Package com.google.common.util.concurrent

Class SettableFuture<V>

    • 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)
      static <V> SettableFuture<V> create()
      Creates a new SettableFuture that can be completed or cancelled by a later method call.
      V get()
      V get​(long timeout, java.util.concurrent.TimeUnit unit)
      boolean isCancelled()  
      boolean isDone()  
      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, toString, wait, wait, wait

    • Method Detail

      • create

        public static <V> SettableFuture<V> create()
        Creates a new SettableFuture that can be completed or cancelled by a later method call.

      • set

        public boolean set​(@Nullable
                   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 by overridden by a call to a set* method, only by a call to AbstractFuture.cancel(boolean).
        Overrides:
        set in class AbstractFuture<V>
        Parameters:
        value - the value to be used as the result
        Returns:
        true if the attempt was accepted, completing the Future

      • setException

        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 by overridden by a call to a set* method, only by a call to AbstractFuture.cancel(boolean).
        Overrides:
        setException in class AbstractFuture<V>
        Parameters:
        throwable - the exception to be used as the failed result
        Returns:
        true if the attempt was accepted, completing the Future

      • setFuture

        @Beta
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 by 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.

        Overrides:
        setFuture in class AbstractFuture<V>
        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

        public final V get()
            throws java.lang.InterruptedException,
                   java.util.concurrent.ExecutionException
        Description copied from class: AbstractFuture

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

        Specified by:
        get in interface java.util.concurrent.Future<V>
        Overrides:
        get in class AbstractFuture<V>
        Throws:
        java.lang.InterruptedException - if the current thread was interrupted before or during the call (optional but recommended).
        java.util.concurrent.ExecutionException

      • get

        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

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

        Specified by:
        get in interface java.util.concurrent.Future<V>
        Overrides:
        get in class AbstractFuture<V>
        Throws:
        java.lang.InterruptedException - if the current thread was interrupted before or during the call (optional but recommended).
        java.util.concurrent.ExecutionException
        java.util.concurrent.TimeoutException

      • isDone

        public final boolean isDone()
        Specified by:
        isDone in interface java.util.concurrent.Future<V>
        Overrides:
        isDone in class AbstractFuture<V>

      • isCancelled

        public final boolean isCancelled()
        Specified by:
        isCancelled in interface java.util.concurrent.Future<V>
        Overrides:
        isCancelled in class AbstractFuture<V>

      • 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: For fast, lightweight listeners that would be safe to execute in any thread, consider MoreExecutors.directExecutor(). Otherwise, avoid it. Heavyweight directExecutor listeners can cause problems, and these problems can be difficult to reproduce because they depend on timing. For example:

        • The listener may be executed by the caller of addListener. That caller may be a UI thread or other latency-sensitive thread. This can harm UI responsiveness.
        • The listener may be executed by the thread that completes this Future. That thread may be an internal system thread such as an RPC network thread. Blocking that thread may stall progress of the whole system. It may even cause a deadlock.
        • The listener may delay other listeners, even listeners that are not themselves directExecutor listeners.

        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.

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

      • cancel

        public final boolean cancel​(boolean mayInterruptIfRunning)
        Description copied from class: AbstractFuture

        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.

        Specified by:
        cancel in interface java.util.concurrent.Future<V>
        Overrides:
        cancel in class AbstractFuture<V>