public class ThreadPoolExecutorFactoryBean extends ExecutorConfigurationSupport implements FactoryBean<ExecutorService>
ThreadPoolExecutorin bean style (through its "corePoolSize", "maxPoolSize", "keepAliveSeconds", "queueCapacity" properties) and exposing it as a bean reference of its native
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).
For an alternative, you may set up a
ThreadPoolExecutor instance directly
using constructor injection, or use a factory method definition that points to the
This is strongly recommended in particular for common
@Bean methods in
configuration classes, where this
FactoryBean variant would force you to
FactoryBean type instead of the actual
|Constructor and Description|
|Modifier and Type||Method and Description|
Create a new instance of
Create the BlockingQueue to use for the ThreadPoolExecutor.
Return an instance (possibly shared or independent) of the object managed by this factory.
Return the type of object that this FactoryBean creates, or
Create the target
Is the object managed by this factory a singleton? That is, will
Specify whether to allow core threads to time out.
Set the ThreadPoolExecutor's core pool size.
Specify whether this FactoryBean should expose an unconfigurable decorator for the created executor.
Set the ThreadPoolExecutor's keep-alive seconds.
Set the ThreadPoolExecutor's maximum pool size.
Specify whether to start all core threads, causing them to idly wait for work.
Set the capacity for the ThreadPoolExecutor's BlockingQueue.
afterPropertiesSet, cancelRemainingTask, destroy, initialize, setAwaitTerminationMillis, setAwaitTerminationSeconds, setBeanName, setRejectedExecutionHandler, setThreadFactory, setThreadNamePrefix, setWaitForTasksToCompleteOnShutdown, shutdown
createThread, getDefaultThreadNamePrefix, getThreadGroup, getThreadNamePrefix, getThreadPriority, isDaemon, nextThreadName, setDaemon, setThreadGroup, setThreadGroupName, setThreadPriority
public void setCorePoolSize(int corePoolSize)
public void setMaxPoolSize(int maxPoolSize)
public void setKeepAliveSeconds(int keepAliveSeconds)
public void setAllowCoreThreadTimeOut(boolean allowCoreThreadTimeOut)
Default is "false".
public void setPrestartAllCoreThreads(boolean prestartAllCoreThreads)
Default is "false".
public void setQueueCapacity(int queueCapacity)
Any positive value will lead to a LinkedBlockingQueue instance; any other value will lead to a SynchronousQueue instance.
public void setExposeUnconfigurableExecutor(boolean exposeUnconfigurableExecutor)
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.
protected ExecutorService initializeExecutor(ThreadFactory threadFactory, RejectedExecutionHandler rejectedExecutionHandler)
ExecutorServiceinstance. Called by
protected ThreadPoolExecutor createExecutor(int corePoolSize, int maxPoolSize, int keepAliveSeconds, BlockingQueue<Runnable> queue, ThreadFactory threadFactory, RejectedExecutionHandler rejectedExecutionHandler)
ThreadPoolExecutoror a subclass thereof.
corePoolSize- the specified core pool size
maxPoolSize- the specified maximum pool size
keepAliveSeconds- the specified keep-alive time in seconds
queue- the BlockingQueue to use
threadFactory- the ThreadFactory to use
rejectedExecutionHandler- the RejectedExecutionHandler to use
protected BlockingQueue<Runnable> createQueue(int queueCapacity)
A LinkedBlockingQueue instance will be created for a positive capacity value; a SynchronousQueue else.
@Nullable public ExecutorService getObject()
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
As of Spring 2.0, FactoryBeans are allowed to return
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.
public Class<? extends ExecutorService> getObjectType()
nullif 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.
nullif not known at the time of the call
public boolean isSingleton()
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
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
may explicitly indicate independent instances through its
SmartFactoryBean.isPrototype() method. Plain
implementations which do not implement this extended interface are
simply assumed to always return independent instances if the
isSingleton() implementation returns
The default implementation returns
true, since a
FactoryBean typically manages a singleton instance.