Class SessionKeepAliveDaemon

java.lang.Object

java.lang.Thread

org.tentackle.task.DefaultTaskDispatcher

org.tentackle.session.SessionKeepAliveDaemon

All Implemented Interfaces:

Runnable, Killable, Supervisable, Terminatable, TaskDispatcher

public class SessionKeepAliveDaemon
extends DefaultTaskDispatcher

A task dispatcher to keep sessions alive.

Author:

harald

Nested Class Summary

Nested classes/interfaces inherited from class Thread

Thread.Builder, Thread.State, Thread.UncaughtExceptionHandler

Field Summary

Fields inherited from class DefaultTaskDispatcher

INSTANCE_COUNTER

Fields inherited from class Thread

MAX_PRIORITY, MIN_PRIORITY, NORM_PRIORITY

Constructor Summary

Constructors

Constructor	Description
SessionKeepAliveDaemon(long minAliveInterval)	Creates the daemon.

Method Summary

Modifier and Type	Method	Description
protected void	cleanup()	Does any necessary cleanup after the dispatcher thread has been terminated.
protected Task	createAliveTask(Session session, long interval)	Creates a keep-alive task.
protected ExecutorService	createExecutorService()	Creates the executor service.
ExecutorService	getExecutorService()	Gets the executor service.
Collection<Session>	getKeepAliveSessions()	Gets the sessions currently kept alive. Useful to hand the registrations over to another daemon, should this one have died.
void	keepAliveIntervalChanged(Session session)	Handles the change of a keep alive-interval of a session.
void	removeAliveTask(Session session)	Removes the task for the given session.
boolean	removeAliveTask(Session session, Task task)	Removes the given task for the given session.
void	run()

Methods inherited from class DefaultTaskDispatcher

addTask, addTaskAndWait, addTaskListener, assertAlive, assertIntervalsInRange, assertNotAlive, assertNotKilled, createLock, executeTask, fireCompleted, fireStarted, getAllTasks, getDeadInterval, getQueueSize, getShutdownIdleTimeout, getSleepInterval, getTask, getTerminationCause, getWaitInterval, interrupt, isDead, isInstanceOfTaskPending, isKilled, isQueueEmpty, isTaskDispatcherThread, isTaskPending, isTerminationRequested, isUsingMutexLocking, kill, lock, lockInternal, nextTask, removeTask, removeTaskListener, requestTermination, setDead, setDeadInterval, setShutdownIdleTimeout, setSleepInterval, setUsingMutexLocking, setWaitInterval, sleepForInterval, startedAt, terminate, terminatedAt, toDiagnosticString, unlock, unlockInternal, waitForTask

Methods inherited from class Thread

activeCount, checkAccess, clone, currentThread, dumpStack, enumerate, getAllStackTraces, getContextClassLoader, getDefaultUncaughtExceptionHandler, getId, getName, getPriority, getStackTrace, getState, getThreadGroup, getUncaughtExceptionHandler, holdsLock, interrupted, isAlive, isDaemon, isInterrupted, isVirtual, join, join, join, join, ofPlatform, ofVirtual, onSpinWait, setContextClassLoader, setDaemon, setDefaultUncaughtExceptionHandler, setName, setPriority, setUncaughtExceptionHandler, sleep, sleep, sleep, start, startVirtualThread, stop, threadId, toString, yield

Methods inherited from class Object

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

Methods inherited from interface Supervisable

getName

Methods inherited from interface TaskDispatcher

isAlive, start

Constructor Details

SessionKeepAliveDaemon

public SessionKeepAliveDaemon(long minAliveInterval)

Creates the daemon.

Parameters:

minAliveInterval - the minimum alive-interval in ms

Method Details

cleanup

protected void cleanup()

Description copied from class: DefaultTaskDispatcher

Does any necessary cleanup after the dispatcher thread has been terminated.

Overrides:

cleanup in class DefaultTaskDispatcher

run

public void run()

Specified by:

run in interface Runnable

Overrides:

run in class DefaultTaskDispatcher

keepAliveIntervalChanged

public void keepAliveIntervalChanged(Session session)

Handles the change of a keep alive-interval of a session.

Parameters:

session - the session

removeAliveTask

public void removeAliveTask(Session session)

Removes the task for the given session.

Parameters:

session - the session

removeAliveTask

public boolean removeAliveTask(Session session,
 Task task)

Removes the given task for the given session.

Unlike removeAliveTask(Session) the task is removed only if it still is the session's current task. This is what a running SessionKeepAliveTask must use to unregister itself: another thread may have replaced it via keepAliveIntervalChanged(Session) in the meantime, and removing by session alone would drop that replacement and leave the session without a keep-alive.

Deliberately not synchronized on the daemon's alive-lock: the invocation comes from the daemon thread while executing the task, and the compare-and-remove is atomic in itself.

Parameters:

session - the session

task - the task requesting its own removal

Returns:

true if removed, false if the task no longer is the session's current task

getKeepAliveSessions

public Collection<Session> getKeepAliveSessions()

Gets the sessions currently kept alive.
Useful to hand the registrations over to another daemon, should this one have died.

Returns:

a snapshot of the sessions, never null

getExecutorService

public ExecutorService getExecutorService()

Gets the executor service.

Returns:

the executor service

createExecutorService

protected ExecutorService createExecutorService()

Creates the executor service.

Returns:

the executor service

createAliveTask

protected Task createAliveTask(Session session,
 long interval)

Creates a keep-alive task.

Parameters:

session - the session

interval - the keep-alive interval in milliseconds

Returns:

the created task