<T>!	copy() Returns a new CompletableFuture that is completed normally with the same value as this CompletableFuture when it completes normally.
open Executor!	defaultExecutor() Returns the default Executor used for async methods that do not specify an Executor.
open static Executor!	delayedExecutor(delay: Long, unit: TimeUnit!) Returns a new Executor that submits a task to the default executor after the given delay (or no delay if non-positive).
open static Executor!	delayedExecutor(delay: Long, unit: TimeUnit!, executor: Executor!) Returns a new Executor that submits a task to the given base executor after the given delay (or no delay if non-positive).
open Throwable!	exceptionNow()
open CompletableFuture<T>!	exceptionally(fn: Function<Throwable!, out T>!)
open CompletableFuture<T>!	exceptionallyAsync(fn: Function<Throwable!, out T>!)
open CompletableFuture<T>!	exceptionallyAsync(fn: Function<Throwable!, out T>!, executor: Executor!)
open CompletableFuture<T>!	exceptionallyCompose(fn: Function<Throwable!, out CompletionStage<T>!>!)
open CompletableFuture<T>!	exceptionallyComposeAsync(fn: Function<Throwable!, out CompletionStage<T>!>!)
open CompletableFuture<T>!	exceptionallyComposeAsync(fn: Function<Throwable!, out CompletionStage<T>!>!, executor: Executor!)
open static CompletableFuture<U>!	failedFuture(ex: Throwable!) Returns a new CompletableFuture that is already completed exceptionally with the given exception.
open static CompletionStage<U>!	failedStage(ex: Throwable!) Returns a new CompletionStage that is already completed exceptionally with the given exception and supports only those methods in interface CompletionStage.
open T	get() Waits if necessary for this future to complete, and then returns its result.
open T	get(timeout: Long, unit: TimeUnit!) Waits if necessary for at most the given time for this future to complete, and then returns its result, if available.
open T	getNow(valueIfAbsent: T) Returns the result value (or throws any encountered exception) if completed, else returns the given valueIfAbsent.
open Int	getNumberOfDependents() Returns the estimated number of CompletableFutures whose completions are awaiting completion of this CompletableFuture.
open CompletableFuture<U>!	handle(fn: BiFunction<in T, Throwable!, out U>!)
open CompletableFuture<U>!	handleAsync(fn: BiFunction<in T, Throwable!, out U>!)
open CompletableFuture<U>!	handleAsync(fn: BiFunction<in T, Throwable!, out U>!, executor: Executor!)
open Boolean	isCancelled() Returns true if this CompletableFuture was cancelled before it completed normally.
open Boolean	isCompletedExceptionally() Returns true if this CompletableFuture completed exceptionally, in any way.
open Boolean	isDone() Returns true if completed in any fashion: normally, exceptionally, or via cancellation.
open T	join() Returns the result value when complete, or throws an (unchecked) exception if completed exceptionally.
open CompletionStage<T>!	minimalCompletionStage() Returns a new CompletionStage that is completed normally with the same value as this CompletableFuture when it completes normally, and cannot be independently completed or otherwise used in ways not defined by the methods of interface CompletionStage.
open CompletableFuture<U>!	newIncompleteFuture() Returns a new incomplete CompletableFuture of the type to be returned by a CompletionStage method.
open Unit	obtrudeException(ex: Throwable!) Forcibly causes subsequent invocations of method get() and related methods to throw the given exception, whether or not already completed.
open Unit	obtrudeValue(value: T) Forcibly sets or resets the value subsequently returned by method get() and related methods, whether or not already completed.
open CompletableFuture<T>!	orTimeout(timeout: Long, unit: TimeUnit!) Exceptionally completes this CompletableFuture with a TimeoutException if not otherwise completed before the given timeout.
open T	resultNow()
open CompletableFuture<Void!>!	runAfterBoth(other: CompletionStage<*>!, action: Runnable!)
open CompletableFuture<Void!>!	runAfterBothAsync(other: CompletionStage<*>!, action: Runnable!)
open CompletableFuture<Void!>!	runAfterBothAsync(other: CompletionStage<*>!, action: Runnable!, executor: Executor!)
open CompletableFuture<Void!>!	runAfterEither(other: CompletionStage<*>!, action: Runnable!)
open CompletableFuture<Void!>!	runAfterEitherAsync(other: CompletionStage<*>!, action: Runnable!)
open CompletableFuture<Void!>!	runAfterEitherAsync(other: CompletionStage<*>!, action: Runnable!, executor: Executor!)
open static CompletableFuture<Void!>!	runAsync(runnable: Runnable!) Returns a new CompletableFuture that is asynchronously completed by a task running in the ForkJoinPool.commonPool() after it runs the given action.
open static CompletableFuture<Void!>!	runAsync(runnable: Runnable!, executor: Executor!) Returns a new CompletableFuture that is asynchronously completed by a task running in the given executor after it runs the given action.
open Future.State!	state()
open static CompletableFuture<U>!	supplyAsync(supplier: Supplier<U>!) Returns a new CompletableFuture that is asynchronously completed by a task running in the ForkJoinPool.commonPool() with the value obtained by calling the given Supplier.
open static CompletableFuture<U>!	supplyAsync(supplier: Supplier<U>!, executor: Executor!) Returns a new CompletableFuture that is asynchronously completed by a task running in the given executor with the value obtained by calling the given Supplier.
open CompletableFuture<Void!>!	thenAccept(action: Consumer<in T>!)
open CompletableFuture<Void!>!	thenAcceptAsync(action: Consumer<in T>!)
open CompletableFuture<Void!>!	thenAcceptAsync(action: Consumer<in T>!, executor: Executor!)
open CompletableFuture<Void!>!	thenAcceptBoth(other: CompletionStage<out U>!, action: BiConsumer<in T, in U>!)
open CompletableFuture<Void!>!	thenAcceptBothAsync(other: CompletionStage<out U>!, action: BiConsumer<in T, in U>!)
open CompletableFuture<Void!>!	thenAcceptBothAsync(other: CompletionStage<out U>!, action: BiConsumer<in T, in U>!, executor: Executor!)
open CompletableFuture<U>!	thenApply(fn: Function<in T, out U>!)
open CompletableFuture<U>!	thenApplyAsync(fn: Function<in T, out U>!)
open CompletableFuture<U>!	thenApplyAsync(fn: Function<in T, out U>!, executor: Executor!)
open CompletableFuture<V>!	thenCombine(other: CompletionStage<out U>!, fn: BiFunction<in T, in U, out V>!)
open CompletableFuture<V>!	thenCombineAsync(other: CompletionStage<out U>!, fn: BiFunction<in T, in U, out V>!)
open CompletableFuture<V>!	thenCombineAsync(other: CompletionStage<out U>!, fn: BiFunction<in T, in U, out V>!, executor: Executor!)
open CompletableFuture<U>!	thenCompose(fn: Function<in T, out CompletionStage<U>!>!)
open CompletableFuture<U>!	thenComposeAsync(fn: Function<in T, out CompletionStage<U>!>!)
open CompletableFuture<U>!	thenComposeAsync(fn: Function<in T, out CompletionStage<U>!>!, executor: Executor!)
open CompletableFuture<Void!>!	thenRun(action: Runnable!)
open CompletableFuture<Void!>!	thenRunAsync(action: Runnable!)
open CompletableFuture<Void!>!	thenRunAsync(action: Runnable!, executor: Executor!)
open CompletableFuture<T>!	toCompletableFuture() Returns this CompletableFuture.
open String	toString() Returns a string identifying this CompletableFuture, as well as its completion state.
open CompletableFuture<T>!	whenComplete(action: BiConsumer<in T, in Throwable!>!)
open CompletableFuture<T>!	whenCompleteAsync(action: BiConsumer<in T, in Throwable!>!)
open CompletableFuture<T>!	whenCompleteAsync(action: BiConsumer<in T, in Throwable!>!, executor: Executor!)

Public constructors

CompletableFuture

Added in API level 24

CompletableFuture()

Creates a new incomplete CompletableFuture.

Public methods

acceptEither

Added in API level 24

open fun acceptEither(
    other: CompletionStage<out T>!, 
    action: Consumer<in T>!
): CompletableFuture<Void!>!

Parameters
other	CompletionStage<out T>!: the other CompletionStage
action	Consumer<in T>!: the action to perform before completing the returned CompletionStage

Return
CompletableFuture<Void!>!	the new CompletionStage

acceptEitherAsync

Added in API level 24

open fun acceptEitherAsync(
    other: CompletionStage<out T>!, 
    action: Consumer<in T>!
): CompletableFuture<Void!>!

Parameters
other	CompletionStage<out T>!: the other CompletionStage
action	Consumer<in T>!: the action to perform before completing the returned CompletionStage

Return
CompletableFuture<Void!>!	the new CompletionStage

acceptEitherAsync

Added in API level 24

open fun acceptEitherAsync(
    other: CompletionStage<out T>!, 
    action: Consumer<in T>!, 
    executor: Executor!
): CompletableFuture<Void!>!

Parameters
other	CompletionStage<out T>!: the other CompletionStage
action	Consumer<in T>!: the action to perform before completing the returned CompletionStage
executor	Executor!: the executor to use for asynchronous execution

Return
CompletableFuture<Void!>!	the new CompletionStage

allOf

Added in API level 24

open static fun allOf(vararg cfs: CompletableFuture<*>!): CompletableFuture<Void!>!

Returns a new CompletableFuture that is completed when all of the given CompletableFutures complete. If any of the given CompletableFutures complete exceptionally, then the returned CompletableFuture also does so, with a CompletionException holding this exception as its cause. Otherwise, the results, if any, of the given CompletableFutures are not reflected in the returned CompletableFuture, but may be obtained by inspecting them individually. If no CompletableFutures are provided, returns a CompletableFuture completed with the value null.

Among the applications of this method is to await completion of a set of independent CompletableFutures before continuing a program, as in: CompletableFuture.allOf(c1, c2, c3).join();.

Parameters
cfs	CompletableFuture<*>!: the CompletableFutures

Return
CompletableFuture<Void!>!	a new CompletableFuture that is completed when all of the given CompletableFutures complete

Exceptions
java.lang.NullPointerException	if the array or any of its elements are null

anyOf

Added in API level 24

open static fun anyOf(vararg cfs: CompletableFuture<*>!): CompletableFuture<Any!>!

Returns a new CompletableFuture that is completed when any of the given CompletableFutures complete, with the same result. Otherwise, if it completed exceptionally, the returned CompletableFuture also does so, with a CompletionException holding this exception as its cause. If no CompletableFutures are provided, returns an incomplete CompletableFuture.

Parameters
cfs	CompletableFuture<*>!: the CompletableFutures

Return
CompletableFuture<Any!>!	a new CompletableFuture that is completed with the result or exception of any of the given CompletableFutures when one completes

Exceptions
java.lang.NullPointerException	if the array or any of its elements are null

applyToEither

Added in API level 24

open fun <U : Any!> applyToEither(
    other: CompletionStage<out T>!, 
    fn: Function<in T, U>!
): CompletableFuture<U>!

Parameters
other	CompletionStage<out T>!: the other CompletionStage
fn	Function<in T, U>!: the function to use to compute the value of the returned CompletionStage
<U>	the function's return type

Return
CompletableFuture<U>!	the new CompletionStage

applyToEitherAsync

Added in API level 24

open fun <U : Any!> applyToEitherAsync(
    other: CompletionStage<out T>!, 
    fn: Function<in T, U>!
): CompletableFuture<U>!

Parameters
other	CompletionStage<out T>!: the other CompletionStage
fn	Function<in T, U>!: the function to use to compute the value of the returned CompletionStage
<U>	the function's return type

Return
CompletableFuture<U>!	the new CompletionStage

applyToEitherAsync

Added in API level 24

open fun <U : Any!> applyToEitherAsync(
    other: CompletionStage<out T>!, 
    fn: Function<in T, U>!, 
    executor: Executor!
): CompletableFuture<U>!

Parameters
other	CompletionStage<out T>!: the other CompletionStage
fn	Function<in T, U>!: the function to use to compute the value of the returned CompletionStage
executor	Executor!: the executor to use for asynchronous execution
<U>	the function's return type

Return
CompletableFuture<U>!	the new CompletionStage

cancel

Added in API level 24

open fun cancel(mayInterruptIfRunning: Boolean): Boolean

If not already completed, completes this CompletableFuture with a CancellationException. Dependent CompletableFutures that have not already completed will also complete exceptionally, with a CompletionException caused by this CancellationException.

Parameters
mayInterruptIfRunning	Boolean: this value has no effect in this implementation because interrupts are not used to control processing.

Return
Boolean	true if this task is now cancelled

complete

Added in API level 24

open fun complete(value: T): Boolean

If not already completed, sets the value returned by get() and related methods to the given value.

Parameters
value	T: the result value

Return
Boolean	true if this invocation caused this CompletableFuture to transition to a completed state, else false

completeAsync

Added in API level 31

open fun completeAsync(supplier: Supplier<out T>!): CompletableFuture<T>!

Completes this CompletableFuture with the result of the given Supplier function invoked from an asynchronous task using the default executor.

Parameters
supplier	Supplier<out T>!: a function returning the value to be used to complete this CompletableFuture

Return
CompletableFuture<T>!	this CompletableFuture

completeAsync

Added in API level 31

open fun completeAsync(
    supplier: Supplier<out T>!, 
    executor: Executor!
): CompletableFuture<T>!

Completes this CompletableFuture with the result of the given Supplier function invoked from an asynchronous task using the given executor.

Parameters
supplier	Supplier<out T>!: a function returning the value to be used to complete this CompletableFuture
executor	Executor!: the executor to use for asynchronous execution

Return
CompletableFuture<T>!	this CompletableFuture

completeExceptionally

Added in API level 24

open fun completeExceptionally(ex: Throwable!): Boolean

If not already completed, causes invocations of get() and related methods to throw the given exception.

Parameters
ex	Throwable!: the exception

Return
Boolean	true if this invocation caused this CompletableFuture to transition to a completed state, else false

completeOnTimeout

Added in API level 31

open fun completeOnTimeout(
    value: T, 
    timeout: Long, 
    unit: TimeUnit!
): CompletableFuture<T>!

Completes this CompletableFuture with the given value if not otherwise completed before the given timeout.

Parameters
value	T: the value to use upon timeout
timeout	Long: how long to wait before completing normally with the given value, in units of unit
unit	TimeUnit!: a TimeUnit determining how to interpret the timeout parameter

Return
CompletableFuture<T>!	this CompletableFuture

completedFuture

Added in API level 24

open static fun <U : Any!> completedFuture(value: U): CompletableFuture<U>!

Returns a new CompletableFuture that is already completed with the given value.

Parameters
value	U: the value
<U>	the type of the value

Return
CompletableFuture<U>!	the completed CompletableFuture

completedStage

Added in API level 31

open static fun <U : Any!> completedStage(value: U): CompletionStage<U>!

Returns a new CompletionStage that is already completed with the given value and supports only those methods in interface CompletionStage.

Parameters
value	U: the value
<U>	the type of the value

Return
CompletionStage<U>!	the completed CompletionStage

copy

Added in API level 31

open fun copy(): CompletableFuture<T>!

Returns a new CompletableFuture that is completed normally with the same value as this CompletableFuture when it completes normally. If this CompletableFuture completes exceptionally, then the returned CompletableFuture completes exceptionally with a CompletionException with this exception as cause. The behavior is equivalent to thenApply(x -> x). This method may be useful as a form of "defensive copying", to prevent clients from completing, while still being able to arrange dependent actions.

Return
CompletableFuture<T>!	the new CompletableFuture

defaultExecutor

Added in API level 31

open fun defaultExecutor(): Executor!

Returns the default Executor used for async methods that do not specify an Executor. This class uses the java.util.concurrent.ForkJoinPool#commonPool() if it supports more than one parallel thread, or else an Executor using one thread per async task. This method may be overridden in subclasses to return an Executor that provides at least one independent thread.

Return
Executor!	the executor

delayedExecutor

Added in API level 31

open static fun delayedExecutor(
    delay: Long, 
    unit: TimeUnit!
): Executor!

Returns a new Executor that submits a task to the default executor after the given delay (or no delay if non-positive). Each delay commences upon invocation of the returned executor's execute method.

Parameters
delay	Long: how long to delay, in units of unit
unit	TimeUnit!: a TimeUnit determining how to interpret the delay parameter

Return
Executor!	the new delayed executor

delayedExecutor

Added in API level 31

open static fun delayedExecutor(
    delay: Long, 
    unit: TimeUnit!, 
    executor: Executor!
): Executor!

Returns a new Executor that submits a task to the given base executor after the given delay (or no delay if non-positive). Each delay commences upon invocation of the returned executor's execute method.

Parameters
delay	Long: how long to delay, in units of unit
unit	TimeUnit!: a TimeUnit determining how to interpret the delay parameter
executor	Executor!: the base executor

Return
Executor!	the new delayed executor

exceptionNow

Added in API level Baklava

open fun exceptionNow(): Throwable!

Return
Throwable!	the exception thrown by the task

Exceptions
java.lang.IllegalStateException	if the task has not completed, the task completed normally, or the task was cancelled

exceptionally

Added in API level 24

open fun exceptionally(fn: Function<Throwable!, out T>!): CompletableFuture<T>!

Parameters
fn	Function<Throwable!, out T>!: the function to use to compute the value of the returned CompletionStage if this CompletionStage completed exceptionally

Return
CompletableFuture<T>!	the new CompletionStage

exceptionallyAsync

Added in API level 34

open fun exceptionallyAsync(fn: Function<Throwable!, out T>!): CompletableFuture<T>!

Parameters
fn	Function<Throwable!, out T>!: the function to use to compute the value of the returned CompletionStage if this CompletionStage completed exceptionally

Return
CompletableFuture<T>!	the new CompletionStage

exceptionallyAsync

Added in API level 34

open fun exceptionallyAsync(
    fn: Function<Throwable!, out T>!, 
    executor: Executor!
): CompletableFuture<T>!

Parameters
fn	Function<Throwable!, out T>!: the function to use to compute the value of the returned CompletionStage if this CompletionStage completed exceptionally
executor	Executor!: the executor to use for asynchronous execution

Return
CompletableFuture<T>!	the new CompletionStage

exceptionallyCompose

Added in API level 34

open fun exceptionallyCompose(fn: Function<Throwable!, out CompletionStage<T>!>!): CompletableFuture<T>!

Parameters
fn	Function<Throwable!, out CompletionStage<T>!>!: the function to use to compute the returned CompletionStage if this CompletionStage completed exceptionally

Return
CompletableFuture<T>!	the new CompletionStage

exceptionallyComposeAsync

Added in API level 34

open fun exceptionallyComposeAsync(fn: Function<Throwable!, out CompletionStage<T>!>!): CompletableFuture<T>!

Parameters
fn	Function<Throwable!, out CompletionStage<T>!>!: the function to use to compute the returned CompletionStage if this CompletionStage completed exceptionally

Return
CompletableFuture<T>!	the new CompletionStage

exceptionallyComposeAsync

Added in API level 34

open fun exceptionallyComposeAsync(
    fn: Function<Throwable!, out CompletionStage<T>!>!, 
    executor: Executor!
): CompletableFuture<T>!

Parameters
fn	Function<Throwable!, out CompletionStage<T>!>!: the function to use to compute the returned CompletionStage if this CompletionStage completed exceptionally
executor	Executor!: the executor to use for asynchronous execution

Return
CompletableFuture<T>!	the new CompletionStage

failedFuture

Added in API level 31

open static fun <U : Any!> failedFuture(ex: Throwable!): CompletableFuture<U>!

Returns a new CompletableFuture that is already completed exceptionally with the given exception.

Parameters
ex	Throwable!: the exception
<U>	the type of the value

Return
CompletableFuture<U>!	the exceptionally completed CompletableFuture

failedStage

Added in API level 31

open static fun <U : Any!> failedStage(ex: Throwable!): CompletionStage<U>!

Returns a new CompletionStage that is already completed exceptionally with the given exception and supports only those methods in interface CompletionStage.

Parameters
ex	Throwable!: the exception
<U>	the type of the value

Return
CompletionStage<U>!	the exceptionally completed CompletionStage

get

Added in API level 24

open fun get(): T

Waits if necessary for this future to complete, and then returns its result.

Return
T	the result value

Exceptions
java.util.concurrent.CancellationException	if this future was cancelled
java.util.concurrent.ExecutionException	if this future completed exceptionally
java.lang.InterruptedException	if the current thread was interrupted while waiting

get

Added in API level 24

open fun get(
    timeout: Long, 
    unit: TimeUnit!
): T

Waits if necessary for at most the given time for this future to complete, and then returns its result, if available.

Parameters
timeout	Long: the maximum time to wait
unit	TimeUnit!: the time unit of the timeout argument

Return
T	the result value

Exceptions
java.util.concurrent.CancellationException	if this future was cancelled
java.util.concurrent.ExecutionException	if this future completed exceptionally
java.lang.InterruptedException	if the current thread was interrupted while waiting
java.util.concurrent.TimeoutException	if the wait timed out

getNow

Added in API level 24

open fun getNow(valueIfAbsent: T): T

Returns the result value (or throws any encountered exception) if completed, else returns the given valueIfAbsent.

Parameters
valueIfAbsent	T: the value to return if not completed

Return
T	the result value, if completed, else the given valueIfAbsent

Exceptions
java.util.concurrent.CancellationException	if the computation was cancelled
java.util.concurrent.CompletionException	if this future completed exceptionally or a completion computation threw an exception

getNumberOfDependents

Added in API level 24

open fun getNumberOfDependents(): Int

Returns the estimated number of CompletableFutures whose completions are awaiting completion of this CompletableFuture. This method is designed for use in monitoring system state, not for synchronization control.

Return
Int	the number of dependent CompletableFutures

handle

Added in API level 24

open fun <U : Any!> handle(fn: BiFunction<in T, Throwable!, out U>!): CompletableFuture<U>!

Parameters
fn	BiFunction<in T, Throwable!, out U>!: the function to use to compute the value of the returned CompletionStage
<U>	the function's return type

Return
CompletableFuture<U>!	the new CompletionStage

handleAsync

Added in API level 24

open fun <U : Any!> handleAsync(fn: BiFunction<in T, Throwable!, out U>!): CompletableFuture<U>!

Parameters
fn	BiFunction<in T, Throwable!, out U>!: the function to use to compute the value of the returned CompletionStage
<U>	the function's return type

Return
CompletableFuture<U>!	the new CompletionStage

handleAsync

Added in API level 24

open fun <U : Any!> handleAsync(
    fn: BiFunction<in T, Throwable!, out U>!, 
    executor: Executor!
): CompletableFuture<U>!

Parameters
fn	BiFunction<in T, Throwable!, out U>!: the function to use to compute the value of the returned CompletionStage
executor	Executor!: the executor to use for asynchronous execution
<U>	the function's return type

Return
CompletableFuture<U>!	the new CompletionStage

isCancelled

Added in API level 24

open fun isCancelled(): Boolean

Returns true if this CompletableFuture was cancelled before it completed normally.

Return
Boolean	true if this CompletableFuture was cancelled before it completed normally

isCompletedExceptionally

Added in API level 24

open fun isCompletedExceptionally(): Boolean

Returns true if this CompletableFuture completed exceptionally, in any way. Possible causes include cancellation, explicit invocation of completeExceptionally, and abrupt termination of a CompletionStage action.

Return
Boolean	true if this CompletableFuture completed exceptionally

isDone

Added in API level 24

open fun isDone(): Boolean

Returns true if completed in any fashion: normally, exceptionally, or via cancellation.

Return
Boolean	true if completed

join

Added in API level 24

open fun join(): T

Returns the result value when complete, or throws an (unchecked) exception if completed exceptionally. To better conform with the use of common functional forms, if a computation involved in the completion of this CompletableFuture threw an exception, this method throws an (unchecked) CompletionException with the underlying exception as its cause.

Return
T	the result value

Exceptions
java.util.concurrent.CancellationException	if the computation was cancelled
java.util.concurrent.CompletionException	if this future completed exceptionally or a completion computation threw an exception

minimalCompletionStage

Added in API level 31

open fun minimalCompletionStage(): CompletionStage<T>!

Returns a new CompletionStage that is completed normally with the same value as this CompletableFuture when it completes normally, and cannot be independently completed or otherwise used in ways not defined by the methods of interface CompletionStage. If this CompletableFuture completes exceptionally, then the returned CompletionStage completes exceptionally with a CompletionException with this exception as cause.

Unless overridden by a subclass, a new non-minimal CompletableFuture with all methods available can be obtained from a minimal CompletionStage via toCompletableFuture(). For example, completion of a minimal stage can be awaited by

<code>minimalStage.toCompletableFuture().join(); </code>

Return
CompletionStage<T>!	the new CompletionStage

newIncompleteFuture

Added in API level 31

open fun <U : Any!> newIncompleteFuture(): CompletableFuture<U>!

Returns a new incomplete CompletableFuture of the type to be returned by a CompletionStage method. Subclasses should normally override this method to return an instance of the same class as this CompletableFuture. The default implementation returns an instance of class CompletableFuture.

Parameters
<U>	the type of the value

Return
CompletableFuture<U>!	a new CompletableFuture

obtrudeException

Added in API level 24

open fun obtrudeException(ex: Throwable!): Unit

Forcibly causes subsequent invocations of method get() and related methods to throw the given exception, whether or not already completed. This method is designed for use only in error recovery actions, and even in such situations may result in ongoing dependent completions using established versus overwritten outcomes.

Parameters
ex	Throwable!: the exception

Exceptions
java.lang.NullPointerException	if the exception is null

obtrudeValue

Added in API level 24

open fun obtrudeValue(value: T): Unit

Forcibly sets or resets the value subsequently returned by method get() and related methods, whether or not already completed. This method is designed for use only in error recovery actions, and even in such situations may result in ongoing dependent completions using established versus overwritten outcomes.

Parameters
value	T: the completion value

orTimeout

Added in API level 31

open fun orTimeout(
    timeout: Long, 
    unit: TimeUnit!
): CompletableFuture<T>!

Exceptionally completes this CompletableFuture with a TimeoutException if not otherwise completed before the given timeout.

Parameters
timeout	Long: how long to wait before completing exceptionally with a TimeoutException, in units of unit
unit	TimeUnit!: a TimeUnit determining how to interpret the timeout parameter

Return
CompletableFuture<T>!	this CompletableFuture

resultNow

Added in API level Baklava

open fun resultNow(): T

Return
T	the computed result

Exceptions
java.lang.IllegalStateException	if the task has not completed or the task did not complete with a result

runAfterBoth

Added in API level 24

open fun runAfterBoth(
    other: CompletionStage<*>!, 
    action: Runnable!
): CompletableFuture<Void!>!

Parameters
other	CompletionStage<*>!: the other CompletionStage
action	Runnable!: the action to perform before completing the returned CompletionStage

Return
CompletableFuture<Void!>!	the new CompletionStage

runAfterBothAsync

Added in API level 24

open fun runAfterBothAsync(
    other: CompletionStage<*>!, 
    action: Runnable!
): CompletableFuture<Void!>!

Parameters
other	CompletionStage<*>!: the other CompletionStage
action	Runnable!: the action to perform before completing the returned CompletionStage

Return
CompletableFuture<Void!>!	the new CompletionStage

runAfterBothAsync

Added in API level 24

open fun runAfterBothAsync(
    other: CompletionStage<*>!, 
    action: Runnable!, 
    executor: Executor!
): CompletableFuture<Void!>!

Parameters
other	CompletionStage<*>!: the other CompletionStage
action	Runnable!: the action to perform before completing the returned CompletionStage
executor	Executor!: the executor to use for asynchronous execution

Return
CompletableFuture<Void!>!	the new CompletionStage

runAfterEither

Added in API level 24

open fun runAfterEither(
    other: CompletionStage<*>!, 
    action: Runnable!
): CompletableFuture<Void!>!

Parameters
other	CompletionStage<*>!: the other CompletionStage
action	Runnable!: the action to perform before completing the returned CompletionStage

Return
CompletableFuture<Void!>!	the new CompletionStage

runAfterEitherAsync

Added in API level 24

open fun runAfterEitherAsync(
    other: CompletionStage<*>!, 
    action: Runnable!
): CompletableFuture<Void!>!

Parameters
other	CompletionStage<*>!: the other CompletionStage
action	Runnable!: the action to perform before completing the returned CompletionStage

Return
CompletableFuture<Void!>!	the new CompletionStage

runAfterEitherAsync

Added in API level 24

open fun runAfterEitherAsync(
    other: CompletionStage<*>!, 
    action: Runnable!, 
    executor: Executor!
): CompletableFuture<Void!>!

Parameters
other	CompletionStage<*>!: the other CompletionStage
action	Runnable!: the action to perform before completing the returned CompletionStage
executor	Executor!: the executor to use for asynchronous execution

Return
CompletableFuture<Void!>!	the new CompletionStage

runAsync

Added in API level 24

open static fun runAsync(runnable: Runnable!): CompletableFuture<Void!>!

Returns a new CompletableFuture that is asynchronously completed by a task running in the ForkJoinPool.commonPool() after it runs the given action.

Parameters
runnable	Runnable!: the action to run before completing the returned CompletableFuture

Return
CompletableFuture<Void!>!	the new CompletableFuture

runAsync

Added in API level 24

open static fun runAsync(
    runnable: Runnable!, 
    executor: Executor!
): CompletableFuture<Void!>!

Returns a new CompletableFuture that is asynchronously completed by a task running in the given executor after it runs the given action.

Parameters
runnable	Runnable!: the action to run before completing the returned CompletableFuture
executor	Executor!: the executor to use for asynchronous execution

Return
CompletableFuture<Void!>!	the new CompletableFuture

state

Added in API level Baklava

open fun state(): Future.State!

supplyAsync

Added in API level 24

open static fun <U : Any!> supplyAsync(supplier: Supplier<U>!): CompletableFuture<U>!

Returns a new CompletableFuture that is asynchronously completed by a task running in the ForkJoinPool.commonPool() with the value obtained by calling the given Supplier.

Parameters
supplier	Supplier<U>!: a function returning the value to be used to complete the returned CompletableFuture
<U>	the function's return type

Return
CompletableFuture<U>!	the new CompletableFuture

supplyAsync

Added in API level 24

open static fun <U : Any!> supplyAsync(
    supplier: Supplier<U>!, 
    executor: Executor!
): CompletableFuture<U>!

Returns a new CompletableFuture that is asynchronously completed by a task running in the given executor with the value obtained by calling the given Supplier.

Parameters
supplier	Supplier<U>!: a function returning the value to be used to complete the returned CompletableFuture
executor	Executor!: the executor to use for asynchronous execution
<U>	the function's return type

Return
CompletableFuture<U>!	the new CompletableFuture

thenAccept

Added in API level 24

open fun thenAccept(action: Consumer<in T>!): CompletableFuture<Void!>!

Parameters
action	Consumer<in T>!: the action to perform before completing the returned CompletionStage

Return
CompletableFuture<Void!>!	the new CompletionStage

thenAcceptAsync

Added in API level 24

open fun thenAcceptAsync(action: Consumer<in T>!): CompletableFuture<Void!>!

Parameters
action	Consumer<in T>!: the action to perform before completing the returned CompletionStage

Return
CompletableFuture<Void!>!	the new CompletionStage

thenAcceptAsync

Added in API level 24

open fun thenAcceptAsync(
    action: Consumer<in T>!, 
    executor: Executor!
): CompletableFuture<Void!>!

Parameters
action	Consumer<in T>!: the action to perform before completing the returned CompletionStage
executor	Executor!: the executor to use for asynchronous execution

Return
CompletableFuture<Void!>!	the new CompletionStage

thenAcceptBoth

Added in API level 24

open fun <U : Any!> thenAcceptBoth(
    other: CompletionStage<out U>!, 
    action: BiConsumer<in T, in U>!
): CompletableFuture<Void!>!

Parameters
other	CompletionStage<out U>!: the other CompletionStage
action	BiConsumer<in T, in U>!: the action to perform before completing the returned CompletionStage
<U>	the type of the other CompletionStage's result

Return
CompletableFuture<Void!>!	the new CompletionStage

thenAcceptBothAsync

Added in API level 24

open fun <U : Any!> thenAcceptBothAsync(
    other: CompletionStage<out U>!, 
    action: BiConsumer<in T, in U>!
): CompletableFuture<Void!>!

Parameters
other	CompletionStage<out U>!: the other CompletionStage
action	BiConsumer<in T, in U>!: the action to perform before completing the returned CompletionStage
<U>	the type of the other CompletionStage's result

Return
CompletableFuture<Void!>!	the new CompletionStage

thenAcceptBothAsync

Added in API level 24

open fun <U : Any!> thenAcceptBothAsync(
    other: CompletionStage<out U>!, 
    action: BiConsumer<in T, in U>!, 
    executor: Executor!
): CompletableFuture<Void!>!

Parameters
other	CompletionStage<out U>!: the other CompletionStage
action	BiConsumer<in T, in U>!: the action to perform before completing the returned CompletionStage
executor	Executor!: the executor to use for asynchronous execution
<U>	the type of the other CompletionStage's result

Return
CompletableFuture<Void!>!	the new CompletionStage

thenApply

Added in API level 24

open fun <U : Any!> thenApply(fn: Function<in T, out U>!): CompletableFuture<U>!

Parameters
fn	Function<in T, out U>!: the function to use to compute the value of the returned CompletionStage
<U>	the function's return type

Return
CompletableFuture<U>!	the new CompletionStage

thenApplyAsync

Added in API level 24

open fun <U : Any!> thenApplyAsync(fn: Function<in T, out U>!): CompletableFuture<U>!

Parameters
fn	Function<in T, out U>!: the function to use to compute the value of the returned CompletionStage
<U>	the function's return type

Return
CompletableFuture<U>!	the new CompletionStage

thenApplyAsync

Added in API level 24

open fun <U : Any!> thenApplyAsync(
    fn: Function<in T, out U>!, 
    executor: Executor!
): CompletableFuture<U>!

Parameters
fn	Function<in T, out U>!: the function to use to compute the value of the returned CompletionStage
executor	Executor!: the executor to use for asynchronous execution
<U>	the function's return type

Return
CompletableFuture<U>!	the new CompletionStage

thenCombine

Added in API level 24

open fun <U : Any!, V : Any!> thenCombine(
    other: CompletionStage<out U>!, 
    fn: BiFunction<in T, in U, out V>!
): CompletableFuture<V>!

Parameters
other	CompletionStage<out U>!: the other CompletionStage
fn	BiFunction<in T, in U, out V>!: the function to use to compute the value of the returned CompletionStage
<U>	the type of the other CompletionStage's result
<V>	the function's return type

Return
CompletableFuture<V>!	the new CompletionStage

thenCombineAsync

Added in API level 24

open fun <U : Any!, V : Any!> thenCombineAsync(
    other: CompletionStage<out U>!, 
    fn: BiFunction<in T, in U, out V>!
): CompletableFuture<V>!

Parameters
other	CompletionStage<out U>!: the other CompletionStage
fn	BiFunction<in T, in U, out V>!: the function to use to compute the value of the returned CompletionStage
<U>	the type of the other CompletionStage's result
<V>	the function's return type

Return
CompletableFuture<V>!	the new CompletionStage

thenCombineAsync

Added in API level 24

open fun <U : Any!, V : Any!> thenCombineAsync(
    other: CompletionStage<out U>!, 
    fn: BiFunction<in T, in U, out V>!, 
    executor: Executor!
): CompletableFuture<V>!

Parameters
other	CompletionStage<out U>!: the other CompletionStage
fn	BiFunction<in T, in U, out V>!: the function to use to compute the value of the returned CompletionStage
executor	Executor!: the executor to use for asynchronous execution
<U>	the type of the other CompletionStage's result
<V>	the function's return type

Return
CompletableFuture<V>!	the new CompletionStage

thenCompose

Added in API level 24

open fun <U : Any!> thenCompose(fn: Function<in T, out CompletionStage<U>!>!): CompletableFuture<U>!

Parameters
fn	Function<in T, out CompletionStage<U>!>!: the function to use to compute another CompletionStage
<U>	the type of the returned CompletionStage's result

Return
CompletableFuture<U>!	the new CompletionStage

thenComposeAsync

Added in API level 24

open fun <U : Any!> thenComposeAsync(fn: Function<in T, out CompletionStage<U>!>!): CompletableFuture<U>!

Parameters
fn	Function<in T, out CompletionStage<U>!>!: the function to use to compute another CompletionStage
<U>	the type of the returned CompletionStage's result

Return
CompletableFuture<U>!	the new CompletionStage

thenComposeAsync

Added in API level 24

open fun <U : Any!> thenComposeAsync(
    fn: Function<in T, out CompletionStage<U>!>!, 
    executor: Executor!
): CompletableFuture<U>!

Parameters
fn	Function<in T, out CompletionStage<U>!>!: the function to use to compute another CompletionStage
executor	Executor!: the executor to use for asynchronous execution
<U>	the type of the returned CompletionStage's result

Return
CompletableFuture<U>!	the new CompletionStage

thenRun

Added in API level 24

open fun thenRun(action: Runnable!): CompletableFuture<Void!>!

Parameters
action	Runnable!: the action to perform before completing the returned CompletionStage

Return
CompletableFuture<Void!>!	the new CompletionStage

thenRunAsync

Added in API level 24

open fun thenRunAsync(action: Runnable!): CompletableFuture<Void!>!

Parameters
action	Runnable!: the action to perform before completing the returned CompletionStage

Return
CompletableFuture<Void!>!	the new CompletionStage

thenRunAsync

Added in API level 24

open fun thenRunAsync(
    action: Runnable!, 
    executor: Executor!
): CompletableFuture<Void!>!

Parameters
action	Runnable!: the action to perform before completing the returned CompletionStage
executor	Executor!: the executor to use for asynchronous execution

Return
CompletableFuture<Void!>!	the new CompletionStage

toCompletableFuture

Added in API level 24

open fun toCompletableFuture(): CompletableFuture<T>!

Returns this CompletableFuture.

Return
CompletableFuture<T>!	this CompletableFuture

toString

Added in API level 24

open fun toString(): String

Returns a string identifying this CompletableFuture, as well as its completion state. The state, in brackets, contains the String "Completed Normally" or the String "Completed Exceptionally", or the String "Not completed" followed by the number of CompletableFutures dependent upon its completion, if any.

Return
String	a string identifying this CompletableFuture, as well as its state

whenComplete

Added in API level 24

open fun whenComplete(action: BiConsumer<in T, in Throwable!>!): CompletableFuture<T>!

Parameters
action	BiConsumer<in T, in Throwable!>!: the action to perform

Return
CompletableFuture<T>!	the new CompletionStage

whenCompleteAsync

Added in API level 24

open fun whenCompleteAsync(action: BiConsumer<in T, in Throwable!>!): CompletableFuture<T>!

Parameters
action	BiConsumer<in T, in Throwable!>!: the action to perform

Return
CompletableFuture<T>!	the new CompletionStage

whenCompleteAsync

Added in API level 24

open fun whenCompleteAsync(
    action: BiConsumer<in T, in Throwable!>!, 
    executor: Executor!
): CompletableFuture<T>!

Parameters
action	BiConsumer<in T, in Throwable!>!: the action to perform
executor	Executor!: the executor to use for asynchronous execution

Return
CompletableFuture<T>!	the new CompletionStage