- WS-BaseNotification
WS-BaseNotification is a
web services specification which defines the interfaceWS-Notification clients (consumers) and servers (producers) should expose.Subscription
The "subscribe" method (exposed through the NotificationProducer interface) allows consumers to register their interest in topics; using the method, it is also possible to set a subscription expiry time and a custom
boolean filter. A subscription to a topic implies a subscription to all children of that topic in the "topic space".A useful feature of WS-BaseNotification is that the client calling "subscribe" can subscribe on behalf of the consumer - this is very useful in areas such as
grid computing , where often subscriptions require specificprivileges , but the service with that privilege wishes to defer processing to another service.Subscription filters
An
XPath filter can be provided at subscribe-time that narrows down the notifications a consumer will receive. Before any notification is dispatched, the producer will run the XPath expression; if the expression does not match the notification being processed then that consumer will not receive a notificationPausing/resuming subscriptions
The "PauseSubscription" and "ResumeSubscription" methods (exposed through the "SubscriptionManager" interface) allow consumers to temporarily suspend their subscriptions and allows the resumption of notifications.
Subscriptions can be resumed with one of the following policies regarding missed notifications:
* Send notification on next new change - a similar effect to unsubscribing and then resubscribing.
* Send the last notification that the consumer would have received had the subscription not been paused.
* Send all the notifications that the consumer missed out on while the subscription was paused.Unsubscription
As its name implies, the "unsubscribe" method allows a consumer to cancel an existing subscription. (Available in 1.3)
Notification
The consumer's "notify" method (exposed through the "NotificationConsumer" interface) is invoked every time a notification is available on a topic to which they have subscribed, and that notification has passed.
ee also
* [http://docs.oasis-open.org/wsn/wsn-ws_base_notification-1.3-spec-os.pdf Ws-BaseNotification 1.3 Specification]
*Globus Toolkit (contains an implementation of WS-BaseNotification)
Wikimedia Foundation. 2010.
