CompletableFuture (Java Platform SE 8 )

java.lang.Object
- java.util.concurrent.CompletableFuture<T>

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). To simplify monitoring, debugging, and tracking, all generated asynchronous tasks are instances of the marker interface CompletableFuture.AsynchronousCompletionTask.
- 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, 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.
Since:

1.8

Nested Class Summary

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

Constructor Summary

Constructors
Constructor and Description

CompletableFuture()
Creates a new incomplete CompletableFuture.

Constructors
Constructor and Description
`CompletableFuture()` Creates a new incomplete CompletableFuture.

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method and 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 function.
`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.
`<U> CompletableFuture<U>`	`applyToEither(CompletionStage<? extends T> other, Function<? super T,U> fn)` 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 function.
`<U> CompletableFuture<U>`	`applyToEitherAsync(CompletionStage<? extends T> other, Function<? super T,U> fn)` 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 function.
`<U> CompletableFuture<U>`	`applyToEitherAsync(CompletionStage<? extends T> other, Function<? super T,U> fn, 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 function.
`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.
`static <U> CompletableFuture<U>`	`completedFuture(U value)` Returns a new CompletableFuture that is already completed with the given value.
`boolean`	`completeExceptionally(Throwable ex)` If not already completed, causes invocations of `get()` and related methods to throw the given exception.
`CompletableFuture<T>`	`exceptionally(Function<Throwable,? extends T> fn)` Returns a new CompletableFuture that is completed when this CompletableFuture completes, with the result of the given function of the exception triggering this CompletableFuture's completion when it completes exceptionally; otherwise, if this CompletableFuture completes normally, then the returned CompletableFuture also completes normally with the same value.
`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.
`<U> CompletableFuture<U>`	`handle(BiFunction<? super T,Throwable,? extends U> fn)` Returns a new CompletionStage that, when this stage completes either normally or exceptionally, is executed with this stage's result and exception as arguments to the supplied function.
`<U> CompletableFuture<U>`	`handleAsync(BiFunction<? super T,Throwable,? extends U> fn)` Returns a new CompletionStage that, when this stage completes either normally or exceptionally, is executed using this stage's default asynchronous execution facility, with this stage's result and exception as arguments to the supplied function.
`<U> CompletableFuture<U>`	`handleAsync(BiFunction<? super T,Throwable,? extends U> fn, Executor executor)` Returns a new CompletionStage that, when this stage completes either normally or exceptionally, is executed using the supplied executor, with this stage's result and exception as arguments to the supplied function.
`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.
`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<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 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 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 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 complete normally, is executed using the supplied executor, with the two results as arguments to the supplied function.
`<U> CompletableFuture<U>`	`thenApply(Function<? super T,? extends U> fn)` Returns a new CompletionStage that, when this stage completes normally, is executed with this stage's result as the argument to the supplied function.
`<U> CompletableFuture<U>`	`thenApplyAsync(Function<? super T,? extends U> fn)` 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 function.
`<U> CompletableFuture<U>`	`thenApplyAsync(Function<? super T,? extends U> fn, 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 function.
`<U,V> CompletableFuture<V>`	`thenCombine(CompletionStage<? extends U> other, BiFunction<? super T,? super U,? extends V> fn)` 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 function.
`<U,V> CompletableFuture<V>`	`thenCombineAsync(CompletionStage<? extends U> other, BiFunction<? super T,? super U,? extends V> fn)` Returns a new CompletionStage that, when this and the other given stage complete normally, is executed using this stage's default asynchronous execution facility, with the two results as arguments to the supplied function.
`<U,V> CompletableFuture<V>`	`thenCombineAsync(CompletionStage<? extends U> other, BiFunction<? super T,? super U,? extends V> fn, Executor executor)` Returns a new CompletionStage that, when this and the other given stage complete normally, is executed using the supplied executor, with the two results as arguments to the supplied function.
`<U> CompletableFuture<U>`	`thenCompose(Function<? super T,? extends CompletionStage<U>> fn)` Returns a new CompletionStage that, when this stage completes normally, is executed with this stage as the argument to the supplied function.
`<U> CompletableFuture<U>`	`thenComposeAsync(Function<? super T,? extends CompletionStage<U>> fn)` Returns a new CompletionStage that, when this stage completes normally, is executed using this stage's default asynchronous execution facility, with this stage as the argument to the supplied function.
`<U> CompletableFuture<U>`	`thenComposeAsync(Function<? super T,? extends CompletionStage<U>> fn, 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 function.
`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.
`CompletableFuture<T>`	`whenComplete(BiConsumer<? super T,? super Throwable> action)` Returns a new CompletionStage with the same result or exception as this stage, that executes the given action when this stage completes.
`CompletableFuture<T>`	`whenCompleteAsync(BiConsumer<? super T,? super Throwable> action)` Returns a new CompletionStage with the same result or exception as this stage, that executes the given action using this stage's default asynchronous execution facility when this stage completes.
`CompletableFuture<T>`	`whenCompleteAsync(BiConsumer<? super T,? super Throwable> action, Executor executor)` Returns a new CompletionStage with the same result or exception as this stage, that executes the given action using the supplied Executor when this stage completes.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

- Constructor Detail
 - CompletableFuture
```
public CompletableFuture()
```
 Creates a new incomplete CompletableFuture.
- Method Detail
 - 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
 - thenApply
```
public  CompletableFuture thenApply(Function<? super T,? extends U> fn)
```
 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 function. See the CompletionStage documentation for rules covering exceptional completion.
 
 Specified by:
 
 thenApply in interface CompletionStage<T>
 
 Type Parameters:
 
 U - the function's return type
 
 Parameters:
 
 fn - the function to use to compute the value of the returned CompletionStage
 
 Returns:
 
 the new CompletionStage
 - thenApplyAsync
```
public  CompletableFuture thenApplyAsync(Function<? super T,? extends U> fn)
```
 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 function. See the CompletionStage documentation for rules covering exceptional completion.
 
 Specified by:
 
 thenApplyAsync in interface CompletionStage<T>
 
 Type Parameters:
 
 U - the function's return type
 
 Parameters:
 
 fn - the function to use to compute the value of the returned CompletionStage
 
 Returns:
 
 the new CompletionStage
 - thenApplyAsync
```
public  CompletableFuture thenApplyAsync(Function<? super T,? extends U> fn,
 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 function. See the CompletionStage documentation for rules covering exceptional completion.
 
 Specified by:
 
 thenApplyAsync in interface CompletionStage<T>
 
 Type Parameters:
 
 U - the function's return type
 
 Parameters:
 
 fn - the function to use to compute the value of the returned CompletionStage
 
 executor - the executor to use for asynchronous execution
 
 Returns:
 
 the new CompletionStage
 - 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
 - thenCombine
```
public <U,V> CompletableFuture<V> thenCombine(CompletionStage<? extends U> other,
 BiFunction<? super T,? super U,? extends V> fn)
```
 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 function. See the CompletionStage documentation for rules covering exceptional completion.
 
 Specified by:
 
 thenCombine in interface CompletionStage<T>
 
 Type Parameters:
 
 U - the type of the other CompletionStage's result
 
 V - the function's return type
 
 Parameters:
 
 other - the other CompletionStage
 
 fn - the function to use to compute the value of the returned CompletionStage
 
 Returns:
 
 the new CompletionStage
 - thenCombineAsync
```
public <U,V> CompletableFuture<V> thenCombineAsync(CompletionStage<? extends U> other,
 BiFunction<? super T,? super U,? extends V> fn)
```
 Description copied from interface: CompletionStage
 
 Returns a new CompletionStage that, when this and the other given stage complete normally, is executed using this stage's default asynchronous execution facility, with the two results as arguments to the supplied function. See the CompletionStage documentation for rules covering exceptional completion.
 
 Specified by:
 
 thenCombineAsync in interface CompletionStage<T>
 
 Type Parameters:
 
 U - the type of the other CompletionStage's result
 
 V - the function's return type
 
 Parameters:
 
 other - the other CompletionStage
 
 fn - the function to use to compute the value of the returned CompletionStage
 
 Returns:
 
 the new CompletionStage
 - thenCombineAsync
```
public <U,V> CompletableFuture<V> thenCombineAsync(CompletionStage<? extends U> other,
 BiFunction<? super T,? super U,? extends V> fn,
 Executor executor)
```
 Description copied from interface: CompletionStage
 
 Returns a new CompletionStage that, when this and the other given stage complete normally, is executed using the supplied executor, with the two results as arguments to the supplied function. See the CompletionStage documentation for rules covering exceptional completion.
 
 Specified by:
 
 thenCombineAsync in interface CompletionStage<T>
 
 Type Parameters:
 
 U - the type of the other CompletionStage's result
 
 V - the function's return type
 
 Parameters:
 
 other - the other CompletionStage
 
 fn - the function to use to compute the value of 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 complete normally, is executed using this stage's default asynchronous execution facility, with the two results as arguments to the supplied action.
 
 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 complete normally, is executed using the supplied executor, with the two results as arguments to the supplied function.
 
 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 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 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
 - applyToEither
```
public  CompletableFuture applyToEither(CompletionStage<? extends T> other,
 Function<? super T,U> fn)
```
 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 function. See the CompletionStage documentation for rules covering exceptional completion.
 
 Specified by:
 
 applyToEither in interface CompletionStage<T>
 
 Type Parameters:
 
 U - the function's return type
 
 Parameters:
 
 other - the other CompletionStage
 
 fn - the function to use to compute the value of the returned CompletionStage
 
 Returns:
 
 the new CompletionStage
 - applyToEitherAsync
```
public  CompletableFuture applyToEitherAsync(CompletionStage<? extends T> other,
 Function<? super T,U> fn)
```
 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 function. See the CompletionStage documentation for rules covering exceptional completion.
 
 Specified by:
 
 applyToEitherAsync in interface CompletionStage<T>
 
 Type Parameters:
 
 U - the function's return type
 
 Parameters:
 
 other - the other CompletionStage
 
 fn - the function to use to compute the value of the returned CompletionStage
 
 Returns:
 
 the new CompletionStage
 - applyToEitherAsync
```
public  CompletableFuture applyToEitherAsync(CompletionStage<? extends T> other,
 Function<? super T,U> fn,
 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 function. See the CompletionStage documentation for rules covering exceptional completion.
 
 Specified by:
 
 applyToEitherAsync in interface CompletionStage<T>
 
 Type Parameters:
 
 U - the function's return type
 
 Parameters:
 
 other - the other CompletionStage
 
 fn - the function to use to compute the value of 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 function. 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
 - thenCompose
```
public  CompletableFuture thenCompose(Function<? super T,? extends CompletionStage> fn)
```
 Description copied from interface: CompletionStage
 
 Returns a new CompletionStage that, when this stage completes normally, is executed with this stage as the argument to the supplied function. See the CompletionStage documentation for rules covering exceptional completion.
 
 Specified by:
 
 thenCompose in interface CompletionStage<T>
 
 Type Parameters:
 
 U - the type of the returned CompletionStage's result
 
 Parameters:
 
 fn - the function returning a new CompletionStage
 
 Returns:
 
 the CompletionStage
 - thenComposeAsync
```
public  CompletableFuture thenComposeAsync(Function<? super T,? extends CompletionStage> fn)
```
 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 as the argument to the supplied function. See the CompletionStage documentation for rules covering exceptional completion.
 
 Specified by:
 
 thenComposeAsync in interface CompletionStage<T>
 
 Type Parameters:
 
 U - the type of the returned CompletionStage's result
 
 Parameters:
 
 fn - the function returning a new CompletionStage
 
 Returns:
 
 the CompletionStage
 - thenComposeAsync
```
public  CompletableFuture thenComposeAsync(Function<? super T,? extends CompletionStage> fn,
 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 function. See the CompletionStage documentation for rules covering exceptional completion.
 
 Specified by:
 
 thenComposeAsync in interface CompletionStage<T>
 
 Type Parameters:
 
 U - the type of the returned CompletionStage's result
 
 Parameters:
 
 fn - the function returning a new CompletionStage
 
 executor - the executor to use for asynchronous execution
 
 Returns:
 
 the CompletionStage
 - whenComplete
```
public CompletableFuture<T> whenComplete(BiConsumer<? super T,? super Throwable> action)
```
 Description copied from interface: CompletionStage
 
 Returns a new CompletionStage with the same result or exception as this stage, that executes the given action when this stage completes.
 When this stage is complete, the given action is invoked with the result (or null if none) and the exception (or null if none) of this stage as arguments. The returned stage is completed when the action returns. If the supplied action itself encounters an exception, then the returned stage exceptionally completes with this exception unless this stage also completed exceptionally.
 
 Specified by:
 
 whenComplete in interface CompletionStage<T>
 
 Parameters:
 
 action - the action to perform
 
 Returns:
 
 the new CompletionStage
 - whenCompleteAsync
```
public CompletableFuture<T> whenCompleteAsync(BiConsumer<? super T,? super Throwable> action)
```
 Description copied from interface: CompletionStage
 
 Returns a new CompletionStage with the same result or exception as this stage, that executes the given action using this stage's default asynchronous execution facility when this stage completes.
 When this stage is complete, the given action is invoked with the result (or null if none) and the exception (or null if none) of this stage as arguments. The returned stage is completed when the action returns. If the supplied action itself encounters an exception, then the returned stage exceptionally completes with this exception unless this stage also completed exceptionally.
 
 Specified by:
 
 whenCompleteAsync in interface CompletionStage<T>
 
 Parameters:
 
 action - the action to perform
 
 Returns:
 
 the new CompletionStage
 - whenCompleteAsync
```
public CompletableFuture<T> whenCompleteAsync(BiConsumer<? super T,? super Throwable> action,
 Executor executor)
```
 Description copied from interface: CompletionStage
 
 Returns a new CompletionStage with the same result or exception as this stage, that executes the given action using the supplied Executor when this stage completes.
 When this stage is complete, the given action is invoked with the result (or null if none) and the exception (or null if none) of this stage as arguments. The returned stage is completed when the action returns. If the supplied action itself encounters an exception, then the returned stage exceptionally completes with this exception unless this stage also completed exceptionally.
 
 Specified by:
 
 whenCompleteAsync in interface CompletionStage<T>
 
 Parameters:
 
 action - the action to perform
 
 executor - the executor to use for asynchronous execution
 
 Returns:
 
 the new CompletionStage
 - handle
```
public  CompletableFuture handle(BiFunction<? super T,Throwable,? extends U> fn)
```
 Description copied from interface: CompletionStage
 
 Returns a new CompletionStage that, when this stage completes either normally or exceptionally, is executed with this stage's result and exception as arguments to the supplied function.
 When this stage is complete, the given function is invoked with the result (or null if none) and the exception (or null if none) of this stage as arguments, and the function's result is used to complete the returned stage.
 
 Specified by:
 
 handle in interface CompletionStage<T>
 
 Type Parameters:
 
 U - the function's return type
 
 Parameters:
 
 fn - the function to use to compute the value of the returned CompletionStage
 
 Returns:
 
 the new CompletionStage
 - handleAsync
```
public  CompletableFuture handleAsync(BiFunction<? super T,Throwable,? extends U> fn)
```
 Description copied from interface: CompletionStage
 
 Returns a new CompletionStage that, when this stage completes either normally or exceptionally, is executed using this stage's default asynchronous execution facility, with this stage's result and exception as arguments to the supplied function.
 When this stage is complete, the given function is invoked with the result (or null if none) and the exception (or null if none) of this stage as arguments, and the function's result is used to complete the returned stage.
 
 Specified by:
 
 handleAsync in interface CompletionStage<T>
 
 Type Parameters:
 
 U - the function's return type
 
 Parameters:
 
 fn - the function to use to compute the value of the returned CompletionStage
 
 Returns:
 
 the new CompletionStage
 - handleAsync
```
public  CompletableFuture handleAsync(BiFunction<? super T,Throwable,? extends U> fn,
 Executor executor)
```
 Description copied from interface: CompletionStage
 
 Returns a new CompletionStage that, when this stage completes either normally or exceptionally, is executed using the supplied executor, with this stage's result and exception as arguments to the supplied function.
 When this stage is complete, the given function is invoked with the result (or null if none) and the exception (or null if none) of this stage as arguments, and the function's result is used to complete the returned stage.
 
 Specified by:
 
 handleAsync in interface CompletionStage<T>
 
 Type Parameters:
 
 U - the function's return type
 
 Parameters:
 
 fn - the function to use to compute the value of 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
 - exceptionally
```
public CompletableFuture<T> exceptionally(Function<Throwable,? extends T> fn)
```
 Returns a new CompletableFuture that is completed when this CompletableFuture completes, with the result of the given function of the exception triggering this CompletableFuture's completion when it completes exceptionally; otherwise, if this CompletableFuture completes normally, then the returned CompletableFuture also completes normally with the same value. Note: More flexible versions of this functionality are available using methods whenComplete and handle.
 
 Specified by:
 
 exceptionally in interface CompletionStage<T>
 
 Parameters:
 
 fn - the function to use to compute the value of the returned CompletableFuture if this CompletableFuture completed exceptionally
 
 Returns:
 
 the new 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

Submit a bug or feature
For further API reference and developer documentation, see Java SE Documentation. That documentation contains more detailed, developer-targeted descriptions, with conceptual overviews, definitions of terms, workarounds, and working code examples.
Copyright © 1993, 2024, Oracle and/or its affiliates. All rights reserved. Use is subject to license terms. Also see the documentation redistribution policy.

Class CompletableFuture<T>

Nested Class Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Constructor Detail

CompletableFuture

Method Detail

supplyAsync

supplyAsync

runAsync

runAsync

completedFuture

isDone

get

get

join

getNow

complete

completeExceptionally

thenApply

thenApplyAsync

thenApplyAsync

thenAccept

thenAcceptAsync

thenAcceptAsync

thenRun

thenRunAsync

thenRunAsync

thenCombine

thenCombineAsync

thenCombineAsync

thenAcceptBoth

thenAcceptBothAsync

thenAcceptBothAsync

runAfterBoth

runAfterBothAsync

runAfterBothAsync

applyToEither

applyToEitherAsync

applyToEitherAsync

acceptEither

acceptEitherAsync

acceptEitherAsync

runAfterEither

runAfterEitherAsync

runAfterEitherAsync

thenCompose

thenComposeAsync

thenComposeAsync

whenComplete

whenCompleteAsync

whenCompleteAsync

handle

handleAsync

handleAsync

toCompletableFuture

exceptionally

allOf

anyOf

cancel

isCancelled

isCompletedExceptionally

obtrudeValue

obtrudeException

getNumberOfDependents

toString