how to use persistent MBeans

[mucsij]

Hi
I added the sample JMX-enabled class from the Spring pdf and when I run it on Tomcat 5, the MBean shows up in JConsole all right. However, the persistent behavior of the MBean does not work. How do I test MBean persistence?
Here is my annotated class:

@ManagedResource(objectName = "bean:name=testBean4", description = "My Managed Bean",
log = true, logFile = "c:/temp/jmx.log", currencyTimeLimit = 15, persistPolicy = "OnUpdate",
persistPeriod = 200, persistLocation = "c:/temp/foo", persistName = "bar")
public class AnnotationTestBean

Thanks.

[ibw]

This is similar to another post "java 5 persist attribute" on this forum. The answer given on that post was that the JMX agent in the Java 5 runtime doesn't support this advanced feature.

I've been doing a bit of research myself into this topic, because it would be so much more useful for JMX attribute modifications to survive application restarts. It would also be useful to be able to change an attribute for all the servers in a load-balanced cluster.

Rather than use the standard JMX persistence and cluster transparency features (which don't seem to work, as you noticed, and also they use a flat file and I quite wanted to use a database), I've written a class which extends MBeanExporter, adding persistence (and optionally cluster-transparency). It does this by creating a Sping AOP proxy for each MBean, which writes attributes to a database (provided in a "dataSource" property of the exporter). It registers the proxy instead of the MBean, and also reads in the saved values after a restart. Just use this class instead of MBeanExporter, and all your JMX properties will be persistent.

The cluster-transparency uses a "broadcaster" class which is supposed to spread method calls around using a UDP broadcast, but I haven't actually tested it yet so it probably doesn't work.

[mucsij]

I looked at your code, it is a quite reasonable solution.
I looked at the unit tests in the

org.springframework.jmx.export.assembler

package and of course only the correctness of the model mbean descriptors is tested....

[Sudheesh]

Did u find any better solution to this?

is there anyway to Persist the Values using SPRING itself in the BEAN DEFINITION xmls?

[gospodinno]

I also have this problem.
Is there SPRING solution for this?

[Sudheesh]

http://forum.springsource.org/showth...light=Exporter

[wims.tijd]

i used Preferences to store those properties

<aop:config proxy-target-class="true">
		<aop:pointcut id="jmx.export.attribute" expression="execution(* set*(java.lang.String)) and @annotation(org.springframework.jmx.export.annotation.ManagedAttribute)"/>
		<aop:advisor advice-ref="jmx.prefs.advice" pointcut-ref="jmx.export.attribute"/>
	</aop:config>

	<bean id="jmx.prefs.advice" class="wims.cycle.prefs.PreferencesPersisterAdvice"
		p:userTreePath="wims.cycle"
	/>

with an AfterReturningAdvice

public class PreferencesPersisterAdvice implements AfterReturningAdvice{

	private String userTreePath;
	private Preferences userPrefs;

	Log logger = LogFactory.getLog(getClass());
	
	public void afterReturning(Object returnValue, Method method,
			Object[] args, Object target) throws Throwable {
		logger.info(method);
		try{
			userPrefs.node(pathName(target)).put(key(method), value(args));
		}catch(Exception e){
			e.printStackTrace();
		}
	}
	
	public void setUserTreePath(String userTreePath) {
		this.userTreePath = userTreePath;
	}
	
	String pathName(Object target){
		return target.getClass().getName();
	}
	
	String key(Method method){
		return StringUtils.uncapitalize(StringUtils.delete(method.getName(), "set"));
	}
	
	String value(Object[] args){
		if(args !=null && args.length==1 && args[0]!= null)
			return args[0].toString();
		throw new IllegalArgumentException();
	}
	
	@PostConstruct
	void postConstruct(){
		this.userPrefs = (this.userTreePath != null) ?
			    Preferences.userRoot().node(this.userTreePath) : Preferences.userRoot();   
	}

now how to read them back is already provided in Spring :

<bean id="prefs.config" class="org.springframework.beans.factory.config.PreferencesPlaceholderConfigurer"
     	p:userTreePath="wims.cycle" p:properties-ref="prefs.props"
     />
     
     <util:properties id="prefs.props">
     	<prop key="wims.cycle.rss.RssReader/sourceAddress">http://newsrss.bbc.co.uk/rss/sportonline_world_edition/other_sports/cycling/rss.xml</prop>
     </util:properties>

convention between configurer and advice is to use the full class name as node