001/*
002 * This library is part of OpenCms -
003 * the Open Source Content Management System
004 *
005 * Copyright (c) Alkacon Software GmbH & Co. KG (http://www.alkacon.com)
006 *
007 * This library is free software; you can redistribute it and/or
008 * modify it under the terms of the GNU Lesser General Public
009 * License as published by the Free Software Foundation; either
010 * version 2.1 of the License, or (at your option) any later version.
011 *
012 * This library is distributed in the hope that it will be useful,
013 * but WITHOUT ANY WARRANTY; without even the implied warranty of
014 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
015 * Lesser General Public License for more details.
016 *
017 * For further information about Alkacon Software GmbH & Co. KG, please see the
018 * company website: http://www.alkacon.com
019 *
020 * For further information about OpenCms, please see the
021 * project website: http://www.opencms.org
022 *
023 * You should have received a copy of the GNU Lesser General Public
024 * License along with this library; if not, write to the Free Software
025 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
026 */
027
028package org.opencms.main;
029
030import org.opencms.util.CmsCollectionsGenericWrapper;
031import org.opencms.util.CmsUUID;
032
033import java.util.ArrayList;
034import java.util.ConcurrentModificationException;
035import java.util.Iterator;
036import java.util.List;
037import java.util.Map;
038
039import org.apache.commons.collections.FastHashMap;
040
041/**
042 * The default session storage provider implementation.<p>
043 *
044 * Implementation based on a {@link FastHashMap}.<p>
045 *
046 * @since 6.5.5
047 */
048public class CmsDefaultSessionStorageProvider implements I_CmsSessionStorageProvider {
049
050    /** Stores the session info objects mapped to the session id. */
051    private FastHashMap m_sessions;
052
053    /**
054     * @see org.opencms.main.I_CmsSessionStorageProvider#get(org.opencms.util.CmsUUID)
055     */
056    public CmsSessionInfo get(CmsUUID sessionId) {
057
058        return (CmsSessionInfo)m_sessions.get(sessionId);
059    }
060
061    /**
062     * @see org.opencms.main.I_CmsSessionStorageProvider#getAll()
063     */
064    public List<CmsSessionInfo> getAll() {
065
066        return getAllOfUser(null);
067    }
068
069    /**
070     * @see org.opencms.main.I_CmsSessionStorageProvider#getAllOfUser(org.opencms.util.CmsUUID)
071     */
072    public List<CmsSessionInfo> getAllOfUser(CmsUUID userId) {
073
074        try {
075            return getAllSelected(CmsCollectionsGenericWrapper.<CmsUUID, CmsSessionInfo> map(m_sessions), userId);
076        } catch (ConcurrentModificationException e) {
077            // try again with a clone this time
078            return getAllSelected(
079                CmsCollectionsGenericWrapper.<CmsUUID, CmsSessionInfo> map(m_sessions.clone()),
080                userId);
081        }
082    }
083
084    /**
085     * @see org.opencms.main.I_CmsSessionStorageProvider#getSize()
086     */
087    public int getSize() {
088
089        return m_sessions.size();
090    }
091
092    /**
093     * @see org.opencms.main.I_CmsSessionStorageProvider#initialize()
094     */
095    public void initialize() {
096
097        // create a map for all sessions, these will be mapped using their session id
098        m_sessions = new FastHashMap();
099        // set to "fast" mode (will be reset for write access)
100        m_sessions.setFast(true);
101    }
102
103    /**
104     * @see org.opencms.main.I_CmsSessionStorageProvider#put(org.opencms.main.CmsSessionInfo)
105     */
106    public CmsSessionInfo put(CmsSessionInfo sessionInfo) {
107
108        return (CmsSessionInfo)m_sessions.put(sessionInfo.getSessionId(), sessionInfo);
109    }
110
111    /**
112     * @see org.opencms.main.I_CmsSessionStorageProvider#remove(org.opencms.util.CmsUUID)
113     */
114    public CmsSessionInfo remove(CmsUUID sessionId) {
115
116        return (CmsSessionInfo)m_sessions.remove(sessionId);
117    }
118
119    /**
120     * @see org.opencms.main.I_CmsSessionStorageProvider#shutdown()
121     */
122    public void shutdown() {
123
124        m_sessions.clear();
125        m_sessions = null;
126    }
127
128    /**
129     * @see org.opencms.main.I_CmsSessionStorageProvider#validate()
130     */
131    public void validate() {
132
133        try {
134            // change session map to full synchronization or "slow" mode
135            m_sessions.setFast(false);
136            Iterator<Map.Entry<CmsUUID, CmsSessionInfo>> sessions = CmsCollectionsGenericWrapper.<CmsUUID, CmsSessionInfo> map(
137                m_sessions).entrySet().iterator();
138            while (sessions.hasNext()) {
139                Map.Entry<CmsUUID, CmsSessionInfo> entry = sessions.next();
140                CmsUUID sessionId = entry.getKey();
141                CmsSessionInfo sessionInfo = entry.getValue();
142                if ((sessionInfo != null) && (m_sessions.get(sessionId) != null)) {
143                    // may be the case in case of concurrent modification
144                    if (sessionInfo.isExpired()) {
145                        // session is invalid, try to remove it
146                        try {
147                            sessions.remove();
148                        } catch (ConcurrentModificationException ex) {
149                            // ignore, better luck next time...
150                        }
151                    }
152                }
153            }
154        } catch (ConcurrentModificationException ex) {
155            // CME can also be triggered from the Iterator#next() method.
156            // ignore, better luck next time...
157        } finally {
158            // it may be null during shutdown
159            if (m_sessions != null) {
160                // reset session map to "fast" mode
161                m_sessions.setFast(true);
162            }
163        }
164    }
165
166    /**
167     * Returns all sessions or all sessions matching the user id from the provided Map.<p>
168     *
169     * @param allSessions the Map of existing sessions
170     * @param userId the id of the user, if null all sessions will be returned
171     *
172     * @return all sessions or all sessions matching the user id from the provided Map
173     */
174    private List<CmsSessionInfo> getAllSelected(Map<CmsUUID, CmsSessionInfo> allSessions, CmsUUID userId) {
175
176        List<CmsSessionInfo> userSessions = new ArrayList<CmsSessionInfo>();
177        Iterator<Map.Entry<CmsUUID, CmsSessionInfo>> i = allSessions.entrySet().iterator();
178        while (i.hasNext()) {
179            Map.Entry<CmsUUID, CmsSessionInfo> entry = i.next();
180            CmsSessionInfo sessionInfo = entry.getValue();
181            if ((sessionInfo != null) && ((userId == null) || userId.equals(sessionInfo.getUserId()))) {
182                // sessionInfo == null may be the case in case of concurrent modification
183                userSessions.add(sessionInfo);
184            }
185        }
186        return userSessions;
187    }
188}