Class ForwardingListenableFuture<V>

    • Method Detail

      • addListener

        public void addListener​(java.lang.Runnable listener,
                                java.util.concurrent.Executor exec)
        Description copied from interface: ListenableFuture
        Registers a listener to be run on the given executor. The listener will run when the Future's computation is complete or, if the computation is already complete, immediately.

        There is no guaranteed ordering of execution of listeners, but any listener added through this method is guaranteed to be called once the computation is complete.

        Exceptions thrown by a listener will be propagated up to the executor. Any exception thrown during Executor.execute (e.g., a RejectedExecutionException or an exception thrown by inline execution) will be caught and logged.

        Note: For fast, lightweight listeners that would be safe to execute in any thread, consider MoreExecutors.sameThreadExecutor(). For heavier listeners, sameThreadExecutor() carries some caveats. For example, the listener may run on an unpredictable or undesirable thread:

        • If this Future is done at the time addListener is called, addListener will execute the listener inline.
        • If this Future is not yet done, addListener will schedule the listener to be run by the thread that completes this Future, which may be an internal system thread such as an RPC network thread.

        Also note that, regardless of which thread executes the sameThreadExecutor() listener, all other registered but unexecuted listeners are prevented from running during its execution, even if those listeners are to run in other executors.

        This is the most general listener interface. For common operations performed using listeners, see Futures. For a simplified but general listener interface, see addCallback().

        Specified by:
        addListener in interface ListenableFuture<V>
        listener - the listener to run when the computation is complete
        exec - the executor to run the listener in