org.springframework.core.task
Class SimpleAsyncTaskExecutor

java.lang.Object
  extended by org.springframework.util.CustomizableThreadCreator
      extended by org.springframework.core.task.SimpleAsyncTaskExecutor
All Implemented Interfaces:
Serializable, Executor, AsyncTaskExecutor, TaskExecutor

public class SimpleAsyncTaskExecutor
extends CustomizableThreadCreator
implements AsyncTaskExecutor, Serializable

TaskExecutor implementation that fires up a new Thread for each task, executing it asynchronously.

Supports limiting concurrent threads through the "concurrencyLimit" bean property. By default, the number of concurrent threads is unlimited.

NOTE: This implementation does not reuse threads! Consider a thread-pooling TaskExecutor implementation instead, in particular for executing a large number of short-lived tasks.

Since:
2.0
Author:
Juergen Hoeller
See Also:
setConcurrencyLimit(int), SyncTaskExecutor, TimerTaskExecutor, ThreadPoolTaskExecutor, WorkManagerTaskExecutor, Serialized Form

Field Summary
static int NO_CONCURRENCY
          Switch concurrency 'off': that is, don't allow any concurrent invocations.
static int UNBOUNDED_CONCURRENCY
          Permit any number of concurrent invocations: that is, don't throttle concurrency.
 
Fields inherited from interface org.springframework.core.task.AsyncTaskExecutor
TIMEOUT_IMMEDIATE, TIMEOUT_INDEFINITE
 
Constructor Summary
SimpleAsyncTaskExecutor()
          Create a new SimpleAsyncTaskExecutor with default thread name prefix.
SimpleAsyncTaskExecutor(String threadNamePrefix)
          Create a new SimpleAsyncTaskExecutor with the given thread name prefix.
SimpleAsyncTaskExecutor(ThreadFactory threadFactory)
          Create a new SimpleAsyncTaskExecutor with the given external thread factory.
 
Method Summary
protected  void doExecute(Runnable task)
          Template method for the actual execution of a task.
 void execute(Runnable task)
          Executes the given task, within a concurrency throttle if configured (through the superclass's settings).
 void execute(Runnable task, long startTimeout)
          Executes the given task, within a concurrency throttle if configured (through the superclass's settings).
 int getConcurrencyLimit()
          Return the maximum number of parallel accesses allowed.
 ThreadFactory getThreadFactory()
          Return the external factory to use for creating new Threads, if any.
 boolean isThrottleActive()
          Return whether this throttle is currently active.
 void setConcurrencyLimit(int concurrencyLimit)
          Set the maximum number of parallel accesses allowed.
 void setThreadFactory(ThreadFactory threadFactory)
          Specify an external factory to use for creating new Threads, instead of relying on the local properties of this executor.
<T> Future<T>
submit(Callable<T> task)
          Submit a Callable task for execution, receiving a Future representing that task.
 Future<?> submit(Runnable task)
          Submit a Runnable task for execution, receiving a Future representing that task.
 
Methods inherited from class org.springframework.util.CustomizableThreadCreator
createThread, getDefaultThreadNamePrefix, getThreadGroup, getThreadNamePrefix, getThreadPriority, isDaemon, nextThreadName, setDaemon, setThreadGroup, setThreadGroupName, setThreadNamePrefix, setThreadPriority
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Field Detail

UNBOUNDED_CONCURRENCY

public static final int UNBOUNDED_CONCURRENCY
Permit any number of concurrent invocations: that is, don't throttle concurrency.

See Also:
Constant Field Values

NO_CONCURRENCY

public static final int NO_CONCURRENCY
Switch concurrency 'off': that is, don't allow any concurrent invocations.

See Also:
Constant Field Values
Constructor Detail

SimpleAsyncTaskExecutor

public SimpleAsyncTaskExecutor()
Create a new SimpleAsyncTaskExecutor with default thread name prefix.


SimpleAsyncTaskExecutor

public SimpleAsyncTaskExecutor(String threadNamePrefix)
Create a new SimpleAsyncTaskExecutor with the given thread name prefix.

Parameters:
threadNamePrefix - the prefix to use for the names of newly created threads

SimpleAsyncTaskExecutor

public SimpleAsyncTaskExecutor(ThreadFactory threadFactory)
Create a new SimpleAsyncTaskExecutor with the given external thread factory.

Parameters:
threadFactory - the factory to use for creating new Threads
Method Detail

setThreadFactory

public void setThreadFactory(ThreadFactory threadFactory)
Specify an external factory to use for creating new Threads, instead of relying on the local properties of this executor.

You may specify an inner ThreadFactory bean or also a ThreadFactory reference obtained from JNDI (on a Java EE 6 server) or some other lookup mechanism.

See Also:
CustomizableThreadCreator.setThreadNamePrefix(java.lang.String), CustomizableThreadCreator.setThreadPriority(int)

getThreadFactory

public final ThreadFactory getThreadFactory()
Return the external factory to use for creating new Threads, if any.


setConcurrencyLimit

public void setConcurrencyLimit(int concurrencyLimit)
Set the maximum number of parallel accesses allowed. -1 indicates no concurrency limit at all.

In principle, this limit can be changed at runtime, although it is generally designed as a config time setting. NOTE: Do not switch between -1 and any concrete limit at runtime, as this will lead to inconsistent concurrency counts: A limit of -1 effectively turns off concurrency counting completely.

See Also:
UNBOUNDED_CONCURRENCY

getConcurrencyLimit

public final int getConcurrencyLimit()
Return the maximum number of parallel accesses allowed.


isThrottleActive

public final boolean isThrottleActive()
Return whether this throttle is currently active.

Returns:
true if the concurrency limit for this instance is active
See Also:
getConcurrencyLimit(), setConcurrencyLimit(int)

execute

public void execute(Runnable task)
Executes the given task, within a concurrency throttle if configured (through the superclass's settings).

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

execute

public void execute(Runnable task,
                    long startTimeout)
Executes the given task, within a concurrency throttle if configured (through the superclass's settings).

Executes urgent tasks (with 'immediate' timeout) directly, bypassing the concurrency throttle (if active). All other tasks are subject to throttling.

Specified by:
execute in interface AsyncTaskExecutor
Parameters:
task - the Runnable to execute (never null)
startTimeout - the time duration (milliseconds) within which the task is supposed to start. This is intended as a hint to the executor, allowing for preferred handling of immediate tasks. Typical values are AsyncTaskExecutor.TIMEOUT_IMMEDIATE or AsyncTaskExecutor.TIMEOUT_INDEFINITE (the default as used by TaskExecutor.execute(Runnable)).
See Also:
AsyncTaskExecutor.TIMEOUT_IMMEDIATE, doExecute(Runnable)

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.

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.

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

doExecute

protected void doExecute(Runnable task)
Template method for the actual execution of a task.

The default implementation creates a new Thread and starts it.

Parameters:
task - the Runnable to execute
See Also:
setThreadFactory(java.util.concurrent.ThreadFactory), CustomizableThreadCreator.createThread(java.lang.Runnable), Thread.start()