Package org.springframework.scheduling.concurrent

Class ThreadPoolTaskScheduler

java.lang.Object

org.springframework.util.CustomizableThreadCreator

org.springframework.scheduling.concurrent.CustomizableThreadFactory

org.springframework.scheduling.concurrent.ExecutorConfigurationSupport

org.springframework.scheduling.concurrent.ThreadPoolTaskScheduler

All Implemented Interfaces:

Serializable, Executor, ThreadFactory, EventListener, Aware, BeanNameAware, DisposableBean, InitializingBean, ApplicationContextAware, ApplicationListener<ContextClosedEvent>, Lifecycle, Phased, SmartLifecycle, AsyncListenableTaskExecutor, AsyncTaskExecutor, TaskExecutor, SchedulingTaskExecutor, TaskScheduler

public class ThreadPoolTaskScheduler
extends ExecutorConfigurationSupport
implements AsyncListenableTaskExecutor, SchedulingTaskExecutor, TaskScheduler

A standard implementation of Spring's TaskScheduler interface, wrapping a native ScheduledThreadPoolExecutor and providing all applicable configuration options for it. The default number of scheduler threads is 1; a higher number can be configured through setPoolSize(int).

This is Spring's traditional scheduler variant, staying as close as possible to ScheduledExecutorService semantics. Task execution happens on the scheduler thread(s) rather than on separate execution threads. As a consequence, a ScheduledFuture handle (e.g. from schedule(Runnable, Instant)) represents the actual completion of the provided task (or series of repeated tasks).

Since:

3.0

Author:

Juergen Hoeller, Mark Fisher

See Also:

• setPoolSize(int)
• setRemoveOnCancelPolicy(boolean)
• setContinueExistingPeriodicTasksAfterShutdownPolicy(boolean)
• setExecuteExistingDelayedTasksAfterShutdownPolicy(boolean)
• ExecutorConfigurationSupport.setThreadFactory(java.util.concurrent.ThreadFactory)
• setErrorHandler(org.springframework.util.ErrorHandler)
• ThreadPoolTaskExecutor
• SimpleAsyncTaskScheduler
• Serialized Form

Field Summary

Fields inherited from class org.springframework.scheduling.concurrent.ExecutorConfigurationSupport

DEFAULT_PHASE, logger

Fields inherited from interface org.springframework.core.task.AsyncTaskExecutor

TIMEOUT_IMMEDIATE, TIMEOUT_INDEFINITE

Constructor Summary

Constructors

Constructor	Description
ThreadPoolTaskScheduler()

Method Summary

Modifier and Type	Method	Description
protected void	cancelRemainingTask(Runnable task)	Cancel the given remaining task which never commenced execution, as returned from ExecutorService.shutdownNow().
protected ScheduledExecutorService	createExecutor(int poolSize, ThreadFactory threadFactory, RejectedExecutionHandler rejectedExecutionHandler)	Create a new ScheduledExecutorService instance.
void	execute(Runnable task)	Execute the given task.
int	getActiveCount()	Return the number of currently active threads.
Clock	getClock()	Return the clock to use for scheduling purposes.
int	getPoolSize()	Return the current pool size.
ScheduledExecutorService	getScheduledExecutor()	Return the underlying ScheduledExecutorService for native access.
ScheduledThreadPoolExecutor	getScheduledThreadPoolExecutor()	Return the underlying ScheduledThreadPoolExecutor, if available.
protected ExecutorService	initializeExecutor(ThreadFactory threadFactory, RejectedExecutionHandler rejectedExecutionHandler)	Create the target ExecutorService instance.
boolean	isRemoveOnCancelPolicy()	Deprecated. as of 5.3.9, in favor of direct getScheduledThreadPoolExecutor() access
ScheduledFuture<?>	schedule(Runnable task, Instant startTime)	Schedule the given Runnable, invoking it at the specified execution time.
ScheduledFuture<?>	schedule(Runnable task, Trigger trigger)	Schedule the given Runnable, invoking it whenever the trigger indicates a next execution time.
ScheduledFuture<?>	scheduleAtFixedRate(Runnable task, Duration period)	Schedule the given Runnable, starting as soon as possible and invoking it with the given period.
ScheduledFuture<?>	scheduleAtFixedRate(Runnable task, Instant startTime, Duration period)	Schedule the given Runnable, invoking it at the specified execution time and subsequently with the given period.
ScheduledFuture<?>	scheduleWithFixedDelay(Runnable task, Duration delay)	Schedule the given Runnable, starting as soon as possible and invoking it with the given delay between the completion of one execution and the start of the next.
ScheduledFuture<?>	scheduleWithFixedDelay(Runnable task, Instant startTime, Duration delay)	Schedule the given Runnable, invoking it at the specified execution time and subsequently with the given delay between the completion of one execution and the start of the next.
void	setClock(Clock clock)	Set the clock to use for scheduling purposes.
void	setContinueExistingPeriodicTasksAfterShutdownPolicy(boolean flag)	Set whether to continue existing periodic tasks even when this executor has been shutdown.
void	setErrorHandler(ErrorHandler errorHandler)	Set a custom ErrorHandler strategy.
void	setExecuteExistingDelayedTasksAfterShutdownPolicy(boolean flag)	Set whether to execute existing delayed tasks even when this executor has been shutdown.
void	setPoolSize(int poolSize)	Set the ScheduledExecutorService's pool size.
void	setRemoveOnCancelPolicy(boolean flag)	Set the remove-on-cancel mode on ScheduledThreadPoolExecutor.
void	setTaskDecorator(TaskDecorator taskDecorator)	Specify a custom TaskDecorator to be applied to any Runnable about to be executed.
Future<?>	submit(Runnable task)	Submit a Runnable task for execution, receiving a Future representing that task.
<T> Future<T>	submit(Callable<T> task)	Submit a Callable task for execution, receiving a Future representing that task.
ListenableFuture<?>	submitListenable(Runnable task)	Submit a Runnable task for execution, receiving a ListenableFuture representing that task.
<T> ListenableFuture<T>	submitListenable(Callable<T> task)	Submit a Callable task for execution, receiving a ListenableFuture representing that task.

Methods inherited from class org.springframework.scheduling.concurrent.ExecutorConfigurationSupport

afterExecute, afterPropertiesSet, beforeExecute, destroy, getPhase, initialize, initiateEarlyShutdown, initiateShutdown, isRunning, onApplicationEvent, setAcceptTasksAfterContextClose, setApplicationContext, setAwaitTerminationMillis, setAwaitTerminationSeconds, setBeanName, setPhase, setRejectedExecutionHandler, setThreadFactory, setThreadNamePrefix, setWaitForTasksToCompleteOnShutdown, shutdown, start, stop, stop

Methods inherited from class org.springframework.scheduling.concurrent.CustomizableThreadFactory

newThread

Methods inherited from class org.springframework.util.CustomizableThreadCreator

createThread, getDefaultThreadNamePrefix, getThreadGroup, getThreadNamePrefix, getThreadPriority, isDaemon, nextThreadName, setDaemon, setThreadGroup, setThreadGroupName, setThreadPriority

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.springframework.context.ApplicationListener

supportsAsyncExecution

Methods inherited from interface org.springframework.core.task.AsyncTaskExecutor

execute, submitCompletable, submitCompletable

Methods inherited from interface org.springframework.scheduling.SchedulingTaskExecutor

prefersShortLivedTasks

Methods inherited from interface org.springframework.context.SmartLifecycle

isAutoStartup

Methods inherited from interface org.springframework.scheduling.TaskScheduler

schedule, scheduleAtFixedRate, scheduleAtFixedRate, scheduleWithFixedDelay, scheduleWithFixedDelay

Constructor Details

ThreadPoolTaskScheduler

public ThreadPoolTaskScheduler()

Method Details

setPoolSize

public void setPoolSize(int poolSize)

Set the ScheduledExecutorService's pool size. Default is 1.

This setting can be modified at runtime, for example through JMX.

setRemoveOnCancelPolicy

public void setRemoveOnCancelPolicy(boolean flag)

Set the remove-on-cancel mode on ScheduledThreadPoolExecutor.

Default is false. If set to true, the target executor will be switched into remove-on-cancel mode (if possible).

This setting can be modified at runtime, for example through JMX.

See Also:

• ScheduledThreadPoolExecutor.setRemoveOnCancelPolicy(boolean)

setContinueExistingPeriodicTasksAfterShutdownPolicy

public void setContinueExistingPeriodicTasksAfterShutdownPolicy(boolean flag)

Set whether to continue existing periodic tasks even when this executor has been shutdown.

Default is false. If set to true, the target executor will be switched into continuing periodic tasks (if possible).

This setting can be modified at runtime, for example through JMX.

Since:

5.3.9

See Also:

• ScheduledThreadPoolExecutor.setContinueExistingPeriodicTasksAfterShutdownPolicy(boolean)

setExecuteExistingDelayedTasksAfterShutdownPolicy

public void setExecuteExistingDelayedTasksAfterShutdownPolicy(boolean flag)

Set whether to execute existing delayed tasks even when this executor has been shutdown.

Default is true. If set to false, the target executor will be switched into dropping remaining tasks (if possible).

This setting can be modified at runtime, for example through JMX.

Since:

5.3.9

See Also:

• ScheduledThreadPoolExecutor.setExecuteExistingDelayedTasksAfterShutdownPolicy(boolean)

setTaskDecorator

public void setTaskDecorator(TaskDecorator taskDecorator)

Specify a custom TaskDecorator to be applied to any Runnable about to be executed.

Note that such a decorator is not being applied to the user-supplied Runnable/Callable but rather to the scheduled execution callback (a wrapper around the user-supplied task).

The primary use case is to set some execution context around the task's invocation, or to provide some monitoring/statistics for task execution.

Since:

6.2

setErrorHandler

public void setErrorHandler(ErrorHandler errorHandler)

Set a custom ErrorHandler strategy.

setClock

public void setClock(Clock clock)

Set the clock to use for scheduling purposes.

The default clock is the system clock for the default time zone.

Since:

5.3

See Also:

• Clock.systemDefaultZone()

getClock

public Clock getClock()

Description copied from interface: TaskScheduler

Return the clock to use for scheduling purposes.

Specified by:

getClock in interface TaskScheduler

See Also:

• Clock.systemDefaultZone()

initializeExecutor

protected ExecutorService initializeExecutor(ThreadFactory threadFactory,
 RejectedExecutionHandler rejectedExecutionHandler)

Description copied from class: ExecutorConfigurationSupport

Create the target ExecutorService instance. Called by afterPropertiesSet.

Specified by:

initializeExecutor in class ExecutorConfigurationSupport

Parameters:

threadFactory - the ThreadFactory to use

rejectedExecutionHandler - the RejectedExecutionHandler to use

Returns:

a new ExecutorService instance

See Also:

• ExecutorConfigurationSupport.afterPropertiesSet()

createExecutor

protected ScheduledExecutorService createExecutor(int poolSize,
 ThreadFactory threadFactory,
 RejectedExecutionHandler rejectedExecutionHandler)

Create a new ScheduledExecutorService instance.

The default implementation creates a ScheduledThreadPoolExecutor. Can be overridden in subclasses to provide custom ScheduledExecutorService instances.

Parameters:

poolSize - the specified pool size

threadFactory - the ThreadFactory to use

rejectedExecutionHandler - the RejectedExecutionHandler to use

Returns:

a new ScheduledExecutorService instance

See Also:

• ExecutorConfigurationSupport.afterPropertiesSet()
• ScheduledThreadPoolExecutor

getScheduledExecutor

public ScheduledExecutorService getScheduledExecutor()
                                              throws IllegalStateException

Return the underlying ScheduledExecutorService for native access.

Returns:

the underlying ScheduledExecutorService (never null)

Throws:

IllegalStateException - if the ThreadPoolTaskScheduler hasn't been initialized yet

getScheduledThreadPoolExecutor

public ScheduledThreadPoolExecutor getScheduledThreadPoolExecutor()
                                                           throws IllegalStateException

Return the underlying ScheduledThreadPoolExecutor, if available.

Returns:

the underlying ScheduledExecutorService (never null)

Throws:

IllegalStateException - if the ThreadPoolTaskScheduler hasn't been initialized yet or if the underlying ScheduledExecutorService isn't a ScheduledThreadPoolExecutor

See Also:

• getScheduledExecutor()

getPoolSize

public int getPoolSize()

Return the current pool size.

Requires an underlying ScheduledThreadPoolExecutor.

See Also:

• getScheduledThreadPoolExecutor()
• ThreadPoolExecutor.getPoolSize()

getActiveCount

public int getActiveCount()

Return the number of currently active threads.

Requires an underlying ScheduledThreadPoolExecutor.

See Also:

• getScheduledThreadPoolExecutor()
• ThreadPoolExecutor.getActiveCount()

isRemoveOnCancelPolicy

@Deprecated
public boolean isRemoveOnCancelPolicy()

Deprecated.

as of 5.3.9, in favor of direct getScheduledThreadPoolExecutor() access

Return the current setting for the remove-on-cancel mode.

Requires an underlying ScheduledThreadPoolExecutor.

execute

public void execute(Runnable task)

Description copied from interface: TaskExecutor

Execute the given task.

The call might return immediately if the implementation uses an asynchronous execution strategy, or might block in the case of synchronous execution.

Specified by:

execute in interface Executor

Specified by:

execute in interface TaskExecutor

Parameters:

task - the Runnable to execute (never null)

submit

public Future<?> submit(Runnable task)

Description copied from interface: AsyncTaskExecutor

Submit a Runnable task for execution, receiving a Future representing that task. The Future will return a null result upon completion.

As of 6.1, this method comes with a default implementation that delegates to TaskExecutor.execute(Runnable).

Specified by:

submit in interface AsyncTaskExecutor

Parameters:

task - the Runnable to execute (never null)

Returns:

a Future representing pending completion of the task

submit

public <T> Future<T> submit(Callable<T> task)

Description copied from interface: AsyncTaskExecutor

Submit a Callable task for execution, receiving a Future representing that task. The Future will return the Callable's result upon completion.

As of 6.1, this method comes with a default implementation that delegates to TaskExecutor.execute(Runnable).

Specified by:

submit in interface AsyncTaskExecutor

Parameters:

task - the Callable to execute (never null)

Returns:

a Future representing pending completion of the task

submitListenable

public ListenableFuture<?> submitListenable(Runnable task)

Description copied from interface: AsyncListenableTaskExecutor

Submit a Runnable task for execution, receiving a ListenableFuture representing that task. The Future will return a null result upon completion.

Specified by:

submitListenable in interface AsyncListenableTaskExecutor

Parameters:

task - the Runnable to execute (never null)

Returns:

a ListenableFuture representing pending completion of the task

submitListenable

public <T> ListenableFuture<T> submitListenable(Callable<T> task)

Description copied from interface: AsyncListenableTaskExecutor

Submit a Callable task for execution, receiving a ListenableFuture representing that task. The Future will return the Callable's result upon completion.

Specified by:

submitListenable in interface AsyncListenableTaskExecutor

Parameters:

task - the Callable to execute (never null)

Returns:

a ListenableFuture representing pending completion of the task

cancelRemainingTask

protected void cancelRemainingTask(Runnable task)

Description copied from class: ExecutorConfigurationSupport

Cancel the given remaining task which never commenced execution, as returned from ExecutorService.shutdownNow().

Overrides:

cancelRemainingTask in class ExecutorConfigurationSupport

Parameters:

task - the task to cancel (typically a RunnableFuture)

See Also:

• ExecutorConfigurationSupport.shutdown()
• Future.cancel(boolean)

schedule

@Nullable
public ScheduledFuture<?> schedule(Runnable task,
 Trigger trigger)

Description copied from interface: TaskScheduler

Schedule the given Runnable, invoking it whenever the trigger indicates a next execution time.

Execution will end once the scheduler shuts down or the returned ScheduledFuture gets cancelled.

Specified by:

schedule in interface TaskScheduler

Parameters:

task - the Runnable to execute whenever the trigger fires

trigger - an implementation of the Trigger interface, e.g. a CronTrigger object wrapping a cron expression

Returns:

a ScheduledFuture representing pending execution of the task, or null if the given Trigger object never fires (i.e. returns null from Trigger.nextExecution(org.springframework.scheduling.TriggerContext))

See Also:

• CronTrigger

schedule

public ScheduledFuture<?> schedule(Runnable task,
 Instant startTime)

Description copied from interface: TaskScheduler

Schedule the given Runnable, invoking it at the specified execution time.

Execution will end once the scheduler shuts down or the returned ScheduledFuture gets cancelled.

Specified by:

schedule in interface TaskScheduler

Parameters:

task - the Runnable to execute whenever the trigger fires

startTime - the desired execution time for the task (if this is in the past, the task will be executed immediately, i.e. as soon as possible)

Returns:

a ScheduledFuture representing pending execution of the task

scheduleAtFixedRate

public ScheduledFuture<?> scheduleAtFixedRate(Runnable task,
 Instant startTime,
 Duration period)

Description copied from interface: TaskScheduler

Schedule the given Runnable, invoking it at the specified execution time and subsequently with the given period.

Execution will end once the scheduler shuts down or the returned ScheduledFuture gets cancelled.

Specified by:

scheduleAtFixedRate in interface TaskScheduler

Parameters:

task - the Runnable to execute whenever the trigger fires

startTime - the desired first execution time for the task (if this is in the past, the task will be executed immediately, i.e. as soon as possible)

period - the interval between successive executions of the task

Returns:

a ScheduledFuture representing pending execution of the task

scheduleAtFixedRate

public ScheduledFuture<?> scheduleAtFixedRate(Runnable task,
 Duration period)

Description copied from interface: TaskScheduler

Schedule the given Runnable, starting as soon as possible and invoking it with the given period.

Execution will end once the scheduler shuts down or the returned ScheduledFuture gets cancelled.

Specified by:

scheduleAtFixedRate in interface TaskScheduler

Parameters:

task - the Runnable to execute whenever the trigger fires

period - the interval between successive executions of the task

Returns:

a ScheduledFuture representing pending execution of the task

scheduleWithFixedDelay

public ScheduledFuture<?> scheduleWithFixedDelay(Runnable task,
 Instant startTime,
 Duration delay)

Description copied from interface: TaskScheduler

Schedule the given Runnable, invoking it at the specified execution time and subsequently with the given delay between the completion of one execution and the start of the next.

Execution will end once the scheduler shuts down or the returned ScheduledFuture gets cancelled.

Specified by:

scheduleWithFixedDelay in interface TaskScheduler

Parameters:

task - the Runnable to execute whenever the trigger fires

startTime - the desired first execution time for the task (if this is in the past, the task will be executed immediately, i.e. as soon as possible)

delay - the delay between the completion of one execution and the start of the next

Returns:

a ScheduledFuture representing pending execution of the task

scheduleWithFixedDelay

public ScheduledFuture<?> scheduleWithFixedDelay(Runnable task,
 Duration delay)

Description copied from interface: TaskScheduler

Schedule the given Runnable, starting as soon as possible and invoking it with the given delay between the completion of one execution and the start of the next.

Execution will end once the scheduler shuts down or the returned ScheduledFuture gets cancelled.

Specified by:

scheduleWithFixedDelay in interface TaskScheduler

Parameters:

task - the Runnable to execute whenever the trigger fires

delay - the delay between the completion of one execution and the start of the next

Returns:

a ScheduledFuture representing pending execution of the task