Class CompletableFuture<T>
- java.lang.Object
-
- java.util.concurrent.CompletableFuture<T>
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- All Implemented Interfaces:
- CompletionStage<T>, Future<T>
public class CompletableFuture<T> extends Object implements Future<T>, CompletionStage<T>
AFuture
that may be explicitly completed (setting its value and status), and may be used as aCompletionStage
, supporting dependent functions and actions that trigger upon its completion.When two or more threads attempt to
complete
,completeExceptionally
, orcancel
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 interfaceCompletableFuture.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. Methodcancel
has the same effect ascompleteExceptionally(new CancellationException())
. MethodisCompletedExceptionally()
can be used to determine if a CompletableFuture completed in any exceptional fashion. - In case of exceptional completion with a CompletionException, methods
get()
andget(long, TimeUnit)
throw anExecutionException
with the same cause as held in the corresponding CompletionException. To simplify usage in most contexts, this class also defines methodsjoin()
andgetNow(T)
that instead throw the CompletionException directly in these cases.
- Since:
- 1.8
-
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Nested Class Summary
Nested Classes Modifier and Type Class and Description static interface
CompletableFuture.AsynchronousCompletionTask
A marker interface identifying asynchronous tasks produced byasync
methods.
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Constructor Summary
Constructors Constructor and Description CompletableFuture()
Creates a new incomplete CompletableFuture.
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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 aCancellationException
.boolean
complete(T value)
If not already completed, sets the value returned byget()
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 ofget()
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()
Returnstrue
if this CompletableFuture was cancelled before it completed normally.boolean
isCompletedExceptionally()
Returnstrue
if this CompletableFuture completed exceptionally, in any way.boolean
isDone()
Returnstrue
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 methodget()
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 methodget()
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 theForkJoinPool.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 theForkJoinPool.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.
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Constructor Detail
CompletableFuture
public CompletableFuture()
Creates a new incomplete CompletableFuture.
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Method Detail
supplyAsync
public static <U> CompletableFuture<U> supplyAsync(Supplier<U> supplier)
Returns a new CompletableFuture that is asynchronously completed by a task running in theForkJoinPool.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 <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.- 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 theForkJoinPool.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 <U> CompletableFuture<U> 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()
Returnstrue
if completed in any fashion: normally, exceptionally, or via cancellation.
get
public T get() throws InterruptedException, ExecutionException
Waits if necessary for this future to complete, and then returns its result.- Specified by:
-
get
in interfaceFuture<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 interfaceFuture<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 byget()
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, elsefalse
completeExceptionally
public boolean completeExceptionally(Throwable ex)
If not already completed, causes invocations ofget()
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, elsefalse
thenApply
public <U> CompletableFuture<U> 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 theCompletionStage
documentation for rules covering exceptional completion.- Specified by:
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thenApply
in interfaceCompletionStage<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 <U> CompletableFuture<U> 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 theCompletionStage
documentation for rules covering exceptional completion.- Specified by:
-
thenApplyAsync
in interfaceCompletionStage<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 <U> CompletableFuture<U> 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 theCompletionStage
documentation for rules covering exceptional completion.- Specified by:
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thenApplyAsync
in interfaceCompletionStage<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 theCompletionStage
documentation for rules covering exceptional completion.- Specified by:
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thenAccept
in interfaceCompletionStage<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 theCompletionStage
documentation for rules covering exceptional completion.- Specified by:
-
thenAcceptAsync
in interfaceCompletionStage<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 theCompletionStage
documentation for rules covering exceptional completion.- Specified by:
-
thenAcceptAsync
in interfaceCompletionStage<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 theCompletionStage
documentation for rules covering exceptional completion.- Specified by:
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thenRun
in interfaceCompletionStage<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 theCompletionStage
documentation for rules covering exceptional completion.- Specified by:
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thenRunAsync
in interfaceCompletionStage<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 theCompletionStage
documentation for rules covering exceptional completion.- Specified by:
-
thenRunAsync
in interfaceCompletionStage<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 theCompletionStage
documentation for rules covering exceptional completion.- Specified by:
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thenCombine
in interfaceCompletionStage<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 theCompletionStage
documentation for rules covering exceptional completion.- Specified by:
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thenCombineAsync
in interfaceCompletionStage<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 theCompletionStage
documentation for rules covering exceptional completion.- Specified by:
-
thenCombineAsync
in interfaceCompletionStage<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 <U> 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 theCompletionStage
documentation for rules covering exceptional completion.- Specified by:
-
thenAcceptBoth
in interfaceCompletionStage<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 <U> 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:
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thenAcceptBothAsync
in interfaceCompletionStage<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 <U> 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 interfaceCompletionStage<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 theCompletionStage
documentation for rules covering exceptional completion.- Specified by:
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runAfterBoth
in interfaceCompletionStage<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 theCompletionStage
documentation for rules covering exceptional completion.- Specified by:
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runAfterBothAsync
in interfaceCompletionStage<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 theCompletionStage
documentation for rules covering exceptional completion.- Specified by:
-
runAfterBothAsync
in interfaceCompletionStage<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 <U> CompletableFuture<U> 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 theCompletionStage
documentation for rules covering exceptional completion.- Specified by:
-
applyToEither
in interfaceCompletionStage<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 <U> CompletableFuture<U> 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 theCompletionStage
documentation for rules covering exceptional completion.- Specified by:
-
applyToEitherAsync
in interfaceCompletionStage<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 <U> CompletableFuture<U> 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 theCompletionStage
documentation for rules covering exceptional completion.- Specified by:
-
applyToEitherAsync
in interfaceCompletionStage<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 theCompletionStage
documentation for rules covering exceptional completion.- Specified by:
-
acceptEither
in interfaceCompletionStage<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 theCompletionStage
documentation for rules covering exceptional completion.- Specified by:
-
acceptEitherAsync
in interfaceCompletionStage<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 theCompletionStage
documentation for rules covering exceptional completion.- Specified by:
-
acceptEitherAsync
in interfaceCompletionStage<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 theCompletionStage
documentation for rules covering exceptional completion.- Specified by:
-
runAfterEither
in interfaceCompletionStage<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 theCompletionStage
documentation for rules covering exceptional completion.- Specified by:
-
runAfterEitherAsync
in interfaceCompletionStage<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 theCompletionStage
documentation for rules covering exceptional completion.- Specified by:
-
runAfterEitherAsync
in interfaceCompletionStage<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 <U> CompletableFuture<U> thenCompose(Function<? super T,? extends CompletionStage<U>> 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 theCompletionStage
documentation for rules covering exceptional completion.- Specified by:
-
thenCompose
in interfaceCompletionStage<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 <U> CompletableFuture<U> thenComposeAsync(Function<? super T,? extends CompletionStage<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 as the argument to the supplied function. See theCompletionStage
documentation for rules covering exceptional completion.- Specified by:
-
thenComposeAsync
in interfaceCompletionStage<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 <U> CompletableFuture<U> thenComposeAsync(Function<? super T,? extends CompletionStage<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 theCompletionStage
documentation for rules covering exceptional completion.- Specified by:
-
thenComposeAsync
in interfaceCompletionStage<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 (ornull
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 interfaceCompletionStage<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 (ornull
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 interfaceCompletionStage<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 (ornull
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 interfaceCompletionStage<T>
- Parameters:
-
action
- the action to perform -
executor
- the executor to use for asynchronous execution - Returns:
- the new CompletionStage
handle
public <U> CompletableFuture<U> 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 (ornull
if none) of this stage as arguments, and the function's result is used to complete the returned stage.- Specified by:
-
handle
in interfaceCompletionStage<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 <U> CompletableFuture<U> 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 (ornull
if none) of this stage as arguments, and the function's result is used to complete the returned stage.- Specified by:
-
handleAsync
in interfaceCompletionStage<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 <U> CompletableFuture<U> 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 (ornull
if none) of this stage as arguments, and the function's result is used to complete the returned stage.- Specified by:
-
handleAsync
in interfaceCompletionStage<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 interfaceCompletionStage<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 methodswhenComplete
andhandle
.- Specified by:
-
exceptionally
in interfaceCompletionStage<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 valuenull
.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 arenull
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 arenull
cancel
public boolean cancel(boolean mayInterruptIfRunning)
If not already completed, completes this CompletableFuture with aCancellationException
. Dependent CompletableFutures that have not already completed will also complete exceptionally, with aCompletionException
caused by thisCancellationException
.
isCancelled
public boolean isCancelled()
Returnstrue
if this CompletableFuture was cancelled before it completed normally.- Specified by:
-
isCancelled
in interfaceFuture<T>
- Returns:
-
true
if this CompletableFuture was cancelled before it completed normally
isCompletedExceptionally
public boolean isCompletedExceptionally()
Returnstrue
if this CompletableFuture completed exceptionally, in any way. Possible causes include cancellation, explicit invocation ofcompleteExceptionally
, 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 methodget()
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 methodget()
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.
-
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.
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