Package de.aristaflow.adept2.util.threading

Class LoggingScheduledThreadPoolExecutor

java.lang.Object

java.util.concurrent.AbstractExecutorService

java.util.concurrent.ThreadPoolExecutor

java.util.concurrent.ScheduledThreadPoolExecutor

de.aristaflow.adept2.util.threading.LoggingScheduledThreadPoolExecutor

All Implemented Interfaces:

Executor, ExecutorService, ScheduledExecutorService

public class LoggingScheduledThreadPoolExecutor
extends ScheduledThreadPoolExecutor

This class creates logging futures when scheduling. These log their outcome (results and exceptions) if no one retrieved it. This is especially useful when scheduling work for polling where no one checks the result and therefore also the exceptions are ignored.

Nested Class Summary

Nested classes/interfaces inherited from class java.util.concurrent.ThreadPoolExecutor

ThreadPoolExecutor.AbortPolicy, ThreadPoolExecutor.CallerRunsPolicy, ThreadPoolExecutor.DiscardOldestPolicy, ThreadPoolExecutor.DiscardPolicy

Field Summary

Fields

Modifier and Type	Field	Description
protected final boolean	continueRegularAfterException	Whether regular executions should continue even in case of exceptions.
protected final Logger	logger	The logger for logging unhandled results, Exception, RuntimeException or Error.
protected final Collection<Thread>	periodicScheduler	All threads that are currently adding a periodic runnable via scheduleAtFixedRate(Runnable, long, long, TimeUnit) or scheduleWithFixedDelay(Runnable, long, long, TimeUnit).

Constructor Summary

Constructors

Constructor	Description
LoggingScheduledThreadPoolExecutor(int corePoolSize, Adept2ThreadFactory threadFactory, boolean continueRegularAfterException)	Creates a new LoggingScheduledThreadPoolExecutor with the designated core pool size and thread factory also providing the logger.
LoggingScheduledThreadPoolExecutor(int corePoolSize, Adept2ThreadFactory threadFactory, RejectedExecutionHandler handler, boolean continueRegularAfterException)	Creates a new LoggingScheduledThreadPoolExecutor with the designated core pool size, rejected execution handler and thread factory also providing the logger.

Method Summary

Modifier and Type	Method	Description
protected void	afterExecute(Runnable r, Throwable t)
protected void	beforeExecute(Thread t, Runnable r)
protected <V> RunnableScheduledFuture<V>	decorateTask(Runnable runnable, RunnableScheduledFuture<V> task)
protected <V> RunnableScheduledFuture<V>	decorateTask(Callable<V> callable, RunnableScheduledFuture<V> task)
void	execute(Runnable command, boolean logException)	Calls ScheduledThreadPoolExecutor.execute(Runnable) and optionally wraps the runnable to catch and log an occurring runtime exception and virtual machine error.
ScheduledFuture<?>	schedule(Runnable command, long delay, TimeUnit unit, boolean logException, boolean rethrowException)	Calls ScheduledThreadPoolExecutor.schedule(Runnable, long, TimeUnit) and optionally wraps the runnable to log an occurring runtime exception and virtual machine error.
<V> ScheduledFuture<V>	schedule(Callable<V> callable, long delay, TimeUnit unit, boolean logException)	Calls ScheduledThreadPoolExecutor.schedule(Callable, long, TimeUnit) and optionally wraps the callable to catch and log an occurred exception.
ScheduledFuture<?>	scheduleAtFixedRate(Runnable command, long initialDelay, long period, TimeUnit unit)
ScheduledFuture<?>	scheduleWithFixedDelay(Runnable command, long initialDelay, long delay, TimeUnit unit)
Future<?>	submit(Runnable task, boolean logException, boolean rethrowException)	Calls ScheduledThreadPoolExecutor.submit(Runnable) and optionally wraps the runnable to log an occurring exception.
<T> Future<T>	submit(Runnable task, T result, boolean logException)	Calls ScheduledThreadPoolExecutor.submit(Runnable, Object) and optionally wraps the runnable to log an occurring exception.
<T> Future<T>	submit(Callable<T> task, boolean logException)	Calls ScheduledThreadPoolExecutor.submit(Callable) and optionally wraps the callable to catch and log an occurred exception.
protected <V> Callable<V>	wrapCallable(Callable<V> command, boolean loggingRequested, boolean rethrow)	Wraps the designated command by a callable catching and logging an occurred exception and optionally rethrowing it to provide it via the returned callable.
protected Runnable	wrapRunnable(Runnable command, boolean loggingRequested, boolean rethrow)	Wraps the designated command by a runnable logging runtime exceptions and virtual machine errors instead of forwarding them if requested.

Methods inherited from class java.util.concurrent.ScheduledThreadPoolExecutor

execute, getContinueExistingPeriodicTasksAfterShutdownPolicy, getExecuteExistingDelayedTasksAfterShutdownPolicy, getQueue, getRemoveOnCancelPolicy, schedule, schedule, setContinueExistingPeriodicTasksAfterShutdownPolicy, setExecuteExistingDelayedTasksAfterShutdownPolicy, setRemoveOnCancelPolicy, shutdown, shutdownNow, submit, submit, submit

Methods inherited from class java.util.concurrent.ThreadPoolExecutor

allowCoreThreadTimeOut, allowsCoreThreadTimeOut, awaitTermination, finalize, getActiveCount, getCompletedTaskCount, getCorePoolSize, getKeepAliveTime, getLargestPoolSize, getMaximumPoolSize, getPoolSize, getRejectedExecutionHandler, getTaskCount, getThreadFactory, isShutdown, isTerminated, isTerminating, prestartAllCoreThreads, prestartCoreThread, purge, remove, setCorePoolSize, setKeepAliveTime, setMaximumPoolSize, setRejectedExecutionHandler, setThreadFactory, terminated, toString

Methods inherited from class java.util.concurrent.AbstractExecutorService

invokeAll, invokeAll, invokeAny, invokeAny, newTaskFor, newTaskFor

Methods inherited from class java.lang.Object

clone, equals, getClass, hashCode, notify, notifyAll, wait, wait, wait

Methods inherited from interface java.util.concurrent.ExecutorService

awaitTermination, invokeAll, invokeAll, invokeAny, invokeAny, isShutdown, isTerminated

Field Details

logger

protected final Logger logger

The logger for logging unhandled results, Exception, RuntimeException or Error.

continueRegularAfterException

protected final boolean continueRegularAfterException

Whether regular executions should continue even in case of exceptions. The exceptions will be logged.

periodicScheduler

protected final Collection<Thread> periodicScheduler

All threads that are currently adding a periodic runnable via scheduleAtFixedRate(Runnable, long, long, TimeUnit) or scheduleWithFixedDelay(Runnable, long, long, TimeUnit). In this case we do not decorate using a LoggingScheduledFuture since the RunnableScheduledFuture (task) will get a reference to the surrounding decorator which causes an object cycle with the cleanup and prevents it from being garbage-collected.
This is not a big problem since periodic tasks do not have a result at all so cleanup-logging is irrelevant.

Constructor Details

LoggingScheduledThreadPoolExecutor

public LoggingScheduledThreadPoolExecutor(int corePoolSize,
 Adept2ThreadFactory threadFactory,
 boolean continueRegularAfterException)

Creates a new LoggingScheduledThreadPoolExecutor with the designated core pool size and thread factory also providing the logger. Optionally regular scheduled tasks (ScheduledExecutorService.scheduleAtFixedRate(Runnable, long, long, TimeUnit) and ScheduledExecutorService.scheduleWithFixedDelay(Runnable, long, long, TimeUnit) may be set to log runtime exceptions and virtual machine errors and continue regular execution instead of failing and stopping.

Parameters:

corePoolSize - The number of threads to keep in the pool, even if they are idle.

threadFactory - The factory to use when the executor creates a new thread and which provides the logger for unhandled results and exceptions.

continueRegularAfterException - Whether regular executions should continue even in case of runtime exceptions and virtual machine errors. These exceptions will be logged.

See Also:

• ScheduledThreadPoolExecutor(int, java.util.concurrent.ThreadFactory)

LoggingScheduledThreadPoolExecutor

public LoggingScheduledThreadPoolExecutor(int corePoolSize,
 Adept2ThreadFactory threadFactory,
 RejectedExecutionHandler handler,
 boolean continueRegularAfterException)

Creates a new LoggingScheduledThreadPoolExecutor with the designated core pool size, rejected execution handler and thread factory also providing the logger. Optionally regular scheduled tasks (ScheduledExecutorService.scheduleAtFixedRate(Runnable, long, long, TimeUnit) and ScheduledExecutorService.scheduleWithFixedDelay(Runnable, long, long, TimeUnit) may be set to log runtime exceptions and virtual machine errors and continue regular execution instead of failing and stopping.

Parameters:

corePoolSize - The number of threads to keep in the pool, even if they are idle.

threadFactory - The factory to use when the executor creates a new thread and which provides the logger for unhandled results and exceptions.

handler - The handler to use when execution is blocked.

continueRegularAfterException - Whether regular executions should continue even in case of runtime exceptions and virtual machine errors. These exceptions will be logged.

See Also:

• ScheduledThreadPoolExecutor(int, java.util.concurrent.ThreadFactory, RejectedExecutionHandler)

Method Details

schedule

public ScheduledFuture<?> schedule(Runnable command,
 long delay,
 TimeUnit unit,
 boolean logException,
 boolean rethrowException)

Calls ScheduledThreadPoolExecutor.schedule(Runnable, long, TimeUnit) and optionally wraps the runnable to log an occurring runtime exception and virtual machine error. This will be provided via the returned future if rethrown. If you are about to check the returned future, you should let the runtime exception/virtual machine error be rethrown.

Parameters:

logException - Whether to log an occurred runtime exception/virtual machine error.

rethrowException - Whether to rethrow the logged runtime exception/virtual machine error. This parameter will be ignored if logException is false.

schedule

public <V> ScheduledFuture<V> schedule(Callable<V> callable,
 long delay,
 TimeUnit unit,
 boolean logException)

Calls ScheduledThreadPoolExecutor.schedule(Callable, long, TimeUnit) and optionally wraps the callable to catch and log an occurred exception. The exception will always be provided via the designated callable and the returned future.

Parameters:

logException - Whether to additionally log an occurred exception.

scheduleAtFixedRate

public ScheduledFuture<?> scheduleAtFixedRate(Runnable command,
 long initialDelay,
 long period,
 TimeUnit unit)

Specified by:

scheduleAtFixedRate in interface ScheduledExecutorService

Overrides:

scheduleAtFixedRate in class ScheduledThreadPoolExecutor

scheduleWithFixedDelay

public ScheduledFuture<?> scheduleWithFixedDelay(Runnable command,
 long initialDelay,
 long delay,
 TimeUnit unit)

Specified by:

scheduleWithFixedDelay in interface ScheduledExecutorService

Overrides:

scheduleWithFixedDelay in class ScheduledThreadPoolExecutor

execute

public void execute(Runnable command,
 boolean logException)

Calls ScheduledThreadPoolExecutor.execute(Runnable) and optionally wraps the runnable to catch and log an occurring runtime exception and virtual machine error. Since there is no one expecting the exception, it will not be rethrown after logging.

Parameters:

logException - Whether to additionally log an occurred runtime exception/virtual machine error.

submit

public Future<?> submit(Runnable task,
 boolean logException,
 boolean rethrowException)

Calls ScheduledThreadPoolExecutor.submit(Runnable) and optionally wraps the runnable to log an occurring exception. The exception will be provided via the returned future if rethrown. If you are about to check the returned future, you should let the exception be rethrown.

Parameters:

logException - Whether to log an occurred exception.

rethrowException - Whether to rethrow the logged exception. This will be ignored if logException is false.

submit

public <T> Future<T> submit(Runnable task,
 T result,
 boolean logException)

Calls ScheduledThreadPoolExecutor.submit(Runnable, Object) and optionally wraps the runnable to log an occurring exception. The exception will always be provided via the returned future.

Parameters:

logException - Whether to additionally log an occurred exception.

submit

public <T> Future<T> submit(Callable<T> task,
 boolean logException)

Calls ScheduledThreadPoolExecutor.submit(Callable) and optionally wraps the callable to catch and log an occurred exception. The exception will always be provided via the returned callable.

Parameters:

logException - Whether to additionally log an occurred exception.

decorateTask

protected <V> RunnableScheduledFuture<V> decorateTask(Runnable runnable,
 RunnableScheduledFuture<V> task)

Overrides:

decorateTask in class ScheduledThreadPoolExecutor

decorateTask

protected <V> RunnableScheduledFuture<V> decorateTask(Callable<V> callable,
 RunnableScheduledFuture<V> task)

Overrides:

decorateTask in class ScheduledThreadPoolExecutor

beforeExecute

protected void beforeExecute(Thread t,
 Runnable r)

Overrides:

beforeExecute in class ThreadPoolExecutor

afterExecute

protected void afterExecute(Runnable r,
 Throwable t)

Overrides:

afterExecute in class ThreadPoolExecutor

wrapRunnable

protected Runnable wrapRunnable(Runnable command,
 boolean loggingRequested,
 boolean rethrow)

Wraps the designated command by a runnable logging runtime exceptions and virtual machine errors instead of forwarding them if requested. Optionally, the runtime exception/virtual machine error may be rethrown to store it in the returned future.

Parameters:

command - The command which to wrap.

loggingRequested - Whether to actually wrap the runnable.

rethrow - Whether to rethrow the exception to store it in the returned future.

Returns:

The command optionally wrapped by a runnable logging runtime exceptions and virtual machine errors and optionally rethrowing them.

wrapCallable

protected <V> Callable<V> wrapCallable(Callable<V> command,
 boolean loggingRequested,
 boolean rethrow)

Wraps the designated command by a callable catching and logging an occurred exception and optionally rethrowing it to provide it via the returned callable.

Parameters:

command - The command which to wrap.

loggingRequested - Whether to actually wrap the callable.

rethrow - Whether to rethrow the exception to provide it via the returned callable.

Returns:

The command optionally wrapped by a callable catching and logging an occurred exception and optionally rethrowing it.