Module io.netty5.common
Package io.netty5.util.concurrent

Class 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.

    • 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