Hi,
I'd like to watch a workspace for any changes in property "State" of all
"Document" nodes. Whenever that property is updated, an event listener
should create a log entry and send it to another system.
So I need to:
1. watch all sessions connecting to the specific workspace
2. make sure the events are "indeed" fired and the listener invoked
I can of course register EventListeners on a per session basis - by
Workspace.getObservationManager().addEventListener(). But is there a way
to associate listeners to the Repository (or Workspace) itself and set the
"scope" to "all_sessions"?
This way then listeners can be registered at application initialization
time, and I don't have to check on every user login to see if the specific
workspace is being accessed?
I also came across a thread by Marcel Reutegger, explaining why some
events are not delivered to EventListener (as below).
>
> Events are delivered with an asynchronous background thread. This way
> the internals of jackrabbit do not have to wait for listener
> implementations to complete the commit of changes.
>
> because your code logs out the session immediately after save() it may
> happen that the notification of your listener does not happen within
> that short period of time. As soon as a session is logged out all its
> associated EventListeners are invalidated and are not notified
> anymore. This is because the Event instances are bound to the
> namespace mappings of the current session. Event.getPath() must return
> the namespace prefixes according to the currently set mapping in the
> Session. When the session is gone, Event.getPath() would not be able
> to return any sensible value anymore.
If I do something like following in web application, what do I need to
ensure the EventListener is triggered?
try{
transaction.start();
... node modifications code
session.save();
transaction.commit();
}finally{
session.logout();
}
Regards,
Lei
