bloritsch 2002/08/14 17:54:29
Added: assembly/src/java/org/apache/excalibur/merlin/resource
ThreadLocalLifestyleHandler.java
Log:
Add the "PerThread" or THreadLocal version of component lifestyle
Revision Changes Path
1.1
jakarta-avalon-excalibur/assembly/src/java/org/apache/excalibur/merlin/resource/ThreadLocalLifestyleHandler.java
Index: ThreadLocalLifestyleHandler.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.
*
* Original contribution by OSM SARL, http://www.osm.net
*/
package org.apache.excalibur.merlin.resource;
import org.apache.avalon.framework.activity.Disposable;
import org.apache.avalon.framework.logger.AbstractLogEnabled;
import org.apache.avalon.framework.context.DefaultContext;
import org.apache.avalon.framework.context.Context;
import org.apache.excalibur.merlin.assembly.ContainerManager;
import org.apache.excalibur.merlin.model.Profile;
import org.apache.excalibur.merlin.model.Resource;
import org.apache.excalibur.meta.info.PhaseDescriptor;
import org.apache.excalibur.meta.info.ExtensionDescriptor;
/**
* Lifestyle implementation that provides suppport for the per thread
* policy. Request for a single instance will allways return the
* same instance for each request.
*
* NOTE: Need to register a listener for threaddeath so I can properly
* dispose of the component when the associated thread dies.
*
* NOTE 2: This is untested.
*
* @author <a href="mailto:[EMAIL PROTECTED]";>Stephen McConnell</a>
*/
public class ThreadLocalLifestyleHandler extends AbstractLifestyleHandler
{
private Profile m_profile;
private ContainerManager m_manager;
private ThreadLocalComponent m_instance;
/**
* Creation of a new singleton lifecycle manager.
* @param manager the type manager
* @param provider the resource provider
* @param helper the lifecycle helper
* @param profile the profile defining the object type
* @param context the establishment context
*/
public ThreadLocalLifestyleHandler(
final ContainerManager manager,
final DeploymentHelper deployment,
final LifecycleHelper helper,
final Profile profile,
final Context context )
{
super( manager, deployment, helper, profile, context );
m_profile = profile;
m_manager = manager;
m_instance = new ThreadLocalComponent( this );
}
/**
* Returns an instance of the object type supported by the
* manager to the client.
*
* @return an instance of the type defined by the profile
*/
public Object get() throws Exception
{
if( m_disposed )
throw new IllegalStateException("disposed");
getLogger().debug("get");
Object object = m_instance.get();
super.processAccessStage( object );
return object;
}
/**
* Invoked by a client to return an instance of the object type previously
* supported by the manager. The singleton manager does nothing as the
* object may be used across an arbitary number of clients.
*
* @param object the object to return
*/
public void put( Object object ) throws Exception
{
if( m_disposed )
throw new IllegalStateException("disposed");
getLogger().debug("put");
if( object == null )
return;
if( object.equals( m_instance.get() ) )
{
super.processReleaseStage( object );
}
else
{
final String warning =
"Illegal attempt to release an object that was not provided by this
handler.";
getLogger().warn( warning );
}
}
/**
* Request for disposal of the manager. This operation is normally invoked
* by the client that initialy instantiated the manager. The implementation
* handles the disposal of the singleton resoruce and release of associated
* references.
*/
public void dispose()
{
handleShutdown( m_instance.get() );
m_instance = null;
m_profile = null;
m_manager = null;
super.dispose();
}
private static final class ThreadLocalComponent extends ThreadLocal
{
private final ThreadLocalLifestyleHandler m_lifestyle;
protected ThreadLocalComponent( ThreadLocalLifestyleHandler handler )
{
m_lifestyle = handler;
}
protected Object initialValue()
{
try
{
return m_lifestyle.createInstance();
}
catch( Exception e )
{
return null;
}
}
}
}
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