org.springframework.scheduling.concurrent

Class ForkJoinPoolFactoryBean

java.lang.Object

org.springframework.scheduling.concurrent.ForkJoinPoolFactoryBean

All Implemented Interfaces:

DisposableBean, FactoryBean<ForkJoinPool>, InitializingBean

public class ForkJoinPoolFactoryBean
extends Object
implements FactoryBean<ForkJoinPool>, InitializingBean, DisposableBean

A Spring FactoryBean that builds and exposes a preconfigured ForkJoinPool. May be used on Java 7 and 8 as well as on Java 6 with jsr166.jar on the classpath (ideally on the VM bootstrap classpath).

For details on the ForkJoinPool API and its use with RecursiveActions, see the JDK 7 javadoc.

jsr166.jar, containing java.util.concurrent updates for Java 6, can be obtained from the concurrency interest website.

Since:

3.1

Author:

Juergen Hoeller

Constructor Summary

Constructors

Constructor and Description
ForkJoinPoolFactoryBean()

Method Summary

Modifier and Type	Method and Description
void	afterPropertiesSet() Invoked by a BeanFactory after it has set all bean properties supplied (and satisfied BeanFactoryAware and ApplicationContextAware).
void	destroy() Invoked by a BeanFactory on destruction of a singleton.
ForkJoinPool	getObject() Return an instance (possibly shared or independent) of the object managed by this factory.
Class<?>	getObjectType() Return the type of object that this FactoryBean creates, or null if not known in advance.
boolean	isSingleton() Is the object managed by this factory a singleton? That is, will FactoryBean.getObject() always return the same object (a reference that can be cached)?
void	setAsyncMode(boolean asyncMode) Specify whether to establish a local first-in-first-out scheduling mode for forked tasks that are never joined.
void	setAwaitTerminationSeconds(int awaitTerminationSeconds) Set the maximum number of seconds that this ForkJoinPool is supposed to block on shutdown in order to wait for remaining tasks to complete their execution before the rest of the container continues to shut down.
void	setCommonPool(boolean commonPool) Set whether to expose JDK 8's 'common' ForkJoinPool.
void	setParallelism(int parallelism) Specify the parallelism level.
void	setThreadFactory(ForkJoinPool.ForkJoinWorkerThreadFactory threadFactory) Set the factory for creating new ForkJoinWorkerThreads.
void	setUncaughtExceptionHandler(Thread.UncaughtExceptionHandler uncaughtExceptionHandler) Set the handler for internal worker threads that terminate due to unrecoverable errors encountered while executing tasks.

Methods inherited from class java.lang.Object

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

Constructor Detail

ForkJoinPoolFactoryBean

public ForkJoinPoolFactoryBean()

Method Detail

setCommonPool

public void setCommonPool(boolean commonPool)

Set whether to expose JDK 8's 'common' ForkJoinPool.

Default is "false", creating a local ForkJoinPool instance based on the "parallelism", "threadFactory", "uncaughtExceptionHandler" and "asyncMode" properties on this FactoryBean.

NOTE: Setting this flag to "true" effectively ignores all other properties on this FactoryBean, reusing the shared common JDK ForkJoinPool instead. This is a fine choice on JDK 8 but does remove the application's ability to customize ForkJoinPool behavior, in particular the use of custom threads.

Since:

3.2

See Also:

ForkJoinPool.commonPool()

setParallelism

public void setParallelism(int parallelism)

Specify the parallelism level. Default is Runtime.availableProcessors().

setThreadFactory

public void setThreadFactory(ForkJoinPool.ForkJoinWorkerThreadFactory threadFactory)

Set the factory for creating new ForkJoinWorkerThreads. Default is ForkJoinPool.defaultForkJoinWorkerThreadFactory.

setUncaughtExceptionHandler

public void setUncaughtExceptionHandler(Thread.UncaughtExceptionHandler uncaughtExceptionHandler)

Set the handler for internal worker threads that terminate due to unrecoverable errors encountered while executing tasks. Default is none.

setAsyncMode

public void setAsyncMode(boolean asyncMode)

Specify whether to establish a local first-in-first-out scheduling mode for forked tasks that are never joined. This mode (asyncMode = true) may be more appropriate than the default locally stack-based mode in applications in which worker threads only process event-style asynchronous tasks. Default is false.

setAwaitTerminationSeconds

public void setAwaitTerminationSeconds(int awaitTerminationSeconds)

Set the maximum number of seconds that this ForkJoinPool is supposed to block on shutdown in order to wait for remaining tasks to complete their execution before the rest of the container continues to shut down. This is particularly useful if your remaining tasks are likely to need access to other resources that are also managed by the container.

By default, this ForkJoinPool won't wait for the termination of tasks at all. It will continue to fully execute all ongoing tasks as well as all remaining tasks in the queue, in parallel to the rest of the container shutting down. In contrast, if you specify an await-termination period using this property, this executor will wait for the given time (max) for the termination of tasks.

Note that this feature works for the "commonPool" mode as well. The underlying ForkJoinPool won't actually terminate in that case but will wait for all tasks to terminate.

See Also:

ForkJoinPool.shutdown(), ForkJoinPool.awaitTermination(long, java.util.concurrent.TimeUnit)

afterPropertiesSet

public void afterPropertiesSet()

Description copied from interface: InitializingBean

Invoked by a BeanFactory after it has set all bean properties supplied (and satisfied BeanFactoryAware and ApplicationContextAware).

This method allows the bean instance to perform initialization only possible when all bean properties have been set and to throw an exception in the event of misconfiguration.

Specified by:

afterPropertiesSet in interface InitializingBean

getObject

public ForkJoinPool getObject()

Description copied from interface: FactoryBean

Return an instance (possibly shared or independent) of the object managed by this factory.

As with a BeanFactory, this allows support for both the Singleton and Prototype design pattern.

If this FactoryBean is not fully initialized yet at the time of the call (for example because it is involved in a circular reference), throw a corresponding FactoryBeanNotInitializedException.

As of Spring 2.0, FactoryBeans are allowed to return null objects. The factory will consider this as normal value to be used; it will not throw a FactoryBeanNotInitializedException in this case anymore. FactoryBean implementations are encouraged to throw FactoryBeanNotInitializedException themselves now, as appropriate.

Specified by:

getObject in interface FactoryBean<ForkJoinPool>

Returns:

an instance of the bean (can be null)

See Also:

FactoryBeanNotInitializedException

getObjectType

public Class<?> getObjectType()

Description copied from interface: FactoryBean

Return the type of object that this FactoryBean creates, or null if not known in advance.

This allows one to check for specific types of beans without instantiating objects, for example on autowiring.

In the case of implementations that are creating a singleton object, this method should try to avoid singleton creation as far as possible; it should rather estimate the type in advance. For prototypes, returning a meaningful type here is advisable too.

This method can be called before this FactoryBean has been fully initialized. It must not rely on state created during initialization; of course, it can still use such state if available.

NOTE: Autowiring will simply ignore FactoryBeans that return null here. Therefore it is highly recommended to implement this method properly, using the current state of the FactoryBean.

Specified by:

getObjectType in interface FactoryBean<ForkJoinPool>

Returns:

the type of object that this FactoryBean creates, or null if not known at the time of the call

See Also:

ListableBeanFactory.getBeansOfType(java.lang.Class<T>)

isSingleton

public boolean isSingleton()

Description copied from interface: FactoryBean

Is the object managed by this factory a singleton? That is, will FactoryBean.getObject() always return the same object (a reference that can be cached)?

NOTE: If a FactoryBean indicates to hold a singleton object, the object returned from getObject() might get cached by the owning BeanFactory. Hence, do not return true unless the FactoryBean always exposes the same reference.

The singleton status of the FactoryBean itself will generally be provided by the owning BeanFactory; usually, it has to be defined as singleton there.

NOTE: This method returning false does not necessarily indicate that returned objects are independent instances. An implementation of the extended SmartFactoryBean interface may explicitly indicate independent instances through its SmartFactoryBean.isPrototype() method. Plain FactoryBean implementations which do not implement this extended interface are simply assumed to always return independent instances if the isSingleton() implementation returns false.

Specified by:

isSingleton in interface FactoryBean<ForkJoinPool>

Returns:

whether the exposed object is a singleton

See Also:

FactoryBean.getObject(), SmartFactoryBean.isPrototype()

destroy

public void destroy()

Description copied from interface: DisposableBean

Invoked by a BeanFactory on destruction of a singleton.

Specified by:

destroy in interface DisposableBean