public class Timer extends NotificationBroadcasterSupport implements TimerMBean, MBeanRegistration
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:
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. Timer
. In order to use fixed-rate execution, use the overloaded addNotification(String, String, Object, Date, long, long, boolean)
method. NotificationBroadcasterSupport
. public static final long ONE_SECOND
Number of milliseconds in one second. Useful constant for the addNotification
method.
public static final long ONE_MINUTE
Number of milliseconds in one minute. Useful constant for the addNotification
method.
public static final long ONE_HOUR
Number of milliseconds in one hour. Useful constant for the addNotification
method.
public static final long ONE_DAY
Number of milliseconds in one day. Useful constant for the addNotification
method.
public static final long ONE_WEEK
Number of milliseconds in one week. Useful constant for the addNotification
method.
public Timer()
Default constructor.
public ObjectName preRegister(MBeanServer server, ObjectName name) throws Exception
Allows the timer MBean to perform any operations it needs before being registered in the MBean server.
Not used in this context.
preRegister
in interface MBeanRegistration
server
- The MBean server in which the timer MBean will be registered.name
- The object name of the timer MBean.Exception
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.
postRegister
in interface MBeanRegistration
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() throws Exception
Allows the timer MBean to perform any operations it needs before being unregistered by the MBean server.
Stops the timer.
preDeregister
in interface MBeanRegistration
Exception
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.
postDeregister
in interface MBeanRegistration
public MBeanNotificationInfo[] getNotificationInfo()
Description copied from interface: NotificationBroadcaster
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.
getNotificationInfo
in interface NotificationBroadcaster
getNotificationInfo
in class NotificationBroadcasterSupport
public 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.
start
in interface TimerMBean
public void stop()
Stops the timer.
stop
in interface TimerMBean
public Integer addNotification(String type, String message, Object userData, Date date, long period, long nbOccurences, boolean fixedRate) throws 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 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
.
addNotification
in interface TimerMBean
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.IllegalArgumentException
- The date is null
or the period or the number of occurrences is negative.addNotification(String, String, Object, Date, long, long)
public Integer addNotification(String type, String message, Object userData, Date date, long period, long nbOccurences) throws 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 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.
addNotification
in interface TimerMBean
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.IllegalArgumentException
- The date is null
or the period or the number of occurrences is negative.addNotification(String, String, Object, Date, long, long, boolean)
public Integer addNotification(String type, String message, Object userData, Date date, long period) throws 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 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.
addNotification
in interface TimerMBean
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).IllegalArgumentException
- The date is null
or the period is negative.public Integer addNotification(String type, String message, Object userData, Date date) throws 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 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.
addNotification
in interface TimerMBean
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.IllegalArgumentException
- The date is null
.public void removeNotification(Integer id) throws InstanceNotFoundException
Removes the timer notification corresponding to the specified identifier from the list of notifications.
removeNotification
in interface TimerMBean
id
- The timer notification identifier.InstanceNotFoundException
- The specified identifier does not correspond to any timer notification in the list of notifications of this timer MBean.public void removeNotifications(String type) throws InstanceNotFoundException
Removes all the timer notifications corresponding to the specified type from the list of notifications.
removeNotifications
in interface TimerMBean
type
- The timer notification type.InstanceNotFoundException
- The specified type does not correspond to any timer notification in the list of notifications of this timer MBean.public void removeAllNotifications()
Removes all the timer notifications from the list of notifications and resets the counter used to update the timer notification identifiers.
removeAllNotifications
in interface TimerMBean
public int getNbNotifications()
Gets the number of timer notifications registered into the list of notifications.
getNbNotifications
in interface TimerMBean
public Vector<Integer> getAllNotificationIDs()
Gets all timer notification identifiers registered into the list of notifications.
getAllNotificationIDs
in interface TimerMBean
Integer
objects containing all the timer notification identifiers. public Vector<Integer> getNotificationIDs(String type)
Gets all the identifiers of timer notifications corresponding to the specified type.
getNotificationIDs
in interface TimerMBean
type
- The timer notification type.Integer
objects containing all the identifiers of timer notifications with the specified type
. type
.public String getNotificationType(Integer id)
Gets the timer notification type corresponding to the specified identifier.
getNotificationType
in interface TimerMBean
id
- The timer notification identifier.public String getNotificationMessage(Integer id)
Gets the timer notification detailed message corresponding to the specified identifier.
getNotificationMessage
in interface TimerMBean
id
- The timer notification identifier.public Object getNotificationUserData(Integer id)
Gets the timer notification user data object corresponding to the specified identifier.
getNotificationUserData
in interface TimerMBean
id
- The timer notification identifier.public Date getDate(Integer id)
Gets a copy of the date associated to a timer notification.
getDate
in interface TimerMBean
id
- The timer notification identifier.public Long getPeriod(Integer id)
Gets a copy of the period (in milliseconds) associated to a timer notification.
getPeriod
in interface TimerMBean
id
- The timer notification identifier.public Long getNbOccurences(Integer id)
Gets a copy of the remaining number of occurrences associated to a timer notification.
getNbOccurences
in interface TimerMBean
id
- The timer notification identifier.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.
getFixedRate
in interface TimerMBean
id
- The timer notification identifier.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
.
getSendPastNotifications
in interface TimerMBean
setSendPastNotifications(boolean)
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
.
setSendPastNotifications
in interface TimerMBean
value
- The past notifications sending on/off flag value.getSendPastNotifications()
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
.
isActive
in interface TimerMBean
true
if the timer MBean is active, false
otherwise.public boolean isEmpty()
Tests whether the list of timer notifications is empty.
isEmpty
in interface TimerMBean
true
if the list of timer notifications is empty, false
otherwise.
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