org.cache2k.impl.threading

Class GlobalPooledExecutor

java.lang.Object

org.cache2k.impl.threading.GlobalPooledExecutor

public class GlobalPooledExecutor
extends Object

A thread pool to be shared amount several client caches for different purposes. The pool creates a new thread whenever a new task is submitted but one task is still in the queue and waiting for execution. After reaching a hard thread limit new submissions fill the queue and stall if the queue is full. The hard limit is only a precaution and not to be intended to be reached within normal operation.

The general idea is that a thread limit adapted to a specific use case is introduced on top, so the thread pool is not used directly but by using a LimitedPooledExecutor which provides an ExecutorService interface.

After some time waiting a pool thread will die. If there is no work to be done no thread will be kept alive. Instead of defining a low pool size to have some threads always available for the typical workloads, each thread waits for a randomized idle time up to 30 minutes until it dies. This way the amount of threads staying in the pool adapts to the workload itself (hopefully...).

Author:

Jens Wilke; created: 2014-05-12 FIXME: implementation is faulty, we need to come up with a better implementation or a different approach. Discovered a design error: If one task keeps busy or is stuck the pool is not spawning a new thread, since there is no real measure of active threads. I think we should adapt the thread pool executor.

See Also:

LimitedPooledExecutor, ExecutorService

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static interface	GlobalPooledExecutor.ProgressNotifier
static class	GlobalPooledExecutor.Tunable

Constructor Summary

Constructors

Constructor and Description
GlobalPooledExecutor(String _name)

Method Summary

Methods

Modifier and Type	Method and Description
void	close() Remove pending jobs from the task queue and stop threads in the pool.
<V> Future<V>	execute(Callable<V> c)
<V> Future<V>	execute(Callable<V> c, GlobalPooledExecutor.ProgressNotifier n)
<V> Future<V>	execute(Callable<V> c, GlobalPooledExecutor.ProgressNotifier n, long _timeoutMillis)
void	execute(Runnable r)
void	execute(Runnable r, GlobalPooledExecutor.ProgressNotifier n)
int	getDiedThreadCount()
int	getPeakThreadCount()
int	getThreadInUseCount()
int	getTotalStartedThreadCount()
void	waitUntilAllDied()
boolean	wasWarningLimitReached() Used for alerting.

Methods inherited from class java.lang.Object

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

Constructor Detail

GlobalPooledExecutor

public GlobalPooledExecutor(String _name)

Parameters:

_name - used for the thread name prefix.

Method Detail

execute

public void execute(Runnable r)
             throws InterruptedException,
                    TimeoutException

Throws:

InterruptedException

TimeoutException

execute

public <V> Future<V> execute(Callable<V> c)
                  throws InterruptedException,
                         TimeoutException

Throws:

InterruptedException

TimeoutException

execute

public void execute(Runnable r,
           GlobalPooledExecutor.ProgressNotifier n)
             throws InterruptedException,
                    TimeoutException

Throws:

InterruptedException

TimeoutException

execute

public <V> Future<V> execute(Callable<V> c,
                    GlobalPooledExecutor.ProgressNotifier n)
                  throws InterruptedException,
                         TimeoutException

Throws:

InterruptedException

TimeoutException

execute

public <V> Future<V> execute(Callable<V> c,
                    GlobalPooledExecutor.ProgressNotifier n,
                    long _timeoutMillis)
                  throws InterruptedException,
                         TimeoutException

Parameters:

_timeoutMillis - 0 means immediately timeout, if no space is available

Throws:

InterruptedException

TimeoutException

waitUntilAllDied

public void waitUntilAllDied()

close

public void close()

Remove pending jobs from the task queue and stop threads in the pool. Threads which run jobs will finish them.

getTotalStartedThreadCount

public int getTotalStartedThreadCount()

getThreadInUseCount

public int getThreadInUseCount()

getDiedThreadCount

public int getDiedThreadCount()

wasWarningLimitReached

public boolean wasWarningLimitReached()

Used for alerting.

getPeakThreadCount

public int getPeakThreadCount()