/*
* JBoss, Home of Professional Open Source.
* Copyright 2008, Red Hat Middleware LLC, and individual contributors
* as indicated by the @author tags. See the copyright.txt file in the
* distribution for a full listing of individual contributors.
*
* This is free software; you can redistribute it and/or modify it
* under the terms of the GNU Lesser General Public License as
* published by the Free Software Foundation; either version 2.1 of
* the License, or (at your option) any later version.
*
* This software is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this software; if not, write to the Free
* Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
* 02110-1301 USA, or see the FSF site: http://www.fsf.org.
*/
package org.jboss.web.tomcat.service.session;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Map;
import java.util.Set;
import org.jboss.web.tomcat.service.session.distributedcache.spi.DistributableSessionMetadata;
import org.jboss.web.tomcat.service.session.distributedcache.spi.OutgoingAttributeGranularitySessionData;
/**
* Implementation of a clustered session where the replication granularity
* level is attribute based; that is, we replicate only the dirty attributes.
* <p/>
* Note that the isolation level of the cache dictates the
* concurrency behavior. Also note that session and its associated attribtues are stored in different nodes.
* This will be ok since cache will take care of concurrency. When replicating, we will need to replicate both
* session and its attributes.</p>
*
* @author Ben Wang
* @author Brian Stansberry
*
* @version $Revision: 87304 $
*/
class AttributeBasedClusteredSession
extends ClusteredSession<OutgoingAttributeGranularitySessionData>
{
static final long serialVersionUID = -5625209785550936713L;
/**
* Descriptive information describing this Session implementation.
*/
protected static final String info = "AttributeBasedClusteredSession/1.0";
// Transient map to store attr changes for replication.
private transient Map<String, Object> attrModifiedMap_ = new HashMap<String, Object>();
// Transient set to store attr removals for replication
private transient Set<String> attrRemovedSet_ = new HashSet<String>();
// ------------------------------------------------------------ Constructors
public AttributeBasedClusteredSession(ClusteredManager<OutgoingAttributeGranularitySessionData> manager)
{
super(manager);
}
// ----------------------------------------------- Overridden Public Methods
@Override
public String getInfo()
{
return (info);
}
/**
* Override the superclass to additionally reset this class' fields.
* <p>
* <strong>NOTE:</strong> It is not anticipated that this method will be
* called on a ClusteredSession, but we are overriding the method to be
* thorough.
* </p>
*/
@Override
public void recycle()
{
super.recycle();
clearAttrChangedMaps();
}
// -------------------------------------------- Overridden Protected Methods
@Override
protected OutgoingAttributeGranularitySessionData getOutgoingSessionData()
{
Map<String, Object> modAttrs = null;
Set<String> removeAttrs = null;
if (isSessionAttributeMapDirty())
{
if (attrModifiedMap_.size() > 0)
{
modAttrs = new HashMap<String, Object>(attrModifiedMap_);
}
if (attrRemovedSet_.size() > 0)
{
removeAttrs = new HashSet<String>(attrRemovedSet_);
}
clearAttrChangedMaps();
}
DistributableSessionMetadata metadata = isSessionMetadataDirty() ? getSessionMetadata() : null;
Long timestamp = modAttrs != null || removeAttrs != null || metadata != null || getMustReplicateTimestamp() ? Long.valueOf(getSessionTimestamp()) : null;
return new OutgoingData(getRealId(), getVersion(), timestamp, metadata, modAttrs, removeAttrs);
}
@Override
protected Object getAttributeInternal(String name)
{
Object result = getAttributesInternal().get(name);
// Do dirty check even if result is null, as w/ SET_AND_GET null
// still makes us dirty (ensures timely replication w/o using ACCESS)
if (isGetDirty(result) && !replicationExcludes.contains(name))
{
attributeChanged(name, result, false);
}
return result;
}
@Override
protected Object removeAttributeInternal(String name,
boolean localCall,
boolean localOnly)
{
Object result = getAttributesInternal().remove(name);
if (localCall && !replicationExcludes.contains(name))
attributeChanged(name, result, true);
return result;
}
@Override
protected Object setAttributeInternal(String key, Object value)
{
Object old = getAttributesInternal().put(key, value);
if (!replicationExcludes.contains(key))
attributeChanged(key, value, false);
return old;
}
// ------------------------------------------------------- Private Methods
private synchronized void attributeChanged(String key, Object value, boolean removal)
{
if (removal)
{
if (attrModifiedMap_.containsKey(key))
{
attrModifiedMap_.remove(key);
}
attrRemovedSet_.add(key);
}
else
{
if (attrRemovedSet_.contains(key))
{
attrRemovedSet_.remove(key);
}
attrModifiedMap_.put(key, value);
}
sessionAttributesDirty();
}
private synchronized void clearAttrChangedMaps()
{
attrRemovedSet_.clear();
attrModifiedMap_.clear();
}
// ----------------------------------------------------------------- Classes
private static class OutgoingData
extends OutgoingDistributableSessionDataImpl
implements OutgoingAttributeGranularitySessionData
{
private final Map<String, Object> modifiedAttributes;
private final Set<String> removedAttributes;
public OutgoingData(String realId, int version,
Long timestamp, DistributableSessionMetadata metadata,
Map<String, Object> modifiedAttributes, Set<String> removedAttributes)
{
super(realId, version, timestamp, metadata);
this.modifiedAttributes = modifiedAttributes;
this.removedAttributes = removedAttributes;
}
public Map<String, Object> getModifiedSessionAttributes()
{
return modifiedAttributes;
}
public Set<String> getRemovedSessionAttributes()
{
return removedAttributes;
}
}
}