org.opendaylight.infrautils.testutils.concurrent

Class CompletionStageTestAwaiter<T>

java.lang.Object

org.opendaylight.infrautils.testutils.concurrent.CompletionStageTestAwaiter<T>

public final class CompletionStageTestAwaiter<T>
extends Object

Test utility to await the completion of a CompletionStage.

Note that if you have a CompletableFuture instead of a CompletionStage, then you could just use CompletableFuture.join(), which does the same thing as the await500ms(CompletionStage) here. However, to test operations which return only a CompletionStage but not a full CompletableFuture, you use this. (CompletionStage is often a more suitable operation return type, because it "does not define methods for initially creating, forcibly completing normally or exceptionally, probing completion status or results, or awaiting completion of a stage".)

Note that the CompletionStage.toCompletableFuture() "back-door" may "throw an UnsupportedOperationException if an implementation does not inter-operate with CompletableFuture".

In production code, you normally never should have to await/join/get results returned as CompletionStage. If you are, you're probably using an API wrong. (Valid deviations to this rule include scenarios where you bridge an async API to an existing legacy API, which you cannot change, using synchronous signature methods which do not return an async types such as CompletionStage or (a subtype of) Future.)

See the CompletionStageAwaitExampleTest for an illustration how to use this.

Author:

Michael Vorburger.ch

Method Summary

Modifier and Type	Method and Description
static <T> T	await(CompletionStage<T> completionStage, long timeout, TimeUnit unit) Await a configurable amount of time for the CompletionStage argument to complete.
static <T> T	await500ms(CompletionStage<T> completionStage) Await max.

Methods inherited from class java.lang.Object

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

Method Detail

await500ms

public static <T> T await500ms(CompletionStage<T> completionStage)
                        throws TimeoutException

Await max. 500ms for the CompletionStage argument to complete.

Throws:

CompletionException - if it completed unsuccessfully

CancellationException - if it got cancelled while awaiting completion

TimeoutException - if it timed out awaiting completion

await

public static <T> T await(CompletionStage<T> completionStage,
                          long timeout,
                          TimeUnit unit)
                   throws TimeoutException

Await a configurable amount of time for the CompletionStage argument to complete.

Throws:

CompletionException - if it completed unsuccessfully

CancellationException - if it got cancelled while awaiting completion

TimeoutException - if it timed out awaiting completion