org.apache.catalina.session
Class PersistentManagerBase

java.lang.Object
  org.apache.catalina.util.LifecycleBase
      org.apache.catalina.util.LifecycleMBeanBase
          org.apache.catalina.session.ManagerBase
              org.apache.catalina.session.PersistentManagerBase

All Implemented Interfaces:

PropertyChangeListener, EventListener, MBeanRegistration, Lifecycle, Manager

Direct Known Subclasses:

PersistentManager

public abstract class PersistentManagerBase
extends ManagerBase

Extends the ManagerBase class to implement most of the functionality required by a Manager which supports any kind of persistence, even if only for 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.

Version:

$Id: PersistentManagerBase.java 1058571 2011-01-13 14:08:24Z markt $

Author:

Craig R. McClanahan, Jean-Francois Arcand

Nested Class Summary

Nested classes/interfaces inherited from class org.apache.catalina.session.ManagerBase

ManagerBase.SessionTiming

Field Summary

protected int	maxIdleBackup How long a session must be idle before it should be backed up
protected int	maxIdleSwap The maximum time a session may be idle before it should be swapped to file just on general principle.
protected int	minIdleSwap Minimum time a session must be idle before it is swapped to disk.
protected boolean	saveOnRestart Whether to save and reload sessions when the Manager unload and load methods are called.
protected Store	store Store object which will manage the Session store.

Fields inherited from class org.apache.catalina.session.ManagerBase

container, distributable, duplicates, expiredSessions, maxActive, maxActiveSessions, maxInactiveInterval, processExpiresFrequency, processingTime, rejectedSessions, secureRandomAlgorithm, secureRandomClass, secureRandomProvider, sessionCounter, sessionCreationTiming, sessionExpirationTiming, sessionIdGenerator, sessionIdLength, sessionMaxAliveTime, sessions, sm, support, TIMING_STATS_CACHE_SIZE

Fields inherited from class org.apache.catalina.util.LifecycleMBeanBase

mserver

Fields inherited from interface org.apache.catalina.Lifecycle

AFTER_DESTROY_EVENT, AFTER_INIT_EVENT, AFTER_START_EVENT, AFTER_STOP_EVENT, BEFORE_DESTROY_EVENT, BEFORE_INIT_EVENT, BEFORE_START_EVENT, BEFORE_STOP_EVENT, CONFIGURE_START_EVENT, CONFIGURE_STOP_EVENT, PERIODIC_EVENT, START_EVENT, STOP_EVENT

Constructor Summary

PersistentManagerBase()

Method Summary

void	clearStore() Clear all sessions from the Store.
Session	findSession(String id) Return the active Session, associated with this Manager, with the specified session id (if any); otherwise return null.
String	getInfo() Return descriptive information about this Manager implementation and the corresponding version number, in the format <description>/<version>.
int	getMaxIdleBackup() 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.
int	getMaxIdleSwap() The time in seconds after which a session should be swapped out of memory to disk.
int	getMinIdleSwap() 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.
String	getName() Return the descriptive short name of this Manager implementation.
boolean	getSaveOnRestart() Indicates whether sessions are saved when the Manager is shut down properly.
Store	getStore() Return the Store object which manages persistent Session storage for this Manager.
boolean	isLoaded(String id) Return true, if the session id is loaded in memory otherwise false is returned
void	load() Load all sessions found in the persistence mechanism, assuming they are marked as valid and have not passed their expiration limit.
void	processExpires() Implements the Manager interface, direct call to processExpires and processPersistenceChecks
protected void	processMaxActiveSwaps() Swap idle sessions out to Store if too many are active
protected void	processMaxIdleBackups() Back up idle sessions.
protected void	processMaxIdleSwaps() Swap idle sessions out to Store if they are idle too long.
void	processPersistenceChecks() Called by the background thread after active sessions have been checked for expiration, to allow sessions to be swapped out, backed up, etc.
void	remove(Session session, boolean update) Remove this Session from the active Sessions for this Manager, and from the Store.
protected void	removeSession(String id) Remove this Session from the active Sessions for this Manager, and from the Store.
void	removeSuper(Session session) Remove this Session from the active Sessions for this Manager, but not from the Store.
void	setMaxIdleBackup(int backup) Sets the option to back sessions up to the Store after they are used in a request.
void	setMaxIdleSwap(int max) Sets the time in seconds after which a session should be swapped out of memory to disk.
void	setMinIdleSwap(int min) Sets the minimum time in seconds that a session must be idle before it can be swapped out of memory due to maxActiveSession.
void	setSaveOnRestart(boolean saveOnRestart) Set the option to save sessions to the Store when the Manager is shut down, then loaded when the Manager starts again.
void	setStore(Store store) Set the Store object which will manage persistent Session storage for this Manager.
protected void	startInternal() Start this component and implement the requirements of LifecycleBase.startInternal().
protected void	stopInternal() Stop this component and implement the requirements of LifecycleBase.stopInternal().
protected Session	swapIn(String id) Look for a session in the Store and, if found, restore it in the Manager's list of active sessions if appropriate.
protected void	swapOut(Session session) Remove the session from the Manager's list of active sessions and write it out to the Store.
void	unload() Save all currently active sessions in the appropriate persistence mechanism, if any.
protected void	writeSession(Session session) Write the provided session to the Store without modifying the copy in memory or triggering passivation events.

Methods inherited from class org.apache.catalina.session.ManagerBase

add, addPropertyChangeListener, backgroundProcess, changeSessionId, createEmptySession, createSession, expireSession, findSessions, generateSessionId, getActiveSessions, getClassName, getContainer, getCreationTime, getCreationTimestamp, getDistributable, getDomainInternal, getDuplicates, getEngine, getExpiredSessions, getJvmRoute, getLastAccessedTime, getLastAccessedTimestamp, getMaxActive, getMaxActiveSessions, getMaxInactiveInterval, getNewSession, getObjectNameKeyProperties, getProcessExpiresFrequency, getProcessingTime, getRejectedSessions, getSecureRandomAlgorithm, getSecureRandomClass, getSecureRandomProvider, getSession, getSessionAttribute, getSessionAverageAliveTime, getSessionCounter, getSessionCreateRate, getSessionExpireRate, getSessionIdLength, getSessionMaxAliveTime, getThisAccessedTime, getThisAccessedTimestamp, initInternal, listSessionIds, propertyChange, remove, removePropertyChangeListener, setContainer, setDistributable, setDuplicates, setExpiredSessions, setMaxActive, setMaxActiveSessions, setMaxInactiveInterval, setProcessExpiresFrequency, setProcessingTime, setSecureRandomAlgorithm, setSecureRandomClass, setSecureRandomProvider, setSessionCounter, setSessionIdLength, setSessionMaxAliveTime, toString, updateSessionMaxAliveTime

Methods inherited from class org.apache.catalina.util.LifecycleMBeanBase

destroyInternal, getDomain, getObjectName, postDeregister, postRegister, preDeregister, preRegister, register, setDomain, unregister

Methods inherited from class org.apache.catalina.util.LifecycleBase

addLifecycleListener, destroy, findLifecycleListeners, fireLifecycleEvent, getState, getStateName, init, removeLifecycleListener, setState, setState, start, stop

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Field Detail

store

protected Store store

Store object which will manage the Session store.

saveOnRestart

protected boolean saveOnRestart

Whether to save and reload sessions when the Manager unload and load methods are called.

maxIdleBackup

protected int maxIdleBackup

How long a session must be idle before it should be backed up. -1 means sessions won't be backed up.

minIdleSwap

protected int minIdleSwap

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.

maxIdleSwap

protected int maxIdleSwap

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.

Constructor Detail

PersistentManagerBase

public PersistentManagerBase()

Method Detail

getMaxIdleBackup

public int getMaxIdleBackup()

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.

setMaxIdleBackup

public void setMaxIdleBackup(int backup)

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.

Parameters:

backup - The number of seconds after their last accessed time when they should be written to the Store.

getMaxIdleSwap

public int getMaxIdleSwap()

The time in seconds after which a session should be swapped out of memory to disk.

setMaxIdleSwap

public void setMaxIdleSwap(int max)

Sets the time in seconds after which a session should be swapped out of memory to disk.

getMinIdleSwap

public int getMinIdleSwap()

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.

setMinIdleSwap

public void setMinIdleSwap(int min)

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.

getInfo

public String getInfo()

Return descriptive information about this Manager implementation and the corresponding version number, in the format <description>/<version>.

Specified by:

getInfo in interface Manager

Overrides:

getInfo in class ManagerBase

isLoaded

public boolean isLoaded(String id)

Return true, if the session id is loaded in memory otherwise false is returned

Parameters:

id - The session id for the session to be searched for

getName

public String getName()

Return the descriptive short name of this Manager implementation.

Overrides:

getName in class ManagerBase

setStore

public void setStore(Store store)

Set the Store object which will manage persistent Session storage for this Manager.

Parameters:

store - the associated Store

getStore

public Store getStore()

Return the Store object which manages persistent Session storage for this Manager.

getSaveOnRestart

public boolean getSaveOnRestart()

Indicates whether sessions are saved when the Manager is shut down properly. This requires the unload() method to be called.

setSaveOnRestart

public void setSaveOnRestart(boolean 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.

Parameters:

saveOnRestart - true if sessions should be saved on restart, false if they should be ignored.

clearStore

public void clearStore()

Clear all sessions from the Store.

processExpires

public void processExpires()

Implements the Manager interface, direct call to processExpires and processPersistenceChecks

Overrides:

processExpires in class ManagerBase

processPersistenceChecks

public void processPersistenceChecks()

Called by the background thread after active sessions have been checked for expiration, to allow sessions to be swapped out, backed up, etc.

findSession

public Session findSession(String id)
                    throws IOException

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.

Specified by:

findSession in interface Manager

Overrides:

findSession in class ManagerBase

Parameters:

id - The session id for the session to be returned

Throws:

IllegalStateException - if a new session cannot be instantiated for any reason

IOException - if an input/output error occurs while processing this request

removeSuper

public void removeSuper(Session session)

Remove this Session from the active Sessions for this Manager, but not from the Store. (Used by the PersistentValve)

Parameters:

session - Session to be removed

load

public void load()

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.

remove

public void remove(Session session,
                   boolean update)

Remove this Session from the active Sessions for this Manager, and from the Store.

Specified by:

remove in interface Manager

Overrides:

remove in class ManagerBase

Parameters:

session - Session to be removed

update - Should the expiration statistics be updated

removeSession

protected void removeSession(String id)

Remove this Session from the active Sessions for this Manager, and from the Store.

Parameters:

id - Session's id to be removed

unload

public void unload()

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.

swapIn

protected Session swapIn(String id)
                  throws IOException

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.

Throws:

IOException

swapOut

protected void swapOut(Session session)
                throws IOException

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.

Parameters:

session - The Session to write out.

Throws:

IOException

writeSession

protected void writeSession(Session session)
                     throws IOException

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.

Throws:

IOException

startInternal

protected void startInternal()
                      throws LifecycleException

Start this component and implement the requirements of LifecycleBase.startInternal().

Overrides:

startInternal in class ManagerBase

Throws:

LifecycleException - if this component detects a fatal error that prevents this component from being used

stopInternal

protected void stopInternal()
                     throws LifecycleException

Stop this component and implement the requirements of LifecycleBase.stopInternal().

Overrides:

stopInternal in class ManagerBase

Throws:

LifecycleException - if this component detects a fatal error that prevents this component from being used

processMaxIdleSwaps

protected void processMaxIdleSwaps()

Swap idle sessions out to Store if they are idle too long.

processMaxActiveSwaps

protected void processMaxActiveSwaps()

Swap idle sessions out to Store if too many are active

processMaxIdleBackups

protected void processMaxIdleBackups()

Back up idle sessions.