reactor.core.scheduler

Class Schedulers

java.lang.Object

reactor.core.scheduler.Schedulers

public abstract class Schedulers
extends Object

Schedulers provide various Scheduler generator useable by publishOn or subscribeOn :

• fromExecutorService(ExecutorService)}.
• newParallel(java.lang.String) : Optimized for fast Runnable executions
• single() : Optimized for low-latency Runnable executions
• immediate().

Author:

Stephane Maldini

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static interface	Schedulers.Factory Public factory hook to override Schedulers behavior globally

Field Summary

Fields

Modifier and Type	Field and Description
static int	DEFAULT_POOL_SIZE Default number of processors available to the runtime on init (min 4)

Constructor Summary

Constructors

Constructor and Description
Schedulers()

Method Summary

Modifier and Type	Method and Description
static ExecutorService	decorateExecutorService(String schedulerType, Supplier<? extends ExecutorService> actual)
static ScheduledExecutorService	decorateScheduledExecutorService(String schedulerType, Supplier<? extends ScheduledExecutorService> actual)
static Scheduler	elastic() Scheduler that dynamically creates ExecutorService-based Workers and caches the thread pools, reusing them once the Workers have been shut down.
static Scheduler	fromExecutor(Executor executor) Create a Scheduler which uses a backing Executor to schedule Runnables for async operators.
static Scheduler	fromExecutor(Executor executor, boolean trampoline) Create a Scheduler which uses a backing Executor to schedule Runnables for async operators.
static Scheduler	fromExecutorService(ExecutorService executorService) Create a Scheduler which uses a backing ExecutorService to schedule Runnables for async operators.
static Scheduler	fromExecutorService(ExecutorService executorService, boolean interruptOnCancel) Create a Scheduler which uses a backing ExecutorService to schedule Runnables for async operators.
static Scheduler	immediate() Executes tasks on the caller's thread immediately.
static Scheduler	newElastic(int ttlSeconds, ThreadFactory threadFactory) Scheduler that dynamically creates ExecutorService-based Workers and caches the thread pools, reusing them once the Workers have been shut down.
static Scheduler	newElastic(String name) Scheduler that dynamically creates ExecutorService-based Workers and caches the thread pools, reusing them once the Workers have been shut down.
static Scheduler	newElastic(String name, int ttlSeconds) Scheduler that dynamically creates ExecutorService-based Workers and caches the thread pools, reusing them once the Workers have been shut down.
static Scheduler	newElastic(String name, int ttlSeconds, boolean daemon) Scheduler that dynamically creates ExecutorService-based Workers and caches the thread pools, reusing them once the Workers have been shut down.
static Scheduler	newParallel(int parallelism, ThreadFactory threadFactory) Scheduler that hosts a fixed pool of single-threaded ExecutorService-based workers and is suited for parallel work.
static Scheduler	newParallel(String name) Scheduler that hosts a fixed pool of single-threaded ExecutorService-based workers and is suited for parallel work.
static Scheduler	newParallel(String name, int parallelism) Scheduler that hosts a fixed pool of single-threaded ExecutorService-based workers and is suited for parallel work.
static Scheduler	newParallel(String name, int parallelism, boolean daemon) Scheduler that hosts a fixed pool of single-threaded ExecutorService-based workers and is suited for parallel work.
static Scheduler	newSingle(String name) Scheduler that hosts a single-threaded ExecutorService-based worker and is suited for parallel work.
static Scheduler	newSingle(String name, boolean daemon) Scheduler that hosts a single-threaded ExecutorService-based worker and is suited for parallel work.
static Scheduler	newSingle(ThreadFactory threadFactory) Scheduler that hosts a single-threaded ExecutorService-based worker and is suited for parallel work.
static TimedScheduler	newTimer(String name) Deprecated. in 3.0.6 and from 3.1 onwards, all Scheduler support time. newSingle(String) is a direct equivalent if required.
static TimedScheduler	newTimer(String name, boolean daemon) Deprecated. in 3.0.6 and from 3.1 onwards, all Scheduler support time. newSingle(String, boolean) is a direct equivalent if required.
static TimedScheduler	newTimer(ThreadFactory threadFactory) Deprecated. in 3.0.6 and from 3.1 onwards, all Scheduler support time. newSingle(ThreadFactory) is a direct equivalent if required.
static void	onHandleError(BiConsumer<Thread,? super Throwable> c) Define a hook that is executed when a Scheduler has handled an error.
static Scheduler	parallel() Scheduler that hosts a fixed pool of single-threaded ExecutorService-based workers and is suited for parallel work.
static void	resetFactory() Re-apply default factory to Schedulers
static void	resetOnHandleError() Reset the onHandleError(BiConsumer) hook to the default no-op behavior.
static void	setFactory(Schedulers.Factory factoryInstance) Override Schedulers finite signatures of newParallel(java.lang.String), newSingle(java.lang.String), newTimer(java.lang.String) and newElastic(java.lang.String) factory using the matching method signature in the target class.
static void	shutdownNow() Clear any cached Scheduler and call dispose on them.
static Scheduler	single() Scheduler that hosts a single-threaded ExecutorService-based worker and is suited for parallel work.
static Scheduler	single(Scheduler original) Wraps a single worker of some other Scheduler and provides Scheduler.Worker services on top of it.
static TimedScheduler	timer() Deprecated. in 3.0.6 and from 3.1 onwards, all Scheduler support time. single() is a direct equivalent if required.

Methods inherited from class java.lang.Object

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

Field Detail

DEFAULT_POOL_SIZE

public static final int DEFAULT_POOL_SIZE

Default number of processors available to the runtime on init (min 4)

See Also:

Runtime.availableProcessors()

Constructor Detail

Schedulers

public Schedulers()

Method Detail

fromExecutor

public static Scheduler fromExecutor(Executor executor)

Create a Scheduler which uses a backing Executor to schedule Runnables for async operators.

Parameters:

executor - an Executor

Returns:

a new Scheduler

fromExecutor

public static Scheduler fromExecutor(Executor executor,
                                     boolean trampoline)

Create a Scheduler which uses a backing Executor to schedule Runnables for async operators.

Parameters:

executor - an Executor

trampoline - set to false if this Scheduler is used by "operators" that already conflate Runnable executions (publishOn, subscribeOn...)

Returns:

a new Scheduler

fromExecutorService

public static Scheduler fromExecutorService(ExecutorService executorService)

Create a Scheduler which uses a backing ExecutorService to schedule Runnables for async operators.

Parameters:

executorService - an ExecutorService

Returns:

a new Scheduler

fromExecutorService

public static Scheduler fromExecutorService(ExecutorService executorService,
                                            boolean interruptOnCancel)

Create a Scheduler which uses a backing ExecutorService to schedule Runnables for async operators.

Parameters:

executorService - an ExecutorService

interruptOnCancel - delegate to future.cancel(true) on Disposable.dispose()

Returns:

a new Scheduler

elastic

public static Scheduler elastic()

Scheduler that dynamically creates ExecutorService-based Workers and caches the thread pools, reusing them once the Workers have been shut down.

The maximum number of created thread pools is unbounded.

The default time-to-live for unused thread pools is 60 seconds, use the appropriate factory to set a different value.

This scheduler is not restartable.

Returns:

a new Scheduler that hosts a fixed pool of single-threaded ExecutorService-based workers and is suited for parallel work

immediate

public static Scheduler immediate()

Executes tasks on the caller's thread immediately.

Returns:

a reusable Scheduler

newElastic

public static Scheduler newElastic(String name)

Scheduler that dynamically creates ExecutorService-based Workers and caches the thread pools, reusing them once the Workers have been shut down.

The maximum number of created thread pools is unbounded.

The default time-to-live for unused thread pools is 60 seconds, use the appropriate factory to set a different value.

This scheduler is not restartable.

Parameters:

name - Thread prefix

Returns:

a new Scheduler that hosts a fixed pool of single-threaded ExecutorService-based workers and is suited for parallel work

newElastic

public static Scheduler newElastic(String name,
                                   int ttlSeconds)

Scheduler that dynamically creates ExecutorService-based Workers and caches the thread pools, reusing them once the Workers have been shut down.

The maximum number of created thread pools is unbounded.

This scheduler is not restartable.

Parameters:

name - Thread prefix

ttlSeconds - Time-to-live for an idle Scheduler.Worker

Returns:

a new Scheduler that hosts a fixed pool of single-threaded ExecutorService-based workers and is suited for parallel work

newElastic

public static Scheduler newElastic(String name,
                                   int ttlSeconds,
                                   boolean daemon)

Scheduler that dynamically creates ExecutorService-based Workers and caches the thread pools, reusing them once the Workers have been shut down.

The maximum number of created thread pools is unbounded.

This scheduler is not restartable.

Parameters:

name - Thread prefix

ttlSeconds - Time-to-live for an idle Scheduler.Worker

daemon - false if the Scheduler requires an explicit Scheduler.dispose() to exit the VM.

Returns:

a new Scheduler that hosts a fixed pool of single-threaded ExecutorService-based workers and is suited for parallel work

newElastic

public static Scheduler newElastic(int ttlSeconds,
                                   ThreadFactory threadFactory)

Scheduler that dynamically creates ExecutorService-based Workers and caches the thread pools, reusing them once the Workers have been shut down.

The maximum number of created thread pools is unbounded.

This scheduler is not restartable.

Parameters:

ttlSeconds - Time-to-live for an idle Scheduler.Worker

threadFactory - a ThreadFactory to use each thread initialization

Returns:

a new Scheduler that dynamically creates ExecutorService-based Workers and caches the thread pools, reusing them once the Workers have been shut down.

newParallel

public static Scheduler newParallel(String name)

Scheduler that hosts a fixed pool of single-threaded ExecutorService-based workers and is suited for parallel work.

Parameters:

name - Thread prefix

Returns:

a new Scheduler that hosts a fixed pool of single-threaded ExecutorService-based workers and is suited for parallel work

newParallel

public static Scheduler newParallel(String name,
                                    int parallelism)

Scheduler that hosts a fixed pool of single-threaded ExecutorService-based workers and is suited for parallel work.

Parameters:

name - Thread prefix

parallelism - Number of pooled workers.

Returns:

a new Scheduler that hosts a fixed pool of single-threaded ExecutorService-based workers and is suited for parallel work

newParallel

public static Scheduler newParallel(String name,
                                    int parallelism,
                                    boolean daemon)

Scheduler that hosts a fixed pool of single-threaded ExecutorService-based workers and is suited for parallel work.

Parameters:

name - Thread prefix

parallelism - Number of pooled workers.

daemon - false if the Scheduler requires an explicit Scheduler.dispose() to exit the VM.

Returns:

a new Scheduler that hosts a fixed pool of single-threaded ExecutorService-based workers and is suited for parallel work

newParallel

public static Scheduler newParallel(int parallelism,
                                    ThreadFactory threadFactory)

Scheduler that hosts a fixed pool of single-threaded ExecutorService-based workers and is suited for parallel work.

Parameters:

parallelism - Number of pooled workers.

threadFactory - a ThreadFactory to use for the fixed initialized number of Thread

Returns:

a new Scheduler that hosts a fixed pool of single-threaded ExecutorService-based workers and is suited for parallel work

newSingle

public static Scheduler newSingle(String name)

Scheduler that hosts a single-threaded ExecutorService-based worker and is suited for parallel work.

Parameters:

name - Component and thread name prefix

Returns:

a new Scheduler that hosts a single-threaded ExecutorService-based worker

newSingle

public static Scheduler newSingle(String name,
                                  boolean daemon)

Scheduler that hosts a single-threaded ExecutorService-based worker and is suited for parallel work.

Parameters:

name - Component and thread name prefix

daemon - false if the Scheduler requires an explicit Scheduler.dispose() to exit the VM.

Returns:

a new Scheduler that hosts a single-threaded ExecutorService-based worker

newSingle

public static Scheduler newSingle(ThreadFactory threadFactory)

Scheduler that hosts a single-threaded ExecutorService-based worker and is suited for parallel work.

Parameters:

threadFactory - a ThreadFactory to use for the unique thread of the Scheduler

Returns:

a new Scheduler that hosts a single-threaded ExecutorService-based worker

newTimer

@Deprecated
public static TimedScheduler newTimer(String name)

Deprecated. in 3.0.6 and from 3.1 onwards, all Scheduler support time. newSingle(String) is a direct equivalent if required.

Create a new Scheduler backed by a single threaded ScheduledExecutorService, making it guaranteed to be capable of scheduling tasks in the future.

Parameters:

name - timer thread prefix

Returns:

a new time-capable Scheduler

newTimer

@Deprecated
public static TimedScheduler newTimer(String name,
                                                  boolean daemon)

Deprecated. in 3.0.6 and from 3.1 onwards, all Scheduler support time. newSingle(String, boolean) is a direct equivalent if required.

Create a new Scheduler backed by a single threaded ScheduledExecutorService, making it guaranteed to be capable of scheduling tasks in the future.

Parameters:

name - Component and thread name prefix

daemon - false if the Scheduler requires an explicit Scheduler.dispose() to exit the VM.

Returns:

a new time-capable Scheduler

newTimer

@Deprecated
public static TimedScheduler newTimer(ThreadFactory threadFactory)

Deprecated. in 3.0.6 and from 3.1 onwards, all Scheduler support time. newSingle(ThreadFactory) is a direct equivalent if required.

Create a new Scheduler backed by a single threaded ScheduledExecutorService, making it guaranteed to be capable of scheduling tasks in the future.

Parameters:

threadFactory - a ThreadFactory to use for the unique thread of the Scheduler

Returns:

a new time-capable Scheduler

onHandleError

public static void onHandleError(BiConsumer<Thread,? super Throwable> c)

Define a hook that is executed when a Scheduler has handled an error. Note that it is executed after the error has been passed to the thread uncaughtErrorHandler, which is not the case when a fatal error occurs (see Exceptions.throwIfJvmFatal(Throwable)).

Parameters:

c - the new hook to set, or null to ignore (default).

parallel

public static Scheduler parallel()

Scheduler that hosts a fixed pool of single-threaded ExecutorService-based workers and is suited for parallel work.

Returns:

a reusable Scheduler that hosts a fixed pool of single-threaded ExecutorService-based workers

resetFactory

public static void resetFactory()

Re-apply default factory to Schedulers

resetOnHandleError

public static void resetOnHandleError()

Reset the onHandleError(BiConsumer) hook to the default no-op behavior.

setFactory

public static void setFactory(Schedulers.Factory factoryInstance)

Override Schedulers finite signatures of newParallel(java.lang.String), newSingle(java.lang.String), newTimer(java.lang.String) and newElastic(java.lang.String) factory using the matching method signature in the target class. A finite signature corresponds to those including a ThreadFactory argument and should be instance methods.

This method should be called safely and with caution, typically on app startup.

Note that cached schedulers (like single()) are also shut down and will be re-created from the new factory upon next use.

Parameters:

factoryInstance - an arbitrary Schedulers.Factory instance.

shutdownNow

public static void shutdownNow()

Clear any cached Scheduler and call dispose on them.

single

public static Scheduler single()

Scheduler that hosts a single-threaded ExecutorService-based worker and is suited for parallel work. Will cache the returned schedulers for subsequent calls until dispose.

Returns:

a cached Scheduler that hosts a single-threaded ExecutorService-based worker

single

public static Scheduler single(Scheduler original)

Wraps a single worker of some other Scheduler and provides Scheduler.Worker services on top of it.

Use the Scheduler.dispose() to release the wrapped worker.

Parameters:

original - a Scheduler to call upon to get the single Scheduler.Worker

Returns:

a wrapping Scheduler consistently returning a same worker from a source Scheduler

timer

@Deprecated
public static TimedScheduler timer()

Deprecated. in 3.0.6 and from 3.1 onwards, all Scheduler support time. single() is a direct equivalent if required.

Create or reuse a time-capable Scheduler.

Returns:

a cached time-capable Scheduler

decorateExecutorService

public static ExecutorService decorateExecutorService(String schedulerType,
                                                      Supplier<? extends ExecutorService> actual)

decorateScheduledExecutorService

public static ScheduledExecutorService decorateScheduledExecutorService(String schedulerType,
                                                                        Supplier<? extends ScheduledExecutorService> actual)