/*
* 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.Collection;
import java.util.Map;
import org.jboss.aop.Advised;
import org.jboss.web.tomcat.service.session.distributedcache.spi.DistributableSessionMetadata;
import org.jboss.web.tomcat.service.session.distributedcache.spi.OutgoingDistributableSessionData;
/**
* <p>
* Implementation of a clustered session for JBossCacheManager. The replication granularity
* level is field based; that is, we replicate only the dirty field in a POJO that is part of
* a session attribute. E.g., once a user do setAttribute("pojo", pojo), pojo will be monitored
* automatically for field changes and accessing. It offers couple of advantages:
* <ul>
* <li>pojo.setName(), for example, will only replicate the name field in the pojo. And thus is more efficient.</li>
* <li>If pojo has a complex object graph, we will handle that automtically providing that the
* children object is also aspectized.</li>
* </ul>
* Note that in current version, all the attributes and its associated childre graph objects are
* required to be aspectized. That is, you can't simply declare them as Serializable. This is restricted
* because of the marshalling/unmarshalling issue.</p>
*
* <p>We use PojoCache for our internal, replicated data store.
* <p/>
*
* @author Ben Wang
* @author Brian Stansberry
*
* @version $Revision: 87304 $
*/
class FieldBasedClusteredSession
extends ClusteredSession<OutgoingDistributableSessionData>
{
/** The serialVersionUID */
private static final long serialVersionUID = 8347544395334247623L;
/**
* Descriptive information describing this Session implementation.
*/
protected static final String info = "FieldBasedClusteredSession/1.0";
// ------------------------------------------------------------ Constructors
public FieldBasedClusteredSession(ClusteredManager<OutgoingDistributableSessionData> manager)
{
super(manager);
}
// ----------------------------------------------- Overridden Public Methods
@Override
public String getInfo()
{
return (info);
}
// --------------------------------------------- Overridden Protected Methods
@Override
protected OutgoingDistributableSessionData getOutgoingSessionData()
{
DistributableSessionMetadata metadata = isSessionMetadataDirty() ? getSessionMetadata() : null;
Long timestamp = metadata != null || isSessionAttributeMapDirty() || getMustReplicateTimestamp() ? Long.valueOf(getSessionTimestamp()) : null;
return new OutgoingDistributableSessionDataImpl(getRealId(), getVersion(), timestamp, metadata);
}
/**
* Overrides the superclass to treat classes implementing Subject
* as "immutable", since as an Observer we will detect any changes
* to those types.
*/
@Override
protected boolean isMutable(Object attribute)
{
boolean pojo = (attribute instanceof Advised);
boolean mutable = (!pojo && super.isMutable(attribute));
return mutable;
}
@Override
protected Object removeAttributeInternal(String name, boolean localCall, boolean localOnly)
{
// Remove it from the underlying store
if (localCall && !replicationExcludes.contains(name))
{
if (localOnly)
getDistributedCacheManager().removeAttributeLocal(getRealId(), name);
else
getDistributedCacheManager().removeAttribute(getRealId(), name);
sessionAttributesDirty();
}
return getAttributesInternal().remove(name);
}
/**
* Overrides the superclass to allow instrumented classes and
* non-serializable Collections and Maps.
*/
@Override
protected boolean canAttributeBeReplicated(Object attribute)
{
return (attribute == null || Util.checkPojoType(attribute));
}
/**
* This is the hook for setAttribute. Note that in this FieldBasedClusteredSession using aop,
* user should not call setAttribute call too often since this will re-connect the attribute with the internal
* cache (and this is expensive).
* @param key
* @param value
* @return Object
*/
@Override
protected Object setAttributeInternal(String key, Object value)
{
if (!replicationExcludes.contains(key))
{
String myRealId = getRealId();
getDistributedCacheManager().putAttribute(myRealId, key, value);
// Special case for Collection classes.
if( value instanceof Map || value instanceof Collection)
{
// We need to obtain the proxy first.
value = getDistributedCacheManager().getAttribute(myRealId, key);
}
// Only mark session dirty if we can replicate the attribute
sessionAttributesDirty();
}
// Still need to put it in the map to track locally.
return getAttributesInternal().put(key, value);
}
}