leif 02/01/23 18:57:17
Added: src/scratchpad/org/apache/avalon/excalibur/thread/impl
ResourceLimitingThreadPool.java
Log:
Add new ThreadPool based on ResourceLimiting Pool
Revision Changes Path
1.1
jakarta-avalon-excalibur/src/scratchpad/org/apache/avalon/excalibur/thread/impl/ResourceLimitingThreadPool.java
Index: ResourceLimitingThreadPool.java
===================================================================
/*
* Copyright (C) The Apache Software Foundation. All rights reserved.
*
* This software is published under the terms of the Apache Software License
* version 1.1, a copy of which has been included with this distribution in
* the LICENSE.txt file.
*/
package org.apache.avalon.excalibur.thread.impl;
import org.apache.avalon.excalibur.pool.ResourceLimitingPool;
import org.apache.avalon.excalibur.lang.ThreadContext;
import org.apache.avalon.excalibur.pool.ObjectFactory;
import org.apache.avalon.excalibur.pool.Poolable;
import org.apache.avalon.excalibur.thread.ThreadPool;
import org.apache.avalon.excalibur.thread.ThreadControl;
import org.apache.avalon.framework.activity.Disposable;
import org.apache.avalon.framework.activity.Executable;
import org.apache.avalon.framework.logger.LogEnabled;
import org.apache.avalon.framework.logger.Logger;
import org.apache.avalon.framework.logger.LogKitLogger;
/**
* A Thread Pool which can be configured to have a hard limit on the maximum
number of threads
* which will be allocated. This is very important for servers to avoid
running out of system
* resources. The pool can be configured to block for a new thread or throw
an exception.
* The maximum block time can also be set.
*
* Based on org.apache.avalon.excalibur.thread.impl.DefaultThreadPool in the
Excalibur
* sandbox.
*
* @author <a href="mailto:[EMAIL PROTECTED]">Leif Mortenson</a>
* @author <a href="mailto:[EMAIL PROTECTED]">Stefano Mazzocchi</a>
* @author <a href="mailto:[EMAIL PROTECTED]">Peter Donald</a>
*/
public class ResourceLimitingThreadPool
extends ThreadGroup
implements ObjectFactory, LogEnabled, Disposable, ThreadPool
{
private ResourceLimitingPool m_pool;
private int m_level;
private Logger m_logger;
private ThreadContext m_context;
/*---------------------------------------------------------------
* Constructors
*-------------------------------------------------------------*/
/**
* Creates a new <code>ResourceLimitingThreadPool</code>.
*
* @param max Maximum number of Poolables which can be stored in the
pool, 0 implies no limit.
*/
public ResourceLimitingThreadPool( final int max )
{
this( "Worker Pool", max );
}
/**
* Creates a new <code>ResourceLimitingThreadPool</code> with maxStrict
enabled,
* blocking enabled, no block timeout and a trim interval of 10 seconds.
*
* @param name Name which will used as the thread group name as well as
the prefix of the
* names of all threads created by the pool.
* @param max Maximum number of WorkerThreads which can be stored in the
pool,
* 0 implies no limit.
*/
public ResourceLimitingThreadPool( final String name, final int max )
{
this( name, max, true, true, 0, 10000 );
}
/**
* Creates a new <code>ResourceLimitingThreadPool</code>.
*
* @param name Name which will used as the thread group name as well as
the prefix of the
* names of all threads created by the pool.
* @param max Maximum number of WorkerThreads which can be stored in the
pool,
* 0 implies no limit.
* @param maxStrict true if the pool should never allow more than max
WorkerThreads to
* be created. Will cause an exception to be thrown if more than max
WorkerThreads are
* requested and blocking is false.
* @param blocking true if the pool should cause a thread calling get()
to block when
* WorkerThreads are not currently available on the pool.
* @param blockTimeout The maximum amount of time, in milliseconds, that
a call to get() will
* block before an exception is thrown. A value of 0 implies an
indefinate wait.
* @param trimInterval The minimum interval with which old unused
WorkerThreads will be
* removed from the pool. A value of 0 will cause the pool to never
trim WorkerThreads.
*/
public ResourceLimitingThreadPool( final String name,
final int max,
final boolean maxStrict,
final boolean blocking,
final long blockTimeout,
final long trimInterval )
{
this( name, max, maxStrict, blocking, blockTimeout, trimInterval,
null );
}
/**
* Creates a new <code>ResourceLimitingThreadPool</code>.
*
* @param name Name which will used as the thread group name as well as
the prefix of the
* names of all threads created by the pool.
* @param max Maximum number of WorkerThreads which can be stored in the
pool,
* 0 implies no limit.
* @param maxStrict true if the pool should never allow more than max
WorkerThreads to
* be created. Will cause an exception to be thrown if more than max
WorkerThreads are
* requested and blocking is false.
* @param blocking true if the pool should cause a thread calling get()
to block when
* WorkerThreads are not currently available on the pool.
* @param blockTimeout The maximum amount of time, in milliseconds, that
a call to get() will
* block before an exception is thrown. A value of 0 implies an
indefinate wait.
* @param trimInterval The minimum interval with which old unused
WorkerThreads will be
* removed from the pool. A value of 0 will cause the pool to never
trim WorkerThreads.
* @param context ThreadContext
*/
public ResourceLimitingThreadPool(final String name,
final int max,
final boolean maxStrict,
final boolean blocking,
final long blockTimeout,
final long trimInterval,
final ThreadContext context)
{
super(name);
m_pool = new ResourceLimitingPool
( this, max, maxStrict, blocking, blockTimeout, trimInterval );
m_context = context;
}
/*---------------------------------------------------------------
* ObjectFactory Methods
*-------------------------------------------------------------*/
/**
* Creates and returns a new <code>WorkerThread</code>.
*
* @return new worker thread
*
*/
public Object newInstance()
{
final String name =
new StringBuffer( getName()).append( " Worker #" ).append(
m_level++ ).toString();
final WorkerThread worker = new WorkerThread( this, name, m_pool,
m_context );
worker.enableLogging( m_logger );
worker.start();
return worker;
}
/**
* Returns the class of which this <code>ObjectFactory</code> creates
instances.
*
* @return WorkerThread.class
*
*/
public Class getCreatedClass()
{
return WorkerThread.class;
}
/**
* Cleans up any resources associated with the specified object and takes
it
* out of commission.
*
* @param object the object to be decommissioned
*
*/
public void decommission(final Object object)
{
if ( object instanceof WorkerThread ) {
((WorkerThread) object).dispose();
}
}
/*---------------------------------------------------------------
* LogEnabled Methods
*-------------------------------------------------------------*/
/**
* Set the logger.
*
* @param logger
*
*/
public void enableLogging( final Logger logger )
{
m_logger = logger;
m_pool.enableLogging( m_logger );
}
/*---------------------------------------------------------------
* Disposable Methods
*-------------------------------------------------------------*/
/**
* Clean up resources and references.
*
*/
public void dispose()
{
m_pool.dispose();
m_pool = null;
}
/*---------------------------------------------------------------
* ThreadPool Methods
*-------------------------------------------------------------*/
/**
* Run work in separate thread.
* Return a valid ThreadControl to control work thread.
*
* @param work the work to be executed.
* @return the ThreadControl
*/
public ThreadControl execute( final Runnable work )
{
return execute( new ExecutableRunnable( work ) );
}
/**
* Run work in separate thread.
* Return a valid ThreadControl to control work thread.
*
* @param work the work to be executed.
* @return the ThreadControl
*/
public ThreadControl execute( final Executable work )
{
final WorkerThread worker = getWorker();
return worker.execute( work );
}
/*---------------------------------------------------------------
* Methods
*-------------------------------------------------------------*/
/**
* Retrieve a worker thread from pool.
*
* @return the worker thread retrieved from pool
*
* @todo remove the line:
*
<code>worker.setContextClassLoader(Thread.currentThread().getContextClassLoader());</code>
*/
protected WorkerThread getWorker()
{
try
{
final WorkerThread worker = (WorkerThread)m_pool.get();
// TODO: Remove next line
worker.setContextClassLoader(
Thread.currentThread().getContextClassLoader() );
return worker;
}
catch ( final Exception e )
{
throw new IllegalStateException( "Unable to access thread pool
due to " + e );
}
}
}
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