Java tutorial
/* * This library is part of OpenCms - * the Open Source Content Management System * * Copyright (c) Alkacon Software GmbH (http://www.alkacon.com) * * This library 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 library 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. * * For further information about Alkacon Software GmbH, please see the * company website: http://www.alkacon.com * * For further information about OpenCms, please see the * project website: http://www.opencms.org * * You should have received a copy of the GNU Lesser General Public * License along with this library; if not, write to the Free Software * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */ package org.opencms.main; import org.opencms.util.CmsCollectionsGenericWrapper; import org.opencms.util.CmsUUID; import java.util.ArrayList; import java.util.ConcurrentModificationException; import java.util.Iterator; import java.util.List; import java.util.Map; import org.apache.commons.collections.FastHashMap; /** * The default session storage provider implementation.<p> * * Implementation based on a {@link FastHashMap}.<p> * * @since 6.5.5 */ public class CmsDefaultSessionStorageProvider implements I_CmsSessionStorageProvider { /** Stores the session info objects mapped to the session id. */ private FastHashMap m_sessions; /** * @see org.opencms.main.I_CmsSessionStorageProvider#get(org.opencms.util.CmsUUID) */ public CmsSessionInfo get(CmsUUID sessionId) { return (CmsSessionInfo) m_sessions.get(sessionId); } /** * @see org.opencms.main.I_CmsSessionStorageProvider#getAll() */ public List<CmsSessionInfo> getAll() { return getAllOfUser(null); } /** * @see org.opencms.main.I_CmsSessionStorageProvider#getAllOfUser(org.opencms.util.CmsUUID) */ public List<CmsSessionInfo> getAllOfUser(CmsUUID userId) { try { return getAllSelected(CmsCollectionsGenericWrapper.<CmsUUID, CmsSessionInfo>map(m_sessions), userId); } catch (ConcurrentModificationException e) { // try again with a clone this time return getAllSelected(CmsCollectionsGenericWrapper.<CmsUUID, CmsSessionInfo>map(m_sessions.clone()), userId); } } /** * @see org.opencms.main.I_CmsSessionStorageProvider#getSize() */ public int getSize() { return m_sessions.size(); } /** * @see org.opencms.main.I_CmsSessionStorageProvider#initialize() */ public void initialize() { // create a map for all sessions, these will be mapped using their session id m_sessions = new FastHashMap(); // set to "fast" mode (will be reset for write access) m_sessions.setFast(true); } /** * @see org.opencms.main.I_CmsSessionStorageProvider#put(org.opencms.main.CmsSessionInfo) */ public CmsSessionInfo put(CmsSessionInfo sessionInfo) { return (CmsSessionInfo) m_sessions.put(sessionInfo.getSessionId(), sessionInfo); } /** * @see org.opencms.main.I_CmsSessionStorageProvider#remove(org.opencms.util.CmsUUID) */ public CmsSessionInfo remove(CmsUUID sessionId) { return (CmsSessionInfo) m_sessions.remove(sessionId); } /** * @see org.opencms.main.I_CmsSessionStorageProvider#shutdown() */ public void shutdown() { m_sessions.clear(); m_sessions = null; } /** * @see org.opencms.main.I_CmsSessionStorageProvider#validate() */ public void validate() { try { // change session map to full synchronization or "slow" mode m_sessions.setFast(false); Iterator<Map.Entry<CmsUUID, CmsSessionInfo>> sessions = CmsCollectionsGenericWrapper .<CmsUUID, CmsSessionInfo>map(m_sessions).entrySet().iterator(); while (sessions.hasNext()) { Map.Entry<CmsUUID, CmsSessionInfo> entry = sessions.next(); CmsUUID sessionId = entry.getKey(); CmsSessionInfo sessionInfo = entry.getValue(); if ((sessionInfo != null) && (m_sessions.get(sessionId) != null)) { // may be the case in case of concurrent modification if (sessionInfo.isExpired()) { // session is invalid, try to remove it try { sessions.remove(); } catch (ConcurrentModificationException ex) { // ignore, better luck next time... } } } } } catch (ConcurrentModificationException ex) { // CME can also be triggered from the Iterator#next() method. // ignore, better luck next time... } finally { // it may be null during shutdown if (m_sessions != null) { // reset session map to "fast" mode m_sessions.setFast(true); } } } /** * Returns all sessions or all sessions matching the user id from the provided Map.<p> * * @param allSessions the Map of existing sessions * @param userId the id of the user, if null all sessions will be returned * * @return all sessions or all sessions matching the user id from the provided Map */ private List<CmsSessionInfo> getAllSelected(Map<CmsUUID, CmsSessionInfo> allSessions, CmsUUID userId) { List<CmsSessionInfo> userSessions = new ArrayList<CmsSessionInfo>(); Iterator<Map.Entry<CmsUUID, CmsSessionInfo>> i = allSessions.entrySet().iterator(); while (i.hasNext()) { Map.Entry<CmsUUID, CmsSessionInfo> entry = i.next(); CmsSessionInfo sessionInfo = entry.getValue(); if ((sessionInfo != null) && ((userId == null) || userId.equals(sessionInfo.getUserId()))) { // sessionInfo == null may be the case in case of concurrent modification userSessions.add(sessionInfo); } } return userSessions; } }