Thanks Amy ! That was my initial understanding.
The problem is that the ModelMBean implementation in JMX-RI and MX4J don't seem to behave this way, and the spec wording is ( page 84 in the 1.1 PDF ): "In the model MBean, AttributeChangeNotifications are sent to a separate set of listeners than those that other notifications would go to. All other notifications should go to listeners who registered using the methods defined in the NotificationBroadcaster interface. AttributeChangeNotifications can also be sent to all notification listeners simply by using the NotificationBroadcaster interface alone." Since we are using model mbeans, ACN are sent to the "separate set", and "all other" notifications go to listeners registered using NotificationBrodacaster. That's the current behavior for JMX-RI, MX4J and modeler. Is there any clarification of the spec - or another part that I overlooked? I understand that this particular restriction is only on model mbeans - and it would be possible for regular mbeans to send attribute changes to all listeners. So a possible solution would be to modify modeler and make it a "dynamic mbean" ( or keep it model mbean but not implement this separation ). Costin Amy Roh wrote: > Costin, > > Costin Manolache wrote: >> Craig, Amy - or anyone who knows JMX, I need help :-) >> >> I just can't find any way to add an attribute change listener >> in the whole JMX spec, unless I have the instance of the model >> mbean. And there is no way to get that instance. >> > > I talked to Hans Hrasna in JMX team and I got the following answers. > > It IS possible to manage all attribute changes via JMX and persist them > using attribute change listener using the current spec. > > It's up to the MBean owning the attribute of interest to create and send > attribute change notifications when the attribute change occurs. So the > NotificationBroadcaster interface has to be implemented by any MBean for > which an attribute change is of interest. > > Example: If an MBean called myMbean needs to notify registered listeners > when its attribute: > > String myString > > is modified, myMbean creates and emits the following notification: > > new AttributeChangeNotification(myMbean, sequenceNumber, timeStamp, > msg, "myString", "String", oldValue, newValue); > > > One just adds a NotificationListener. AttributeChangeNotification is > emitted just like any other notification. > > >> All query and get methods in MBeanServer return ObjectInstance - >> i.e. name and class, but no 'instance'. >> >> There is an 'addNotificationListener' that takes the object name - >> but the spec ( and implementation ) doesn't allow this to register >> attribute change listeners, and att changes are not sent to >> listeners registered with this method ( there is an "all other but >> attribute changes" in the PDF file ). > > > NotificationListeners registered on an MBean will receive the > AttributeChangeNotifications just like any other notification. There is > no such special type "attribute change listeners". > > Hope this helps. > Amy > >> >> I'm stuck. I can add some code to the modeler mbean to work >> around, but the solution won't work for other mbeans. >> >> What I want to do is find all attribute changes done via JMX and persist >> them - if you remember my old proposal. At the moment I'm not very sure >> it can be implemented. The only possible solution to revive it would be >> to force all attribute changes to go through a modeler-specific interface >> or to require the use of the modeler for all mbeans. >> >> Costin >> >> >> >> -- >> To unsubscribe, e-mail: >> <mailto:tomcat-dev-unsubscribe@;jakarta.apache.org> For additional >> commands, e-mail: <mailto:tomcat-dev-help@;jakarta.apache.org> >> -- To unsubscribe, e-mail: <mailto:tomcat-dev-unsubscribe@;jakarta.apache.org> For additional commands, e-mail: <mailto:tomcat-dev-help@;jakarta.apache.org>
