Class SettableFuture<V extends @Nullable java.lang.Object>

    • Method Summary

      All Methods Static Methods Instance Methods Concrete Methods 
      Modifier and Type Method Description
      void addListener​(java.lang.Runnable listener, java.util.concurrent.Executor executor)
      Registers a listener to be run on the given executor.
      boolean cancel​(boolean mayInterruptIfRunning)
      Attempts to cancel execution of this task.
      static <V extends @Nullable java.lang.Object>
      SettableFuture<V>
      create()
      Creates a new SettableFuture that can be completed or cancelled by a later method call.
      V get()
      Waits if necessary for the computation to complete, and then retrieves its result.
      V get​(long timeout, java.util.concurrent.TimeUnit unit)
      Waits if necessary for at most the given time for the computation to complete, and then retrieves its result, if available.
      boolean isCancelled()
      Returns true if this task was cancelled before it completed normally.
      boolean isDone()
      Returns true if this task completed.
      boolean set​(V value)
      Sets the result of this Future unless this Future has already been cancelled or set (including set asynchronously).
      boolean setException​(java.lang.Throwable throwable)
      Sets the failed result of this Future unless this Future has already been cancelled or set (including set asynchronously).
      boolean setFuture​(ListenableFuture<? extends V> future)
      Sets the result of this Future to match the supplied input Future once the supplied Future is done, unless this Future has already been cancelled or set (including "set asynchronously," defined below).
      • Methods inherited from class java.lang.Object

        clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait
    • Method Detail

      • create

        public static <V extends @Nullable java.lang.Object> SettableFuture<V> create()
        Creates a new SettableFuture that can be completed or cancelled by a later method call.
      • set

        @CanIgnoreReturnValue
        public boolean set​(V value)
        Description copied from class: AbstractFuture
        Sets the result of this Future unless this Future has already been cancelled or set (including set asynchronously). When a call to this method returns, the Future is guaranteed to be done only if the call was accepted (in which case it returns true). If it returns false, the Future may have previously been set asynchronously, in which case its result may not be known yet. That result, though not yet known, cannot be overridden by a call to a set* method, only by a call to AbstractFuture.cancel(boolean).

        Beware of completing a future while holding a lock. Its listeners may do slow work or acquire other locks, risking deadlocks.

        Overrides:
        set in class AbstractFuture<V extends @Nullable java.lang.Object>
        Parameters:
        value - the value to be used as the result
        Returns:
        true if the attempt was accepted, completing the Future
      • setException

        @CanIgnoreReturnValue
        public boolean setException​(java.lang.Throwable throwable)
        Description copied from class: AbstractFuture
        Sets the failed result of this Future unless this Future has already been cancelled or set (including set asynchronously). When a call to this method returns, the Future is guaranteed to be done only if the call was accepted (in which case it returns true). If it returns false, the Future may have previously been set asynchronously, in which case its result may not be known yet. That result, though not yet known, cannot be overridden by a call to a set* method, only by a call to AbstractFuture.cancel(boolean).

        Beware of completing a future while holding a lock. Its listeners may do slow work or acquire other locks, risking deadlocks.

        Overrides:
        setException in class AbstractFuture<V extends @Nullable java.lang.Object>
        Parameters:
        throwable - the exception to be used as the failed result
        Returns:
        true if the attempt was accepted, completing the Future
      • setFuture

        @CanIgnoreReturnValue
        public boolean setFuture​(ListenableFuture<? extends V> future)
        Description copied from class: AbstractFuture
        Sets the result of this Future to match the supplied input Future once the supplied Future is done, unless this Future has already been cancelled or set (including "set asynchronously," defined below).

        If the supplied future is done when this method is called and the call is accepted, then this future is guaranteed to have been completed with the supplied future by the time this method returns. If the supplied future is not done and the call is accepted, then the future will be set asynchronously. Note that such a result, though not yet known, cannot be overridden by a call to a set* method, only by a call to AbstractFuture.cancel(boolean).

        If the call setFuture(delegate) is accepted and this Future is later cancelled, cancellation will be propagated to delegate. Additionally, any call to setFuture after any cancellation will propagate cancellation to the supplied Future.

        Note that, even if the supplied future is cancelled and it causes this future to complete, it will never trigger interruption behavior. In particular, it will not cause this future to invoke the AbstractFuture.interruptTask() method, and the AbstractFuture.wasInterrupted() method will not return true.

        Beware of completing a future while holding a lock. Its listeners may do slow work or acquire other locks, risking deadlocks.

        Overrides:
        setFuture in class AbstractFuture<V extends @Nullable java.lang.Object>
        Parameters:
        future - the future to delegate to
        Returns:
        true if the attempt was accepted, indicating that the Future was not previously cancelled or set.
      • get

        @CanIgnoreReturnValue
        public final V get()
                    throws java.lang.InterruptedException,
                           java.util.concurrent.ExecutionException
        Description copied from class: AbstractFuture
        Waits if necessary for the computation to complete, and then retrieves its result.

        The default AbstractFuture implementation throws InterruptedException if the current thread is interrupted during the call, even if the value is already available.

        Specified by:
        get in interface java.util.concurrent.Future<V extends @Nullable java.lang.Object>
        Overrides:
        get in class AbstractFuture<V extends @Nullable java.lang.Object>
        Returns:
        the computed result
        Throws:
        java.lang.InterruptedException - if the current thread was interrupted while waiting
        java.util.concurrent.ExecutionException - if the computation threw an exception
      • get

        @CanIgnoreReturnValue
        public final V get​(long timeout,
                           java.util.concurrent.TimeUnit unit)
                    throws java.lang.InterruptedException,
                           java.util.concurrent.ExecutionException,
                           java.util.concurrent.TimeoutException
        Description copied from class: AbstractFuture
        Waits if necessary for at most the given time for the computation to complete, and then retrieves its result, if available.

        The default AbstractFuture implementation throws InterruptedException if the current thread is interrupted during the call, even if the value is already available.

        Specified by:
        get in interface java.util.concurrent.Future<V extends @Nullable java.lang.Object>
        Overrides:
        get in class AbstractFuture<V extends @Nullable java.lang.Object>
        Parameters:
        timeout - the maximum time to wait
        unit - the time unit of the timeout argument
        Returns:
        the computed result
        Throws:
        java.lang.InterruptedException - if the current thread was interrupted while waiting
        java.util.concurrent.ExecutionException - if the computation threw an exception
        java.util.concurrent.TimeoutException - if the wait timed out
      • isDone

        public final boolean isDone()
        Description copied from interface: java.util.concurrent.Future
        Returns true if this task completed. Completion may be due to normal termination, an exception, or cancellation -- in all of these cases, this method will return true.
        Specified by:
        isDone in interface java.util.concurrent.Future<V extends @Nullable java.lang.Object>
        Overrides:
        isDone in class AbstractFuture<V extends @Nullable java.lang.Object>
        Returns:
        true if this task completed
      • isCancelled

        public final boolean isCancelled()
        Description copied from interface: java.util.concurrent.Future
        Returns true if this task was cancelled before it completed normally.
        Specified by:
        isCancelled in interface java.util.concurrent.Future<V extends @Nullable java.lang.Object>
        Overrides:
        isCancelled in class AbstractFuture<V extends @Nullable java.lang.Object>
        Returns:
        true if this task was cancelled before it completed
      • addListener

        public final void addListener​(java.lang.Runnable listener,
                                      java.util.concurrent.Executor executor)
        Description copied from class: AbstractFuture
        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 direct execution) will be caught and logged.

        Note: If your listener is lightweight -- and will not cause stack overflow by completing more futures or adding more directExecutor() listeners inline -- consider MoreExecutors.directExecutor(). Otherwise, avoid it: See the warnings on the docs for directExecutor.

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

        Memory consistency effects: Actions in a thread prior to adding a listener happen-before its execution begins, perhaps in another thread.

        Guava implementations of ListenableFuture promptly release references to listeners after executing them.

        Specified by:
        addListener in interface ListenableFuture<V extends @Nullable java.lang.Object>
        Overrides:
        addListener in class AbstractFuture<V extends @Nullable java.lang.Object>
        Parameters:
        listener - the listener to run when the computation is complete
        executor - the executor to run the listener in
      • cancel

        @CanIgnoreReturnValue
        public final boolean cancel​(boolean mayInterruptIfRunning)
        Description copied from class: AbstractFuture
        Attempts to cancel execution of this task. This attempt will fail if the task has already completed, has already been cancelled, or could not be cancelled for some other reason. If successful, and this task has not started when cancel is called, this task should never run. If the task has already started, then the mayInterruptIfRunning parameter determines whether the thread executing this task should be interrupted in an attempt to stop the task.

        After this method returns, subsequent calls to Future.isDone() will always return true. Subsequent calls to Future.isCancelled() will always return true if this method returned true.

        If a cancellation attempt succeeds on a Future that had previously been set asynchronously, then the cancellation will also be propagated to the delegate Future that was supplied in the setFuture call.

        Rather than override this method to perform additional cancellation work or cleanup, subclasses should override AbstractFuture.afterDone(), consulting AbstractFuture.isCancelled() and AbstractFuture.wasInterrupted() as necessary. This ensures that the work is done even if the future is cancelled without a call to cancel, such as by calling setFuture(cancelledFuture).

        Beware of completing a future while holding a lock. Its listeners may do slow work or acquire other locks, risking deadlocks.

        Specified by:
        cancel in interface java.util.concurrent.Future<V extends @Nullable java.lang.Object>
        Overrides:
        cancel in class AbstractFuture<V extends @Nullable java.lang.Object>
        Parameters:
        mayInterruptIfRunning - true if the thread executing this task should be interrupted; otherwise, in-progress tasks are allowed to complete
        Returns:
        false if the task could not be cancelled, typically because it has already completed normally; true otherwise