WS-BaseNotification

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WS-BaseNotification is a web services specification which defines the interface WS-Notification clients (consumers) and servers (producers) should expose.

1 Subscription
2 Subscription filters
3 Pausing/resuming subscriptions
4 Unsubscription
5 Notification
6 See also

[edit] 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 specific privileges, but the service with that privilege wishes to defer processing to another service.

[edit] 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 notification

[edit] Pausing/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.

[edit] Unsubscription

As its name implies, the unsubscribe method allows a consumer to cancel an existing subscription. (Available in 1.3)

[edit] 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.