Package rma.util.concurrent

Class DynamicallySizedThreadPool

java.lang.Object

java.util.concurrent.AbstractExecutorService

java.util.concurrent.ThreadPoolExecutor

rma.util.concurrent.DynamicallySizedThreadPool

All Implemented Interfaces:

Executor, ExecutorService

public class DynamicallySizedThreadPool
extends ThreadPoolExecutor

This class extends ThreadPoolExecutor to support dynamically sized thread pools. The ThreadPoolExecutor only supports dynamic resizing of the thread pool when it has a limited size queue. This means that eventually the queue would fill up, and the threads would fill up, and we'd no longer be able to submit Runnables onto the threads, and the Runnable gets handed off to the RejectionHandler. To bypass this, we're throttling up the corePoolSize to a point where we create enough threads to handle the Runnable throughput, or max out the threads. Once the Runnables have all completed their job, the corePoolSize is reduced to the minimumPoolSize handed to the constructor. After a period of time, the extra threads will die off (keepAliveTime, and unit from ctor). The strategy for adjusting the corePoolSize is that when a Runnable is queued up due to insufficient Threads the corePoolSize is increased to pick up all new Runnables. The corePoolSize does not go down until all runnables have been completed, and the corePoolSize is reset to the minimumPoolSize. This forces the corePoolSize to the maximumPoolSize very quickly when a huge influx of Runnables are submitted, but when a steady stream of quick Runnables are submitted, it will maintain a balanced size to fit the needs of the submitted Runnables. Before modifying this code, please contact Ryan Miles and Peter Morris.

Nested Class Summary

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

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

Constructor Summary

Constructors

Constructor	Description
DynamicallySizedThreadPool(int minimumPoolSize, int maximumPoolSize, long keepAliveTime, TimeUnit unit, BlockingQueue<Runnable> workQueue, ThreadFactory threadFactory)
DynamicallySizedThreadPool(int corePoolSize, int maximumPoolSize, long keepAliveTime, TimeUnit unit, BlockingQueue<Runnable> workQueue, ThreadFactory threadFactory, RejectedExecutionHandler handler)

Method Summary

Modifier and Type	Method	Description
protected void	afterExecute(Runnable task, Throwable t)
void	execute(Runnable task)

Methods inherited from class java.util.concurrent.ThreadPoolExecutor

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

Methods inherited from class java.util.concurrent.AbstractExecutorService

invokeAll, invokeAll, invokeAny, invokeAny, newTaskFor, newTaskFor, submit, submit, submit

Methods inherited from class java.lang.Object

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

Constructor Details

DynamicallySizedThreadPool

public DynamicallySizedThreadPool(int minimumPoolSize,
 int maximumPoolSize,
 long keepAliveTime,
 TimeUnit unit,
 BlockingQueue<Runnable> workQueue,
 ThreadFactory threadFactory)

DynamicallySizedThreadPool

public DynamicallySizedThreadPool(int corePoolSize,
 int maximumPoolSize,
 long keepAliveTime,
 TimeUnit unit,
 BlockingQueue<Runnable> workQueue,
 ThreadFactory threadFactory,
 RejectedExecutionHandler handler)

Method Details

afterExecute

protected void afterExecute(Runnable task,
 Throwable t)

Overrides:

afterExecute in class ThreadPoolExecutor

execute

public void execute(Runnable task)

Specified by:

execute in interface Executor

Overrides:

execute in class ThreadPoolExecutor