Guava: Google Core Libraries for Java 32.1.2-jre · com.google.common.util.concurrent.AbstractFuture

An abstract implementation of ListenableFuture, intended for advanced users only. More common ways to create a ListenableFuture include instantiating a SettableFuture, submitting a task to a ListeningExecutorService, and deriving a Future from an existing one, typically using methods like Futures.transform and Futures.catching.

This class implements all methods in ListenableFuture. Subclasses should provide a way to set the result of the computation through the protected methods set(Object), setFuture(ListenableFuture) and setException(Throwable). Subclasses may also override afterDone(), which will be invoked automatically when the future completes. Subclasses should rarely override other methods.

Nested and Inner Type Summary

Modifier and Type	Class and Description
private abstract static class	AbstractFuture.AtomicHelper
private static class	AbstractFuture.Cancellation A special value to represent cancellation and the 'wasInterrupted' bit.
private static class	AbstractFuture.Failure A special value to represent failure, when `setException` is called successfully.
private static class	AbstractFuture.Listener Listeners also form a stack through the `listeners` field.
private static class	AbstractFuture.SafeAtomicHelper `AtomicHelper` based on `AtomicReferenceFieldUpdater`.
private static class	AbstractFuture.SetFuture<V extends @Nullable Object> A special value that encodes the 'setFuture' state.
private static class	AbstractFuture.SynchronizedHelper `AtomicHelper` based on `synchronized` and volatile writes.
pack-priv static interface	AbstractFuture.Trusted<V extends @Nullable Object> Tag interface marking trusted subclasses.
pack-priv abstract static class	AbstractFuture.TrustedFuture<V extends @Nullable Object> A less abstract subclass of AbstractFuture.
private static class	AbstractFuture.UnsafeAtomicHelper `AtomicHelper` based on `sun.misc.Unsafe`.
private static class	AbstractFuture.Waiter Waiter links form a Treiber stack, in the `waiters` field.

Field Summary

Modifier and Type	Field and Description
private static final AbstractFuture.AtomicHelper	ATOMIC_HELPER
pack-priv static final boolean	GENERATE_CANCELLATION_CAUSES
private volatile AbstractFuture.Listener	listeners All listeners.
private static final Logger	log
private static final Object	NULL A special value to represent `null`.
private static final long	SPIN_THRESHOLD_NANOS
private volatile Object	value This field encodes the current state of the future.
private volatile AbstractFuture.Waiter	waiters All waiting threads.

Constructor Summary

Access	Constructor and Description
protected	AbstractFuture() Constructor for use by subclasses.

Method Summary

Modifier and Type	Method and Description
private void	addDoneString(StringBuilder builder)
public void	addListener(Runnable the listener to run when the computation is complete listener, Executor the executor to run the listener in executor) Implements com.google.common.util.concurrent.ListenableFuture.addListener. Registers a listener to be run on the given executor.
private void	addPendingString(StringBuilder builder)
protected void	afterDone() Callback method that is called exactly once after the future is completed.
private void	appendResultObject(StringBuilder builder, Object o) Any object can be the result of a Future, and not every object has a reasonable toString() implementation.
private void	appendUserObject(StringBuilder builder, Object o) Helper for printing user supplied objects into our toString method.
public boolean	cancel(boolean `true` if the thread executing this task should be interrupted (if the thread is known to the implementation); otherwise, in-progress tasks are allowed to complete mayInterruptIfRunning) Implements java.util.concurrent.Future.cancel. Attempts to cancel execution of this task.
private static CancellationException	cancellationExceptionWithCause(String message, Throwable cause)
private AbstractFuture.Listener	clearListeners(AbstractFuture.Listener onto) Clears the `listeners` list and prepends its contents to `onto`, least recently added first.
private static void	complete(AbstractFuture<?> param, boolean callInterruptTask) Unblocks all threads and runs all listeners.
private static void	executeListener(Runnable runnable, Executor executor) Submits the given runnable to the given `Executor` catching and logging all runtime exceptions thrown by the executor.
public V	get(long the maximum time to wait timeout, TimeUnit the time unit of the timeout argument unit) Implements java.util.concurrent.Future.get. Waits if necessary for at most the given time for the computation to complete, and then retrieves its result, if available.
public V	get() Implements java.util.concurrent.Future.get. Waits if necessary for the computation to complete, and then retrieves its result.
private V	getDoneValue(Object obj) Unboxes `obj`.
private static Object	getFutureValue(ListenableFuture<?> future) Returns a value that satisfies the contract of the `value` field based on the state of given future.
private static <V extends @Nullable Object> V	getUninterruptibly(Future<V> future) An inlined private copy of `Uninterruptibles#getUninterruptibly` used to break an internal dependency on other /util/concurrent classes.
protected void	interruptTask() Subclasses can override this method to implement interruption of the future's computation.
public boolean	isCancelled() Implements java.util.concurrent.Future.isCancelled. Returns `true` if this task was cancelled before it completed normally.
public boolean	isDone() Implements java.util.concurrent.Future.isDone. Returns `true` if this task completed.
pack-priv final void	maybePropagateCancellationTo(Future<?> related) If this future has been cancelled (and possibly interrupted), cancels (and possibly interrupts) the given future (if available).
protected String	Returns: null if an explanation cannot be provided (e.g. because the future is done). pendingToString() Provide a human-readable explanation of why this future has not yet completed.
private void	releaseWaiters() Releases all threads in the `waiters` list, and clears the list.
private void	removeWaiter(AbstractFuture.Waiter node) Marks the given node as 'deleted' (null waiter) and then scans the list to unlink all deleted nodes.
protected boolean	Returns: true if the attempt was accepted, completing the `Future` set(V the value to be used as the result value) Sets the result of this `Future` unless this `Future` has already been cancelled or set (including set asynchronously).
protected boolean	Returns: true if the attempt was accepted, completing the `Future` setException(Throwable the exception to be used as the failed result throwable) Sets the failed result of this `Future` unless this `Future` has already been cancelled or set (including set asynchronously).
protected boolean	Returns: true if the attempt was accepted, indicating that the `Future` was not previously cancelled or set. setFuture(ListenableFuture<? extends V> the future to delegate to 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).
public String	toString() Overrides java.lang.Object.toString. Returns a string representation of the object.
protected final Throwable	tryInternalFastPathGetFailure() Implements abstract com.google.common.util.concurrent.internal.InternalFutureFailureAccess.tryInternalFastPathGetFailure. Usually returns `null` but, if this `Future` has failed, may optionally return the cause of the failure.
protected final boolean	wasInterrupted() Returns true if this future was cancelled with `mayInterruptIfRunning` set to `true`.

public abstract Class AbstractFuture<V extends @Nullable Object>

Nested and Inner Type Summary

Field Summary

Constructor Summary

Method Summary