JBoss Common Classes 2.2.17.GA

org.jboss.util.threadpool
Class MinPooledExecutor

java.lang.Object
  extended by java.util.concurrent.AbstractExecutorService
      extended by java.util.concurrent.ThreadPoolExecutor
          extended by org.jboss.util.threadpool.MinPooledExecutor
All Implemented Interfaces:
Executor, ExecutorService

public class MinPooledExecutor
extends ThreadPoolExecutor

A pooled executor where the minimum pool size threads are kept alive. This is needed in order for the waitWhenBlocked option to work because of a race condition inside the Executor. The race condition goes something like: RT - Requesting Thread wanting to use the pool LT - Last Thread in the pool RT: Check there are enough free threads to process, yes LT is there, so no need to create a new thread. LT: Times out on the keep alive, LT is destroyed. RT: Try to execute, blocks because there are no available threads. In fact, the pool is now empty which the executor mistakenly inteprets as all of them being in use. Doug Lea says he isn't going to fix. In fact, the version in j2se 1.5 doesn't have this option. In order for this to work, the min pool size must be > 0.

Version:
$Revision: 2787 $
Author:
Scott.Stark@jboss.org, adrian@jboss.org

Nested Class Summary
 
Nested classes/interfaces inherited from class java.util.concurrent.ThreadPoolExecutor
ThreadPoolExecutor.AbortPolicy, ThreadPoolExecutor.CallerRunsPolicy, ThreadPoolExecutor.DiscardOldestPolicy, ThreadPoolExecutor.DiscardPolicy
 
Field Summary
protected  int keepAliveSize
          The number of threads to keep alive threads
 
Constructor Summary
MinPooledExecutor(BlockingQueue queue, int poolSize)
          Construct a new executor
MinPooledExecutor(int poolSize)
          Construct a new executor
 
Method Summary
 int getKeepAliveSize()
           
 void setKeepAliveSize(int keepAliveSize)
           
 
Methods inherited from class java.util.concurrent.ThreadPoolExecutor
afterExecute, allowCoreThreadTimeOut, allowsCoreThreadTimeOut, awaitTermination, beforeExecute, execute, 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
 
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, toString, wait, wait, wait
 

Field Detail

keepAliveSize

protected int keepAliveSize
The number of threads to keep alive threads

Constructor Detail

MinPooledExecutor

public MinPooledExecutor(int poolSize)
Construct a new executor

Parameters:
poolSize - the maximum pool size

MinPooledExecutor

public MinPooledExecutor(BlockingQueue queue,
                         int poolSize)
Construct a new executor

Parameters:
queue - the queue for any requests
poolSize - the maximum pool size
Method Detail

getKeepAliveSize

public int getKeepAliveSize()
Returns:
the number of threads to keep alive

setKeepAliveSize

public void setKeepAliveSize(int keepAliveSize)
Parameters:
keepAliveSize - the number of threads to keep alive

JBoss Common Classes 2.2.17.GA

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