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:
MBeanRegistration, DistributedManager, JmxEnabled, Lifecycle, Manager, StoreManager
Direct Known Subclasses:
PersistentManager
public abstract class PersistentManagerBase extends ManagerBase implements StoreManager
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 Lifecycle.start() and Lifecycle.stop() methods of this class at the correct times.

Author:
Craig R. McClanahan

  • Field Details

    • 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
      The minimum time in seconds a session must be idle before it is eligible to be swapped to disk to keep the active session count below maxActiveSessions. Setting to -1 means sessions will not be swapped out to keep the active session count down.

    • maxIdleSwap

      protected int maxIdleSwap
      The maximum time in seconds a session may be idle before it is eligible to be swapped to disk due to inactivity. Setting this to -1 means sessions should not be swapped out just because of inactivity.

  • Constructor Details

    • PersistentManagerBase

      public PersistentManagerBase()

  • Method Details

    • 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.
      Returns:
      the timeout after which sessions are ripe for back 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()
      Returns:
      The maximum time in seconds a session may be idle before it is eligible to be swapped to disk due to inactivity. A value of -1 means sessions should not be swapped out just because of inactivity.

    • setMaxIdleSwap

      public void setMaxIdleSwap(int max)
      Sets the maximum time in seconds a session may be idle before it is eligible to be swapped to disk due to inactivity. Setting this to -1 means sessions should not be swapped out just because of inactivity.
      Parameters:
      max - time in seconds to wait for possible swap out

    • getMinIdleSwap

      public int getMinIdleSwap()
      Returns:
      The minimum time in seconds a session must be idle before it is eligible to be swapped to disk to keep the active session count below maxActiveSessions. A value of -1 means sessions will not be swapped out to keep the active session count down.

    • setMinIdleSwap

      public void setMinIdleSwap(int min)
      Sets the minimum time in seconds a session must be idle before it is eligible to be swapped to disk to keep the active session count below maxActiveSessions. Setting to -1 means sessions will not be swapped out to keep the active session count down.
      Parameters:
      min - time in seconds before a possible swap out

    • isLoaded

      public boolean isLoaded(String id)
      Check, whether a session is loaded in memory
      Parameters:
      id - The session id for the session to be searched for
      Returns:
      true, if the session id is loaded in memory otherwise false is returned

    • getName

      public String getName()
      Overrides:
      getName in class ManagerBase
      Returns:
      The descriptive short name of this Manager implementation.

    • 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()
      Specified by:
      getStore in interface StoreManager
      Returns:
      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.
      Returns:
      true, when sessions should be saved on restart, {code false} otherwise

    • 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()
      Invalidate all sessions that have expired.

      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
      Returns:
      the request session or null if a session with the requested ID could not be found
      Throws:
      IOException - if an input/output error occurs while processing this request

    • removeSuper

      public void removeSuper(Session session)
      Description copied from interface: StoreManager
      Remove this Session from the active Sessions for this Manager, but not from the Store. (Used by the PersistentValve)
      Specified by:
      removeSuper in interface StoreManager
      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.

      Specified by:
      load in interface Manager

    • remove

      public void remove(Session session, boolean update)
      Remove this Session from the active Sessions for this Manager.

      Remove this Session 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.

      Specified by:
      unload in interface Manager

    • getActiveSessionsFull

      public int getActiveSessionsFull()
      Description copied from interface: DistributedManager
      Returns the total session count for primary, backup and proxy.
      Specified by:
      getActiveSessionsFull in interface DistributedManager
      Returns:
      The total session count across the cluster.

    • getSessionIdsFull

      public Set<String> getSessionIdsFull()
      Description copied from interface: DistributedManager
      Returns the list of all sessions IDS (primary, backup and proxy).
      Specified by:
      getSessionIdsFull in interface DistributedManager
      Returns:
      The complete set of sessions IDs across the cluster.

    • 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.
      Parameters:
      id - The id of the session that should be swapped in
      Returns:
      restored session, or null, if none is found
      Throws:
      IOException - an IO error occurred

    • 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 - an IO error occurred

    • 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.
      Parameters:
      session - The session that should be written
      Throws:
      IOException - an IO error occurred

    • 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.