Module org.neo4j.driver

Package org.neo4j.driver.internal.util

Class Futures

java.lang.Object

org.neo4j.driver.internal.util.Futures

public final class Futures
extends Object

Method Summary

Modifier and Type	Method	Description
static CompletionException	asCompletionException(Throwable error)	Helped method to turn given exception into a CompletionException.
static void	assertNotInEventLoopThread()	Assert that current thread is not an event loop used for async IO operations.
static <V> V	blockingGet(CompletionStage<V> stage)
static <V> V	blockingGet(CompletionStage<V> stage, Runnable interruptHandler)
static CompletionException	combineErrors(Throwable error1, Throwable error2)	Combine given errors into a single CompletionException to be rethrown from inside a CompletionStage chain.
static <T> CompletableFuture<T>	completedWithNull()
static Throwable	completionExceptionCause(Throwable error)	Helper method to extract cause of a CompletionException.
static <T> BiConsumer<T,Throwable>	futureCompletingConsumer(CompletableFuture<T> future)
static <T> T	getNow(CompletionStage<T> stage)
static boolean	isEventLoopThread(Thread thread)	Check if given thread is an event loop IO thread.

Methods inherited from class java.lang.Object

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

Method Details

completedWithNull

public static <T> CompletableFuture<T> completedWithNull()

blockingGet

public static <V> V blockingGet(CompletionStage<V> stage)

blockingGet

public static <V> V blockingGet(CompletionStage<V> stage,
 Runnable interruptHandler)

getNow

public static <T> T getNow(CompletionStage<T> stage)

completionExceptionCause

public static Throwable completionExceptionCause(Throwable error)

Helper method to extract cause of a CompletionException.

When using CompletionStage.whenComplete(BiConsumer) and CompletionStage.handle(BiFunction) propagated exceptions might get wrapped in a CompletionException.

Parameters:

error - the exception to get cause for.

Returns:

cause of the given exception if it is a CompletionException, given exception otherwise.

asCompletionException

public static CompletionException asCompletionException(Throwable error)

Helped method to turn given exception into a CompletionException.

Parameters:

error - the exception to convert.

Returns:

given exception wrapped with CompletionException if it's not one already.

combineErrors

public static CompletionException combineErrors(Throwable error1,
 Throwable error2)

Combine given errors into a single CompletionException to be rethrown from inside a CompletionStage chain.

Parameters:

error1 - the first error or null.

error2 - the second error or null.

Returns:

null if both errors are null, CompletionException otherwise.

futureCompletingConsumer

public static <T> BiConsumer<T,Throwable> futureCompletingConsumer(CompletableFuture<T> future)

assertNotInEventLoopThread

public static void assertNotInEventLoopThread()
                                       throws IllegalStateException

Assert that current thread is not an event loop used for async IO operations. This check is needed because blocking API methods are implemented on top of corresponding async API methods. Deadlocks might happen when IO thread executes blocking API call and has to wait for itself to read from the network.

Throws:

IllegalStateException - when current thread is an event loop IO thread.

isEventLoopThread

public static boolean isEventLoopThread(Thread thread)

Check if given thread is an event loop IO thread.

Parameters:

thread - the thread to check.

Returns:

true when given thread belongs to the event loop, false otherwise.