software.amazon.awssdk.utils

Class CompletableFutureUtils

java.lang.Object

software.amazon.awssdk.utils.CompletableFutureUtils

public final class CompletableFutureUtils
extends Object

Utility class for working with CompletableFuture.

Method Summary

Modifier and Type	Method and Description
static CompletionException	errorAsCompletionException(Throwable t) Wraps the given error in a CompletionException if necessary.
static <U> CompletableFuture<U>	failedFuture(Throwable t) Convenience method for creating a future that is immediately completed exceptionally with the given Throwable.
static <T> CompletableFuture<T>	forwardExceptionTo(CompletableFuture<T> src, CompletableFuture<?> dst) Forward the Throwable from src to dst.
static <T> CompletableFuture<T>	forwardResultTo(CompletableFuture<T> src, CompletableFuture<T> dst, Executor executor) Completes the dst future based on the result of the src future asynchronously on the provided Executor and return the src future.
static <T> CompletableFuture<T>	forwardTransformedExceptionTo(CompletableFuture<T> src, CompletableFuture<?> dst, Function<Throwable,Throwable> transformationFunction) Forward the Throwable that can be transformed as per the transformationFunction from src to dst.
static <SourceT,DestT> CompletableFuture<SourceT>	forwardTransformedResultTo(CompletableFuture<SourceT> src, CompletableFuture<DestT> dst, Function<SourceT,DestT> function) Completes the dst future based on the result of the src future, synchronously, after applying the provided transformation Function if successful.

Methods inherited from class java.lang.Object

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

Method Detail

failedFuture

public static <U> CompletableFuture<U> failedFuture(Throwable t)

Convenience method for creating a future that is immediately completed exceptionally with the given Throwable.

Similar to CompletableFuture#failedFuture which was added in Java 9.

Type Parameters:

U - The type of the element.

Parameters:

t - The failure.

Returns:

The failed future.

errorAsCompletionException

public static CompletionException errorAsCompletionException(Throwable t)

Wraps the given error in a CompletionException if necessary. Useful if an exception needs to be rethrown from within CompletableFuture.handle(java.util.function.BiFunction) or similar methods.

Parameters:

t - The error.

Returns:

The error as a CompletionException.

forwardExceptionTo

public static <T> CompletableFuture<T> forwardExceptionTo(CompletableFuture<T> src,
                                                          CompletableFuture<?> dst)

Forward the Throwable from src to dst.

Parameters:

src - The source of the Throwable.

dst - The destination where the Throwable will be forwarded to.

Returns:

src.

forwardTransformedExceptionTo

public static <T> CompletableFuture<T> forwardTransformedExceptionTo(CompletableFuture<T> src,
                                                                     CompletableFuture<?> dst,
                                                                     Function<Throwable,Throwable> transformationFunction)

Forward the Throwable that can be transformed as per the transformationFunction from src to dst.

Parameters:

src - The source of the Throwable.

dst - The destination where the Throwable will be forwarded to

transformationFunction - Transformation function taht will be applied on to the forwarded exception.

Returns:

forwardResultTo

public static <T> CompletableFuture<T> forwardResultTo(CompletableFuture<T> src,
                                                       CompletableFuture<T> dst,
                                                       Executor executor)

Completes the dst future based on the result of the src future asynchronously on the provided Executor and return the src future.

Parameters:

src - The source CompletableFuture

dst - The destination where the Throwable or response will be forwarded to.

executor - the executor to complete the des future

Returns:

the src future.

forwardTransformedResultTo

public static <SourceT,DestT> CompletableFuture<SourceT> forwardTransformedResultTo(CompletableFuture<SourceT> src,
                                                                                    CompletableFuture<DestT> dst,
                                                                                    Function<SourceT,DestT> function)

Completes the dst future based on the result of the src future, synchronously, after applying the provided transformation Function if successful.

Parameters:

src - The source CompletableFuture

dst - The destination where the Throwable or transformed result will be forwarded to.

Returns:

the src future.