org.apache.zookeeper.server

Class SessionTrackerImpl

java.lang.Object

java.lang.Thread

org.apache.zookeeper.server.ZooKeeperThread

org.apache.zookeeper.server.ZooKeeperCriticalThread

org.apache.zookeeper.server.SessionTrackerImpl

All Implemented Interfaces:

Runnable, SessionTracker

Direct Known Subclasses:

LocalSessionTracker

public class SessionTrackerImpl
extends ZooKeeperCriticalThread
implements SessionTracker

This is a full featured SessionTracker. It tracks session in grouped by tick interval. It always rounds up the tick interval to provide a sort of grace period. Sessions are thus expired in batches made up of sessions that expire in a given interval.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	SessionTrackerImpl.SessionImpl

Nested classes/interfaces inherited from class java.lang.Thread

Thread.State, Thread.UncaughtExceptionHandler

Nested classes/interfaces inherited from interface org.apache.zookeeper.server.SessionTracker

SessionTracker.Session, SessionTracker.SessionExpirer

Field Summary

Fields

Modifier and Type	Field and Description
protected ConcurrentHashMap<Long,SessionTrackerImpl.SessionImpl>	sessionsById

Fields inherited from class java.lang.Thread

MAX_PRIORITY, MIN_PRIORITY, NORM_PRIORITY

Constructor Summary

Constructors

Constructor and Description
SessionTrackerImpl(SessionTracker.SessionExpirer expirer, ConcurrentMap<Long,Integer> sessionsWithTimeout, int tickTime, long serverId, ZooKeeperServerListener listener)

Method Summary

Modifier and Type	Method and Description
void	checkGlobalSession(long sessionId, Object owner) Strictly check that a given session is a global session or not
void	checkSession(long sessionId, Object owner) Checks whether the SessionTracker is aware of this session, the session is still active, and the owner matches.
boolean	commitSession(long id, int sessionTimeout) Add the session to the local session map or global one in zkDB.
long	createSession(int sessionTimeout)
void	dumpSessions(PrintWriter pwriter) Text dump of session information, suitable for debugging.
long	getLocalSessionCount() If this session tracker supports local sessions, return how many.
Map<Long,Set<Long>>	getSessionExpiryMap() Returns a mapping from time to session IDs of sessions expiring at that time.
int	getSessionTimeout(long sessionId)
static long	initializeNextSessionId(long id) Generates an initial sessionId.
boolean	isLocalSessionsEnabled()
boolean	isTrackingSession(long sessionId)
void	removeSession(long sessionId)
void	run()
void	setOwner(long id, Object owner)
void	setSessionClosing(long sessionId) Mark that the session is in the process of closing.
void	shutdown()
String	toString()
boolean	touchSession(long sessionId, int timeout)
boolean	trackSession(long id, int sessionTimeout) Track the session expire, not add to ZkDb.

Methods inherited from class org.apache.zookeeper.server.ZooKeeperCriticalThread

handleException

Methods inherited from class java.lang.Thread

activeCount, checkAccess, clone, countStackFrames, currentThread, destroy, dumpStack, enumerate, getAllStackTraces, getContextClassLoader, getDefaultUncaughtExceptionHandler, getId, getName, getPriority, getStackTrace, getState, getThreadGroup, getUncaughtExceptionHandler, holdsLock, interrupt, interrupted, isAlive, isDaemon, isInterrupted, join, join, join, resume, setContextClassLoader, setDaemon, setDefaultUncaughtExceptionHandler, setName, setPriority, setUncaughtExceptionHandler, sleep, sleep, start, stop, stop, suspend, yield

Methods inherited from class java.lang.Object

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

Field Detail

sessionsById

protected final ConcurrentHashMap<Long,SessionTrackerImpl.SessionImpl> sessionsById

Constructor Detail

SessionTrackerImpl

public SessionTrackerImpl(SessionTracker.SessionExpirer expirer,
                          ConcurrentMap<Long,Integer> sessionsWithTimeout,
                          int tickTime,
                          long serverId,
                          ZooKeeperServerListener listener)

Method Detail

initializeNextSessionId

public static long initializeNextSessionId(long id)

Generates an initial sessionId.

High order 1 byte is serverId, next 5 bytes are from timestamp, and low order 2 bytes are 0s. Use ">>> 8", not ">> 8" to make sure that the high order 1 byte is entirely up to the server Id.

See also http://jira.apache.org/jira/browse/ZOOKEEPER-1622

Parameters:

id - server Id

Returns:

the session Id

dumpSessions

public void dumpSessions(PrintWriter pwriter)

Description copied from interface: SessionTracker

Text dump of session information, suitable for debugging.

Specified by:

dumpSessions in interface SessionTracker

Parameters:

pwriter - the output writer

getSessionExpiryMap

public Map<Long,Set<Long>> getSessionExpiryMap()

Returns a mapping from time to session IDs of sessions expiring at that time.

Specified by:

getSessionExpiryMap in interface SessionTracker

toString

public String toString()

Overrides:

toString in class Thread

run

public void run()

Specified by:

run in interface Runnable

Overrides:

run in class Thread

touchSession

public boolean touchSession(long sessionId,
                            int timeout)

Specified by:

touchSession in interface SessionTracker

Returns:

false if session is no longer active

getSessionTimeout

public int getSessionTimeout(long sessionId)

setSessionClosing

public void setSessionClosing(long sessionId)

Description copied from interface: SessionTracker

Mark that the session is in the process of closing.

Specified by:

setSessionClosing in interface SessionTracker

removeSession

public void removeSession(long sessionId)

Specified by:

removeSession in interface SessionTracker

shutdown

public void shutdown()

Specified by:

shutdown in interface SessionTracker

createSession

public long createSession(int sessionTimeout)

Specified by:

createSession in interface SessionTracker

trackSession

public boolean trackSession(long id,
                            int sessionTimeout)

Description copied from interface: SessionTracker

Track the session expire, not add to ZkDb.

Specified by:

trackSession in interface SessionTracker

Parameters:

id - sessionId

sessionTimeout - sessionTimeout

Returns:

whether the session was newly tracked (if false, already tracked)

commitSession

public boolean commitSession(long id,
                             int sessionTimeout)

Description copied from interface: SessionTracker

Add the session to the local session map or global one in zkDB.

Specified by:

commitSession in interface SessionTracker

Parameters:

id - sessionId

sessionTimeout - sessionTimeout

Returns:

whether the session was newly added (if false, already existed)

isTrackingSession

public boolean isTrackingSession(long sessionId)

Specified by:

isTrackingSession in interface SessionTracker

Returns:

whether or not the SessionTracker is aware of this session

checkSession

public void checkSession(long sessionId,
                         Object owner)
                  throws KeeperException.SessionExpiredException,
                         KeeperException.SessionMovedException,
                         KeeperException.UnknownSessionException

Description copied from interface: SessionTracker

Checks whether the SessionTracker is aware of this session, the session is still active, and the owner matches. If the owner wasn't previously set, this sets the owner of the session. UnknownSessionException should never been thrown to the client. It is only used internally to deal with possible local session from other machine

Specified by:

checkSession in interface SessionTracker

Throws:

KeeperException.SessionExpiredException

KeeperException.SessionMovedException

KeeperException.UnknownSessionException

setOwner

public void setOwner(long id,
                     Object owner)
              throws KeeperException.SessionExpiredException

Specified by:

setOwner in interface SessionTracker

Throws:

KeeperException.SessionExpiredException

checkGlobalSession

public void checkGlobalSession(long sessionId,
                               Object owner)
                        throws KeeperException.SessionExpiredException,
                               KeeperException.SessionMovedException

Description copied from interface: SessionTracker

Strictly check that a given session is a global session or not

Specified by:

checkGlobalSession in interface SessionTracker

Throws:

KeeperException.SessionExpiredException

KeeperException.SessionMovedException

getLocalSessionCount

public long getLocalSessionCount()

Description copied from interface: SessionTracker

If this session tracker supports local sessions, return how many. otherwise returns 0;

Specified by:

getLocalSessionCount in interface SessionTracker

isLocalSessionsEnabled

public boolean isLocalSessionsEnabled()

Specified by:

isLocalSessionsEnabled in interface SessionTracker