Scheduling

The timer service is a notification broadcaster that send notifications at specific dates and times. This provides a scheduling mechanism that may be used to trigger actions in the listeners. Timer notifications may be single events, repeated events or indefinitely repeating events. The timer notifications are sent to all of the service's listeners when a timer event occurs.

The timer service manages a list of dated notifications, each with its own schedule. Users may add or remove scheduled notifications from this list at any time. When adding a notification, users provide its schedule, defined by the trigger date and repetition policy, and information which identifies the notification to its listeners. The timer service uses a single Java thread to trigger all notifications at their designated time.

The timer service may be stopped to prevent it from sending notifications. When it is started again, notifications which could not be sent while the timer was stopped are either sent immediately or discarded, as determined by the configuration of the service.

Like all other agent services, the timer is implemented as an MBean so that it may be registered in an agent and configured by remote applications. However, the timer MBean may also be used as a stand-alone object in any application that needs a simple scheduling service.

For more information regarding the timer service, please refer to the JMX specification document.