FutureUtils (Flink : 1.18-SNAPSHOT API)

java.lang.Object
- org.apache.flink.util.concurrent.FutureUtils

```
public class FutureUtils
extends Object
```
A collection of utilities that expand the usage of CompletableFuture.

Nested Class Summary

Nested Classes
Modifier and Type	Class and Description
`static class`	`FutureUtils.ConjunctFuture<T>` A future that is complete once multiple other futures completed.
`static class`	`FutureUtils.RetryException` Exception with which the returned future is completed if the `retry(Supplier, int, Executor)` operation fails.

Constructor Summary

Constructors
Constructor and Description

FutureUtils()

Constructors
Constructor and Description
`FutureUtils()`

Method Summary

All Methods Static Methods Concrete Methods
Modifier and Type	Method and Description
`static void`	`assertNoException(CompletableFuture<?> completableFuture)` Asserts that the given `CompletableFuture` is not completed exceptionally.
`static <T> T`	`checkStateAndGet(CompletableFuture<T> future)` Perform check state that future has completed normally and return the result.
`static <T> FutureUtils.ConjunctFuture<Collection<T>>`	`combineAll(Collection<? extends CompletableFuture<? extends T>> futures)` Creates a future that is complete once multiple other futures completed.
`static FutureUtils.ConjunctFuture<Void>`	`completeAll(Collection<? extends CompletableFuture<?>> futuresToComplete)` Creates a `FutureUtils.ConjunctFuture` which is only completed after all given futures have completed.
`static <T> void`	`completeDelayed(CompletableFuture<T> future, T success, Duration delay)` Asynchronously completes the future after a certain delay.
`static <T> CompletableFuture<T>`	`completedExceptionally(Throwable cause)` Returns an exceptionally completed `CompletableFuture`.
`static CompletableFuture<Void>`	`completedVoidFuture()` Returns a completed future of type `Void`.
`static <T> void`	`completeFromCallable(CompletableFuture<T> future, Callable<T> operation)` Fakes asynchronous execution by immediately executing the operation and completing the supplied future either normally or exceptionally.
`static CompletableFuture<Void>`	`composeAfterwards(CompletableFuture<?> future, Supplier<CompletableFuture<?>> composedAction)` Run the given asynchronous action after the completion of the given future.
`static <T> void`	`doForward(T value, Throwable throwable, CompletableFuture<T> target)` Completes the given future with either the given value or throwable, depending on which parameter is not null.
`static <T> void`	`forward(CompletableFuture<T> source, CompletableFuture<T> target)` Forwards the value from the source future to the target future.
`static <T> void`	`forwardAsync(CompletableFuture<T> source, CompletableFuture<T> target, Executor executor)` Forwards the value from the source future to the target future using the provided executor.
`static <T> T`	`getOrDefault(CompletableFuture<T> future, T defaultValue)`
`static <T> T`	`getWithoutException(CompletableFuture<T> future)` Gets the result of a completable future without any exception thrown.
`static <IN,OUT> CompletableFuture<OUT>`	`handleAsyncIfNotDone(CompletableFuture<IN> completableFuture, Executor executor, BiFunction<? super IN,Throwable,? extends OUT> handler)` This function takes a `CompletableFuture` and a handler function for the result of this future.
`static <T,E extends Throwable> CompletableFuture<T>`	`handleException(CompletableFuture<? extends T> completableFuture, Class<E> exceptionClass, Function<? super E,? extends T> exceptionHandler)` Checks that the given `CompletableFuture` is not completed exceptionally with the specified class.
`static void`	`handleUncaughtException(CompletableFuture<?> completableFuture, Thread.UncaughtExceptionHandler uncaughtExceptionHandler)` Checks that the given `CompletableFuture` is not completed exceptionally.
`static boolean`	`isCompletedNormally(CompletableFuture<?> future)`
`static <T> CompletableFuture<T>`	`orTimeout(CompletableFuture<T> future, long timeout, TimeUnit timeUnit, Executor timeoutFailExecutor, String timeoutMsg)` Times the given future out after the timeout.
`static <T> CompletableFuture<T>`	`orTimeout(CompletableFuture<T> future, long timeout, TimeUnit timeUnit, String timeoutMsg)` Times the given future out after the timeout.
`static <T> CompletableFuture<T>`	`retry(Supplier<CompletableFuture<T>> operation, int retries, Executor executor)` Retry the given operation the given number of times in case of a failure.
`static <T> CompletableFuture<T>`	`retry(Supplier<CompletableFuture<T>> operation, int retries, Predicate<Throwable> retryPredicate, Executor executor)` Retry the given operation the given number of times in case of a failure only when an exception is retryable.
`static <T> CompletableFuture<T>`	`retrySuccessfulWithDelay(Supplier<CompletableFuture<T>> operation, Duration retryDelay, Deadline deadline, Predicate<T> acceptancePredicate, ScheduledExecutor scheduledExecutor)` Retry the given operation with the given delay in between successful completions where the result does not match a given predicate.
`static <T> CompletableFuture<T>`	`retryWithDelay(Supplier<CompletableFuture<T>> operation, RetryStrategy retryStrategy, Predicate<Throwable> retryPredicate, ScheduledExecutor scheduledExecutor)` Retry the given operation with the given delay in between failures.
`static <T> CompletableFuture<T>`	`retryWithDelay(Supplier<CompletableFuture<T>> operation, RetryStrategy retryStrategy, ScheduledExecutor scheduledExecutor)` Retry the given operation with the given delay in between failures.
`static CompletableFuture<Void>`	`runAfterwards(CompletableFuture<?> future, RunnableWithException runnable)` Run the given action after the completion of the given future.
`static CompletableFuture<Void>`	`runAfterwardsAsync(CompletableFuture<?> future, RunnableWithException runnable)` Run the given action after the completion of the given future.
`static CompletableFuture<Void>`	`runAfterwardsAsync(CompletableFuture<?> future, RunnableWithException runnable, Executor executor)` Run the given action after the completion of the given future.
`static <T> T`	`runIfNotDoneAndGet(RunnableFuture<T> future)` Run the given `RunnableFuture` if it is not done, and then retrieves its result.
`static <T> CompletableFuture<T>`	`supplyAsync(SupplierWithException<T,?> supplier, Executor executor)` Returns a future which is completed with the result of the `SupplierWithException`.
`static <T> CompletableFuture<T>`	`switchExecutor(CompletableFuture<? extends T> source, Executor executor)` Switches the execution context of the given source future.
`static <IN> CompletableFuture<Void>`	`thenAcceptAsyncIfNotDone(CompletableFuture<IN> completableFuture, Executor executor, Consumer<? super IN> consumer)` This function takes a `CompletableFuture` and a consumer to accept the result of this future.
`static <IN,OUT> CompletableFuture<OUT>`	`thenApplyAsyncIfNotDone(CompletableFuture<IN> completableFuture, Executor executor, Function<? super IN,? extends OUT> applyFun)` This function takes a `CompletableFuture` and a function to apply to this future.
`static <IN,OUT> CompletableFuture<OUT>`	`thenComposeAsyncIfNotDone(CompletableFuture<IN> completableFuture, Executor executor, Function<? super IN,? extends CompletionStage<OUT>> composeFun)` This function takes a `CompletableFuture` and a function to compose with this future.
`static void`	`throwIfCompletedExceptionally(CompletableFuture<?> future)` Throws the causing exception if the given future is completed exceptionally, otherwise do nothing.
`static <T> CompletableFuture<T>`	`unsupportedOperationFuture()` Returns an exceptionally completed future with an `UnsupportedOperationException`.
`static FutureUtils.ConjunctFuture<Void>`	`waitForAll(Collection<? extends CompletableFuture<?>> futures)` Creates a future that is complete once all of the given futures have completed.
`static <IN> CompletableFuture<IN>`	`whenCompleteAsyncIfNotDone(CompletableFuture<IN> completableFuture, Executor executor, BiConsumer<? super IN,? super Throwable> whenCompleteFun)` This function takes a `CompletableFuture` and a bi-consumer to call on completion of this future.

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

- Constructor Detail
  - FutureUtils
```
public FutureUtils()
```
- Method Detail
  - completedVoidFuture
```
public static CompletableFuture<Void> completedVoidFuture()
```
    Returns a completed future of type Void.
    
    Returns:
    
    a completed future of type Void
  - unsupportedOperationFuture
```
public static <T> CompletableFuture<T> unsupportedOperationFuture()
```
    Returns an exceptionally completed future with an UnsupportedOperationException.
    
    Type Parameters:
    
    T - type of the future
    
    Returns:
    
    exceptionally completed future
  - completeFromCallable
```
public static <T> void completeFromCallable(CompletableFuture<T> future,
                                            Callable<T> operation)
```
    Fakes asynchronous execution by immediately executing the operation and completing the supplied future either normally or exceptionally.
    
    Type Parameters:
    
    T - type of the result
    
    Parameters:
    
    operation - to executed
  - retry
```
public static <T> CompletableFuture<T> retry(Supplier<CompletableFuture<T>> operation,
                                             int retries,
                                             Executor executor)
```
    Retry the given operation the given number of times in case of a failure.
    
    Type Parameters:
    
    T - type of the result
    
    Parameters:
    
    operation - to executed
    
    retries - if the operation failed
    
    executor - to use to run the futures
    
    Returns:
    
    Future containing either the result of the operation or a FutureUtils.RetryException
  - retry
```
public static <T> CompletableFuture<T> retry(Supplier<CompletableFuture<T>> operation,
                                             int retries,
                                             Predicate<Throwable> retryPredicate,
                                             Executor executor)
```
    Retry the given operation the given number of times in case of a failure only when an exception is retryable.
    
    Type Parameters:
    
    T - type of the result
    
    Parameters:
    
    operation - to executed
    
    retries - if the operation failed
    
    retryPredicate - Predicate to test whether an exception is retryable
    
    executor - to use to run the futures
    
    Returns:
    
    Future containing either the result of the operation or a FutureUtils.RetryException
  - retryWithDelay
```
public static <T> CompletableFuture<T> retryWithDelay(Supplier<CompletableFuture<T>> operation,
                                                      RetryStrategy retryStrategy,
                                                      Predicate<Throwable> retryPredicate,
                                                      ScheduledExecutor scheduledExecutor)
```
    Retry the given operation with the given delay in between failures.
    
    Type Parameters:
    
    T - type of the result
    
    Parameters:
    
    operation - to retry
    
    retryStrategy - the RetryStrategy
    
    retryPredicate - Predicate to test whether an exception is retryable
    
    scheduledExecutor - executor to be used for the retry operation
    
    Returns:
    
    Future which retries the given operation a given amount of times and delays the retry in case of failures
  - retryWithDelay
```
public static <T> CompletableFuture<T> retryWithDelay(Supplier<CompletableFuture<T>> operation,
                                                      RetryStrategy retryStrategy,
                                                      ScheduledExecutor scheduledExecutor)
```
    Retry the given operation with the given delay in between failures.
    
    Type Parameters:
    
    T - type of the result
    
    Parameters:
    
    operation - to retry
    
    retryStrategy - the RetryStrategy
    
    scheduledExecutor - executor to be used for the retry operation
    
    Returns:
    
    Future which retries the given operation a given amount of times and delays the retry in case of failures
  - retrySuccessfulWithDelay
```
public static <T> CompletableFuture<T> retrySuccessfulWithDelay(Supplier<CompletableFuture<T>> operation,
                                                                Duration retryDelay,
                                                                Deadline deadline,
                                                                Predicate<T> acceptancePredicate,
                                                                ScheduledExecutor scheduledExecutor)
```
    Retry the given operation with the given delay in between successful completions where the result does not match a given predicate.
    
    Type Parameters:
    
    T - type of the result
    
    Parameters:
    
    operation - to retry
    
    retryDelay - delay between retries
    
    deadline - A deadline that specifies at what point we should stop retrying
    
    acceptancePredicate - Predicate to test whether the result is acceptable
    
    scheduledExecutor - executor to be used for the retry operation
    
    Returns:
    
    Future which retries the given operation a given amount of times and delays the retry in case the predicate isn't matched
  - orTimeout
```
public static <T> CompletableFuture<T> orTimeout(CompletableFuture<T> future,
                                                 long timeout,
                                                 TimeUnit timeUnit,
                                                 @Nullable
                                                 String timeoutMsg)
```
    Times the given future out after the timeout.
    
    Type Parameters:
    
    T - type of the given future
    
    Parameters:
    
    future - to time out
    
    timeout - after which the given future is timed out
    
    timeUnit - time unit of the timeout
    
    timeoutMsg - timeout message for exception
    
    Returns:
    
    The timeout enriched future
  - orTimeout
```
public static <T> CompletableFuture<T> orTimeout(CompletableFuture<T> future,
                                                 long timeout,
                                                 TimeUnit timeUnit,
                                                 Executor timeoutFailExecutor,
                                                 @Nullable
                                                 String timeoutMsg)
```
    Times the given future out after the timeout.
    
    Type Parameters:
    
    T - type of the given future
    
    Parameters:
    
    future - to time out
    
    timeout - after which the given future is timed out
    
    timeUnit - time unit of the timeout
    
    timeoutFailExecutor - executor that will complete the future exceptionally after the timeout is reached
    
    timeoutMsg - timeout message for exception
    
    Returns:
    
    The timeout enriched future
  - completeDelayed
```
public static <T> void completeDelayed(CompletableFuture<T> future,
                                       T success,
                                       Duration delay)
```
    Asynchronously completes the future after a certain delay.
    
    Parameters:
    
    future - The future to complete.
    
    success - The element to complete the future with.
    
    delay - The delay after which the future should be completed.
  - runIfNotDoneAndGet
```
public static <T> T runIfNotDoneAndGet(RunnableFuture<T> future)
                                throws ExecutionException,
                                       InterruptedException
```
    Run the given RunnableFuture if it is not done, and then retrieves its result.
    
    Type Parameters:
    
    T - type of the result
    
    Parameters:
    
    future - to run if not done and get
    
    Returns:
    
    the result after running the future
    
    Throws:
    
    ExecutionException - if a problem occurred
    
    InterruptedException - if the current thread has been interrupted
  - runAfterwards
```
public static CompletableFuture<Void> runAfterwards(CompletableFuture<?> future,
                                                    RunnableWithException runnable)
```
    Run the given action after the completion of the given future. The given future can be completed normally or exceptionally. In case of an exceptional completion the, the action's exception will be added to the initial exception.
    
    Parameters:
    
    future - to wait for its completion
    
    runnable - action which is triggered after the future's completion
    
    Returns:
    
    Future which is completed after the action has completed. This future can contain an exception, if an error occurred in the given future or action.
  - runAfterwardsAsync
```
public static CompletableFuture<Void> runAfterwardsAsync(CompletableFuture<?> future,
                                                         RunnableWithException runnable)
```
    Run the given action after the completion of the given future. The given future can be completed normally or exceptionally. In case of an exceptional completion the, the action's exception will be added to the initial exception.
    
    Parameters:
    
    future - to wait for its completion
    
    runnable - action which is triggered after the future's completion
    
    Returns:
    
    Future which is completed after the action has completed. This future can contain an exception, if an error occurred in the given future or action.
  - runAfterwardsAsync
```
public static CompletableFuture<Void> runAfterwardsAsync(CompletableFuture<?> future,
                                                         RunnableWithException runnable,
                                                         Executor executor)
```
    Run the given action after the completion of the given future. The given future can be completed normally or exceptionally. In case of an exceptional completion the action's exception will be added to the initial exception.
    
    Parameters:
    
    future - to wait for its completion
    
    runnable - action which is triggered after the future's completion
    
    executor - to run the given action
    
    Returns:
    
    Future which is completed after the action has completed. This future can contain an exception, if an error occurred in the given future or action.
  - composeAfterwards
```
public static CompletableFuture<Void> composeAfterwards(CompletableFuture<?> future,
                                                        Supplier<CompletableFuture<?>> composedAction)
```
    Run the given asynchronous action after the completion of the given future. The given future can be completed normally or exceptionally. In case of an exceptional completion, the asynchronous action's exception will be added to the initial exception.
    
    Parameters:
    
    future - to wait for its completion
    
    composedAction - asynchronous action which is triggered after the future's completion
    
    Returns:
    
    Future which is completed after the asynchronous action has completed. This future can contain an exception if an error occurred in the given future or asynchronous action.
  - combineAll
```
public static <T> FutureUtils.ConjunctFuture<Collection<T>> combineAll(Collection<? extends CompletableFuture<? extends T>> futures)
```
    Creates a future that is complete once multiple other futures completed. The future fails (completes exceptionally) once one of the futures in the conjunction fails. Upon successful completion, the future returns the collection of the futures' results.
    The ConjunctFuture gives access to how many Futures in the conjunction have already completed successfully, via FutureUtils.ConjunctFuture.getNumFuturesCompleted().
    
    Parameters:
    
    futures - The futures that make up the conjunction. No null entries are allowed.
    
    Returns:
    
    The ConjunctFuture that completes once all given futures are complete (or one fails).
  - waitForAll
```
public static FutureUtils.ConjunctFuture<Void> waitForAll(Collection<? extends CompletableFuture<?>> futures)
```
    Creates a future that is complete once all of the given futures have completed. The future fails (completes exceptionally) once one of the given futures fails.
    The ConjunctFuture gives access to how many Futures have already completed successfully, via FutureUtils.ConjunctFuture.getNumFuturesCompleted().
    
    Parameters:
    
    futures - The futures to wait on. No null entries are allowed.
    
    Returns:
    
    The WaitingFuture that completes once all given futures are complete (or one fails).
  - completeAll
```
public static FutureUtils.ConjunctFuture<Void> completeAll(Collection<? extends CompletableFuture<?>> futuresToComplete)
```
    Creates a FutureUtils.ConjunctFuture which is only completed after all given futures have completed. Unlike waitForAll(Collection), the resulting future won't be completed directly if one of the given futures is completed exceptionally. Instead, all occurring exception will be collected and combined to a single exception. If at least on exception occurs, then the resulting future will be completed exceptionally.
    
    Parameters:
    
    futuresToComplete - futures to complete
    
    Returns:
    
    Future which is completed after all given futures have been completed.
  - completedExceptionally
```
public static <T> CompletableFuture<T> completedExceptionally(Throwable cause)
```
    Returns an exceptionally completed CompletableFuture.
    
    Type Parameters:
    
    T - type of the future
    
    Parameters:
    
    cause - to complete the future with
    
    Returns:
    
    An exceptionally completed CompletableFuture
  - supplyAsync
```
public static <T> CompletableFuture<T> supplyAsync(SupplierWithException<T,?> supplier,
                                                   Executor executor)
```
    Returns a future which is completed with the result of the SupplierWithException.
    
    Type Parameters:
    
    T - type of the result
    
    Parameters:
    
    supplier - to provide the future's value
    
    executor - to execute the supplier
    
    Returns:
    
    Future which is completed with the value of the supplier
  - thenApplyAsyncIfNotDone
```
public static <IN,OUT> CompletableFuture<OUT> thenApplyAsyncIfNotDone(CompletableFuture<IN> completableFuture,
                                                                      Executor executor,
                                                                      Function<? super IN,? extends OUT> applyFun)
```
    This function takes a CompletableFuture and a function to apply to this future. If the input future is already done, this function returns CompletableFuture.thenApply(Function). Otherwise, the return value is CompletableFuture.thenApplyAsync(Function, Executor) with the given executor.
    
    Type Parameters:
    
    IN - type of the input future.
    
    OUT - type of the output future.
    
    Parameters:
    
    completableFuture - the completable future for which we want to apply.
    
    executor - the executor to run the apply function if the future is not yet done.
    
    applyFun - the function to apply.
    
    Returns:
    
    a completable future that is applying the given function to the input future.
  - thenComposeAsyncIfNotDone
```
public static <IN,OUT> CompletableFuture<OUT> thenComposeAsyncIfNotDone(CompletableFuture<IN> completableFuture,
                                                                        Executor executor,
                                                                        Function<? super IN,? extends CompletionStage<OUT>> composeFun)
```
    This function takes a CompletableFuture and a function to compose with this future. If the input future is already done, this function returns CompletableFuture.thenCompose(Function). Otherwise, the return value is CompletableFuture.thenComposeAsync(Function, Executor) with the given executor.
    
    Type Parameters:
    
    IN - type of the input future.
    
    OUT - type of the output future.
    
    Parameters:
    
    completableFuture - the completable future for which we want to compose.
    
    executor - the executor to run the compose function if the future is not yet done.
    
    composeFun - the function to compose.
    
    Returns:
    
    a completable future that is a composition of the input future and the function.
  - whenCompleteAsyncIfNotDone
```
public static <IN> CompletableFuture<IN> whenCompleteAsyncIfNotDone(CompletableFuture<IN> completableFuture,
                                                                    Executor executor,
                                                                    BiConsumer<? super IN,? super Throwable> whenCompleteFun)
```
    This function takes a CompletableFuture and a bi-consumer to call on completion of this future. If the input future is already done, this function returns CompletableFuture.whenComplete(BiConsumer). Otherwise, the return value is CompletableFuture.whenCompleteAsync(BiConsumer, Executor) with the given executor.
    
    Type Parameters:
    
    IN - type of the input future.
    
    Parameters:
    
    completableFuture - the completable future for which we want to call #whenComplete.
    
    executor - the executor to run the whenComplete function if the future is not yet done.
    
    whenCompleteFun - the bi-consumer function to call when the future is completed.
    
    Returns:
    
    the new completion stage.
  - thenAcceptAsyncIfNotDone
```
public static <IN> CompletableFuture<Void> thenAcceptAsyncIfNotDone(CompletableFuture<IN> completableFuture,
                                                                    Executor executor,
                                                                    Consumer<? super IN> consumer)
```
    This function takes a CompletableFuture and a consumer to accept the result of this future. If the input future is already done, this function returns CompletableFuture.thenAccept(Consumer). Otherwise, the return value is CompletableFuture.thenAcceptAsync(Consumer, Executor) with the given executor.
    
    Type Parameters:
    
    IN - type of the input future.
    
    Parameters:
    
    completableFuture - the completable future for which we want to call #thenAccept.
    
    executor - the executor to run the thenAccept function if the future is not yet done.
    
    consumer - the consumer function to call when the future is completed.
    
    Returns:
    
    the new completion stage.
  - handleAsyncIfNotDone
```
public static <IN,OUT> CompletableFuture<OUT> handleAsyncIfNotDone(CompletableFuture<IN> completableFuture,
                                                                   Executor executor,
                                                                   BiFunction<? super IN,Throwable,? extends OUT> handler)
```
    This function takes a CompletableFuture and a handler function for the result of this future. If the input future is already done, this function returns CompletableFuture.handle(BiFunction). Otherwise, the return value is CompletableFuture.handleAsync(BiFunction, Executor) with the given executor.
    
    Type Parameters:
    
    IN - type of the handler input argument.
    
    OUT - type of the handler return value.
    
    Parameters:
    
    completableFuture - the completable future for which we want to call #handle.
    
    executor - the executor to run the handle function if the future is not yet done.
    
    handler - the handler function to call when the future is completed.
    
    Returns:
    
    the new completion stage.
  - isCompletedNormally
```
public static boolean isCompletedNormally(CompletableFuture<?> future)
```
    Returns:
    
    true if future has completed normally, false otherwise.
  - checkStateAndGet
```
public static <T> T checkStateAndGet(CompletableFuture<T> future)
```
    Perform check state that future has completed normally and return the result.
    
    Returns:
    
    the result of completable future.
    
    Throws:
    
    IllegalStateException - Thrown, if future has not completed or it has completed exceptionally.
  - getWithoutException
```
@Nullable
public static <T> T getWithoutException(CompletableFuture<T> future)
```
    Gets the result of a completable future without any exception thrown.
    
    Type Parameters:
    
    T - the type of result
    
    Parameters:
    
    future - the completable future specified.
    
    Returns:
    
    the result of completable future, or null if it's unfinished or finished exceptionally
  - getOrDefault
```
public static <T> T getOrDefault(CompletableFuture<T> future,
                                 T defaultValue)
```
    Returns:
    
    the result of completable future, or the defaultValue if it has not yet completed.
  - assertNoException
```
public static void assertNoException(CompletableFuture<?> completableFuture)
```
    Asserts that the given CompletableFuture is not completed exceptionally. If the future is completed exceptionally, then it will call the FatalExitExceptionHandler.
    
    Parameters:
    
    completableFuture - to assert for no exceptions
  - handleException
```
public static <T,E extends Throwable> CompletableFuture<T> handleException(CompletableFuture<? extends T> completableFuture,
                                                                           Class<E> exceptionClass,
                                                                           Function<? super E,? extends T> exceptionHandler)
```
    Checks that the given CompletableFuture is not completed exceptionally with the specified class. If the future is completed exceptionally with the specific class, then try to recover using a given exception handler. If the exception does not match the specified class, just pass it through to later stages.
    
    Parameters:
    
    completableFuture - to assert for a given exception
    
    exceptionClass - exception class to assert for
    
    exceptionHandler - to call if the future is completed exceptionally with the specific exception
    
    Returns:
    
    completable future, that can recover from a specified exception
  - handleUncaughtException
```
public static void handleUncaughtException(CompletableFuture<?> completableFuture,
                                           Thread.UncaughtExceptionHandler uncaughtExceptionHandler)
```
    Checks that the given CompletableFuture is not completed exceptionally. If the future is completed exceptionally, then it will call the given uncaught exception handler.
    
    Parameters:
    
    completableFuture - to assert for no exceptions
    
    uncaughtExceptionHandler - to call if the future is completed exceptionally
  - forward
```
public static <T> void forward(CompletableFuture<T> source,
                               CompletableFuture<T> target)
```
    Forwards the value from the source future to the target future.
    
    Type Parameters:
    
    T - type of the value
    
    Parameters:
    
    source - future to forward the value from
    
    target - future to forward the value to
  - forwardAsync
```
public static <T> void forwardAsync(CompletableFuture<T> source,
                                    CompletableFuture<T> target,
                                    Executor executor)
```
    Forwards the value from the source future to the target future using the provided executor.
    
    Type Parameters:
    
    T - type of the value
    
    Parameters:
    
    source - future to forward the value from
    
    target - future to forward the value to
    
    executor - executor to forward the source value to the target future
  - throwIfCompletedExceptionally
```
public static void throwIfCompletedExceptionally(CompletableFuture<?> future)
                                          throws Exception
```
    Throws the causing exception if the given future is completed exceptionally, otherwise do nothing.
    
    Parameters:
    
    future - the future to check.
    
    Throws:
    
    Exception - when the future is completed exceptionally.
  - doForward
```
public static <T> void doForward(@Nullable
                                 T value,
                                 @Nullable
                                 Throwable throwable,
                                 CompletableFuture<T> target)
```
    Completes the given future with either the given value or throwable, depending on which parameter is not null.
    
    Type Parameters:
    
    T - completed future
    
    Parameters:
    
    value - value with which the future should be completed
    
    throwable - throwable with which the future should be completed exceptionally
    
    target - future to complete
  - switchExecutor
```
public static <T> CompletableFuture<T> switchExecutor(CompletableFuture<? extends T> source,
                                                      Executor executor)
```
    Switches the execution context of the given source future. This works for normally and exceptionally completed futures.
    
    Type Parameters:
    
    T - type of the source
    
    Parameters:
    
    source - source to switch the execution context for
    
    executor - executor representing the new execution context
    
    Returns:
    
    future which is executed by the given executor

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Class FutureUtils

Nested Class Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Constructor Detail

FutureUtils

Method Detail

completedVoidFuture

unsupportedOperationFuture

completeFromCallable

retry

retry

retryWithDelay

retryWithDelay

retrySuccessfulWithDelay

orTimeout

orTimeout

completeDelayed

runIfNotDoneAndGet

runAfterwards

runAfterwardsAsync

runAfterwardsAsync

composeAfterwards

combineAll

waitForAll

completeAll

completedExceptionally

supplyAsync

thenApplyAsyncIfNotDone

thenComposeAsyncIfNotDone

whenCompleteAsyncIfNotDone

thenAcceptAsyncIfNotDone

handleAsyncIfNotDone

isCompletedNormally

checkStateAndGet

getWithoutException

getOrDefault

assertNoException

handleException

handleUncaughtException

forward

forwardAsync

throwIfCompletedExceptionally

doForward

switchExecutor

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