org.springframework.scheduling.concurrent

Class ThreadPoolTaskExecutor

java.lang.Object

org.springframework.util.CustomizableThreadCreator

org.springframework.scheduling.concurrent.CustomizableThreadFactory

org.springframework.scheduling.concurrent.ExecutorConfigurationSupport

org.springframework.scheduling.concurrent.ThreadPoolTaskExecutor

All Implemented Interfaces:

java.io.Serializable, java.util.concurrent.Executor, java.util.concurrent.ThreadFactory, Aware, BeanNameAware, DisposableBean, InitializingBean, AsyncListenableTaskExecutor, AsyncTaskExecutor, TaskExecutor, SchedulingTaskExecutor

public class ThreadPoolTaskExecutor
extends ExecutorConfigurationSupport
implements AsyncListenableTaskExecutor, SchedulingTaskExecutor

JavaBean that allows for configuring a ThreadPoolExecutor in bean style (through its "corePoolSize", "maxPoolSize", "keepAliveSeconds", "queueCapacity" properties) and exposing it as a Spring TaskExecutor. This class is also well suited for management and monitoring (e.g. through JMX), providing several useful attributes: "corePoolSize", "maxPoolSize", "keepAliveSeconds" (all supporting updates at runtime); "poolSize", "activeCount" (for introspection only).

The default configuration is a core pool size of 1, with unlimited max pool size and unlimited queue capacity. This is roughly equivalent to Executors.newSingleThreadExecutor(), sharing a single thread for all tasks. Setting "queueCapacity" to 0 mimics Executors.newCachedThreadPool(), with immediate scaling of threads in the pool to a potentially very high number. Consider also setting a "maxPoolSize" at that point, as well as possibly a higher "corePoolSize" (see also the "allowCoreThreadTimeOut" mode of scaling).

NOTE: This class implements Spring's TaskExecutor interface as well as the Executor interface, with the former being the primary interface, the other just serving as secondary convenience. For this reason, the exception handling follows the TaskExecutor contract rather than the Executor contract, in particular regarding the TaskRejectedException.

For an alternative, you may set up a ThreadPoolExecutor instance directly using constructor injection, or use a factory method definition that points to the Executors class. To expose such a raw Executor as a Spring TaskExecutor, simply wrap it with a ConcurrentTaskExecutor adapter.

Since:

2.0

Author:

Juergen Hoeller

See Also:

TaskExecutor, ThreadPoolExecutor, ThreadPoolExecutorFactoryBean, ConcurrentTaskExecutor, Serialized Form

Field Summary

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

logger

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

TIMEOUT_IMMEDIATE, TIMEOUT_INDEFINITE

Constructor Summary

Constructors

Constructor and Description
ThreadPoolTaskExecutor()

Method Summary

Modifier and Type	Method and Description
protected void	cancelRemainingTask(java.lang.Runnable task) Cancel the given remaining task which never commended execution, as returned from ExecutorService.shutdownNow().
protected java.util.concurrent.BlockingQueue<java.lang.Runnable>	createQueue(int queueCapacity) Create the BlockingQueue to use for the ThreadPoolExecutor.
void	execute(java.lang.Runnable task) Execute the given task.
void	execute(java.lang.Runnable task, long startTimeout) Execute the given task.
int	getActiveCount() Return the number of currently active threads.
int	getCorePoolSize() Return the ThreadPoolExecutor's core pool size.
int	getKeepAliveSeconds() Return the ThreadPoolExecutor's keep-alive seconds.
int	getMaxPoolSize() Return the ThreadPoolExecutor's maximum pool size.
int	getPoolSize() Return the current pool size.
java.util.concurrent.ThreadPoolExecutor	getThreadPoolExecutor() Return the underlying ThreadPoolExecutor for native access.
protected java.util.concurrent.ExecutorService	initializeExecutor(java.util.concurrent.ThreadFactory threadFactory, java.util.concurrent.RejectedExecutionHandler rejectedExecutionHandler) Note: This method exposes an ExecutorService to its base class but stores the actual ThreadPoolExecutor handle internally.
boolean	prefersShortLivedTasks() This task executor prefers short-lived work units.
void	setAllowCoreThreadTimeOut(boolean allowCoreThreadTimeOut) Specify whether to allow core threads to time out.
void	setCorePoolSize(int corePoolSize) Set the ThreadPoolExecutor's core pool size.
void	setKeepAliveSeconds(int keepAliveSeconds) Set the ThreadPoolExecutor's keep-alive seconds.
void	setMaxPoolSize(int maxPoolSize) Set the ThreadPoolExecutor's maximum pool size.
void	setQueueCapacity(int queueCapacity) Set the capacity for the ThreadPoolExecutor's BlockingQueue.
void	setTaskDecorator(TaskDecorator taskDecorator) Specify a custom TaskDecorator to be applied to any Runnable about to be executed.
<T> java.util.concurrent.Future<T>	submit(java.util.concurrent.Callable<T> task) Submit a Callable task for execution, receiving a Future representing that task.
java.util.concurrent.Future<?>	submit(java.lang.Runnable task) Submit a Runnable task for execution, receiving a Future representing that task.
<T> ListenableFuture<T>	submitListenable(java.util.concurrent.Callable<T> task) Submit a Callable task for execution, receiving a ListenableFuture representing that task.
ListenableFuture<?>	submitListenable(java.lang.Runnable task) Submit a Runnable task for execution, receiving a ListenableFuture representing that task.

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

afterPropertiesSet, destroy, initialize, setAwaitTerminationSeconds, setBeanName, setRejectedExecutionHandler, setThreadFactory, setThreadNamePrefix, setWaitForTasksToCompleteOnShutdown, shutdown

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

Constructor Detail

ThreadPoolTaskExecutor

public ThreadPoolTaskExecutor()

Method Detail

setCorePoolSize

public void setCorePoolSize(int corePoolSize)

Set the ThreadPoolExecutor's core pool size. Default is 1.

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

getCorePoolSize

public int getCorePoolSize()

Return the ThreadPoolExecutor's core pool size.

setMaxPoolSize

public void setMaxPoolSize(int maxPoolSize)

Set the ThreadPoolExecutor's maximum pool size. Default is Integer.MAX_VALUE.

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

getMaxPoolSize

public int getMaxPoolSize()

Return the ThreadPoolExecutor's maximum pool size.

setKeepAliveSeconds

public void setKeepAliveSeconds(int keepAliveSeconds)

Set the ThreadPoolExecutor's keep-alive seconds. Default is 60.

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

getKeepAliveSeconds

public int getKeepAliveSeconds()

Return the ThreadPoolExecutor's keep-alive seconds.

setQueueCapacity

public void setQueueCapacity(int queueCapacity)

Set the capacity for the ThreadPoolExecutor's BlockingQueue. Default is Integer.MAX_VALUE.

Any positive value will lead to a LinkedBlockingQueue instance; any other value will lead to a SynchronousQueue instance.

See Also:

LinkedBlockingQueue, SynchronousQueue

setAllowCoreThreadTimeOut

public void setAllowCoreThreadTimeOut(boolean allowCoreThreadTimeOut)

Specify whether to allow core threads to time out. This enables dynamic growing and shrinking even in combination with a non-zero queue (since the max pool size will only grow once the queue is full).

Default is "false".

See Also:

ThreadPoolExecutor.allowCoreThreadTimeOut(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 necessarily being applied to the user-supplied Runnable/Callable but rather to the actual execution callback (which may be 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:

4.3

initializeExecutor

protected java.util.concurrent.ExecutorService initializeExecutor(java.util.concurrent.ThreadFactory threadFactory,
                                                                  java.util.concurrent.RejectedExecutionHandler rejectedExecutionHandler)

Note: This method exposes an ExecutorService to its base class but stores the actual ThreadPoolExecutor handle internally. Do not override this method for replacing the executor, rather just for decorating its ExecutorService handle or storing custom state.

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()

createQueue

protected java.util.concurrent.BlockingQueue<java.lang.Runnable> createQueue(int queueCapacity)

Create the BlockingQueue to use for the ThreadPoolExecutor.

A LinkedBlockingQueue instance will be created for a positive capacity value; a SynchronousQueue else.

Parameters:

queueCapacity - the specified queue capacity

Returns:

the BlockingQueue instance

See Also:

LinkedBlockingQueue, SynchronousQueue

getThreadPoolExecutor

public java.util.concurrent.ThreadPoolExecutor getThreadPoolExecutor()
                                                              throws java.lang.IllegalStateException

Return the underlying ThreadPoolExecutor for native access.

Returns:

the underlying ThreadPoolExecutor (never null)

Throws:

java.lang.IllegalStateException - if the ThreadPoolTaskExecutor hasn't been initialized yet

getPoolSize

public int getPoolSize()

Return the current pool size.

See Also:

ThreadPoolExecutor.getPoolSize()

getActiveCount

public int getActiveCount()

Return the number of currently active threads.

See Also:

ThreadPoolExecutor.getActiveCount()

execute

public void execute(java.lang.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 java.util.concurrent.Executor

Specified by:

execute in interface TaskExecutor

Parameters:

task - the Runnable to execute (never null)

execute

public void execute(java.lang.Runnable task,
                    long startTimeout)

Description copied from interface: AsyncTaskExecutor

Execute the given task.

Specified by:

execute in interface AsyncTaskExecutor

Parameters:

task - the Runnable to execute (never null)

startTimeout - the time duration (milliseconds) within which the task is supposed to start. This is intended as a hint to the executor, allowing for preferred handling of immediate tasks. Typical values are AsyncTaskExecutor.TIMEOUT_IMMEDIATE or AsyncTaskExecutor.TIMEOUT_INDEFINITE (the default as used by TaskExecutor.execute(Runnable)).

submit

public java.util.concurrent.Future<?> submit(java.lang.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.

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> java.util.concurrent.Future<T> submit(java.util.concurrent.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.

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(java.lang.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(java.util.concurrent.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(java.lang.Runnable task)

Description copied from class: ExecutorConfigurationSupport

Cancel the given remaining task which never commended 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)

prefersShortLivedTasks

public boolean prefersShortLivedTasks()

This task executor prefers short-lived work units.

Specified by:

prefersShortLivedTasks in interface SchedulingTaskExecutor

Returns:

true if this TaskExecutor prefers short-lived tasks