/*
============================================================================
The Apache Software License, Version 1.1
============================================================================
Copyright (C) 1999-2003 The Apache Software Foundation. All rights reserved.
Redistribution and use in source and binary forms, with or without modifica-
tion, are permitted provided that the following conditions are met:
1. Redistributions of source code must retain the above copyright notice,
this list of conditions and the following disclaimer.
2. Redistributions in binary form must reproduce the above copyright notice,
this list of conditions and the following disclaimer in the documentation
and/or other materials provided with the distribution.
3. The end-user documentation included with the redistribution, if any, must
include the following acknowledgment: "This product includes software
developed by the Apache Software Foundation (http://www.apache.org/)."
Alternately, this acknowledgment may appear in the software itself, if
and wherever such third-party acknowledgments normally appear.
4. The names "Jakarta", "Avalon", "Excalibur" and "Apache Software Foundation"
must not be used to endorse or promote products derived from this software
without prior written permission. For written permission, please contact
apache@apache.org.
5. Products derived from this software may not be called "Apache", nor may
"Apache" appear in their name, without prior written permission of the
Apache Software Foundation.
THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED WARRANTIES,
INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
APACHE SOFTWARE FOUNDATION OR ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLU-
DING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
This software consists of voluntary contributions made by many individuals
on behalf of the Apache Software Foundation. For more information on the
Apache Software Foundation, please see <http://www.apache.org/>.
*/
package org.apache.excalibur.event.command;
import java.util.Iterator;
import org.apache.avalon.framework.activity.Disposable;
import org.apache.avalon.framework.activity.Initializable;
import org.apache.avalon.framework.logger.AbstractLogEnabled;
import org.apache.commons.collections.StaticBucketMap;
import org.apache.excalibur.event.EventHandler;
import org.apache.excalibur.event.Source;
import EDU.oswego.cs.dl.util.concurrent.Executor;
/**
* Abstract base class for a ThreadManager that has a single ThreadPool for
* all pipelines
*
* @author <a href="mailto:bloritsch@apache.org">Berin Loritsch</a>
* @author <a href="mailto:proyal@apache.org">Peter Royal</a>
*/
public abstract class AbstractThreadManager extends AbstractLogEnabled
implements Runnable, ThreadManager, Initializable, Disposable
{
/** The pipelines we are managing */
private final StaticBucketMap m_pipelines = new StaticBucketMap();
/** The ThreadPool we are using */
private Executor m_executor;
/** Whether we are done or not */
private volatile boolean m_done = false;
/** The number of milliseconds to sleep before runngin again: 1000 (1 sec.) */
private long m_sleepTime = 1000L;
/** Whether this class has been initialized or not */
private volatile boolean m_initialized = false;
/** Return whether the thread manager has been initialized or not */
protected boolean isInitialized()
{
return m_initialized;
}
/**
* Set the amount of time to sleep between checks on the queue
*
* @param sleepTime Number of milliseconds
*/
protected void setSleepTime( long sleepTime )
{
m_sleepTime = sleepTime;
}
/**
* Get the current amount of sleep time.
*/
protected long getSleepTime()
{
return m_sleepTime;
}
/**
* Set the ThreadPool we are using
*
* @param threadPool The ThreadPool
*/
protected void setExecutor( Executor executor )
{
if( null == m_executor )
{
m_executor = executor;
}
else
{
throw new IllegalStateException( "Can only set the executor once" );
}
}
/**
* Set up the ThreadManager. All required parameters must have already been set.
*
* @throws Exception if there is any problem setting up the ThreadManager
*/
public void initialize() throws Exception
{
if( null == m_executor )
{
throw new IllegalStateException( "No thread pool set" );
}
m_executor.execute( this );
this.m_initialized = true;
}
/**
* Register an EventPipeline with the ThreadManager.
*
* @param pipeline The pipeline we are registering
*/
public void register( EventPipeline pipeline )
{
if( !isInitialized() )
{
throw new IllegalStateException( "ThreadManager must be initialized before "
+ "registering a pipeline" );
}
try
{
PipelineRunner runner = new PipelineRunner( pipeline );
runner.enableLogging( getLogger() );
m_pipelines.put( pipeline, runner );
if( m_done )
{
m_executor.execute( this );
}
}
catch( InterruptedException ie )
{
getLogger().warn("Caught InterruptedException in register", ie);
// ignore for now
}
}
/**
* Deregister an EventPipeline with the ThreadManager
*
* @param pipeline The pipeline we are de-registering
*/
public void deregister( EventPipeline pipeline )
{
if( !isInitialized() )
{
throw new IllegalStateException( "ThreadManager must be initialized before "
+ "deregistering a pipeline" );
}
m_pipelines.remove( pipeline );
if( m_pipelines.isEmpty() )
{
m_done = true;
}
}
/**
* Deregisters all EventPipelines from this ThreadManager
*/
public void deregisterAll()
{
if( !isInitialized() )
{
throw new IllegalStateException( "ThreadManager must be initialized "
+ "before deregistering pipelines" );
}
Iterator it = m_pipelines.keySet().iterator();
while ( it.hasNext() )
{
deregister( (EventPipeline) it.next() );
}
m_done = true;
if ( ! m_pipelines.isEmpty() )
{
throw new IllegalStateException("We still have pipelines, but no runners are available!");
}
}
/**
* Get rid of the ThreadManager.
*/
public void dispose()
{
m_done = true;
deregisterAll();
doDispose();
}
protected void doDispose() {} // default impl to work with released code
/**
* The code that is run in the background to manage the ThreadPool and the
* EventPipelines
*/
public void run()
{
while( !m_done )
{
Iterator i = m_pipelines.values().iterator();
while( i.hasNext() )
{
PipelineRunner nextRunner = ( PipelineRunner ) i.next();
try
{
m_executor.execute( nextRunner );
}
catch( Exception e )
{
if( getLogger().isErrorEnabled() )
{
getLogger().error( "Caught exception in ThreadManager management thread", e );
}
}
}
if ( !m_done )
{
try
{
Thread.sleep( m_sleepTime );
}
catch( InterruptedException e )
{
Thread.interrupted();
}
}
}
}
/**
* The PipelineRunner class pulls all the events from the Source, and puts them in the EventHandler.
* Both of those objects are part of the EventPipeline.
*/
public static final class PipelineRunner
extends AbstractLogEnabled
implements Runnable
{
/** The pipeline we are managing */
private final EventPipeline m_pipeline;
/**
* Create a PipelineRunner.
*
* @param pipeline The EventPipeline we are running
*/
protected PipelineRunner( EventPipeline pipeline )
{
m_pipeline = pipeline;
}
/**
* The code that actually pulls the events from the Sources and sends them to the event handler
*/
public void run()
{
Source[] sources = m_pipeline.getSources();
EventHandler handler = m_pipeline.getEventHandler();
for( int i = 0; i < sources.length; i++ )
{
try
{
handler.handleEvents( sources[i].dequeueAll() );
}
catch( Exception e )
{
// We want to catch this, because this is the only
// place where exceptions happening in this thread
// can be logged
if( getLogger().isErrorEnabled() )
{
getLogger().error( "Exception processing EventPipeline [msg: "
+ e.getMessage() + "]", e );
}
}
}
}
}
}