Module io.netty5.common

Package io.netty5.util.concurrent

Class PromiseCombiner

java.lang.Object

io.netty5.util.concurrent.PromiseCombiner

public final class PromiseCombiner
extends Object

A promise combiner monitors the outcome of a number of discrete futures, then notifies a final, aggregate promise when all of the combined futures are finished. The aggregate promise will succeed if and only if all of the combined futures succeed. If any of the combined futures fail, the aggregate promise will fail. The cause failure for the aggregate promise will be the failure for one of the failed combined futures; if more than one of the combined futures fails, exactly which cause of failure will be assigned to the aggregate promise is undefined.

Callers may populate a promise combiner with any number of futures to be combined via the add(Future) and addAll(Future[]) methods. When all futures to be combined have been added, callers must provide an aggregate promise to be notified when all combined promises have finished via the finish(Promise) method.

This implementation is NOT thread-safe and all methods must be called from the EventExecutor thread.

Constructor Summary

Constructors

Constructor	Description
PromiseCombiner(EventExecutor executor)	The EventExecutor to use for notifications.

Method Summary

Modifier and Type	Method	Description
void	add(Future<?> future)	Adds a new future to be combined.
void	addAll(Future<?>... futures)	Adds new futures to be combined.
void	finish(Promise<Void> aggregatePromise)	Sets the promise to be notified when all combined futures have finished.

Methods inherited from class java.lang.Object

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

Constructor Detail

PromiseCombiner

public PromiseCombiner(EventExecutor executor)

The EventExecutor to use for notifications. You must call add(Future), addAll(Future[]) and finish(Promise) from within the EventExecutor thread.

Parameters:

executor - the EventExecutor to use for notifications.

Method Detail

add

public void add(Future<?> future)

Adds a new future to be combined. New futures may be added until an aggregate promise is added via the finish(Promise) method.

Parameters:

future - the future to add to this promise combiner

addAll

public void addAll(Future<?>... futures)

Adds new futures to be combined. New futures may be added until an aggregate promise is added via the finish(Promise) method.

Parameters:

futures - the futures to add to this promise combiner

finish

public void finish(Promise<Void> aggregatePromise)

Sets the promise to be notified when all combined futures have finished. If all combined futures succeed, then the aggregate promise will succeed. If one or more combined futures fails, then the aggregate promise will fail with the cause of one of the failed futures. If more than one combined future fails, then exactly which failure will be assigned to the aggregate promise is undefined.

After this method is called, no more futures may be added via the add(Future) or addAll(Future[]) methods.

Parameters:

aggregatePromise - the promise to notify when all combined futures have finished