Class ScheduledExecutorFactoryBean

  • All Implemented Interfaces:, java.util.concurrent.ThreadFactory, Aware, BeanNameAware, DisposableBean, FactoryBean<java.util.concurrent.ScheduledExecutorService>, InitializingBean

    public class ScheduledExecutorFactoryBean
    extends ExecutorConfigurationSupport
    implements FactoryBean<java.util.concurrent.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".

    Juergen Hoeller
    See Also:
    setPoolSize(int), setRemoveOnCancelPolicy(boolean), ExecutorConfigurationSupport.setThreadFactory(java.util.concurrent.ThreadFactory), ScheduledExecutorTask, ScheduledExecutorService, ScheduledThreadPoolExecutor, Serialized Form
    • 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.

        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:
      • initializeExecutor

        protected java.util.concurrent.ExecutorService initializeExecutor(java.util.concurrent.ThreadFactory threadFactory,
                                                                          java.util.concurrent.RejectedExecutionHandler rejectedExecutionHandler)
        Description copied from class: ExecutorConfigurationSupport
        Create the target ExecutorService instance. Called by afterPropertiesSet.
        Specified by:
        initializeExecutor in class ExecutorConfigurationSupport
        threadFactory - the ThreadFactory to use
        rejectedExecutionHandler - the RejectedExecutionHandler to use
        a new ExecutorService instance
        See Also:
      • createExecutor

        protected java.util.concurrent.ScheduledExecutorService createExecutor(int poolSize,
                                                                               java.util.concurrent.ThreadFactory threadFactory,
                                                                               java.util.concurrent.RejectedExecutionHandler rejectedExecutionHandler)
        Create a new ScheduledExecutorService instance.

        The default implementation creates a ScheduledThreadPoolExecutor. Can be overridden in subclasses to provide custom ScheduledExecutorService instances.

        poolSize - the specified pool size
        threadFactory - the ThreadFactory to use
        rejectedExecutionHandler - the RejectedExecutionHandler to use
        a new ScheduledExecutorService instance
        See Also:
        ExecutorConfigurationSupport.afterPropertiesSet(), ScheduledThreadPoolExecutor
      • registerTasks

        protected void registerTasks(ScheduledExecutorTask[] tasks,
                                     java.util.concurrent.ScheduledExecutorService executor)
        Register the specified ScheduledExecutorTasks on the given ScheduledExecutorService.
        tasks - the specified ScheduledExecutorTasks (never empty)
        executor - the ScheduledExecutorService to register the tasks on.
      • getRunnableToSchedule

        protected java.lang.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.

        task - the ScheduledExecutorTask to schedule
        the actual Runnable to schedule (may be a decorator)
      • getObject

        public java.util.concurrent.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<java.util.concurrent.ScheduledExecutorService>
        an instance of the bean (can be null)
        See Also:
      • getObjectType

        public java.lang.Class<? extends java.util.concurrent.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<java.util.concurrent.ScheduledExecutorService>
        the type of object that this FactoryBean creates, or null if not known at the time of the call
        See Also:
      • 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.

        The default implementation returns true, since a FactoryBean typically manages a singleton instance.

        Specified by:
        isSingleton in interface FactoryBean<java.util.concurrent.ScheduledExecutorService>
        whether the exposed object is a singleton
        See Also:
        FactoryBean.getObject(), SmartFactoryBean.isPrototype()