/jboss-as-7.1.1.Final/web/src/main/java/org/jboss/as/web/session/AttributeBasedClusteredSession.java

  1/*
  2 * JBoss, Home of Professional Open Source.
  3 * Copyright 2008, Red Hat Middleware LLC, and individual contributors
  4 * as indicated by the @author tags. See the copyright.txt file in the
  5 * distribution for a full listing of individual contributors.
  6 *
  7 * This is free software; you can redistribute it and/or modify it
  8 * under the terms of the GNU Lesser General Public License as
  9 * published by the Free Software Foundation; either version 2.1 of
 10 * the License, or (at your option) any later version.
 11 *
 12 * This software is distributed in the hope that it will be useful,
 13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 15 * Lesser General Public License for more details.
 16 *
 17 * You should have received a copy of the GNU Lesser General Public
 18 * License along with this software; if not, write to the Free
 19 * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
 20 * 02110-1301 USA, or see the FSF site: http://www.fsf.org.
 21 */
 22package org.jboss.as.web.session;
 23
 24import java.util.HashMap;
 25import java.util.HashSet;
 26import java.util.Map;
 27import java.util.Set;
 28
 29import org.jboss.as.clustering.web.DistributableSessionMetadata;
 30import org.jboss.as.clustering.web.OutgoingAttributeGranularitySessionData;
 31
 32/**
 33 * Implementation of a clustered session where the replication granularity level is attribute based; that is, we replicate only
 34 * the dirty attributes.
 35 * <p/>
 36 * Note that the isolation level of the cache dictates the concurrency behavior. Also note that session and its associated
 37 * attributes are stored in different nodes. This will be ok since cache will take care of concurrency. When replicating, we
 38 * will need to replicate both session and its attributes.
 39 * </p>
 40 * @author Ben Wang
 41 * @author Brian Stansberry
 42 */
 43class AttributeBasedClusteredSession extends ClusteredSession<OutgoingAttributeGranularitySessionData> {
 44    static final long serialVersionUID = -5625209785550936713L;
 45    /**
 46     * Descriptive information describing this Session implementation.
 47     */
 48    protected static final String info = "AttributeBasedClusteredSession/1.0";
 49
 50    // Transient map to store attr changes for replication.
 51    private transient Map<String, Object> attrModifiedMap_ = new HashMap<String, Object>();
 52    // Transient set to store attr removals for replication
 53    private transient Set<String> attrRemovedSet_ = new HashSet<String>();
 54
 55    // ------------------------------------------------------------ Constructors
 56
 57    public AttributeBasedClusteredSession(ClusteredSessionManager<OutgoingAttributeGranularitySessionData> manager) {
 58        super(manager);
 59    }
 60
 61    // ----------------------------------------------- Overridden Public Methods
 62
 63    @Override
 64    public String getInfo() {
 65        return (info);
 66    }
 67
 68    /**
 69     * Override the superclass to additionally reset this class' fields.
 70     * <p>
 71     * <strong>NOTE:</strong> It is not anticipated that this method will be called on a ClusteredSession, but we are overriding
 72     * the method to be thorough.
 73     * </p>
 74     */
 75    @Override
 76    public void recycle() {
 77        super.recycle();
 78
 79        clearAttrChangedMaps();
 80    }
 81
 82    // -------------------------------------------- Overridden Protected Methods
 83
 84    @Override
 85    protected OutgoingAttributeGranularitySessionData getOutgoingSessionData() {
 86        Map<String, Object> modAttrs = null;
 87        Set<String> removeAttrs = null;
 88        if (isSessionAttributeMapDirty()) {
 89            if (attrModifiedMap_.size() > 0) {
 90                modAttrs = new HashMap<String, Object>(attrModifiedMap_);
 91            }
 92
 93            if (attrRemovedSet_.size() > 0) {
 94                removeAttrs = new HashSet<String>(attrRemovedSet_);
 95            }
 96
 97            clearAttrChangedMaps();
 98        }
 99        DistributableSessionMetadata metadata = isSessionMetadataDirty() ? getSessionMetadata() : null;
100        Long timestamp = modAttrs != null || removeAttrs != null || metadata != null || getMustReplicateTimestamp() ? Long
101                .valueOf(getSessionTimestamp()) : null;
102        return new OutgoingData(getRealId(), getVersion(), timestamp, metadata, modAttrs, removeAttrs);
103    }
104
105    @Override
106    protected Object getAttributeInternal(String name) {
107        Object result = getAttributesInternal().get(name);
108
109        // Do dirty check even if result is null, as w/ SET_AND_GET null
110        // still makes us dirty (ensures timely replication w/o using ACCESS)
111        if (isGetDirty(result) && !replicationExcludes.contains(name)) {
112            attributeChanged(name, result, false);
113        }
114
115        return result;
116    }
117
118    @Override
119    protected Object removeAttributeInternal(String name, boolean localCall, boolean localOnly) {
120        Object result = getAttributesInternal().remove(name);
121        if (localCall && !replicationExcludes.contains(name))
122            attributeChanged(name, result, true);
123        return result;
124    }
125
126    @Override
127    protected Object setAttributeInternal(String key, Object value) {
128        Object old = getAttributesInternal().put(key, value);
129        if (!replicationExcludes.contains(key))
130            attributeChanged(key, value, false);
131        return old;
132    }
133
134    // ------------------------------------------------------- Private Methods
135
136    private synchronized void attributeChanged(String key, Object value, boolean removal) {
137        if (removal) {
138            if (attrModifiedMap_.containsKey(key)) {
139                attrModifiedMap_.remove(key);
140            }
141            attrRemovedSet_.add(key);
142        } else {
143            if (attrRemovedSet_.contains(key)) {
144                attrRemovedSet_.remove(key);
145            }
146            attrModifiedMap_.put(key, value);
147        }
148        sessionAttributesDirty();
149    }
150
151    private synchronized void clearAttrChangedMaps() {
152        attrRemovedSet_.clear();
153        attrModifiedMap_.clear();
154    }
155
156    // ----------------------------------------------------------------- Classes
157
158    private static class OutgoingData extends OutgoingDistributableSessionDataImpl implements
159            OutgoingAttributeGranularitySessionData {
160        private final Map<String, Object> modifiedAttributes;
161        private final Set<String> removedAttributes;
162
163        public OutgoingData(String realId, int version, Long timestamp, DistributableSessionMetadata metadata,
164                Map<String, Object> modifiedAttributes, Set<String> removedAttributes) {
165            super(realId, version, timestamp, metadata);
166            this.modifiedAttributes = modifiedAttributes;
167            this.removedAttributes = removedAttributes;
168        }
169
170        @Override
171        public Map<String, Object> getModifiedSessionAttributes() {
172            return modifiedAttributes;
173        }
174
175        @Override
176        public Set<String> getRemovedSessionAttributes() {
177            return removedAttributes;
178        }
179    }
180}