org.springframework.scheduling.concurrent

Class ScheduledExecutorFactoryBean

java.lang.Object

org.springframework.util.CustomizableThreadCreator

org.springframework.scheduling.concurrent.CustomizableThreadFactory

org.springframework.scheduling.concurrent.ExecutorConfigurationSupport

org.springframework.scheduling.concurrent.ScheduledExecutorFactoryBean

All Implemented Interfaces:

Serializable, ThreadFactory, Aware, BeanNameAware, DisposableBean, FactoryBean<ScheduledExecutorService>, InitializingBean

public class ScheduledExecutorFactoryBean
extends ExecutorConfigurationSupport
implements FactoryBean<ScheduledExecutorService>

FactoryBean that sets up a ScheduledExecutorService (by default: a ScheduledThreadPoolExecutor) and exposes it for bean references.

Allows for registration of ScheduledExecutorTasks, automatically starting the ScheduledExecutorService on initialization and cancelling it on destruction of the context. In scenarios that only require static registration of tasks at startup, there is no need to access the ScheduledExecutorService instance itself in application code at all; ScheduledExecutorFactoryBean is then just being used for lifecycle integration.

For an alternative, you may set up a ScheduledThreadPoolExecutor instance directly using constructor injection, or use a factory method definition that points to the Executors class. This is strongly recommended in particular for common @Bean methods in configuration classes, where this FactoryBean variant would force you to return the FactoryBean type instead of ScheduledExecutorService.

Note that ScheduledExecutorService uses a Runnable instance that is shared between repeated executions, in contrast to Quartz which instantiates a new Job for each execution.

WARNING: Runnables submitted via a native ScheduledExecutorService are removed from the execution schedule once they throw an exception. If you would prefer to continue execution after such an exception, switch this FactoryBean's "continueScheduledExecutionAfterException" property to "true".

Since:

2.0

Author:

Juergen Hoeller

See Also:

setPoolSize(int), setRemoveOnCancelPolicy(boolean), ExecutorConfigurationSupport.setThreadFactory(java.util.concurrent.ThreadFactory), ScheduledExecutorTask, ScheduledExecutorService, ScheduledThreadPoolExecutor, Serialized Form

Field Summary

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

logger

Constructor Summary

Constructors

Constructor and Description
ScheduledExecutorFactoryBean()

Method Summary

Modifier and Type	Method and Description
protected ScheduledExecutorService	createExecutor(int poolSize, ThreadFactory threadFactory, RejectedExecutionHandler rejectedExecutionHandler) Create a new ScheduledExecutorService instance.
ScheduledExecutorService	getObject() Return an instance (possibly shared or independent) of the object managed by this factory.
Class<? extends ScheduledExecutorService>	getObjectType() Return the type of object that this FactoryBean creates, or null if not known in advance.
protected Runnable	getRunnableToSchedule(ScheduledExecutorTask task) Determine the actual Runnable to schedule for the given task.
protected ExecutorService	initializeExecutor(ThreadFactory threadFactory, RejectedExecutionHandler rejectedExecutionHandler) Create the target ExecutorService instance.
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)?
protected void	registerTasks(ScheduledExecutorTask[] tasks, ScheduledExecutorService executor) Register the specified ScheduledExecutorTasks on the given ScheduledExecutorService.
void	setContinueScheduledExecutionAfterException(boolean continueScheduledExecutionAfterException) Specify whether to continue the execution of a scheduled task after it threw an exception.
void	setExposeUnconfigurableExecutor(boolean exposeUnconfigurableExecutor) Specify whether this FactoryBean should expose an unconfigurable decorator for the created executor.
void	setPoolSize(int poolSize) Set the ScheduledExecutorService's pool size.
void	setRemoveOnCancelPolicy(boolean removeOnCancelPolicy) Set the remove-on-cancel mode on ScheduledThreadPoolExecutor (JDK 7+).
void	setScheduledExecutorTasks(ScheduledExecutorTask... scheduledExecutorTasks) Register a list of ScheduledExecutorTask objects with the ScheduledExecutorService that this FactoryBean creates.

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

ScheduledExecutorFactoryBean

public ScheduledExecutorFactoryBean()

Method Detail

setPoolSize

public void setPoolSize(int poolSize)

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

setScheduledExecutorTasks

public void setScheduledExecutorTasks(ScheduledExecutorTask... scheduledExecutorTasks)

Register a list of ScheduledExecutorTask objects with the ScheduledExecutorService that this FactoryBean creates. Depending on each ScheduledExecutorTask's settings, it will be registered via one of ScheduledExecutorService's schedule methods.

See Also:

ScheduledExecutorService.schedule(java.lang.Runnable, long, java.util.concurrent.TimeUnit), ScheduledExecutorService.scheduleWithFixedDelay(java.lang.Runnable, long, long, java.util.concurrent.TimeUnit), ScheduledExecutorService.scheduleAtFixedRate(java.lang.Runnable, long, long, java.util.concurrent.TimeUnit)

setRemoveOnCancelPolicy

public void setRemoveOnCancelPolicy(boolean removeOnCancelPolicy)

Set the remove-on-cancel mode on ScheduledThreadPoolExecutor (JDK 7+).

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

setContinueScheduledExecutionAfterException

public void setContinueScheduledExecutionAfterException(boolean continueScheduledExecutionAfterException)

Specify whether to continue the execution of a scheduled task after it threw an exception.

Default is "false", matching the native behavior of a ScheduledExecutorService. Switch this flag to "true" for exception-proof execution of each task, continuing scheduled execution as in the case of successful execution.

See Also:

ScheduledExecutorService.scheduleAtFixedRate(java.lang.Runnable, long, long, java.util.concurrent.TimeUnit)

setExposeUnconfigurableExecutor

public void setExposeUnconfigurableExecutor(boolean exposeUnconfigurableExecutor)

Specify whether this FactoryBean should expose an unconfigurable decorator for the created executor.

Default is "false", exposing the raw executor as bean reference. Switch this flag to "true" to strictly prevent clients from modifying the executor's configuration.

See Also:

Executors.unconfigurableScheduledExecutorService(java.util.concurrent.ScheduledExecutorService)

initializeExecutor

@UsesJava7
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

registerTasks

protected void registerTasks(ScheduledExecutorTask[] tasks,
                             ScheduledExecutorService executor)

Register the specified ScheduledExecutorTasks on the given ScheduledExecutorService.

Parameters:

tasks - the specified ScheduledExecutorTasks (never empty)

executor - the ScheduledExecutorService to register the tasks on.

getRunnableToSchedule

protected Runnable getRunnableToSchedule(ScheduledExecutorTask task)

Determine the actual Runnable to schedule for the given task.

Wraps the task's Runnable in a DelegatingErrorHandlingRunnable that will catch and log the Exception. If necessary, it will suppress the Exception according to the "continueScheduledExecutionAfterException" flag.

Parameters:

task - the ScheduledExecutorTask to schedule

Returns:

the actual Runnable to schedule (may be a decorator)

getObject

public ScheduledExecutorService 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<ScheduledExecutorService>

Returns:

an instance of the bean (can be null)

See Also:

FactoryBeanNotInitializedException

getObjectType

public Class<? extends ScheduledExecutorService> 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<ScheduledExecutorService>

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<ScheduledExecutorService>

Returns:

whether the exposed object is a singleton

See Also:

FactoryBean.getObject(), SmartFactoryBean.isPrototype()