public class

Timer

extends NotificationBroadcasterSupport
implements MBeanRegistration TimerMBean
java.lang.Object
   ↳ javax.management.NotificationBroadcasterSupport
     ↳ javax.management.timer.Timer

Class Overview

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:

  1. When sending timer notifications, the timer updates the notification sequence number irrespective of the notification type.
  2. The timer service relies on the system date of the host where the Timer class is loaded. Listeners may receive 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.
  3. The default behavior for periodic notifications is fixed-delay execution, as specified in Timer. In order to use fixed-rate execution, use the overloaded addNotification(String, String, Object, Date, long, long, boolean) method.
  4. Notification listeners are potentially all executed in the same thread. Therefore, they should execute rapidly to avoid holding up other listeners or perturbing the regularity of fixed-delay executions. See NotificationBroadcasterSupport.

Summary

Constants
long ONE_DAY Number of milliseconds in one day.
long ONE_HOUR Number of milliseconds in one hour.
long ONE_MINUTE Number of milliseconds in one minute.
long ONE_SECOND Number of milliseconds in one second.
long ONE_WEEK Number of milliseconds in one week.
Public Constructors
Timer()
Default constructor.
Public Methods
synchronized Integer addNotification(String type, String message, Object userData, Date date, long period, long nbOccurences, boolean fixedRate)
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 occurrences.
synchronized Integer addNotification(String type, String message, Object userData, 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 occurrences.
synchronized Integer addNotification(String type, String message, Object userData, 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 occurrences.
synchronized Integer addNotification(String type, String message, Object userData, Date date, long period, long nbOccurences)
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 occurrences.
synchronized Vector<Integer> getAllNotificationIDs()
Gets all timer notification identifiers registered into the list of notifications.
Date getDate(Integer id)
Gets a copy of the date associated to a timer notification.
Boolean getFixedRate(Integer id)
Gets a copy of the flag indicating whether a periodic notification is executed at fixed-delay or at fixed-rate.
int getNbNotifications()
Gets the number of timer notifications registered into the list of notifications.
Long getNbOccurences(Integer id)
Gets a copy of the remaining number of occurrences associated to a timer notification.
synchronized Vector<Integer> getNotificationIDs(String type)
Gets all the identifiers of timer notifications corresponding to the specified type.
synchronized MBeanNotificationInfo[] getNotificationInfo()

Returns an array indicating, for each notification this MBean may send, the name of the Java class of the notification and the notification type.

String getNotificationMessage(Integer id)
Gets the timer notification detailed message corresponding to the specified identifier.
String getNotificationType(Integer id)
Gets the timer notification type corresponding to the specified identifier.
Object getNotificationUserData(Integer id)
Gets the timer notification user data object corresponding to the specified identifier.
Long getPeriod(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 unregistered by the MBean server.
void postRegister(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 unregistered by 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.
synchronized void removeAllNotifications()
Removes all the timer notifications from the list of notifications and resets the counter used to update the timer notification identifiers.
synchronized void removeNotification(Integer id)
Removes the timer notification corresponding to the specified identifier from the list of notifications.
synchronized void removeNotifications(String type)
Removes all the timer notifications corresponding to the specified type from the list of notifications.
void setSendPastNotifications(boolean value)
Sets the flag indicating whether the timer sends past notifications or not.
synchronized void start()
Starts the timer.
synchronized void stop()
Stops the timer.
[Expand]
Inherited Methods
From class javax.management.NotificationBroadcasterSupport
From class java.lang.Object
From interface javax.management.MBeanRegistration
From interface javax.management.NotificationBroadcaster
From interface javax.management.NotificationEmitter
From interface javax.management.timer.TimerMBean

Constants

public static final long ONE_DAY

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

Constant Value: 86400000 (0x0000000005265c00)

public static final long ONE_HOUR

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

Constant Value: 3600000 (0x000000000036ee80)

public static final long ONE_MINUTE

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

Constant Value: 60000 (0x000000000000ea60)

public static final long ONE_SECOND

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

Constant Value: 1000 (0x00000000000003e8)

public static final long ONE_WEEK

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

Constant Value: 604800000 (0x00000000240c8400)

Public Constructors

public Timer ()

Default constructor.

Public Methods

public synchronized Integer addNotification (String type, String message, Object userData, Date date, long period, long nbOccurences, boolean fixedRate)

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 occurrences.

If the timer notification to be inserted has a date that is before the current date, the method behaves as if the specified date were the current date.
For once-off notifications, the notification is delivered immediately.
For periodic notifications, the first notification is delivered immediately and the subsequent ones are spaced as specified by the period parameter.

Note that once the timer notification has been added into the list of notifications, its associated date, period and number of occurrences cannot be updated.

In the case of a periodic notification, the value of parameter fixedRate is used to specify the execution scheme, as specified in Timer.

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.
fixedRate If true and if the notification is periodic, the notification is scheduled with a fixed-rate execution scheme. If false and if the notification is periodic, the notification is scheduled with a fixed-delay execution scheme. Ignored if the notification is not periodic.
Returns
  • The identifier of the new created timer notification.
Throws
IllegalArgumentException The date is null or the period or the number of occurrences is negative.
See Also

public synchronized Integer addNotification (String type, String message, Object userData, 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 occurrences.

The timer notification will repeat continuously using the timer period using a fixed-delay execution scheme, as specified in Timer. In order to use a fixed-rate execution scheme, use addNotification(String, String, Object, Date, long, long, boolean) instead.

If the timer notification to be inserted has a date that is before the current date, the method behaves as if the specified date were the current date. The first notification is delivered immediately and the subsequent ones are spaced as specified by the period parameter.

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
IllegalArgumentException The date is null or the period is negative.

public synchronized Integer addNotification (String type, String message, Object userData, 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 occurrences.

The timer notification will be handled once at the specified date.

If the timer notification to be inserted has a date that is before the current date, the method behaves as if the specified date were the current date and the notification is delivered immediately.

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
IllegalArgumentException The date is null.

public synchronized Integer addNotification (String type, String message, Object userData, Date date, long period, long nbOccurences)

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 occurrences.

If the timer notification to be inserted has a date that is before the current date, the method behaves as if the specified date were the current date.
For once-off notifications, the notification is delivered immediately.
For periodic notifications, the first notification is delivered immediately and the subsequent ones are spaced as specified by the period parameter.

Note that once the timer notification has been added into the list of notifications, its associated date, period and number of occurrences cannot be updated.

In the case of a periodic notification, uses a fixed-delay execution scheme, as specified in Timer. In order to use a fixed-rate execution scheme, use addNotification(String, String, Object, Date, long, long, boolean) instead.

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
IllegalArgumentException The date is null or the period or the number of occurrences is negative.
See Also

public synchronized Vector<Integer> getAllNotificationIDs ()

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

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.

public Date getDate (Integer id)

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

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.

public Boolean getFixedRate (Integer id)

Gets a copy of the flag indicating whether a periodic notification is executed at fixed-delay or at fixed-rate.

Parameters
id The timer notification identifier.
Returns
  • A copy of the flag indicating whether a periodic notification is executed at fixed-delay or at fixed-rate.

public int getNbNotifications ()

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

Returns
  • The number of timer notifications.

public Long getNbOccurences (Integer id)

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

Parameters
id The timer notification identifier.
Returns
  • A copy of the remaining number of occurrences or null if the identifier is not mapped to any timer notification registered for this timer MBean.

public synchronized Vector<Integer> getNotificationIDs (String type)

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

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.

public synchronized MBeanNotificationInfo[] getNotificationInfo ()

Returns an array indicating, for each notification this MBean may send, the name of the Java class of the notification and the notification type.

It is not illegal for the MBean to send notifications not described in this array. However, some clients of the MBean server may depend on the array being complete for their correct functioning.

Returns
  • the array of possible notifications.

public String getNotificationMessage (Integer id)

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

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.

public String getNotificationType (Integer id)

Gets the timer notification type corresponding to the specified identifier.

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.

public Object getNotificationUserData (Integer id)

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

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.

public Long getPeriod (Integer id)

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

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.

public boolean getSendPastNotifications ()

Gets the flag indicating whether or not the timer sends past notifications.
The default value of the past notifications sending on/off flag is false.

Returns
  • The past notifications sending on/off flag value.
See Also

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.
The default value of the active on/off flag is false.

Returns
  • true if the timer MBean is active, false otherwise.

public boolean isEmpty ()

Tests whether the list of timer notifications is empty.

Returns
  • true if the list of timer notifications is empty, false otherwise.

public void postDeregister ()

Allows the timer MBean to perform any operations needed after having been unregistered by the MBean server.

Not used in this context.

public void postRegister (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.

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.

public void preDeregister ()

Allows the timer MBean to perform any operations it needs before being unregistered by the MBean server.

Stops the timer.

Throws
Exception

public ObjectName preRegister (MBeanServer server, ObjectName name)

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

Not used in this context.

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
Exception

public synchronized void removeAllNotifications ()

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

public synchronized void removeNotification (Integer id)

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

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.

public synchronized void removeNotifications (String type)

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

Parameters
type The timer notification type.
Throws
InstanceNotFoundException The specified type does not correspond to any timer notification in the list of notifications of this timer MBean.

public void setSendPastNotifications (boolean value)

Sets the flag indicating whether the timer sends past notifications or not.
The default value of the past notifications sending on/off flag is false.

Parameters
value The past notifications sending on/off flag value.
See Also

public synchronized void start ()

Starts the timer.

If there is one or more timer notifications before the time in the list of notifications, the notification is sent according to the sendPastNotifications flag and then, updated according to its period and remaining number of occurrences. If the timer notification date remains earlier than the current date, this notification is just removed from the list of notifications.

public synchronized void stop ()

Stops the timer.