Package io.vavr.concurrent

Class FutureImpl<T>

java.lang.Object

io.vavr.concurrent.FutureImpl<T>

Type Parameters:

T - Result of the computation.

All Implemented Interfaces:

Future<T>, Value<T>, java.lang.Iterable<T>

final class FutureImpl<T>
extends java.lang.Object
implements Future<T>

INTERNAL API - This class is subject to change.

Field Summary

Fields

Modifier and Type	Field	Description
private Queue<java.util.function.Consumer<Try<T>>>	actions	The queue of actions is filled when calling onComplete() before the Future is completed or cancelled.
private boolean	cancelled	Indicates if this Future is cancelled GuardedBy("lock")
private java.util.concurrent.Executor	executor	Used to start new threads.
private java.util.concurrent.locks.Lock	lock	Used to synchronize state changes.
private java.lang.Thread	thread	The Thread which runs the computation.
private Option<Try<T>>	value	Once the Future is completed, the value is defined.
private Queue<java.lang.Thread>	waiters	The queue of waiters is filled when calling await() before the Future is completed or cancelled.

Fields inherited from interface io.vavr.concurrent.Future

DEFAULT_EXECUTOR

Constructor Summary

Constructors

Modifier	Constructor	Description
private	FutureImpl(java.util.concurrent.Executor executor, Option<Try<T>> value, Queue<java.util.function.Consumer<Try<T>>> actions, Queue<java.lang.Thread> waiters, Task<? extends T> task)

Method Summary

Modifier and Type	Method	Description
private void	_await(long start, long timeout, java.util.concurrent.TimeUnit unit)	Blocks the current thread.
(package private) static <T> FutureImpl<T>	async(java.util.concurrent.Executor executor, Task<? extends T> task)	Creates a FutureImpl that is eventually completed.
Future<T>	await()	Blocks the current thread until this Future is completed, or returns immediately if it is already completed.
Future<T>	await(long timeout, @NonNull java.util.concurrent.TimeUnit unit)	Blocks the current thread until this Future is completed, or returns immediately if it is already completed.
boolean	cancel(boolean mayInterruptIfRunning)	Cancels this Future.
java.util.concurrent.Executor	executor()	Returns the Executor that executes asynchronous handlers for this Future.
java.util.concurrent.ExecutorService	executorService()	Deprecated.
Option<Try<T>>	getValue()	Returns the value of this Future.
private void	handleUncaughtException(java.lang.Throwable x)
boolean	isCancelled()	Checks whether this Future was cancelled, i.e., its computation was interrupted before completion.
boolean	isCompleted()	Checks whether this Future is completed, i.e., whether it has finished with a value, failed, or was cancelled.
(package private) static <T> FutureImpl<T>	of(java.util.concurrent.Executor executor)	Creates a FutureImpl that needs to be automatically completed by calling tryComplete(Try).
(package private) static <T> FutureImpl<T>	of(java.util.concurrent.Executor executor, Try<? extends T> value)	Creates a FutureImpl that is immediately completed with the given value.
Future<T>	onComplete(@NonNull java.util.function.Consumer<? super Try<T>> action)	Performs the given action once this Future is complete.
private void	perform(java.util.function.Consumer<? super Try<T>> action)
(package private) static <T> FutureImpl<T>	sync(java.util.concurrent.Executor executor, Task<? extends T> task)	Creates a FutureImpl that is eventually completed.
java.lang.String	toString()	Clarifies that values have a proper toString() method implemented.
(package private) boolean	tryComplete(Try<? extends T> value)	INTERNAL METHOD, SHOULD BE USED BY THE CONSTRUCTOR, ONLY.
private void	unlock(java.lang.Thread waiter)
private void	updateThread()

Methods inherited from class java.lang.Object

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

Methods inherited from interface io.vavr.concurrent.Future

andThen, cancel, collect, failed, fallbackTo, filter, filterTry, flatMap, flatMapTry, forEach, get, getCause, isAsync, isEmpty, isFailure, isLazy, isSingleValued, isSuccess, iterator, map, mapTo, mapToVoid, mapTry, onFailure, onSuccess, orElse, orElse, peek, recover, recoverWith, stringPrefix, toCompletableFuture, transform, transformValue, zip, zipWith

Methods inherited from interface io.vavr.Value

collect, collect, contains, corresponds, eq, equals, exists, forAll, getOrElse, getOrElse, getOrElseThrow, getOrElseTry, getOrNull, hashCode, out, out, spliterator, stderr, stdout, toArray, toCharSeq, toEither, toEither, toInvalid, toInvalid, toJavaArray, toJavaArray, toJavaArray, toJavaCollection, toJavaList, toJavaList, toJavaMap, toJavaMap, toJavaMap, toJavaOptional, toJavaParallelStream, toJavaSet, toJavaSet, toJavaStream, toLeft, toLeft, toLinkedMap, toLinkedMap, toLinkedSet, toList, toMap, toMap, toOption, toPriorityQueue, toPriorityQueue, toQueue, toRight, toRight, toSet, toSortedMap, toSortedMap, toSortedMap, toSortedMap, toSortedSet, toSortedSet, toStream, toTree, toTree, toTry, toTry, toValid, toValid, toValidation, toValidation, toVector

Field Detail

executor

private final java.util.concurrent.Executor executor

Used to start new threads.

lock

private final java.util.concurrent.locks.Lock lock

Used to synchronize state changes.

cancelled

private volatile boolean cancelled

Indicates if this Future is cancelled GuardedBy("lock")

value

private volatile Option<Try<T>> value

Once the Future is completed, the value is defined. GuardedBy("lock")

actions

private Queue<java.util.function.Consumer<Try<T>>> actions

The queue of actions is filled when calling onComplete() before the Future is completed or cancelled. Otherwise actions = null. GuardedBy("lock")

waiters

private Queue<java.lang.Thread> waiters

The queue of waiters is filled when calling await() before the Future is completed or cancelled. Otherwise waiters = null. GuardedBy("lock")

thread

private java.lang.Thread thread

The Thread which runs the computation. GuardedBy("lock")

Constructor Detail

FutureImpl

private FutureImpl(java.util.concurrent.Executor executor,
                   Option<Try<T>> value,
                   Queue<java.util.function.Consumer<Try<T>>> actions,
                   Queue<java.lang.Thread> waiters,
                   Task<? extends T> task)

Method Detail

of

static <T> FutureImpl<T> of(java.util.concurrent.Executor executor)

Creates a FutureImpl that needs to be automatically completed by calling tryComplete(Try).

Type Parameters:

T - value type of the Future

Parameters:

executor - An Executor to run and control the computation and to perform the actions.

Returns:

a new FutureImpl instance

of

static <T> FutureImpl<T> of(java.util.concurrent.Executor executor,
                            Try<? extends T> value)

Creates a FutureImpl that is immediately completed with the given value. No task will be started.

Type Parameters:

T - value type of the Future

Parameters:

executor - An Executor to run and control the computation and to perform the actions.

value - the result of this Future

Returns:

a new FutureImpl instance

sync

static <T> FutureImpl<T> sync(java.util.concurrent.Executor executor,
                              Task<? extends T> task)

Creates a FutureImpl that is eventually completed. The given computation is synchronously executed, no thread is started.

Type Parameters:

T - value type of the Future

Parameters:

executor - An Executor to run and control the computation and to perform the actions.

task - A non-blocking computation

Returns:

a new FutureImpl instance

async

static <T> FutureImpl<T> async(java.util.concurrent.Executor executor,
                               Task<? extends T> task)

Creates a FutureImpl that is eventually completed. The given computation is asynchronously executed, a new thread is started.

Type Parameters:

T - value type of the Future

Parameters:

executor - An Executor to run and control the computation and to perform the actions.

task - A (possibly blocking) computation

Returns:

a new FutureImpl instance

await

public Future<T> await()

Description copied from interface: Future

Blocks the current thread until this Future is completed, or returns immediately if it is already completed.

If the current thread is interrupted while waiting, a failed Future is returned containing the corresponding InterruptedException.

Specified by:

await in interface Future<T>

Returns:

this Future instance

await

public Future<T> await(long timeout,
                       @NonNull java.util.concurrent.TimeUnit unit)

Description copied from interface: Future

Blocks the current thread until this Future is completed, or returns immediately if it is already completed.

If the current thread is interrupted while waiting, a failed Future is returned containing the corresponding InterruptedException.

If the specified timeout is reached before completion, a failed Future is returned containing a TimeoutException.

Specified by:

await in interface Future<T>

Parameters:

timeout - the maximum time to wait

unit - the time unit of the timeout argument

Returns:

this Future instance

_await

private void _await(long start,
                    long timeout,
                    java.util.concurrent.TimeUnit unit)

Blocks the current thread.

If timeout = 0 then LockSupport.park() is called (start, timeout and unit are not used), otherwise LockSupport.park(timeout, unit} is called.

If a timeout > -1 is specified and the deadline is not met, this Future fails with a TimeoutException.

If this Thread was interrupted, this Future fails with a InterruptedException.

Parameters:

start - the start time in nanos, based on System.nanoTime()

timeout - a timeout in the given unit of time

unit - a time unit

cancel

public boolean cancel(boolean mayInterruptIfRunning)

Description copied from interface: Future

Cancels this Future. A pending future may be interrupted depending on the underlying Executor.

If the future is successfully cancelled, its result becomes a Failure(CancellationException).

Specified by:

cancel in interface Future<T>

Parameters:

mayInterruptIfRunning - true if a running thread should be interrupted; false allows it to complete

Returns:

false if this Future is already completed or could not be cancelled, true otherwise

See Also:

Future.isCancelled(), Future.cancel(boolean)

updateThread

private void updateThread()

executor

public java.util.concurrent.Executor executor()

Description copied from interface: Future

Returns the Executor that executes asynchronous handlers for this Future.

Specified by:

executor in interface Future<T>

Returns:

the underlying Executor

executorService

@Deprecated
public java.util.concurrent.ExecutorService executorService()

Deprecated.

Description copied from interface: Future

This method is deprecated.

THE DEFAULT IMPLEMENTATION (obtained by one of the Future factory methods) MIGHT THROW AN UnsupportedOperationException AT RUNTIME.

Specified by:

executorService in interface Future<T>

Returns:

(never)

getValue

public Option<Try<T>> getValue()

Description copied from interface: Future

Returns the value of this Future.

Specified by:

getValue in interface Future<T>

Returns:

None if the Future is not yet completed or was cancelled; otherwise, Some(Try) containing the result or failure

isCancelled

public boolean isCancelled()

Description copied from interface: Future

Checks whether this Future was cancelled, i.e., its computation was interrupted before completion.

Specified by:

isCancelled in interface Future<T>

Returns:

true if the computation was cancelled, false otherwise

isCompleted

public boolean isCompleted()

Description copied from interface: Future

Checks whether this Future is completed, i.e., whether it has finished with a value, failed, or was cancelled.

Specified by:

isCompleted in interface Future<T>

Returns:

true if the computation has completed in any state, false otherwise

onComplete

public Future<T> onComplete(@NonNull java.util.function.Consumer<? super Try<T>> action)

Description copied from interface: Future

Performs the given action once this Future is complete.

Specified by:

onComplete in interface Future<T>

Parameters:

action - an action to execute when the future completes

Returns:

this Future

toString

public java.lang.String toString()

Description copied from interface: Value

Clarifies that values have a proper toString() method implemented.

See Object.toString().

Specified by:

toString in interface Value<T>

Overrides:

toString in class java.lang.Object

Returns:

A String representation of this object

tryComplete

boolean tryComplete(Try<? extends T> value)

INTERNAL METHOD, SHOULD BE USED BY THE CONSTRUCTOR, ONLY.

Completes this Future with a value and performs all actions.

This method is idempotent. I.e. it does nothing, if this Future is already completed.

Parameters:

value - A Success containing a result or a Failure containing an Exception.

Throws:

java.lang.IllegalStateException - if the Future is already completed or cancelled.

java.lang.NullPointerException - if the given value is null.

perform

private void perform(java.util.function.Consumer<? super Try<T>> action)

unlock

private void unlock(java.lang.Thread waiter)

handleUncaughtException

private void handleUncaughtException(java.lang.Throwable x)