Package com.google.common.util.concurrent

Class AggregateFuture<InputT,​OutputT>

  • Type Parameters:
    InputT - the type of the individual inputs
    OutputT - the type of the output (i.e. this) future
    All Implemented Interfaces:
    AbstractFuture.Trusted<OutputT>, ListenableFuture<OutputT>, java.util.concurrent.Future<OutputT>
    Direct Known Subclasses:
    CollectionFuture, CombinedFuture
    abstract class AggregateFuture<InputT,​OutputT>
extends AggregateFutureState<OutputT>
    A future whose value is derived from a collection of input futures.

    • Field Detail

      • logger

        private static final java.util.logging.Logger logger

      • allMustSucceed

        private final boolean allMustSucceed

      • collectsValues

        private final boolean collectsValues

    • Method Detail

      • afterDone

        protected final void afterDone()
        Description copied from class: AbstractFuture
        Callback method that is called exactly once after the future is completed.

        If AbstractFuture.interruptTask() is also run during completion, AbstractFuture.afterDone() runs after it.

        The default implementation of this method in AbstractFuture does nothing. This is intended for very lightweight cleanup work, for example, timing statistics or clearing fields. If your task does anything heavier consider, just using a listener with an executor.

        Overrides:
        afterDone in class AbstractFuture<OutputT>

      • pendingToString

        protected final java.lang.String pendingToString()
        Description copied from class: AbstractFuture
        Provide a human-readable explanation of why this future has not yet completed.
        Overrides:
        pendingToString in class AbstractFuture<OutputT>
        Returns:
        null if an explanation cannot be provided (e.g. because the future is done).

      • init

        final void init()
        Must be called at the end of each subclass's constructor. This method performs the "real" initialization; we can't put this in the constructor because, in the case where futures are already complete, we would not initialize the subclass before calling collectValueFromNonCancelledFuture(int, java.util.concurrent.Future<? extends InputT>). As this is called after the subclass is constructed, we're guaranteed to have properly initialized the subclass.

      • handleException

        private void handleException​(java.lang.Throwable throwable)
        Fails this future with the given Throwable if allMustSucceed is true. Also, logs the throwable if it is an Error or if allMustSucceed is true, the throwable did not cause this future to fail, and it is the first time we've seen that particular Throwable.

      • log

        private static void log​(java.lang.Throwable throwable)

      • collectValueFromNonCancelledFuture

        private void collectValueFromNonCancelledFuture​(int index,
                                                java.util.concurrent.Future<? extends InputT> future)
        Collects the result (success or failure) of one input future. The input must not have been cancelled. For details on when this is called, see collectOneValue(int, InputT).

      • decrementCountAndMaybeComplete

        private void decrementCountAndMaybeComplete​(ImmutableCollection<? extends java.util.concurrent.Future<? extends InputT>> futuresIfNeedToCollectAtCompletion)

      • processCompleted

        private void processCompleted​(ImmutableCollection<? extends java.util.concurrent.Future<? extends InputT>> futuresIfNeedToCollectAtCompletion)

      • releaseResources

        void releaseResources​(AggregateFuture.ReleaseResourcesReason reason)
        Clears fields that are no longer needed after this future has completed -- or at least all its inputs have completed (more precisely, after handleAllCompleted() has been called). Often called multiple times (that is, both when the inputs complete and when the output completes).

        This is similar to our proposed afterCommit method but not quite the same. See the description of CL 265462958.

      • collectOneValue

        abstract void collectOneValue​(int index,
                              InputT returnValue)
        If allMustSucceed is true, called as each future completes; otherwise, if collectsValues is true, called for each future when all futures complete.

      • handleAllCompleted

        abstract void handleAllCompleted()

      • addCausalChain

        private static boolean addCausalChain​(java.util.Set<java.lang.Throwable> seen,
                                      java.lang.Throwable t)
        Adds the chain to the seen set, and returns whether all the chain was new to us.