Package org.springframework.scheduling.concurrent

Class ThreadPoolTaskExecutor

java.lang.Object
org.springframework.util.CustomizableThreadCreator
org.springframework.scheduling.concurrent.CustomizableThreadFactory
org.springframework.scheduling.concurrent.ExecutorConfigurationSupport
org.springframework.scheduling.concurrent.ThreadPoolTaskExecutor
All Implemented Interfaces:
Serializable, Executor, ThreadFactory, EventListener, Aware, BeanNameAware, DisposableBean, InitializingBean, ApplicationContextAware, ApplicationListener<ContextClosedEvent>, Lifecycle, Phased, SmartLifecycle, AsyncListenableTaskExecutor, AsyncTaskExecutor, TaskExecutor, SchedulingTaskExecutor
public class ThreadPoolTaskExecutor extends ExecutorConfigurationSupport implements AsyncListenableTaskExecutor, SchedulingTaskExecutor
JavaBean that allows for configuring a ThreadPoolExecutor in bean style (through its "corePoolSize", "maxPoolSize", "keepAliveSeconds", "queueCapacity" properties) and exposing it as a Spring TaskExecutor. This class is also well suited for management and monitoring (e.g. through JMX), providing several useful attributes: "corePoolSize", "maxPoolSize", "keepAliveSeconds" (all supporting updates at runtime); "poolSize", "activeCount" (for introspection only).

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).

NOTE: This class implements Spring's TaskExecutor interface as well as the Executor interface, with the former being the primary interface, the other just serving as secondary convenience. For this reason, the exception handling follows the TaskExecutor contract rather than the Executor contract, in particular regarding the TaskRejectedException.

For an alternative, you may set up a ThreadPoolExecutor instance directly using constructor injection, or use a factory method definition that points to the Executors class. To expose such a raw Executor as a Spring TaskExecutor, simply wrap it with a ConcurrentTaskExecutor adapter.

Since:
2.0
Author:
Juergen Hoeller, Rémy Guihard, Sam Brannen
See Also:

  • Constructor Details

    • ThreadPoolTaskExecutor

      public ThreadPoolTaskExecutor()

  • Method Details

    • setCorePoolSize

      public void setCorePoolSize(int corePoolSize)
      Set the ThreadPoolExecutor's core pool size. Default is 1.

      This setting can be modified at runtime, for example through JMX.

    • getCorePoolSize

      public int getCorePoolSize()
      Return the ThreadPoolExecutor's core pool size.

    • setMaxPoolSize

      public void setMaxPoolSize(int maxPoolSize)
      Set the ThreadPoolExecutor's maximum pool size. Default is Integer.MAX_VALUE.

      This setting can be modified at runtime, for example through JMX.

    • getMaxPoolSize

      public int getMaxPoolSize()
      Return the ThreadPoolExecutor's maximum pool size.

    • setKeepAliveSeconds

      public void setKeepAliveSeconds(int keepAliveSeconds)
      Set the ThreadPoolExecutor's keep-alive seconds.

      Default is 60.

      This setting can be modified at runtime, for example through JMX.

    • getKeepAliveSeconds

      public int getKeepAliveSeconds()
      Return the ThreadPoolExecutor's keep-alive seconds.

    • setQueueCapacity

      public void setQueueCapacity(int queueCapacity)
      Set the capacity for the ThreadPoolExecutor's BlockingQueue.

      Default is Integer.MAX_VALUE.

      Any positive value will lead to a LinkedBlockingQueue instance; any other value will lead to a SynchronousQueue instance.

      See Also:

    • getQueueCapacity

      public int getQueueCapacity()
      Return the capacity for the ThreadPoolExecutor's BlockingQueue.
      Since:
      5.3.21
      See Also:

    • setAllowCoreThreadTimeOut

      public void setAllowCoreThreadTimeOut(boolean allowCoreThreadTimeOut)
      Specify whether to allow core threads to time out. This enables dynamic growing and shrinking even in combination with a non-zero queue (since the max pool size will only grow once the queue is full).

      Default is "false".

      See Also:

    • setPrestartAllCoreThreads

      public void setPrestartAllCoreThreads(boolean prestartAllCoreThreads)
      Specify whether to start all core threads, causing them to idly wait for work.

      Default is "false", starting threads and adding them to the pool on demand.

      Since:
      5.3.14
      See Also:

    • setStrictEarlyShutdown

      public void setStrictEarlyShutdown(boolean defaultEarlyShutdown)
      Specify whether to initiate an early shutdown signal on context close, disposing all idle threads and rejecting further task submissions.

      By default, existing tasks will be allowed to complete within the coordinated lifecycle stop phase in any case. This setting just controls whether an explicit ThreadPoolExecutor.shutdown() call will be triggered on context close, rejecting task submissions after that point.

      As of 6.1.4, the default is "false", leniently allowing for late tasks to arrive after context close, still participating in the lifecycle stop phase. Note that this differs from ExecutorConfigurationSupport.setAcceptTasksAfterContextClose(boolean) which completely bypasses the coordinated lifecycle stop phase, with no explicit waiting for the completion of existing tasks at all.

      Switch this to "true" for a strict early shutdown signal analogous to the 6.1-established default behavior of ThreadPoolTaskScheduler. Note that the related flags ExecutorConfigurationSupport.setAcceptTasksAfterContextClose(boolean) and ExecutorConfigurationSupport.setWaitForTasksToCompleteOnShutdown(boolean) will override this setting, leading to a late shutdown without a coordinated lifecycle stop phase.

      Since:
      6.1.4
      See Also:

    • setTaskDecorator

      public void setTaskDecorator(TaskDecorator taskDecorator)
      Specify a custom TaskDecorator to be applied to any Runnable about to be executed.

      Note that such a decorator is not necessarily being applied to the user-supplied Runnable/Callable but rather to the actual execution callback (which may be a wrapper around the user-supplied task).

      The primary use case is to set some execution context around the task's invocation, or to provide some monitoring/statistics for task execution.

      NOTE: Exception handling in TaskDecorator implementations is limited to plain Runnable execution via execute calls. In case of #submit calls, the exposed Runnable will be a FutureTask which does not propagate any exceptions; you might have to cast it and call Future#get to evaluate exceptions. See the ThreadPoolExecutor#afterExecute javadoc for an example of how to access exceptions in such a Future case.

      Since:
      4.3

    • initializeExecutor

      protected ExecutorService initializeExecutor(ThreadFactory threadFactory, RejectedExecutionHandler rejectedExecutionHandler)
      Note: This method exposes an ExecutorService to its base class but stores the actual ThreadPoolExecutor handle internally. Do not override this method for replacing the executor, rather just for decorating its ExecutorService handle or storing custom state.
      Specified by:
      initializeExecutor in class ExecutorConfigurationSupport
      Parameters:
      threadFactory - the ThreadFactory to use
      rejectedExecutionHandler - the RejectedExecutionHandler to use
      Returns:
      a new ExecutorService instance
      See Also:

    • createQueue

      protected BlockingQueue<Runnable> createQueue(int queueCapacity)
      Create the BlockingQueue to use for the ThreadPoolExecutor.

      A LinkedBlockingQueue instance will be created for a positive capacity value; a SynchronousQueue otherwise.

      Parameters:
      queueCapacity - the specified queue capacity
      Returns:
      the BlockingQueue instance
      See Also:

    • getThreadPoolExecutor

      public ThreadPoolExecutor getThreadPoolExecutor() throws IllegalStateException
      Return the underlying ThreadPoolExecutor for native access.
      Returns:
      the underlying ThreadPoolExecutor (never null)
      Throws:
      IllegalStateException - if the ThreadPoolTaskExecutor hasn't been initialized yet

    • getPoolSize

      public int getPoolSize()
      Return the current pool size.
      See Also:

    • getQueueSize

      public int getQueueSize()
      Return the current queue size.
      Since:
      5.3.21
      See Also:

    • getActiveCount

      public int getActiveCount()
      Return the number of currently active threads.
      See Also:

    • execute

      public void execute(Runnable task)
      Description copied from interface: TaskExecutor
      Execute the given task.

      The call might return immediately if the implementation uses an asynchronous execution strategy, or might block in the case of synchronous execution.

      Specified by:
      execute in interface Executor
      Specified by:
      execute in interface TaskExecutor
      Parameters:
      task - the Runnable to execute (never null)

    • submit

      public Future<?> submit(Runnable task)
      Description copied from interface: AsyncTaskExecutor
      Submit a Runnable task for execution, receiving a Future representing that task. The Future will return a null result upon completion.

      As of 6.1, this method comes with a default implementation that delegates to TaskExecutor.execute(Runnable).

      Specified by:
      submit in interface AsyncTaskExecutor
      Parameters:
      task - the Runnable to execute (never null)
      Returns:
      a Future representing pending completion of the task

    • submit

      public <T> Future<T> submit(Callable<T> task)
      Description copied from interface: AsyncTaskExecutor
      Submit a Callable task for execution, receiving a Future representing that task. The Future will return the Callable's result upon completion.

      As of 6.1, this method comes with a default implementation that delegates to TaskExecutor.execute(Runnable).

      Specified by:
      submit in interface AsyncTaskExecutor
      Parameters:
      task - the Callable to execute (never null)
      Returns:
      a Future representing pending completion of the task

    • submitListenable

      public ListenableFuture<?> submitListenable(Runnable task)
      Description copied from interface: AsyncListenableTaskExecutor
      Submit a Runnable task for execution, receiving a ListenableFuture representing that task. The Future will return a null result upon completion.
      Specified by:
      submitListenable in interface AsyncListenableTaskExecutor
      Parameters:
      task - the Runnable to execute (never null)
      Returns:
      a ListenableFuture representing pending completion of the task

    • submitListenable

      public <T> ListenableFuture<T> submitListenable(Callable<T> task)
      Description copied from interface: AsyncListenableTaskExecutor
      Submit a Callable task for execution, receiving a ListenableFuture representing that task. The Future will return the Callable's result upon completion.
      Specified by:
      submitListenable in interface AsyncListenableTaskExecutor
      Parameters:
      task - the Callable to execute (never null)
      Returns:
      a ListenableFuture representing pending completion of the task

    • cancelRemainingTask

      protected void cancelRemainingTask(Runnable task)
      Description copied from class: ExecutorConfigurationSupport
      Cancel the given remaining task which never commenced execution, as returned from ExecutorService.shutdownNow().
      Overrides:
      cancelRemainingTask in class ExecutorConfigurationSupport
      Parameters:
      task - the task to cancel (typically a RunnableFuture)
      See Also:

    • initiateEarlyShutdown

      protected void initiateEarlyShutdown()
      Description copied from class: ExecutorConfigurationSupport
      Early shutdown signal: do not trigger further tasks, let existing tasks complete before hitting the actual destruction step in the ExecutorConfigurationSupport.shutdown() method. This goes along with a coordinated lifecycle stop phase.

      Called from ExecutorConfigurationSupport.onApplicationEvent(ContextClosedEvent) if no indications for a late shutdown have been determined, that is, if the "acceptTasksAfterContextClose and "waitForTasksToCompleteOnShutdown" flags have not been set.

      The default implementation calls ExecutorConfigurationSupport.initiateShutdown().

      Overrides:
      initiateEarlyShutdown in class ExecutorConfigurationSupport
      See Also: