java.util.concurrent.CompletableFuture<T>

Type Parameters:: T - The result type returned by this future's join and get methods

All Implemented Interfaces:: CompletionStage<T>, Future<T>

public class CompletableFuture<T>
extends Object
implements Future<T>, CompletionStage<T>

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). This may be overridden for non-static methods in subclasses by defining method defaultExecutor(). To simplify monitoring, debugging, and tracking, all generated asynchronous tasks are instances of the marker interface CompletableFuture.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.
All CompletionStage methods return CompletableFutures. To restrict usages to only those methods defined in interface CompletionStage, use method minimalCompletionStage(). Or to ensure only that clients do not themselves modify a future, use method copy().

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, 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(T) 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.

Subclasses of this class should normally override the "virtual constructor" method newIncompleteFuture(), which establishes the concrete type returned by CompletionStage methods. For example, here is a class that substitutes a different default Executor and disables the obtrude methods:

 
 class MyCompletableFuture<T> extends CompletableFuture<T> {
   static final Executor myExecutor = ...;
   public MyCompletableFuture() { }
   public <U> CompletableFuture<U> newIncompleteFuture() {
     return new MyCompletableFuture<U>(); }
   public Executor defaultExecutor() {
     return myExecutor; }
   public void obtrudeValue(T value) {
     throw new UnsupportedOperationException(); }
   public void obtrudeException(Throwable ex) {
     throw new UnsupportedOperationException(); }
 }

Since:: 1.8

Nested Class Summary

Nested Classes
Modifier and Type	Class	Description
`static interface`	`CompletableFuture.AsynchronousCompletionTask`	A marker interface identifying asynchronous tasks produced by `async` methods.

Constructor Summary

Constructors

Constructor Description

CompletableFuture()
Creates a new incomplete CompletableFuture.

Method Summary

Modifier and Type	Method	Description
`CompletableFuture<Void>`	`acceptEither(CompletionStage<? extends T> other, Consumer<? super T> action)`	Returns a new CompletionStage that, when either this or the other given stage complete normally, is executed with the corresponding result as argument to the supplied action.
`CompletableFuture<Void>`	`acceptEitherAsync(CompletionStage<? extends T> other, Consumer<? super T> action)`	Returns a new CompletionStage that, when either this or the other given stage complete normally, is executed using this stage's default asynchronous execution facility, with the corresponding result as argument to the supplied action.
`CompletableFuture<Void>`	`acceptEitherAsync(CompletionStage<? extends T> other, Consumer<? super T> action, Executor executor)`	Returns a new CompletionStage that, when either this or the other given stage complete normally, is executed using the supplied executor, with the corresponding result as argument to the supplied action.
`static CompletableFuture<Void>`	`allOf(CompletableFuture<?>... cfs)`	Returns a new CompletableFuture that is completed when all of the given CompletableFutures complete.
`static CompletableFuture<Object>`	`anyOf(CompletableFuture<?>... cfs)`	Returns a new CompletableFuture that is completed when any of the given CompletableFutures complete, with the same result.
`boolean`	`cancel(boolean mayInterruptIfRunning)`	If not already completed, completes this CompletableFuture with a `CancellationException`.
`boolean`	`complete(T value)`	If not already completed, sets the value returned by `get()` and related methods to the given value.
`CompletableFuture<T>`	`completeAsync(Supplier<? extends T> supplier)`	Completes this CompletableFuture with the result of the given Supplier function invoked from an asynchronous task using the default executor.
`CompletableFuture<T>`	`completeAsync(Supplier<? extends T> supplier, Executor executor)`	Completes this CompletableFuture with the result of the given Supplier function invoked from an asynchronous task using the given executor.
`static <U> CompletableFuture<U>`	`completedFuture(U value)`	Returns a new CompletableFuture that is already completed with the given value.
`static <U> CompletionStage<U>`	`completedStage(U value)`	Returns a new CompletionStage that is already completed with the given value and supports only those methods in interface `CompletionStage`.
`boolean`	`completeExceptionally(Throwable ex)`	If not already completed, causes invocations of `get()` and related methods to throw the given exception.
`CompletableFuture<T>`	`completeOnTimeout(T value, long timeout, TimeUnit unit)`	Completes this CompletableFuture with the given value if not otherwise completed before the given timeout.
`CompletableFuture<T>`	`copy()`	Returns a new CompletableFuture that is completed normally with the same value as this CompletableFuture when it completes normally.
`Executor`	`defaultExecutor()`	Returns the default Executor used for async methods that do not specify an Executor.
`static Executor`	`delayedExecutor(long delay, TimeUnit unit)`	Returns a new Executor that submits a task to the default executor after the given delay (or no delay if non-positive).
`static Executor`	`delayedExecutor(long delay, TimeUnit unit, 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).
`static <U> CompletableFuture<U>`	`failedFuture(Throwable ex)`	Returns a new CompletableFuture that is already completed exceptionally with the given exception.
`static <U> CompletionStage<U>`	`failedStage(Throwable ex)`	Returns a new CompletionStage that is already completed exceptionally with the given exception and supports only those methods in interface `CompletionStage`.
`T`	`get()`	Waits if necessary for this future to complete, and then returns its result.
`T`	`get(long timeout, TimeUnit unit)`	Waits if necessary for at most the given time for this future to complete, and then returns its result, if available.
`T`	`getNow(T valueIfAbsent)`	Returns the result value (or throws any encountered exception) if completed, else returns the given valueIfAbsent.
`int`	`getNumberOfDependents()`	Returns the estimated number of CompletableFutures whose completions are awaiting completion of this CompletableFuture.
`boolean`	`isCancelled()`	Returns `true` if this CompletableFuture was cancelled before it completed normally.
`boolean`	`isCompletedExceptionally()`	Returns `true` if this CompletableFuture completed exceptionally, in any way.
`boolean`	`isDone()`	Returns `true` if completed in any fashion: normally, exceptionally, or via cancellation.
`T`	`join()`	Returns the result value when complete, or throws an (unchecked) exception if completed exceptionally.
`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`.
`<U> CompletableFuture<U>`	`newIncompleteFuture()`	Returns a new incomplete CompletableFuture of the type to be returned by a CompletionStage method.
`void`	`obtrudeException(Throwable ex)`	Forcibly causes subsequent invocations of method `get()` and related methods to throw the given exception, whether or not already completed.
`void`	`obtrudeValue(T value)`	Forcibly sets or resets the value subsequently returned by method `get()` and related methods, whether or not already completed.
`CompletableFuture<T>`	`orTimeout(long timeout, TimeUnit unit)`	Exceptionally completes this CompletableFuture with a `TimeoutException` if not otherwise completed before the given timeout.
`CompletableFuture<Void>`	`runAfterBoth(CompletionStage<?> other, Runnable action)`	Returns a new CompletionStage that, when this and the other given stage both complete normally, executes the given action.
`CompletableFuture<Void>`	`runAfterBothAsync(CompletionStage<?> other, Runnable action)`	Returns a new CompletionStage that, when this and the other given stage both complete normally, executes the given action using this stage's default asynchronous execution facility.
`CompletableFuture<Void>`	`runAfterBothAsync(CompletionStage<?> other, Runnable action, Executor executor)`	Returns a new CompletionStage that, when this and the other given stage both complete normally, executes the given action using the supplied executor.
`CompletableFuture<Void>`	`runAfterEither(CompletionStage<?> other, Runnable action)`	Returns a new CompletionStage that, when either this or the other given stage complete normally, executes the given action.
`CompletableFuture<Void>`	`runAfterEitherAsync(CompletionStage<?> other, Runnable action)`	Returns a new CompletionStage that, when either this or the other given stage complete normally, executes the given action using this stage's default asynchronous execution facility.
`CompletableFuture<Void>`	`runAfterEitherAsync(CompletionStage<?> other, Runnable action, Executor executor)`	Returns a new CompletionStage that, when either this or the other given stage complete normally, executes the given action using the supplied executor.
`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.
`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.
`static <U> CompletableFuture<U>`	`supplyAsync(Supplier<U> supplier)`	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.
`static <U> CompletableFuture<U>`	`supplyAsync(Supplier<U> supplier, 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.
`CompletableFuture<Void>`	`thenAccept(Consumer<? super T> action)`	Returns a new CompletionStage that, when this stage completes normally, is executed with this stage's result as the argument to the supplied action.
`CompletableFuture<Void>`	`thenAcceptAsync(Consumer<? super T> action)`	Returns a new CompletionStage that, when this stage completes normally, is executed using this stage's default asynchronous execution facility, with this stage's result as the argument to the supplied action.
`CompletableFuture<Void>`	`thenAcceptAsync(Consumer<? super T> action, Executor executor)`	Returns a new CompletionStage that, when this stage completes normally, is executed using the supplied Executor, with this stage's result as the argument to the supplied action.
`<U> CompletableFuture<Void>`	`thenAcceptBoth(CompletionStage<? extends U> other, BiConsumer<? super T,? super U> action)`	Returns a new CompletionStage that, when this and the other given stage both complete normally, is executed with the two results as arguments to the supplied action.
`<U> CompletableFuture<Void>`	`thenAcceptBothAsync(CompletionStage<? extends U> other, BiConsumer<? super T,? super U> action)`	Returns a new CompletionStage that, when this and the other given stage both complete normally, is executed using this stage's default asynchronous execution facility, with the two results as arguments to the supplied action.
`<U> CompletableFuture<Void>`	`thenAcceptBothAsync(CompletionStage<? extends U> other, BiConsumer<? super T,? super U> action, Executor executor)`	Returns a new CompletionStage that, when this and the other given stage both complete normally, is executed using the supplied executor, with the two results as arguments to the supplied action.
`CompletableFuture<Void>`	`thenRun(Runnable action)`	Returns a new CompletionStage that, when this stage completes normally, executes the given action.
`CompletableFuture<Void>`	`thenRunAsync(Runnable action)`	Returns a new CompletionStage that, when this stage completes normally, executes the given action using this stage's default asynchronous execution facility.
`CompletableFuture<Void>`	`thenRunAsync(Runnable action, Executor executor)`	Returns a new CompletionStage that, when this stage completes normally, executes the given action using the supplied Executor.
`CompletableFuture<T>`	`toCompletableFuture()`	Returns this CompletableFuture.
`String`	`toString()`	Returns a string identifying this CompletableFuture, as well as its completion state.

Methods declared in class java.lang.Object

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

Methods declared in interface java.util.concurrent.CompletionStage

applyToEither, applyToEitherAsync, applyToEitherAsync, exceptionally, exceptionallyAsync, exceptionallyAsync, exceptionallyCompose, exceptionallyComposeAsync, exceptionallyComposeAsync, handle, handleAsync, handleAsync, thenApply, thenApplyAsync, thenApplyAsync, thenCombine, thenCombineAsync, thenCombineAsync, thenCompose, thenComposeAsync, thenComposeAsync, whenComplete, whenCompleteAsync, whenCompleteAsync

Constructor Details
- CompletableFuture
  
  public CompletableFuture()
  
  Creates a new incomplete CompletableFuture.
Method Details
- supplyAsync
 
 public static CompletableFuture supplyAsync(Supplier supplier)
 
 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.
 
 Type Parameters:
 
 U - the function's return type
 
 Parameters:
 
 supplier - a function returning the value to be used to complete the returned CompletableFuture
 
 Returns:
 
 the new CompletableFuture
- supplyAsync
 
 public static CompletableFuture supplyAsync(Supplier supplier, 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.
 
 Type Parameters:
 
 U - the function's return type
 
 Parameters:
 
 supplier - a function returning the value to be used to complete the returned CompletableFuture
 
 executor - the executor to use for asynchronous execution
 
 Returns:
 
 the new CompletableFuture
- runAsync
 
 public 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.
 
 Parameters:
 
 runnable - the action to run before completing the returned CompletableFuture
 
 Returns:
 
 the new CompletableFuture
- runAsync
 
 public 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.
 
 Parameters:
 
 runnable - the action to run before completing the returned CompletableFuture
 
 executor - the executor to use for asynchronous execution
 
 Returns:
 
 the new CompletableFuture
- completedFuture
 
 public static CompletableFuture completedFuture(U value)
 
 Returns a new CompletableFuture that is already completed with the given value.
 
 Type Parameters:
 
 U - the type of the value
 
 Parameters:
 
 value - the value
 
 Returns:
 
 the completed CompletableFuture
- isDone
 
 public boolean isDone()
 
 Returns true if completed in any fashion: normally, exceptionally, or via cancellation.
 
 Specified by:
 
 isDone in interface Future<T>
 
 Returns:
 
 true if completed
- get
 
 public T get() throws InterruptedException, ExecutionException
 
 Waits if necessary for this future to complete, and then returns its result.
 
 Specified by:
 
 get in interface Future<T>
 
 Returns:
 
 the result value
 
 Throws:
 
 CancellationException - if this future was cancelled
 
 ExecutionException - if this future completed exceptionally
 
 InterruptedException - if the current thread was interrupted while waiting
- get
 
 public T get(long timeout, TimeUnit unit) throws InterruptedException, ExecutionException, TimeoutException
 
 Waits if necessary for at most the given time for this future to complete, and then returns its result, if available.
 
 Specified by:
 
 get in interface Future<T>
 
 Parameters:
 
 timeout - the maximum time to wait
 
 unit - the time unit of the timeout argument
 
 Returns:
 
 the result value
 
 Throws:
 
 CancellationException - if this future was cancelled
 
 ExecutionException - if this future completed exceptionally
 
 InterruptedException - if the current thread was interrupted while waiting
 
 TimeoutException - if the wait timed out
- join
 
 public T join()
 
 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.
 
 Returns:
 
 the result value
 
 Throws:
 
 CancellationException - if the computation was cancelled
 
 CompletionException - if this future completed exceptionally or a completion computation threw an exception
- getNow
 
 public T getNow(T valueIfAbsent)
 
 Returns the result value (or throws any encountered exception) if completed, else returns the given valueIfAbsent.
 
 Parameters:
 
 valueIfAbsent - the value to return if not completed
 
 Returns:
 
 the result value, if completed, else the given valueIfAbsent
 
 Throws:
 
 CancellationException - if the computation was cancelled
 
 CompletionException - if this future completed exceptionally or a completion computation threw an exception
- complete
 
 public boolean complete(T value)
 
 If not already completed, sets the value returned by get() and related methods to the given value.
 
 Parameters:
 
 value - the result value
 
 Returns:
 
 true if this invocation caused this CompletableFuture to transition to a completed state, else false
- completeExceptionally
 
 public boolean completeExceptionally(Throwable ex)
 
 If not already completed, causes invocations of get() and related methods to throw the given exception.
 
 Parameters:
 
 ex - the exception
 
 Returns:
 
 true if this invocation caused this CompletableFuture to transition to a completed state, else false
- thenAccept
 
 public CompletableFuture<Void> thenAccept(Consumer<? super T> action)
 
 Description copied from interface: CompletionStage
 
 Returns a new CompletionStage that, when this stage completes normally, is executed with this stage's result as the argument to the supplied action. See the CompletionStage documentation for rules covering exceptional completion.
 
 Specified by:
 
 thenAccept in interface CompletionStage<T>
 
 Parameters:
 
 action - the action to perform before completing the returned CompletionStage
 
 Returns:
 
 the new CompletionStage
- thenAcceptAsync
 
 public CompletableFuture<Void> thenAcceptAsync(Consumer<? super T> action)
 
 Description copied from interface: CompletionStage
 
 Returns a new CompletionStage that, when this stage completes normally, is executed using this stage's default asynchronous execution facility, with this stage's result as the argument to the supplied action. See the CompletionStage documentation for rules covering exceptional completion.
 
 Specified by:
 
 thenAcceptAsync in interface CompletionStage<T>
 
 Parameters:
 
 action - the action to perform before completing the returned CompletionStage
 
 Returns:
 
 the new CompletionStage
- thenAcceptAsync
 
 public CompletableFuture<Void> thenAcceptAsync(Consumer<? super T> action, Executor executor)
 
 Description copied from interface: CompletionStage
 
 Returns a new CompletionStage that, when this stage completes normally, is executed using the supplied Executor, with this stage's result as the argument to the supplied action. See the CompletionStage documentation for rules covering exceptional completion.
 
 Specified by:
 
 thenAcceptAsync in interface CompletionStage<T>
 
 Parameters:
 
 action - the action to perform before completing the returned CompletionStage
 
 executor - the executor to use for asynchronous execution
 
 Returns:
 
 the new CompletionStage
- thenRun
 
 public CompletableFuture<Void> thenRun(Runnable action)
 
 Description copied from interface: CompletionStage
 
 Returns a new CompletionStage that, when this stage completes normally, executes the given action. See the CompletionStage documentation for rules covering exceptional completion.
 
 Specified by:
 
 thenRun in interface CompletionStage<T>
 
 Parameters:
 
 action - the action to perform before completing the returned CompletionStage
 
 Returns:
 
 the new CompletionStage
- thenRunAsync
 
 public CompletableFuture<Void> thenRunAsync(Runnable action)
 
 Description copied from interface: CompletionStage
 
 Returns a new CompletionStage that, when this stage completes normally, executes the given action using this stage's default asynchronous execution facility. See the CompletionStage documentation for rules covering exceptional completion.
 
 Specified by:
 
 thenRunAsync in interface CompletionStage<T>
 
 Parameters:
 
 action - the action to perform before completing the returned CompletionStage
 
 Returns:
 
 the new CompletionStage
- thenRunAsync
 
 public CompletableFuture<Void> thenRunAsync(Runnable action, Executor executor)
 
 Description copied from interface: CompletionStage
 
 Returns a new CompletionStage that, when this stage completes normally, executes the given action using the supplied Executor. See the CompletionStage documentation for rules covering exceptional completion.
 
 Specified by:
 
 thenRunAsync in interface CompletionStage<T>
 
 Parameters:
 
 action - the action to perform before completing the returned CompletionStage
 
 executor - the executor to use for asynchronous execution
 
 Returns:
 
 the new CompletionStage
- thenAcceptBoth
 
 public CompletableFuture<Void> thenAcceptBoth(CompletionStage<? extends U> other, BiConsumer<? super T,? super U> action)
 
 Description copied from interface: CompletionStage
 
 Returns a new CompletionStage that, when this and the other given stage both complete normally, is executed with the two results as arguments to the supplied action. See the CompletionStage documentation for rules covering exceptional completion.
 
 Specified by:
 
 thenAcceptBoth in interface CompletionStage<T>
 
 Type Parameters:
 
 U - the type of the other CompletionStage's result
 
 Parameters:
 
 other - the other CompletionStage
 
 action - the action to perform before completing the returned CompletionStage
 
 Returns:
 
 the new CompletionStage
- thenAcceptBothAsync
 
 public CompletableFuture<Void> thenAcceptBothAsync(CompletionStage<? extends U> other, BiConsumer<? super T,? super U> action)
 
 Description copied from interface: CompletionStage
 
 Returns a new CompletionStage that, when this and the other given stage both complete normally, is executed using this stage's default asynchronous execution facility, with the two results as arguments to the supplied action. See the CompletionStage documentation for rules covering exceptional completion.
 
 Specified by:
 
 thenAcceptBothAsync in interface CompletionStage<T>
 
 Type Parameters:
 
 U - the type of the other CompletionStage's result
 
 Parameters:
 
 other - the other CompletionStage
 
 action - the action to perform before completing the returned CompletionStage
 
 Returns:
 
 the new CompletionStage
- thenAcceptBothAsync
 
 public CompletableFuture<Void> thenAcceptBothAsync(CompletionStage<? extends U> other, BiConsumer<? super T,? super U> action, Executor executor)
 
 Description copied from interface: CompletionStage
 
 Returns a new CompletionStage that, when this and the other given stage both complete normally, is executed using the supplied executor, with the two results as arguments to the supplied action. See the CompletionStage documentation for rules covering exceptional completion.
 
 Specified by:
 
 thenAcceptBothAsync in interface CompletionStage<T>
 
 Type Parameters:
 
 U - the type of the other CompletionStage's result
 
 Parameters:
 
 other - the other CompletionStage
 
 action - the action to perform before completing the returned CompletionStage
 
 executor - the executor to use for asynchronous execution
 
 Returns:
 
 the new CompletionStage
- runAfterBoth
 
 public CompletableFuture<Void> runAfterBoth(CompletionStage<?> other, Runnable action)
 
 Description copied from interface: CompletionStage
 
 Returns a new CompletionStage that, when this and the other given stage both complete normally, executes the given action. See the CompletionStage documentation for rules covering exceptional completion.
 
 Specified by:
 
 runAfterBoth in interface CompletionStage<T>
 
 Parameters:
 
 other - the other CompletionStage
 
 action - the action to perform before completing the returned CompletionStage
 
 Returns:
 
 the new CompletionStage
- runAfterBothAsync
 
 public CompletableFuture<Void> runAfterBothAsync(CompletionStage<?> other, Runnable action)
 
 Description copied from interface: CompletionStage
 
 Returns a new CompletionStage that, when this and the other given stage both complete normally, executes the given action using this stage's default asynchronous execution facility. See the CompletionStage documentation for rules covering exceptional completion.
 
 Specified by:
 
 runAfterBothAsync in interface CompletionStage<T>
 
 Parameters:
 
 other - the other CompletionStage
 
 action - the action to perform before completing the returned CompletionStage
 
 Returns:
 
 the new CompletionStage
- runAfterBothAsync
 
 public CompletableFuture<Void> runAfterBothAsync(CompletionStage<?> other, Runnable action, Executor executor)
 
 Description copied from interface: CompletionStage
 
 Returns a new CompletionStage that, when this and the other given stage both complete normally, executes the given action using the supplied executor. See the CompletionStage documentation for rules covering exceptional completion.
 
 Specified by:
 
 runAfterBothAsync in interface CompletionStage<T>
 
 Parameters:
 
 other - the other CompletionStage
 
 action - the action to perform before completing the returned CompletionStage
 
 executor - the executor to use for asynchronous execution
 
 Returns:
 
 the new CompletionStage
- acceptEither
 
 public CompletableFuture<Void> acceptEither(CompletionStage<? extends T> other, Consumer<? super T> action)
 
 Description copied from interface: CompletionStage
 
 Returns a new CompletionStage that, when either this or the other given stage complete normally, is executed with the corresponding result as argument to the supplied action. See the CompletionStage documentation for rules covering exceptional completion.
 
 Specified by:
 
 acceptEither in interface CompletionStage<T>
 
 Parameters:
 
 other - the other CompletionStage
 
 action - the action to perform before completing the returned CompletionStage
 
 Returns:
 
 the new CompletionStage
- acceptEitherAsync
 
 public CompletableFuture<Void> acceptEitherAsync(CompletionStage<? extends T> other, Consumer<? super T> action)
 
 Description copied from interface: CompletionStage
 
 Returns a new CompletionStage that, when either this or the other given stage complete normally, is executed using this stage's default asynchronous execution facility, with the corresponding result as argument to the supplied action. See the CompletionStage documentation for rules covering exceptional completion.
 
 Specified by:
 
 acceptEitherAsync in interface CompletionStage<T>
 
 Parameters:
 
 other - the other CompletionStage
 
 action - the action to perform before completing the returned CompletionStage
 
 Returns:
 
 the new CompletionStage
- acceptEitherAsync
 
 public CompletableFuture<Void> acceptEitherAsync(CompletionStage<? extends T> other, Consumer<? super T> action, Executor executor)
 
 Description copied from interface: CompletionStage
 
 Returns a new CompletionStage that, when either this or the other given stage complete normally, is executed using the supplied executor, with the corresponding result as argument to the supplied action. See the CompletionStage documentation for rules covering exceptional completion.
 
 Specified by:
 
 acceptEitherAsync in interface CompletionStage<T>
 
 Parameters:
 
 other - the other CompletionStage
 
 action - the action to perform before completing the returned CompletionStage
 
 executor - the executor to use for asynchronous execution
 
 Returns:
 
 the new CompletionStage
- runAfterEither
 
 public CompletableFuture<Void> runAfterEither(CompletionStage<?> other, Runnable action)
 
 Description copied from interface: CompletionStage
 
 Returns a new CompletionStage that, when either this or the other given stage complete normally, executes the given action. See the CompletionStage documentation for rules covering exceptional completion.
 
 Specified by:
 
 runAfterEither in interface CompletionStage<T>
 
 Parameters:
 
 other - the other CompletionStage
 
 action - the action to perform before completing the returned CompletionStage
 
 Returns:
 
 the new CompletionStage
- runAfterEitherAsync
 
 public CompletableFuture<Void> runAfterEitherAsync(CompletionStage<?> other, Runnable action)
 
 Description copied from interface: CompletionStage
 
 Returns a new CompletionStage that, when either this or the other given stage complete normally, executes the given action using this stage's default asynchronous execution facility. See the CompletionStage documentation for rules covering exceptional completion.
 
 Specified by:
 
 runAfterEitherAsync in interface CompletionStage<T>
 
 Parameters:
 
 other - the other CompletionStage
 
 action - the action to perform before completing the returned CompletionStage
 
 Returns:
 
 the new CompletionStage
- runAfterEitherAsync
 
 public CompletableFuture<Void> runAfterEitherAsync(CompletionStage<?> other, Runnable action, Executor executor)
 
 Description copied from interface: CompletionStage
 
 Returns a new CompletionStage that, when either this or the other given stage complete normally, executes the given action using the supplied executor. See the CompletionStage documentation for rules covering exceptional completion.
 
 Specified by:
 
 runAfterEitherAsync in interface CompletionStage<T>
 
 Parameters:
 
 other - the other CompletionStage
 
 action - the action to perform before completing the returned CompletionStage
 
 executor - the executor to use for asynchronous execution
 
 Returns:
 
 the new CompletionStage
- toCompletableFuture
 
 public CompletableFuture<T> toCompletableFuture()
 
 Returns this CompletableFuture.
 
 Specified by:
 
 toCompletableFuture in interface CompletionStage<T>
 
 Returns:
 
 this CompletableFuture
- allOf
 
 public static CompletableFuture<Void> allOf(CompletableFuture<?>... cfs)
 
 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 - the CompletableFutures
 
 Returns:
 
 a new CompletableFuture that is completed when all of the given CompletableFutures complete
 
 Throws:
 
 NullPointerException - if the array or any of its elements are null
- anyOf
 
 public static CompletableFuture<Object> anyOf(CompletableFuture<?>... cfs)
 
 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 - the CompletableFutures
 
 Returns:
 
 a new CompletableFuture that is completed with the result or exception of any of the given CompletableFutures when one completes
 
 Throws:
 
 NullPointerException - if the array or any of its elements are null
- cancel
 
 public boolean cancel(boolean mayInterruptIfRunning)
 
 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.
 
 Specified by:
 
 cancel in interface Future<T>
 
 Parameters:
 
 mayInterruptIfRunning - this value has no effect in this implementation because interrupts are not used to control processing.
 
 Returns:
 
 true if this task is now cancelled
- isCancelled
 
 public boolean isCancelled()
 
 Returns true if this CompletableFuture was cancelled before it completed normally.
 
 Specified by:
 
 isCancelled in interface Future<T>
 
 Returns:
 
 true if this CompletableFuture was cancelled before it completed normally
- isCompletedExceptionally
 
 public boolean isCompletedExceptionally()
 
 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.
 
 Returns:
 
 true if this CompletableFuture completed exceptionally
- obtrudeValue
 
 public void obtrudeValue(T value)
 
 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 - the completion value
- obtrudeException
 
 public void obtrudeException(Throwable ex)
 
 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 - the exception
 
 Throws:
 
 NullPointerException - if the exception is null
- getNumberOfDependents
 
 public int getNumberOfDependents()
 
 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.
 
 Returns:
 
 the number of dependent CompletableFutures
- toString
 
 public String toString()
 
 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.
 
 Overrides:
 
 toString in class Object
 
 Returns:
 
 a string identifying this CompletableFuture, as well as its state
- newIncompleteFuture
 
 public CompletableFuture newIncompleteFuture()
 
 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.
 
 Type Parameters:
 
 U - the type of the value
 
 Returns:
 
 a new CompletableFuture
 
 Since:
 
 9
- defaultExecutor
 
 public Executor defaultExecutor()
 
 Returns the default Executor used for async methods that do not specify an Executor. This class uses the 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.
 
 Returns:
 
 the executor
 
 Since:
 
 9
- copy
 
 public CompletableFuture<T> copy()
 
 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.
 
 Returns:
 
 the new CompletableFuture
 
 Since:
 
 9
- minimalCompletionStage
 
 public 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. 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
 minimalStage.toCompletableFuture().join();
 Returns:
 
 the new CompletionStage
 
 Since:
 
 9
- completeAsync
 
 public CompletableFuture<T> completeAsync(Supplier<? extends T> supplier, Executor executor)
 
 Completes this CompletableFuture with the result of the given Supplier function invoked from an asynchronous task using the given executor.
 
 Parameters:
 
 supplier - a function returning the value to be used to complete this CompletableFuture
 
 executor - the executor to use for asynchronous execution
 
 Returns:
 
 this CompletableFuture
 
 Since:
 
 9
- completeAsync
 
 public CompletableFuture<T> completeAsync(Supplier<? extends T> supplier)
 
 Completes this CompletableFuture with the result of the given Supplier function invoked from an asynchronous task using the default executor.
 
 Parameters:
 
 supplier - a function returning the value to be used to complete this CompletableFuture
 
 Returns:
 
 this CompletableFuture
 
 Since:
 
 9
- orTimeout
 
 public CompletableFuture<T> orTimeout(long timeout, TimeUnit unit)
 
 Exceptionally completes this CompletableFuture with a TimeoutException if not otherwise completed before the given timeout.
 
 Parameters:
 
 timeout - how long to wait before completing exceptionally with a TimeoutException, in units of unit
 
 unit - a TimeUnit determining how to interpret the timeout parameter
 
 Returns:
 
 this CompletableFuture
 
 Since:
 
 9
- completeOnTimeout
 
 public CompletableFuture<T> completeOnTimeout(T value, long timeout, TimeUnit unit)
 
 Completes this CompletableFuture with the given value if not otherwise completed before the given timeout.
 
 Parameters:
 
 value - the value to use upon timeout
 
 timeout - how long to wait before completing normally with the given value, in units of unit
 
 unit - a TimeUnit determining how to interpret the timeout parameter
 
 Returns:
 
 this CompletableFuture
 
 Since:
 
 9
- delayedExecutor
 
 public static Executor delayedExecutor(long delay, TimeUnit unit, 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 - how long to delay, in units of unit
 
 unit - a TimeUnit determining how to interpret the delay parameter
 
 executor - the base executor
 
 Returns:
 
 the new delayed executor
 
 Since:
 
 9
- delayedExecutor
 
 public static Executor delayedExecutor(long delay, TimeUnit unit)
 
 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 - how long to delay, in units of unit
 
 unit - a TimeUnit determining how to interpret the delay parameter
 
 Returns:
 
 the new delayed executor
 
 Since:
 
 9
- completedStage
 
 public static CompletionStage completedStage(U value)
 
 Returns a new CompletionStage that is already completed with the given value and supports only those methods in interface CompletionStage.
 
 Type Parameters:
 
 U - the type of the value
 
 Parameters:
 
 value - the value
 
 Returns:
 
 the completed CompletionStage
 
 Since:
 
 9
- failedFuture
 
 public static CompletableFuture failedFuture(Throwable ex)
 
 Returns a new CompletableFuture that is already completed exceptionally with the given exception.
 
 Type Parameters:
 
 U - the type of the value
 
 Parameters:
 
 ex - the exception
 
 Returns:
 
 the exceptionally completed CompletableFuture
 
 Since:
 
 9
- failedStage
 
 public static CompletionStage failedStage(Throwable ex)
 
 Returns a new CompletionStage that is already completed exceptionally with the given exception and supports only those methods in interface CompletionStage.
 
 Type Parameters:
 
 U - the type of the value
 
 Parameters:
 
 ex - the exception
 
 Returns:
 
 the exceptionally completed CompletionStage
 
 Since:
 
 9

Class CompletableFuture<T>

Nested Class Summary

Constructor Summary

Method Summary

Methods declared in class java.lang.Object

Methods declared in interface java.util.concurrent.CompletionStage

Constructor Details

Method Details