MinPooledExecutor (JBoss/Common API) - JBoss 4.0.1 sp1 common API Documentation 英文版文档

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org.jboss.util.threadpool
Class MinPooledExecutor

java.lang.Object
  EDU.oswego.cs.dl.util.concurrent.ThreadFactoryUser
      EDU.oswego.cs.dl.util.concurrent.PooledExecutor
          org.jboss.util.threadpool.MinPooledExecutor

All Implemented Interfaces:: EDU.oswego.cs.dl.util.concurrent.Executor

public class MinPooledExecutor
extends EDU.oswego.cs.dl.util.concurrent.PooledExecutor

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: 1.3 $
Author:: Scott.Stark@jboss.org, adrian@jboss.org

Nested Class Summary

Nested classes inherited from class EDU.oswego.cs.dl.util.concurrent.PooledExecutor

EDU.oswego.cs.dl.util.concurrent.PooledExecutor.AbortWhenBlocked, EDU.oswego.cs.dl.util.concurrent.PooledExecutor.BlockedExecutionHandler, EDU.oswego.cs.dl.util.concurrent.PooledExecutor.DiscardOldestWhenBlocked, EDU.oswego.cs.dl.util.concurrent.PooledExecutor.DiscardWhenBlocked, EDU.oswego.cs.dl.util.concurrent.PooledExecutor.RunWhenBlocked, EDU.oswego.cs.dl.util.concurrent.PooledExecutor.WaitWhenBlocked, EDU.oswego.cs.dl.util.concurrent.PooledExecutor.Worker

Nested classes inherited from class EDU.oswego.cs.dl.util.concurrent.ThreadFactoryUser

EDU.oswego.cs.dl.util.concurrent.ThreadFactoryUser.DefaultThreadFactory

Field Summary

protected int keepAliveSize
          The number of threads to keep alive threads

Fields inherited from class EDU.oswego.cs.dl.util.concurrent.PooledExecutor

blockedExecutionHandler_, DEFAULT_KEEPALIVETIME, DEFAULT_MAXIMUMPOOLSIZE, DEFAULT_MINIMUMPOOLSIZE, handOff_, keepAliveTime_, maximumPoolSize_, minimumPoolSize_, poolSize_, shutdown_, threads_

Fields inherited from class EDU.oswego.cs.dl.util.concurrent.ThreadFactoryUser

threadFactory_

Constructor Summary

MinPooledExecutor(EDU.oswego.cs.dl.util.concurrent.Channel channel, int poolSize)
          Construct a new executor

MinPooledExecutor(int poolSize)
          Construct a new executor

Method Summary

int getKeepAliveSize()


protected Runnable getTask()


protected boolean keepAlive()
          We keep alive unless we are told to shutdown or there are more than keepAliveSize threads in the pool

void setKeepAliveSize(int keepAliveSize)


Methods inherited from class EDU.oswego.cs.dl.util.concurrent.PooledExecutor

abortWhenBlocked, addThread, awaitTerminationAfterShutdown, awaitTerminationAfterShutdown, createThreads, discardOldestWhenBlocked, discardWhenBlocked, drain, execute, getBlockedExecutionHandler, getKeepAliveTime, getMaximumPoolSize, getMinimumPoolSize, getPoolSize, interruptAll, isTerminatedAfterShutdown, runWhenBlocked, setBlockedExecutionHandler, setKeepAliveTime, setMaximumPoolSize, setMinimumPoolSize, shutdownAfterProcessingCurrentlyQueuedTasks, shutdownAfterProcessingCurrentlyQueuedTasks, shutdownNow, shutdownNow, waitWhenBlocked, workerDone

Methods inherited from class EDU.oswego.cs.dl.util.concurrent.ThreadFactoryUser

getThreadFactory, setThreadFactory

Methods inherited from class java.lang.Object

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

Field Detail

keepAliveSize

protected int keepAliveSize

The number of threads to keep alive threads

Constructor Detail