javax.management.timer
Class Timer

java.lang.Object
  |
  +--javax.management.NotificationBroadcasterSupport
        |
        +--javax.management.timer.Timer

public class Timer

extends NotificationBroadcasterSupport

implements TimerMBean, MBeanRegistration, java.io.Serializable

Provides the implementation of the timer MBean. The timer MBean sends out an alarm at a specified time that wakes up all the listeners registered to receive timer notifications.

This class manages a list of dated timer notifications. A method allows users to add/remove as many notifications as required. When a timer notification is emitted by the timer and becomes obsolete, it is automatically removed from the list of timer notifications.

Additional timer notifications can be added into regularly repeating notifications.

Note:

All notifications before the time when the addNotification method is called are ignored, irrespective of the sendPastNotifications flag.

When sending timer notifications, the timer updates the notification sequence number irrespective of the notification type.

The timer service relies on the system date of the host where the Timer class is loaded. Callers may be unable to add notifications to the timer, and listeners may recieve untimely notifications if their host has a different system date. To avoid such problems, synchronize the system date of all host machines where timing is needed.

Version:

1.27

Author:

Alessio Menale, Attilio Mattiocco

See Also:

Serialized Form

Field Summary

static long	ONE_DAY Number of milliseconds in one day.
static long	ONE_HOUR Number of milliseconds in one hour.
static long	ONE_MINUTE Number of milliseconds in one minute.
static long	ONE_SECOND Number of milliseconds in one second.
static long	ONE_WEEK Number of milliseconds in one week.

Constructor Summary

Timer()
public constructor.

Method Summary

java.lang.Integer	addNotification(java.lang.String type, java.lang.String message, java.lang.Object userData, java.util.Date date) Creates a new timer notification with the specified type, message and userData and inserts it into the list of notifications with a given date and a null period and number of occurences.
java.lang.Integer	addNotification(java.lang.String type, java.lang.String message, java.lang.Object userData, java.util.Date date, long period) Creates a new timer notification with the specified type, message and userData and inserts it into the list of notifications with a given date and period and a null number of occurences.
java.lang.Integer	addNotification(java.lang.String type, java.lang.String message, java.lang.Object userData, java.util.Date date, long period, long nbOccurrences) Creates a new timer notification with the specified type, message and userData and inserts it into the list of notifications with a given date, period and number of occurences.
java.util.Vector	getAllNotificationIDs() Gets all timer notification identifiers registered into the list of notifications.
java.util.Date	getDate(java.lang.Integer id) Gets a copy of the date associated to a timer notification.
int	getNbNotifications() Gets the number of timer notifications registered into the list of notifications.
java.lang.Long	getNbOccurences(java.lang.Integer id) Gets a copy of the remaining number of occurences associated to a timer notification.
java.util.Vector	getNotificationIDs(java.lang.String type) Gets all the identifiers of timer notifications corresponding to the specified type.
java.lang.String	getNotificationMessage(java.lang.Integer id) Gets the timer notification detailed message corresponding to the specified identifier.
java.lang.String	getNotificationType(java.lang.Integer id) Gets the timer notification type corresponding to the specified identifier.
java.lang.Object	getNotificationUserData(java.lang.Integer id) Gets the timer notification user data object corresponding to the specified identifier.
java.lang.Long	getPeriod(java.lang.Integer id) Gets a copy of the period (in milliseconds) associated to a timer notification.
boolean	getSendPastNotifications() Gets the flag indicating whether or not the timer sends past notifications.
boolean	isActive() Tests whether the timer MBean is active.
boolean	isEmpty() Tests whether the list of timer notifications is empty.
void	postDeregister() Allows the timer MBean to perform any operations needed after having been de-registered by the MBean server.
void	postRegister(java.lang.Boolean registrationDone) Allows the timer MBean to perform any operations needed after having been registered in the MBean server or after the registration has failed.
void	preDeregister() Allows the timer MBean to perform any operations it needs before being de-registered in the MBean server.
ObjectName	preRegister(MBeanServer server, ObjectName name) Allows the timer MBean to perform any operations it needs before being registered in the MBean server.
void	removeAllNotifications() Removes all the timer notifications from the list of notifications and resets the counter used to update the timer notification identifiers.
void	removeNotification(java.lang.Integer id) Removes the timer notification corresponding to the specified identifier from the list of notifications.
void	removeNotifications(java.lang.String type) Removes all the timer notifications corresponding to the specified type from the list of notifications.
void	setSendPastNotifications(boolean sendPastNotifications) sets the attribute sendPastNotification, to determine the behavior of the timer when it finds expired notifications
void	start() Starts the timer.
void	stop() stops the timer.

Methods inherited from class javax.management.NotificationBroadcasterSupport

addNotificationListener, getNotificationInfo, removeNotificationListener, sendNotification

Methods inherited from class java.lang.Object

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

Field Detail

ONE_SECOND

public static final long ONE_SECOND

Number of milliseconds in one second. Useful constant for the addNotification method.

ONE_MINUTE

public static final long ONE_MINUTE

Number of milliseconds in one minute. Useful constant for the addNotification method.

ONE_HOUR

public static final long ONE_HOUR

Number of milliseconds in one hour. Useful constant for the addNotification method.

ONE_DAY

public static final long ONE_DAY

Number of milliseconds in one day. Useful constant for the addNotification method.

ONE_WEEK

public static final long ONE_WEEK

Number of milliseconds in one week. Useful constant for the addNotification method.

Constructor Detail

Timer

public Timer()

public constructor.

Method Detail

preRegister

public ObjectName preRegister(MBeanServer server,
                              ObjectName name)
                       throws java.lang.Exception

Allows the timer MBean to perform any operations it needs before being registered in the MBean server. Not used in this context.

Specified by:

preRegister in interface MBeanRegistration

Parameters:

server - The MBean server in which the timer MBean will be registered.

name - The object name of the timer MBean.

Returns:

The name of the timer MBean registered.

Throws:

java.lang.Exception. -

postRegister

public void postRegister(java.lang.Boolean registrationDone)

Allows the timer MBean to perform any operations needed after having been registered in the MBean server or after the registration has failed. Not used in this context.

Specified by:

postRegister in interface MBeanRegistration

Parameters:

registrationDone - Indicates whether or not the MBean has been successfully registered in the MBean server. The value false means that the registration phase has failed.

preDeregister

public void preDeregister()
                   throws java.lang.Exception

Allows the timer MBean to perform any operations it needs before being de-registered in the MBean server. Stops the timer.

Specified by:

preDeregister in interface MBeanRegistration

Tags copied from interface: MBeanRegistration

Throws:

java.lang.Exception - This exception should be caught by the MBean server and re-thrown as an MBeanRegistrationException

postDeregister

public void postDeregister()

Allows the timer MBean to perform any operations needed after having been de-registered by the MBean server. Not used in this context.

Specified by:

postDeregister in interface MBeanRegistration

start

public void start()

Starts the timer. If there is one or more expired timer notifications in the list they are sent according to the sendPastNotifications flag and then updated according to their period and remaining number of occurences. If the timer notification date remains earlier than the current date, this notification is just removed from the list of notifications.

Specified by:

start in interface TimerMBean

stop

public void stop()

stops the timer.

Specified by:

stop in interface TimerMBean

isActive

public boolean isActive()

Tests whether the timer MBean is active. A timer MBean is marked active when the start method is called. It becomes inactive when the stop method is called.

Specified by:

isActive in interface TimerMBean

Returns:

true if the timer is started, otherwise false

isEmpty

public boolean isEmpty()

Tests whether the list of timer notifications is empty.

Specified by:

isEmpty in interface TimerMBean

Returns:

true if the timerNotifications list is empty

getNbNotifications

public int getNbNotifications()

Gets the number of timer notifications registered into the list of notifications.

Specified by:

getNbNotifications in interface TimerMBean

Returns:

The number of timer notifications

setSendPastNotifications

public void setSendPastNotifications(boolean sendPastNotifications)

sets the attribute sendPastNotification, to determine the behavior of the timer when it finds expired notifications

Specified by:

setSendPastNotifications in interface TimerMBean

Parameters:

sendPastNotifications - The past notifications sending on/off flag value.

getSendPastNotifications

public boolean getSendPastNotifications()

Gets the flag indicating whether or not the timer sends past notifications.

Specified by:

getSendPastNotifications in interface TimerMBean

Returns:

The value of the attribute setSendPastNotification

addNotification

public java.lang.Integer addNotification(java.lang.String type,
                                         java.lang.String message,
                                         java.lang.Object userData,
                                         java.util.Date date)
                                  throws java.lang.IllegalArgumentException

Creates a new timer notification with the specified type, message and userData and inserts it into the list of notifications with a given date and a null period and number of occurences. The timer notification will be handled once at the specified date.

Specified by:

addNotification in interface TimerMBean

Parameters:

type - The timer notification type.

message - The timer notification detailed message.

userData - The timer notification user data object.

date - The date when the notification occurs.

Returns:

The identifier of the new created timer notification.

Throws:

java.lang.IllegalArgumentException - - The date notification is before the current date.

addNotification

public java.lang.Integer addNotification(java.lang.String type,
                                         java.lang.String message,
                                         java.lang.Object userData,
                                         java.util.Date date,
                                         long period)
                                  throws java.lang.IllegalArgumentException

Creates a new timer notification with the specified type, message and userData and inserts it into the list of notifications with a given date and period and a null number of occurences.

Specified by:

addNotification in interface TimerMBean

Parameters:

type - The timer notification type.

message - The timer notification detailed message.

userData - The timer notification user data object.

date - The date when the notification occurs.

period - The period of the timer notification (in milliseconds).

Returns:

The identifier of the new created timer notification.

Throws:

java.lang.IllegalArgumentException - - The period is negative or the date notification is before the current date.

addNotification

public java.lang.Integer addNotification(java.lang.String type,
                                         java.lang.String message,
                                         java.lang.Object userData,
                                         java.util.Date date,
                                         long period,
                                         long nbOccurrences)
                                  throws java.lang.IllegalArgumentException

Creates a new timer notification with the specified type, message and userData and inserts it into the list of notifications with a given date, period and number of occurences. If the timer notification to be inserted has a date that is before the current date, the method attempts to update the notification using the defined period. If the defined period is null, the method generates an exception. If the timer notification has a non null period, the date of the notification is updated by adding the period until the notification date is later than the current date. The timer notification is then inserted into the list of notifications. If the specified number of occurences is non null, the following mechanism is employed. The number of times that the period is added is limited by the specified number of occurences. If the notification date remains earlier than the current date, an exception is generated. Note that once the timer notification has been added into the list of notifications, its associated date, period and number of occurences cannot be updated.

Specified by:

addNotification in interface TimerMBean

Parameters:

type - The timer notification type.

message - The timer notification detailed message.

userData - The timer notification user data object.

date - The date when the notification occurs.

period - The period of the timer notification (in milliseconds).

nbOccurences - The total number the timer notification will be emitted.

Returns:

The identifier of the new created timer notification.

Throws:

java.lang.IllegalArgumentException - - The period or the number of occurences is negative or the date notification is before the current date.

removeNotification

public void removeNotification(java.lang.Integer id)
                        throws InstanceNotFoundException

Removes the timer notification corresponding to the specified identifier from the list of notifications.

Specified by:

removeNotification in interface TimerMBean

Parameters:

id - The timer notification identifier.

Throws:

InstanceNotFoundException - - The specified identifier does not correspond to any timer notification in the list of notifications of this timer MBean.

removeNotifications

public void removeNotifications(java.lang.String type)
                         throws InstanceNotFoundException

Removes all the timer notifications corresponding to the specified type from the list of notifications.

Specified by:

removeNotifications in interface TimerMBean

Parameters:

type - The timer notification type.

Throws:

IInstanceNotFoundException - - The specified type does not correspond to any timer notification in the list of notifications of this timer MBean.

removeAllNotifications

public void removeAllNotifications()

Removes all the timer notifications from the list of notifications and resets the counter used to update the timer notification identifiers.

Specified by:

removeAllNotifications in interface TimerMBean

getPeriod

public java.lang.Long getPeriod(java.lang.Integer id)

Gets a copy of the period (in milliseconds) associated to a timer notification.

Specified by:

getPeriod in interface TimerMBean

Parameters:

id - The timer notification identifier.

Returns:

A copy of the period or null if the identifier is not mapped to any timer notification registered for this timer MBean.

getNotificationUserData

public java.lang.Object getNotificationUserData(java.lang.Integer id)

Gets the timer notification user data object corresponding to the specified identifier.

Specified by:

getNotificationUserData in interface TimerMBean

Parameters:

id - The timer notification identifier.

Returns:

The timer notification user data object or null if the identifier is not mapped to any timer notification registered for this timer MBean.

getNotificationType

public java.lang.String getNotificationType(java.lang.Integer id)

Gets the timer notification type corresponding to the specified identifier.

Specified by:

getNotificationType in interface TimerMBean

Parameters:

id - The timer notification identifier.

Returns:

The timer notification type or null if the identifier is not mapped to any timer notification registered for this timer MBean.

getNotificationMessage

public java.lang.String getNotificationMessage(java.lang.Integer id)

Gets the timer notification detailed message corresponding to the specified identifier.

Specified by:

getNotificationMessage in interface TimerMBean

Parameters:

id - The timer notification identifier.

Returns:

The timer notification detailed message or null if the identifier is not mapped to any timer notification registered for this timer MBean.

getDate

public java.util.Date getDate(java.lang.Integer id)

Gets a copy of the date associated to a timer notification.

Specified by:

getDate in interface TimerMBean

Parameters:

id - The timer notification identifier.

Returns:

A copy of the date or null if the identifier is not mapped to any timer notification registered for this timer MBean.

getNbOccurences

public java.lang.Long getNbOccurences(java.lang.Integer id)

Gets a copy of the remaining number of occurences associated to a timer notification.

Specified by:

getNbOccurences in interface TimerMBean

Parameters:

id - The timer notification identifier.

Returns:

A copy of the remaining number of occurences or null if the identifier is not mapped to any timer notification registered for this timer MBean.

getAllNotificationIDs

public java.util.Vector getAllNotificationIDs()

Gets all timer notification identifiers registered into the list of notifications.

Specified by:

getAllNotificationIDs in interface TimerMBean

Returns:

A vector of Integer objects containing all the timer notification identifiers. The vector is empty if there is no timer notification registered for this timer MBean.

getNotificationIDs

public java.util.Vector getNotificationIDs(java.lang.String type)

Gets all the identifiers of timer notifications corresponding to the specified type.

Specified by:

getNotificationIDs in interface TimerMBean

Parameters:

type - The timer notification type..

Returns:

A vector of Integer objects containing all the identifiers of timer notifications with the specified type. The vector is empty if there is no timer notifications registered for this timer MBean with the specified type.