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/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 * 
 *      http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
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package org.apache.catalina.session;

import java.beans.PropertyChangeEvent;
import java.beans.PropertyChangeListener;
import java.io.IOException;
import java.security.AccessController;
import java.security.PrivilegedActionException;
import java.security.PrivilegedExceptionAction;
import java.util.HashMap;
import java.util.Map;

import org.apache.catalina.Container;
import org.apache.catalina.Context;
import org.apache.catalina.Lifecycle;
import org.apache.catalina.LifecycleException;
import org.apache.catalina.LifecycleListener;
import org.apache.catalina.Session;
import org.apache.catalina.Store;
import org.apache.catalina.util.LifecycleSupport;

import org.apache.catalina.security.SecurityUtil;
import org.apache.juli.logging.Log;
import org.apache.juli.logging.LogFactory;
/**
 * Extends the ManagerBase class to implement most of the
 * functionality required by a Manager which supports any kind of
 * persistence, even if onlyfor  restarts.
 * 

* IMPLEMENTATION NOTE: Correct behavior of session storing and * reloading depends upon external calls to the start() and * stop() methods of this class at the correct times. * * @author Craig R. McClanahan * @author Jean-Francois Arcand * @version $Revision: 892872 $ $Date: 2009-12-22 00:38:29 +0800 (Tue, 22 Dec 2009) $ */ public abstract class PersistentManagerBase extends ManagerBase implements Lifecycle, PropertyChangeListener { private static Log log = LogFactory.getLog(PersistentManagerBase.class); // ---------------------------------------------------- Security Classes private class PrivilegedStoreClear implements PrivilegedExceptionAction { PrivilegedStoreClear() { } public Object run() throws Exception{ store.clear(); return null; } } private class PrivilegedStoreRemove implements PrivilegedExceptionAction { private String id; PrivilegedStoreRemove(String id) { this.id = id; } public Object run() throws Exception{ store.remove(id); return null; } } private class PrivilegedStoreLoad implements PrivilegedExceptionAction { private String id; PrivilegedStoreLoad(String id) { this.id = id; } public Object run() throws Exception{ return store.load(id); } } private class PrivilegedStoreSave implements PrivilegedExceptionAction { private Session session; PrivilegedStoreSave(Session session) { this.session = session; } public Object run() throws Exception{ store.save(session); return null; } } private class PrivilegedStoreKeys implements PrivilegedExceptionAction { PrivilegedStoreKeys() { } public Object run() throws Exception{ return store.keys(); } } // ----------------------------------------------------- Instance Variables /** * The descriptive information about this implementation. */ private static final String info = "PersistentManagerBase/1.1"; /** * The lifecycle event support for this component. */ protected LifecycleSupport lifecycle = new LifecycleSupport(this); /** * The maximum number of active Sessions allowed, or -1 for no limit. */ protected int maxActiveSessions = -1; /** * The descriptive name of this Manager implementation (for logging). */ private static String name = "PersistentManagerBase"; /** * Has this component been started yet? */ protected boolean started = false; /** * Store object which will manage the Session store. */ protected Store store = null; /** * Whether to save and reload sessions when the Manager unload * and load methods are called. */ protected boolean saveOnRestart = true; /** * How long a session must be idle before it should be backed up. * -1 means sessions won't be backed up. */ protected int maxIdleBackup = -1; /** * Minimum time a session must be idle before it is swapped to disk. * This overrides maxActiveSessions, to prevent thrashing if there are lots * of active sessions. Setting to -1 means it's ignored. */ protected int minIdleSwap = -1; /** * The maximum time a session may be idle before it should be swapped * to file just on general principle. Setting this to -1 means sessions * should not be forced out. */ protected int maxIdleSwap = -1; /** * Number of session creations that failed due to maxActiveSessions. */ protected int rejectedSessions = 0; /** * Processing time during session expiration and passivation. */ protected long processingTime = 0; /** * Sessions currently being swapped in and the associated locks */ private final Map sessionSwapInLocks = new HashMap(); // ------------------------------------------------------------- Properties /** * Indicates how many seconds old a session can get, after its last use in a * request, before it should be backed up to the store. -1 means sessions * are not backed up. */ public int getMaxIdleBackup() { return maxIdleBackup; } /** * Sets the option to back sessions up to the Store after they * are used in a request. Sessions remain available in memory * after being backed up, so they are not passivated as they are * when swapped out. The value set indicates how old a session * may get (since its last use) before it must be backed up: -1 * means sessions are not backed up. *

* Note that this is not a hard limit: sessions are checked * against this age limit periodically according to processExpiresFrequency. * This value should be considered to indicate when a session is * ripe for backing up. *

* So it is possible that a session may be idle for maxIdleBackup + * processExpiresFrequency * engine.backgroundProcessorDelay seconds, plus the time it takes to handle other * session expiration, swapping, etc. tasks. * * @param backup The number of seconds after their last accessed * time when they should be written to the Store. */ public void setMaxIdleBackup (int backup) { if (backup == this.maxIdleBackup) return; int oldBackup = this.maxIdleBackup; this.maxIdleBackup = backup; support.firePropertyChange("maxIdleBackup", new Integer(oldBackup), new Integer(this.maxIdleBackup)); } /** * The time in seconds after which a session should be swapped out of * memory to disk. */ public int getMaxIdleSwap() { return maxIdleSwap; } /** * Sets the time in seconds after which a session should be swapped out of * memory to disk. */ public void setMaxIdleSwap(int max) { if (max == this.maxIdleSwap) return; int oldMaxIdleSwap = this.maxIdleSwap; this.maxIdleSwap = max; support.firePropertyChange("maxIdleSwap", new Integer(oldMaxIdleSwap), new Integer(this.maxIdleSwap)); } /** * The minimum time in seconds that a session must be idle before * it can be swapped out of memory, or -1 if it can be swapped out * at any time. */ public int getMinIdleSwap() { return minIdleSwap; } /** * Sets the minimum time in seconds that a session must be idle before * it can be swapped out of memory due to maxActiveSession. Set it to -1 * if it can be swapped out at any time. */ public void setMinIdleSwap(int min) { if (this.minIdleSwap == min) return; int oldMinIdleSwap = this.minIdleSwap; this.minIdleSwap = min; support.firePropertyChange("minIdleSwap", new Integer(oldMinIdleSwap), new Integer(this.minIdleSwap)); } /** * Set the Container with which this Manager has been associated. If it is a * Context (the usual case), listen for changes to the session timeout * property. * * @param container * The associated Container */ public void setContainer(Container container) { // De-register from the old Container (if any) if ((this.container != null) && (this.container instanceof Context)) ((Context) this.container).removePropertyChangeListener(this); // Default processing provided by our superclass super.setContainer(container); // Register with the new Container (if any) if ((this.container != null) && (this.container instanceof Context)) { setMaxInactiveInterval ( ((Context) this.container).getSessionTimeout()*60 ); ((Context) this.container).addPropertyChangeListener(this); } } /** * Return descriptive information about this Manager implementation and * the corresponding version number, in the format * <description>/<version>. */ public String getInfo() { return (info); } /** * Return true, if the session id is loaded in memory * otherwise false is returned * * @param id The session id for the session to be searched for */ public boolean isLoaded( String id ){ try { if ( super.findSession(id) != null ) return true; } catch (IOException e) { log.error("checking isLoaded for id, " + id + ", "+e.getMessage(), e); } return false; } /** * Return the maximum number of active Sessions allowed, or -1 for * no limit. */ public int getMaxActiveSessions() { return (this.maxActiveSessions); } /** * Set the maximum number of actives Sessions allowed, or -1 for * no limit. * * @param max The new maximum number of sessions */ public void setMaxActiveSessions(int max) { int oldMaxActiveSessions = this.maxActiveSessions; this.maxActiveSessions = max; support.firePropertyChange("maxActiveSessions", new Integer(oldMaxActiveSessions), new Integer(this.maxActiveSessions)); } /** * Number of session creations that failed due to maxActiveSessions. * * @return The count */ public int getRejectedSessions() { return rejectedSessions; } public void setRejectedSessions(int rejectedSessions) { this.rejectedSessions = rejectedSessions; } /** * Return the descriptive short name of this Manager implementation. */ public String getName() { return (name); } /** * Get the started status. */ protected boolean isStarted() { return started; } /** * Set the started flag */ protected void setStarted(boolean started) { this.started = started; } /** * Set the Store object which will manage persistent Session * storage for this Manager. * * @param store the associated Store */ public void setStore(Store store) { this.store = store; store.setManager(this); } /** * Return the Store object which manages persistent Session * storage for this Manager. */ public Store getStore() { return (this.store); } /** * Indicates whether sessions are saved when the Manager is shut down * properly. This requires the unload() method to be called. */ public boolean getSaveOnRestart() { return saveOnRestart; } /** * Set the option to save sessions to the Store when the Manager is * shut down, then loaded when the Manager starts again. If set to * false, any sessions found in the Store may still be picked up when * the Manager is started again. * * @param saveOnRestart true if sessions should be saved on restart, false if * they should be ignored. */ public void setSaveOnRestart(boolean saveOnRestart) { if (saveOnRestart == this.saveOnRestart) return; boolean oldSaveOnRestart = this.saveOnRestart; this.saveOnRestart = saveOnRestart; support.firePropertyChange("saveOnRestart", new Boolean(oldSaveOnRestart), new Boolean(this.saveOnRestart)); } // --------------------------------------------------------- Public Methods /** * Clear all sessions from the Store. */ public void clearStore() { if (store == null) return; try { if (SecurityUtil.isPackageProtectionEnabled()){ try{ AccessController.doPrivileged(new PrivilegedStoreClear()); }catch(PrivilegedActionException ex){ Exception exception = ex.getException(); log.error("Exception clearing the Store: " + exception); exception.printStackTrace(); } } else { store.clear(); } } catch (IOException e) { log.error("Exception clearing the Store: " + e); e.printStackTrace(); } } /** * Implements the Manager interface, direct call to processExpires and processPersistenceChecks */ public void processExpires() { long timeNow = System.currentTimeMillis(); Session sessions[] = findSessions(); int expireHere = 0 ; if(log.isDebugEnabled()) log.debug("Start expire sessions " + getName() + " at " + timeNow + " sessioncount " + sessions.length); for (int i = 0; i < sessions.length; i++) { if (!sessions[i].isValid()) { expiredSessions++; expireHere++; } } processPersistenceChecks(); if ((getStore() != null) && (getStore() instanceof StoreBase)) { ((StoreBase) getStore()).processExpires(); } long timeEnd = System.currentTimeMillis(); if(log.isDebugEnabled()) log.debug("End expire sessions " + getName() + " processingTime " + (timeEnd - timeNow) + " expired sessions: " + expireHere); processingTime += (timeEnd - timeNow); } /** * Called by the background thread after active sessions have been checked * for expiration, to allow sessions to be swapped out, backed up, etc. */ public void processPersistenceChecks() { processMaxIdleSwaps(); processMaxActiveSwaps(); processMaxIdleBackups(); } /** * Return the active Session, associated with this Manager, with the * specified session id (if any); otherwise return null. * This method checks the persistence store if persistence is enabled, * otherwise just uses the functionality from ManagerBase. * * @param id The session id for the session to be returned * * @exception IllegalStateException if a new session cannot be * instantiated for any reason * @exception IOException if an input/output error occurs while * processing this request */ public Session findSession(String id) throws IOException { Session session = super.findSession(id); // OK, at this point, we're not sure if another thread is trying to // remove the session or not so the only way around this is to lock it // (or attempt to) and then try to get it by this session id again. If // the other code ran swapOut, then we should get a null back during // this run, and if not, we lock it out so we can access the session // safely. if(session != null) { synchronized(session){ session = super.findSession(session.getIdInternal()); if(session != null){ // To keep any external calling code from messing up the // concurrency. session.access(); session.endAccess(); } } } if (session != null) return (session); // See if the Session is in the Store session = swapIn(id); return (session); } /** * Remove this Session from the active Sessions for this Manager, * but not from the Store. (Used by the PersistentValve) * * @param session Session to be removed */ public void removeSuper(Session session) { super.remove (session); } /** * Load all sessions found in the persistence mechanism, assuming * they are marked as valid and have not passed their expiration * limit. If persistence is not supported, this method returns * without doing anything. *

* Note that by default, this method is not called by the MiddleManager * class. In order to use it, a subclass must specifically call it, * for example in the start() and/or processPersistenceChecks() methods. */ public void load() { // Initialize our internal data structures sessions.clear(); if (store == null) return; String[] ids = null; try { if (SecurityUtil.isPackageProtectionEnabled()){ try{ ids = (String[]) AccessController.doPrivileged(new PrivilegedStoreKeys()); }catch(PrivilegedActionException ex){ Exception exception = ex.getException(); log.error("Exception in the Store during load: " + exception); exception.printStackTrace(); } } else { ids = store.keys(); } } catch (IOException e) { log.error("Can't load sessions from store, " + e.getMessage(), e); return; } int n = ids.length; if (n == 0) return; if (log.isDebugEnabled()) log.debug(sm.getString("persistentManager.loading", String.valueOf(n))); for (int i = 0; i < n; i++) try { swapIn(ids[i]); } catch (IOException e) { log.error("Failed load session from store, " + e.getMessage(), e); } } /** * Remove this Session from the active Sessions for this Manager, * and from the Store. * * @param session Session to be removed */ public void remove(Session session) { super.remove (session); if (store != null){ removeSession(session.getIdInternal()); } } /** * Remove this Session from the active Sessions for this Manager, * and from the Store. * * @param id Session's id to be removed */ protected void removeSession(String id){ try { if (SecurityUtil.isPackageProtectionEnabled()){ try{ AccessController.doPrivileged(new PrivilegedStoreRemove(id)); }catch(PrivilegedActionException ex){ Exception exception = ex.getException(); log.error("Exception in the Store during removeSession: " + exception); exception.printStackTrace(); } } else { store.remove(id); } } catch (IOException e) { log.error("Exception removing session " + e.getMessage()); e.printStackTrace(); } } /** * Save all currently active sessions in the appropriate persistence * mechanism, if any. If persistence is not supported, this method * returns without doing anything. *

* Note that by default, this method is not called by the MiddleManager * class. In order to use it, a subclass must specifically call it, * for example in the stop() and/or processPersistenceChecks() methods. */ public void unload() { if (store == null) return; Session sessions[] = findSessions(); int n = sessions.length; if (n == 0) return; if (log.isDebugEnabled()) log.debug(sm.getString("persistentManager.unloading", String.valueOf(n))); for (int i = 0; i < n; i++) try { swapOut(sessions[i]); } catch (IOException e) { ; // This is logged in writeSession() } } // ------------------------------------------------------ Protected Methods /** * Look for a session in the Store and, if found, restore * it in the Manager's list of active sessions if appropriate. * The session will be removed from the Store after swapping * in, but will not be added to the active session list if it * is invalid or past its expiration. */ protected Session swapIn(String id) throws IOException { if (store == null) return null; Object swapInLock = null; /* * The purpose of this sync and these locks is to make sure that a * session is only loaded once. It doesn't matter if the lock is removed * and then another thread enters this method and tries to load the same * session. That thread will re-create a swapIn lock for that session, * quickly find that the session is already in sessions, use it and * carry on. */ synchronized (this) { swapInLock = sessionSwapInLocks.get(id); if (swapInLock == null) { swapInLock = new Object(); sessionSwapInLocks.put(id, swapInLock); } } Session session = null; synchronized (swapInLock) { // First check to see if another thread has loaded the session into // the manager session = sessions.get(id); if (session == null) { try { if (SecurityUtil.isPackageProtectionEnabled()){ try { session = (Session) AccessController.doPrivileged( new PrivilegedStoreLoad(id)); } catch (PrivilegedActionException ex) { Exception e = ex.getException(); log.error(sm.getString( "persistentManager.swapInException", id), e); if (e instanceof IOException){ throw (IOException)e; } else if (e instanceof ClassNotFoundException) { throw (ClassNotFoundException)e; } } } else { session = store.load(id); } } catch (ClassNotFoundException e) { String msg = sm.getString( "persistentManager.deserializeError", id); log.error(msg, e); throw new IllegalStateException(msg, e); } if (session != null && !session.isValid()) { log.error(sm.getString( "persistentManager.swapInInvalid", id)); session.expire(); removeSession(id); session = null; } if (session != null) { if(log.isDebugEnabled()) log.debug(sm.getString("persistentManager.swapIn", id)); session.setManager(this); // make sure the listeners know about it. ((StandardSession)session).tellNew(); add(session); ((StandardSession)session).activate(); // endAccess() to ensure timeouts happen correctly. // access() to keep access count correct or it will end up // negative session.access(); session.endAccess(); } } } // Make sure the lock is removed synchronized (this) { sessionSwapInLocks.remove(id); } return (session); } /** * Remove the session from the Manager's list of active * sessions and write it out to the Store. If the session * is past its expiration or invalid, this method does * nothing. * * @param session The Session to write out. */ protected void swapOut(Session session) throws IOException { if (store == null || !session.isValid()) { return; } ((StandardSession)session).passivate(); writeSession(session); super.remove(session); session.recycle(); } /** * Write the provided session to the Store without modifying * the copy in memory or triggering passivation events. Does * nothing if the session is invalid or past its expiration. */ protected void writeSession(Session session) throws IOException { if (store == null || !session.isValid()) { return; } try { if (SecurityUtil.isPackageProtectionEnabled()){ try{ AccessController.doPrivileged(new PrivilegedStoreSave(session)); }catch(PrivilegedActionException ex){ Exception exception = ex.getException(); log.error("Exception in the Store during writeSession: " + exception); exception.printStackTrace(); } } else { store.save(session); } } catch (IOException e) { log.error(sm.getString ("persistentManager.serializeError", session.getIdInternal(), e)); throw e; } } // ------------------------------------------------------ Lifecycle Methods /** * Add a lifecycle event listener to this component. * * @param listener The listener to add */ public void addLifecycleListener(LifecycleListener listener) { lifecycle.addLifecycleListener(listener); } /** * Get the lifecycle listeners associated with this lifecycle. If this * Lifecycle has no listeners registered, a zero-length array is returned. */ public LifecycleListener[] findLifecycleListeners() { return lifecycle.findLifecycleListeners(); } /** * Remove a lifecycle event listener from this component. * * @param listener The listener to remove */ public void removeLifecycleListener(LifecycleListener listener) { lifecycle.removeLifecycleListener(listener); } /** * Prepare for the beginning of active use of the public methods of this * component. This method should be called after configure(), * and before any of the public methods of the component are utilized. * * @exception LifecycleException if this component detects a fatal error * that prevents this component from being used */ public void start() throws LifecycleException { // Validate and update our current component state if (started) { log.info(sm.getString("standardManager.alreadyStarted")); return; } if( ! initialized ) init(); lifecycle.fireLifecycleEvent(START_EVENT, null); started = true; // Force initialization of the random number generator if (log.isDebugEnabled()) log.debug("Force random number initialization starting"); String dummy = generateSessionId(); if (log.isDebugEnabled()) log.debug("Force random number initialization completed"); if (store == null) log.error("No Store configured, persistence disabled"); else if (store instanceof Lifecycle) ((Lifecycle)store).start(); } /** * Gracefully terminate the active use of the public methods of this * component. This method should be the last one called on a given * instance of this component. * * @exception LifecycleException if this component detects a fatal error * that needs to be reported */ public void stop() throws LifecycleException { if (log.isDebugEnabled()) log.debug("Stopping"); // Validate and update our current component state if (!isStarted()) { log.info(sm.getString("standardManager.notStarted")); return; } lifecycle.fireLifecycleEvent(STOP_EVENT, null); setStarted(false); if (getStore() != null && saveOnRestart) { unload(); } else { // Expire all active sessions Session sessions[] = findSessions(); for (int i = 0; i < sessions.length; i++) { StandardSession session = (StandardSession) sessions[i]; if (!session.isValid()) continue; session.expire(); } } if (getStore() != null && getStore() instanceof Lifecycle) ((Lifecycle)getStore()).stop(); // Require a new random number generator if we are restarted this.random = null; if( initialized ) destroy(); } // ----------------------------------------- PropertyChangeListener Methods /** * Process property change events from our associated Context. * * @param event The property change event that has occurred */ public void propertyChange(PropertyChangeEvent event) { // Validate the source of this event if (!(event.getSource() instanceof Context)) return; Context context = (Context) event.getSource(); // Process a relevant property change if (event.getPropertyName().equals("sessionTimeout")) { try { setMaxInactiveInterval ( ((Integer) event.getNewValue()).intValue()*60 ); } catch (NumberFormatException e) { log.error(sm.getString("standardManager.sessionTimeout", event.getNewValue().toString())); } } } // ------------------------------------------------------ Protected Methods /** * Swap idle sessions out to Store if they are idle too long. */ protected void processMaxIdleSwaps() { if (!isStarted() || maxIdleSwap < 0) return; Session sessions[] = findSessions(); long timeNow = System.currentTimeMillis(); // Swap out all sessions idle longer than maxIdleSwap if (maxIdleSwap >= 0) { for (int i = 0; i < sessions.length; i++) { StandardSession session = (StandardSession) sessions[i]; synchronized (session) { if (!session.isValid()) continue; int timeIdle = // Truncate, do not round up (int) ((timeNow - session.getLastAccessedTime()) / 1000L); if (timeIdle > maxIdleSwap && timeIdle > minIdleSwap) { if (session.accessCount != null && session.accessCount.get() > 0) { // Session is currently being accessed - skip it continue; } if (log.isDebugEnabled()) log.debug(sm.getString ("persistentManager.swapMaxIdle", session.getIdInternal(), new Integer(timeIdle))); try { swapOut(session); } catch (IOException e) { ; // This is logged in writeSession() } } } } } } /** * Swap idle sessions out to Store if too many are active */ protected void processMaxActiveSwaps() { if (!isStarted() || getMaxActiveSessions() < 0) return; Session sessions[] = findSessions(); // FIXME: Smarter algorithm (LRU) if (getMaxActiveSessions() >= sessions.length) return; if(log.isDebugEnabled()) log.debug(sm.getString ("persistentManager.tooManyActive", new Integer(sessions.length))); int toswap = sessions.length - getMaxActiveSessions(); long timeNow = System.currentTimeMillis(); for (int i = 0; i < sessions.length && toswap > 0; i++) { StandardSession session = (StandardSession) sessions[i]; synchronized (session) { int timeIdle = // Truncate, do not round up (int) ((timeNow - session.getLastAccessedTime()) / 1000L); if (timeIdle > minIdleSwap) { if (session.accessCount != null && session.accessCount.get() > 0) { // Session is currently being accessed - skip it continue; } if(log.isDebugEnabled()) log.debug(sm.getString ("persistentManager.swapTooManyActive", session.getIdInternal(), new Integer(timeIdle))); try { swapOut(session); } catch (IOException e) { ; // This is logged in writeSession() } toswap--; } } } } /** * Back up idle sessions. */ protected void processMaxIdleBackups() { if (!isStarted() || maxIdleBackup < 0) return; Session sessions[] = findSessions(); long timeNow = System.currentTimeMillis(); // Back up all sessions idle longer than maxIdleBackup if (maxIdleBackup >= 0) { for (int i = 0; i < sessions.length; i++) { StandardSession session = (StandardSession) sessions[i]; synchronized (session) { if (!session.isValid()) continue; int timeIdle = // Truncate, do not round up (int) ((timeNow - session.getLastAccessedTime()) / 1000L); if (timeIdle > maxIdleBackup) { if (log.isDebugEnabled()) log.debug(sm.getString ("persistentManager.backupMaxIdle", session.getIdInternal(), new Integer(timeIdle))); try { writeSession(session); } catch (IOException e) { ; // This is logged in writeSession() } } } } } } }





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