Package org.apache.cassandra.utils.concurrent

Class AsyncFuture<V>

java.lang.Object

org.apache.cassandra.utils.concurrent.AbstractFuture<V>

org.apache.cassandra.utils.concurrent.AsyncFuture<V>

All Implemented Interfaces:

com.google.common.util.concurrent.ListenableFuture<V>, io.netty.util.concurrent.Future<V>, Future<V>, Awaitable, Future<V>

Direct Known Subclasses:

AsyncPromise, BlockingPartitionRepair, FutureCombiner, FutureTask, ImmediateFuture, PaxosCleanup, PaxosCleanupComplete, PaxosCleanupLocalCoordinator, PaxosCleanupSession, PaxosFinishPrepareCleanup, PaxosStartPrepareCleanup, RepairJob, RepairSession, Scheduler.Task, SnapshotTask, StreamResultFuture, SyncTask, ValidationTask

public class AsyncFuture<V>
extends AbstractFuture<V>

Our default Future implementation, with all state being managed without locks (except those used by the JVM). Some implementation comments versus Netty's default promise: - We permit efficient initial state declaration, avoiding unnecessary CAS or lock acquisitions when mutating a Promise we are ourselves constructing (and can easily add more; only those we use have been added) - We guarantee the order of invocation of listeners (and callbacks etc, and with respect to each other) - We save some space when registering listeners, especially if there is only one listener, as we perform no extra allocations in this case. - We implement our invocation list as a concurrent stack, that is cleared on notification - We handle special values slightly differently. - We do not use a special value for null, instead using a special value to indicate the result has not been set. This means that once isSuccess() holds, the result must be a correctly typed object (modulo generics pitfalls). - All special values are also instances of FailureHolder, which simplifies a number of the logical conditions.

Nested Class Summary

Nested classes/interfaces inherited from interface org.apache.cassandra.utils.concurrent.Awaitable

Awaitable.AbstractAwaitable, Awaitable.AsyncAwaitable, Awaitable.Defaults, Awaitable.SyncAwaitable

Field Summary

Fields inherited from class org.apache.cassandra.utils.concurrent.AbstractFuture

CANCELLED, UNCANCELLABLE, UNSET

Constructor Summary

Constructors

Modifier	Constructor	Description
	AsyncFuture()
protected	AsyncFuture(io.netty.util.concurrent.GenericFutureListener<? extends io.netty.util.concurrent.Future<? super V>> listener)
protected	AsyncFuture(Throwable immediateFailure)
protected	AsyncFuture(org.apache.cassandra.utils.concurrent.AbstractFuture.FailureHolder initialState)
protected	AsyncFuture(org.apache.cassandra.utils.concurrent.AbstractFuture.FailureHolder initialState, io.netty.util.concurrent.GenericFutureListener<? extends io.netty.util.concurrent.Future<? super V>> listener)
protected	AsyncFuture(V immediateSuccess)

Method Summary

Modifier and Type	Method	Description
AsyncFuture<V>	await()	Wait for this future to complete Awaitable.await()
boolean	awaitUntil(long nanoTimeDeadline)	Await until the deadline (in nanoTime), throwing any interrupt.
<T> Future<T>	flatMap(Function<? super V,? extends Future<T>> flatMapper, Executor executor)	Support Futures.transformAsync(ListenableFuture, AsyncFunction, Executor) natively See AbstractFuture.addListener(GenericFutureListener) for ordering semantics.
<T> Future<T>	map(Function<? super V,? extends T> mapper, Executor executor)	Support Futures.transform(com.google.common.util.concurrent.ListenableFuture<I>, com.google.common.base.Function<? super I, ? extends O>, java.util.concurrent.Executor) natively See AbstractFuture.addListener(GenericFutureListener) for ordering semantics.

Methods inherited from class org.apache.cassandra.utils.concurrent.AbstractFuture

addCallback, addCallback, addCallback, addCallback, addCallback, addCallback, addListener, addListener, addListener, addListeners, await, awaitThrowUncheckedOnInterrupt, awaitThrowUncheckedOnInterrupt, awaitUninterruptibly, awaitUninterruptibly, awaitUntilThrowUncheckedOnInterrupt, awaitUntilUninterruptibly, cancel, cause, description, flatMap, get, get, getNow, getWhenDone, isCancellable, isCancelled, isDone, isSuccess, isUncancellable, map, map, notifyExecutor, removeListener, removeListeners, setUncancellable, setUncancellableExclusive, toString, tryFailure, trySuccess

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Methods inherited from interface org.apache.cassandra.utils.concurrent.Future

await, awaitUninterruptibly, flatMap, rethrowIfFailed, sync, syncThrowUncheckedOnInterrupt, syncUninterruptibly

Constructor Details

AsyncFuture

public AsyncFuture()

AsyncFuture

protected AsyncFuture(V immediateSuccess)

AsyncFuture

protected AsyncFuture(Throwable immediateFailure)

AsyncFuture

protected AsyncFuture(org.apache.cassandra.utils.concurrent.AbstractFuture.FailureHolder initialState)

AsyncFuture

protected AsyncFuture(io.netty.util.concurrent.GenericFutureListener<? extends io.netty.util.concurrent.Future<? super V>> listener)

AsyncFuture

protected AsyncFuture(org.apache.cassandra.utils.concurrent.AbstractFuture.FailureHolder initialState,
 io.netty.util.concurrent.GenericFutureListener<? extends io.netty.util.concurrent.Future<? super V>> listener)

Method Details

map

public <T> Future<T> map(Function<? super V,? extends T> mapper,
 Executor executor)

Support Futures.transform(com.google.common.util.concurrent.ListenableFuture<I>, com.google.common.base.Function<? super I, ? extends O>, java.util.concurrent.Executor) natively See AbstractFuture.addListener(GenericFutureListener) for ordering semantics.

flatMap

public <T> Future<T> flatMap(Function<? super V,? extends Future<T>> flatMapper,
 @Nullable
 Executor executor)

Support Futures.transformAsync(ListenableFuture, AsyncFunction, Executor) natively See AbstractFuture.addListener(GenericFutureListener) for ordering semantics.

await

public AsyncFuture<V> await()
                     throws InterruptedException

Wait for this future to complete Awaitable.await()

Throws:

InterruptedException - if interrupted

awaitUntil

public boolean awaitUntil(long nanoTimeDeadline)
                   throws InterruptedException

Description copied from interface: Awaitable

Await until the deadline (in nanoTime), throwing any interrupt. No spurious wakeups.

Returns:

true if we were signalled, false if the deadline elapsed

Throws:

InterruptedException - if interrupted