Help with Drools JON/RHQ plugin

Ian Springer ian.springer at redhat.com
Sun Jul 17 01:43:38 UTC 2011


On 07/15/2011 09:31 AM, John Mazzitelli wrote:
> EMS is necessary - it is a very good third party library that
> encapsulates the multiple ways you can connect to different remote MBean
> Servers (use EMS to connect to WebSphere, JBossAS, WebLogic, standard
> JRE platform MBeanServer, and a plethora of other hosting platforms)
> using one common API.
>
> EMS also provides the ability to isolate JMX classes via a classloader
> strategy that allows the same VM to connect to multiple MBeanServers
> that use different JMX classes (this is needed, for example, to connect
> to multiple things that include JBoss 4 which had its own JMX classes -
> this is also true when connecting to multiple Hibernate apps if those
> apps use different MBean classes)


However, it should be noted that the isolated classloader per managed 
server functionality was added to the RHQ plugin container a while back 
and is used by the jboss-as-5 plugin (implemented by no other than Mazz 
himself), so EMS is no longer needed to provide this functionality. As 
for the common API, I think at this point that common API could 
potentially instead be the JMX API itself (javax.management.*) which is 
part of Java 6, rather than the EMS abstraction layer, with just the 
server-specific connection code used to actually obtain an MBeanServer 
isolated in a connection-specific classloader. That being said, 
refactoring the jmx, jboss-as-4, and tomcat plugins to no longer EMS 
would be a significant amount of work, and it would be hard to justify 
that for no change in functionality or other added benefit from the user 
perspective.
> On 07/15/2011 07:58 AM, Alan Santos wrote:
>> OOC - I assume EMS remains for historic reasons? Is there any reason it's still necessary with contemporary JDKs?
>>
>>
>>
>> On Jul 14, 2011, at 3:31 PM, John Mazzitelli wrote:
>>
>>> I don't have any clue why that would happen. Put a break point in your
>>> MBean code itself and see if you even get into your drools code. If you
>>> do, then I don't know.
>>>
>>> If you don't, the problem is probably in the EMS code that is used to
>>> invoke the operation of the JMX protocol. You might need to debug into
>>> the JMX plugin code or the EMS code if that is the case.
>>>
>>>
>>> On 07/14/2011 10:34 AM, Edson Tirelli wrote:
>>>>      John,
>>>>
>>>>      Final problem with the Drools plugin for RHQ: operations. I added operations to the plugin descriptor as you can see here:
>>>>
>>>> https://github.com/droolsjbpm/droolsjbpm-integration/blob/master/drools-rhq-plugin/src/main/resources/META-INF/rhq-plugin.xml
>>>>
>>>>      Now, when I execute operations with parameters using jconsole, it works fine. See attached screenshot. When I try to execute the same operation with RHQ, with the same parameter, I get a NPException.
>>>>
>>>>      The NPE seems to happen on the drools MBean code, but I don't see how calling an operation from jconsole is different from calling an operation from RHQ? Any pointers?
>>>>
>>>>      Thanks
>>>>        Edson
>>> _______________________________________________
>>> rhq-devel mailing list
>>> rhq-devel at lists.fedorahosted.org
>>> https://fedorahosted.org/mailman/listinfo/rhq-devel
>> Alan Santos
>> JBoss Product Manager
>> 617.818.7735
>> alan.santos at redhat.com
>>
>>
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-- 
Ian Springer
Principal Software Developer
JBoss Operations Network
Red Hat
ian.springer at redhat.com



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