new TopicUpdateHandler()
The TopicUpdateHandler interface for exclusive updates. This interface must be implemented by the user, to be registered via Session.topics#registerUpdateSource.
A topic update handler has a lifecycle that reflects the registration state on the server. This is expressed
through the callback methods. Once onClose has been called, no
further interactions will occur.
When an update handler is registered it will be notified via the onRegister
callback. Once registered it may be in either a active state, where it can provide topic updates, or a
standby state, where it is still registered but is not allowed to perform updates. The state may be
switched in any order, depending on server policy.
- Deprecated:
-
- since 6.2
This class is deprecated. It is only used in conjunction with Session.topics#registerUpdateSource. Use topicUpdate.createUpdateStream instead. This method will be removed in a future release.
- since 6.2
Methods
-
onActive(topicPath, updater)
-
State notification that this handler is now active for the specified topic path and is therefore in a valid state to send updates on topic at or below the registered topic path
Parameters:
Name Type Description topicPathString The registration path
updaterUpdater An updater that can be used to update topics
-
onClose(topicPath, errorReason)
-
Called when the handler is closed. The handler will be closed if the session is closed, or if the handler is unregistered.
Once closed, no further calls will be made for the handler.
Parameters:
Name Type Description topicPathString The registration path
errorReasondiffusion.errors An optional value representing the error; this can be one of the constants defined in diffusion.errors, or a feature-specific reason. It is absent if the handler was closed because the session closed.
-
onRegister(topicPath, deregister)
-
Called when the handler has been successfully registered with the server.
A session can register a single handler for a given branch of the topic tree. If there is already a handler registered for the topic path the operation will fail and onClose will be called.
To deregister the handler, call the
deregisterfunction supplied.Parameters:
Name Type Description topicPathString The path that the handler is registered for
deregisterfunction A function that may be called to deregister this handler
-
onStandBy(topicPath)
-
State notification that this handler is not currently allowed to provide topic updates for the specified topic path. This indicates that another TopicUpdateHandler is currently active for the given topic path.
Server policy will dictate when this handler is set as active.
If this handler was previously in a
activestate, any Updater instances for this topic path will no longer be valid for use.Parameters:
Name Type Description topicPathString The registration path