public class

ScheduledExecutorFactoryBean

extends ExecutorConfigurationSupport
implements FactoryBean<T>
java.lang.Object
   ↳ org.springframework.util.CustomizableThreadCreator
     ↳ org.springframework.scheduling.concurrent.CustomizableThreadFactory
       ↳ org.springframework.scheduling.concurrent.ExecutorConfigurationSupport
         ↳ org.springframework.scheduling.concurrent.ScheduledExecutorFactoryBean

Class Overview

FactoryBean that sets up a JDK 1.5 java.util.concurrent.ScheduledExecutorService (by default: a java.util.concurrent.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 just require static registration of tasks at startup, there is no need to access the ScheduledExecutorService instance itself in application code.

Note that java.util.concurrent.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 java.util.concurrent.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".

See Also

Summary

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Inherited Fields
From class org.springframework.scheduling.concurrent.ExecutorConfigurationSupport
Public Constructors
ScheduledExecutorFactoryBean()
Public Methods
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.
boolean isSingleton()
Is the object managed by this factory a singleton? That is, will 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.

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 setScheduledExecutorTasks(ScheduledExecutorTask[] scheduledExecutorTasks)
Register a list of ScheduledExecutorTask objects with the ScheduledExecutorService that this FactoryBean creates.
Protected Methods
ScheduledExecutorService createExecutor(int poolSize, ThreadFactory threadFactory, RejectedExecutionHandler rejectedExecutionHandler)
Create a new ScheduledExecutorService instance.
Runnable getRunnableToSchedule(ScheduledExecutorTask task)
Determine the actual Runnable to schedule for the given task.
ExecutorService initializeExecutor(ThreadFactory threadFactory, RejectedExecutionHandler rejectedExecutionHandler)
Create the target ExecutorService instance.
void registerTasks(ScheduledExecutorTask[] tasks, ScheduledExecutorService executor)
Register the specified ScheduledExecutorTasks on the given ScheduledExecutorService.
[Expand]
Inherited Methods
From class org.springframework.scheduling.concurrent.ExecutorConfigurationSupport
From class org.springframework.scheduling.concurrent.CustomizableThreadFactory
From class org.springframework.util.CustomizableThreadCreator
From class java.lang.Object
From interface java.util.concurrent.ThreadFactory
From interface org.springframework.beans.factory.BeanNameAware
From interface org.springframework.beans.factory.DisposableBean
From interface org.springframework.beans.factory.FactoryBean
From interface org.springframework.beans.factory.InitializingBean

Public Constructors

public ScheduledExecutorFactoryBean ()

Public Methods

public ScheduledExecutorService getObject ()

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.

Returns
  • an instance of the bean (can be null)

public Class<? extends ScheduledExecutorService> getObjectType ()

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.

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

public boolean isSingleton ()

Is the object managed by this factory a singleton? That is, will 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 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.

Returns
  • whether the exposed object is a singleton

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

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

public void setPoolSize (int poolSize)

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

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

Protected Methods

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

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)

protected ExecutorService initializeExecutor (ThreadFactory threadFactory, RejectedExecutionHandler rejectedExecutionHandler)

Create the target ExecutorService instance. Called by afterPropertiesSet.

Parameters
threadFactory the ThreadFactory to use
rejectedExecutionHandler the RejectedExecutionHandler to use
Returns
  • a new ExecutorService instance

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.