org.mbari.siam.core
Class Scheduler

java.lang.Object
  org.mbari.siam.core.Scheduler

public class Scheduler
extends java.lang.Object

- Scheduler: provides application global view of schedules, supporting operations like showSchedule and getNextScheduledJob - ScheduleTaskImpl: an implementation of ScheduleTask, which encapsulates scheduling timing and control - ScheduleSpecifier: cron-like representation of schedules - Scheduler.ScheduleKey: an inner class of Scheduler, a unique ScheduleOwnerID used in some contexts to resolve ownership of ScheduleTasks (e.g., to differentiate between two ScheduleTasks with the same name, owned by objects of the same class). - ScheduleOwner: an interface that must be fulfilled by things that use schedules To use a schedule, a class must: - implement ScheduleOwner (an interface with 3 methods) - obtain a ScheduleKey object - create one or more ScheduleTasks - register the ScheduleTasks with the Scheduler - start the schedules running (or have them started by something other class) - optionally provide any accessor methods required by the application Scheduler is a cron-like class that schedules periodic events like sampling, using an event/listener model. // HashMap is not inherently synchronized; synchronization must // be manually provided when performing structural mods to the HashMap. // Failure to do this synchronization may result in // undeterministic behavior Set s = _schedules.keySet(); synchronized(_schedules) { // Synchronizing on _schedules, not s! Iterator i = s.iterator(); // Must be in synchronized block while (i.hasNext()){ } } NewScheduler differs from Scheduler as follows: - Objects that wish to receive notification of various events must implement the Schedulable interface, which requires an implementation of SchedulerListener, which extends EventListener.

Nested Class Summary

class

Scheduler.ScheduleKey Scheduler.ScheduleKey: an inner class of Scheduler, a unique ScheduleOwnerID used in some contexts to resolve ownership of ScheduleTasks (e.g., to differentiate between two ScheduleTasks with the same name, owned by objects of the same class).

Field Summary

protected static boolean	_defaultsLoaded True if defaults have been loaded
static long	_nextKey
static Scheduler	_theScheduler the scheduler instance
static int	ALREADY_EXISTS
static int	INVALID_SCHEDULE
static long	MAX_LOOKAHEAD_SEC Max seconds to look ahead for next absolute event
static int	NOT_FOUND
static int	OK
static boolean	OVERWRITE
static boolean	PRESERVE
static int	UNDEFINED

Constructor Summary

Scheduler()

Method Summary

int	addSchedule(ScheduleTask schedule, boolean overwrite) Add schedule with optional overwrite
java.lang.String	getDefaultSampleScheduleName() Get Default Sample Schedule name
java.lang.String	getDefaultSystemScheduleName() Get Default System Schedule name
static Scheduler	getInstance() Get Scheduler instance
long	getNextScheduledJob() Get next Scheduled job
long	getNextScheduledJob(long lookAheadSeconds) Get next Scheduled job
static java.lang.String	getScheduleDirectory() Get Schedule Directory
static Scheduler.ScheduleKey	getScheduleKey(ScheduleOwner owner)
static java.lang.String	getSchedulePath() Get Full Schedule Path ($SIAM_HOME/scheduleDirectory)
static java.util.Properties	getSchedulerProperties() Get SchedulerProperties
java.util.Map	getSchedules() Get Collection of Schedules
static java.lang.String	getSiamHome() Get SiamHome Directory
static java.lang.String	getStatusString(int status) Print error message
static void	loadDefaults() Load default schedules (System, Sampling)
static void	main(java.lang.String[] args)
int	removeSchedule(ScheduleTask schedule) Remove schedule file (scheduleFile is name only; no path)
int	removeSchedules(java.util.Collection schedules) Remove multiple schedules
int	setSchedule(ScheduleTask schedule) Add schedule with overwrite
int	setSchedules(java.util.Collection schedules) Add schedules with overwrite
java.lang.String	showSchedule() Show schedule file
java.lang.String	showSchedule(long lookAheadSeconds) Show all schedules
java.lang.String	showSchedule(Scheduler.ScheduleKey key, long lookAheadSeconds) Show all schedules

Methods inherited from class java.lang.Object

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

Field Detail

OVERWRITE

public static boolean OVERWRITE

PRESERVE

public static boolean PRESERVE

OK

public static final int OK

See Also:

Constant Field Values

ALREADY_EXISTS

public static final int ALREADY_EXISTS

See Also:

Constant Field Values

NOT_FOUND

public static final int NOT_FOUND

See Also:

Constant Field Values

UNDEFINED

public static final int UNDEFINED

See Also:

Constant Field Values

INVALID_SCHEDULE

public static final int INVALID_SCHEDULE

See Also:

Constant Field Values

MAX_LOOKAHEAD_SEC

public static final long MAX_LOOKAHEAD_SEC

Max seconds to look ahead for next absolute event

See Also:

Constant Field Values

_nextKey

public static long _nextKey

_defaultsLoaded

protected static boolean _defaultsLoaded

True if defaults have been loaded

_theScheduler

public static Scheduler _theScheduler

the scheduler instance

Constructor Detail

Scheduler

public Scheduler()

Method Detail

getSchedules

public java.util.Map getSchedules()

Get Collection of Schedules

getInstance

public static Scheduler getInstance()

Get Scheduler instance

getStatusString

public static java.lang.String getStatusString(int status)

Print error message

setSchedules

public int setSchedules(java.util.Collection schedules)

Add schedules with overwrite

removeSchedules

public int removeSchedules(java.util.Collection schedules)

Remove multiple schedules

setSchedule

public int setSchedule(ScheduleTask schedule)

Add schedule with overwrite

addSchedule

public int addSchedule(ScheduleTask schedule,
                       boolean overwrite)

Add schedule with optional overwrite

removeSchedule

public int removeSchedule(ScheduleTask schedule)

Remove schedule file (scheduleFile is name only; no path)

showSchedule

public java.lang.String showSchedule()

Show schedule file

showSchedule

public java.lang.String showSchedule(long lookAheadSeconds)

Show all schedules

showSchedule

public java.lang.String showSchedule(Scheduler.ScheduleKey key,
                                     long lookAheadSeconds)

Show all schedules

getNextScheduledJob

public long getNextScheduledJob()

Get next Scheduled job

getNextScheduledJob

public long getNextScheduledJob(long lookAheadSeconds)

Get next Scheduled job

getSchedulerProperties

public static java.util.Properties getSchedulerProperties()

Get SchedulerProperties

getSiamHome

public static java.lang.String getSiamHome()

Get SiamHome Directory

getScheduleDirectory

public static java.lang.String getScheduleDirectory()

Get Schedule Directory

getDefaultSystemScheduleName

public java.lang.String getDefaultSystemScheduleName()

Get Default System Schedule name

getDefaultSampleScheduleName

public java.lang.String getDefaultSampleScheduleName()

Get Default Sample Schedule name

getSchedulePath

public static java.lang.String getSchedulePath()

Get Full Schedule Path ($SIAM_HOME/scheduleDirectory)

loadDefaults

public static void loadDefaults()

Load default schedules (System, Sampling)

getScheduleKey

public static final Scheduler.ScheduleKey getScheduleKey(ScheduleOwner owner)

main

public static void main(java.lang.String[] args)