Porblem in Ejb3 using TimerService with @Singleton and @Management

[sbutt]

Hi All,

I am trying to understand an old code written by a colleague who has left the company now.

The problem is about calling a start() method, which should then initialize a timeerservice and further invokes a method.

The code was presumably working fine earlier on jboss 5, but since we have now migrated to jboss 6, it does not seems to work.

The EJB is as follows:

package com.abc.potsdam.middleware.cache;


import java.util.StringTokenizer;


import javax.annotation.Resource;
import javax.ejb.EJB;
import javax.ejb.SessionContext;
import javax.ejb.Singleton;
import javax.ejb.Stateless;
import javax.ejb.Timeout;
import javax.ejb.Timer;
import javax.ejb.TimerService;
import javax.ejb.TransactionAttribute;
import javax.ejb.TransactionAttributeType;


import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.jboss.annotation.ejb.Service;


import com.traveltainment.potsdam.common.configuration.ConfigService;


@Singleton
@Stateless
@TransactionAttribute(TransactionAttributeType.NEVER)
public class CacheLoaderBean implements CacheLoader, CacheLoaderManagement {
  private Log log = LogFactory.getLog(this.getClass());


  @EJB(mappedName = "/ConfigServiceBean/local")
  ConfigService configService;


  @EJB
  DroolsSession droolsSession;


  @Resource
  private SessionContext sessionContext;


  /**
  * after 10000 ms starting of loading persistence units
  * 
  * @param timer
  */
  @Timeout
  public void startTimeout(Timer timer) {
  loadPersistenceUnitsToCache();
  }


  public void loadPersistenceUnitsToCache() {
  String persistenceUnits = configService
  .getProperty("AvailablePersistenceUnits");
  log.info("reloading persistence units: " + persistenceUnits);


  StringTokenizer stringTokenizer = new StringTokenizer(persistenceUnits,
  ",");


  while (stringTokenizer.hasMoreTokens()) {
  String persistenceUnitName = stringTokenizer.nextToken();


  droolsSession.initSession(persistenceUnitName);
  }
  }


  public void start() {
  // create timer for 10000 ms to start loading cache
  TimerService timerService = sessionContext.getTimerService();
  Timer timer = timerService.createTimer(10000, "cache loading timer");
  }
}

The imported interfaces are:

package com.abc.potsdam.middleware.cache;


import org.jboss.ejb3.annotation.Management;


@Management


public interface CacheLoaderManagement
{
  public void loadPersistenceUnitsToCache();
  
  public void start();
}

package com.abc.potsdam.middleware.cache;


import javax.ejb.Local;


import org.jboss.annotation.ejb.Management;


@Local
public interface CacheLoader
{
  public void loadPersistenceUnitsToCache();
}

The problem is that in my implementation bean, I don't see the start() method ever getting executed. If it is to be invoked via JMX-Console then also I am a bit unaware as to how I can do that?

Since the start method never gets executed, the rest of the functionality is also never invoked.

I have done a bit of research on the topic, and found out at some threads that probably @Singleton and @Management have some issues together when using jboss 6?

The compilation is all done fine, it is only then the code never gets executed and I don't see the log messages appearing.

Could some please give me some pointers as to how I can set a timer for my scenario here?

Thanks.

[wdfink]

What you try to achieve? And what version of JBoss do you use, did you migrate to JBossAS6 - this is an old outdated version and it dosn't make sense - you should migrate to WildFly 8.0.0.Final.

From the code @Stateless and @Singleton seems wrong the bean type is only one of it.

[sbutt]

Thanks for replying, Wolf.

My main objective is to execute the loadPersistenceUnitsToCache() every 10 seconds automatically.

I have now removed the annotation @Stateless, but still no effect. The start method is not executed and am not sure if it should be executed through jmx-console or it gets executed automatically by the application server at deployment time?

Yes the entire application is migrated from Jboss 5.1 to jboss-6.1.0.Final.

Other parts of the application are working fine, but this one.

Thanks.

[sbutt]

I have now created a very simple Stateless bean, which is utilizing JavaEE 6 Scheduler annotation:

[CODE]

package com.abc.potsdam.middleware.cache;

import javax.ejb.Schedule; 

import javax.ejb.ScheduleExpression; 

import javax.ejb.Stateless; 

import javax.ejb.Timeout; 

import javax.ejb.Timer; 

import javax.ejb.TimerConfig; 

import javax.ejb.TimerService; 

import javax.naming.Context; 

import javax.naming.InitialContext;

import java.util.*;

@Stateless 

public class AutoTimerBean  

{ 

   /**

    * This method will be invoked every day at 5:00:00 in the morning

    * @param timer The timer instance

    */ 

   //@Schedule (hour = "5", persistent=false)

     @Schedule(second="*/10", minute="*", hour="*", dayOfWeek="*", dayOfMonth="*", month="*", year="*", info="MyTimer")

   private void executeEveryTenSeconds(Timer timer) 

   { 

      // do some task here.  

      System.out.println("Auto-timer method invoked at " + new Date() + " for bean " + this.getClass().getSimpleName()); 

   } 

} 

[/CODE]

But strangely, I don't get to see the timer message appearing every ten seconds. In-fact it does not appear at all.

I am using JEE 6 and Jboss 6.1-Final.

If I see inside 'JMX MBean View', I can see the class as part of a .war deployed.

Name	Domain	jboss.j2ee
	service	EJB3
	name	AutoTimerBean
	ear	30potsdam.middleware.ear
	jar	potsdam.middleware.cache-2.5.01-SNAPSHOT.jar
Java Class	org.jboss.ejb3.stateless.StatelessDelegateWrapper
Description	Management Bean.

Attribute Name	Access	Type	Description	Attribute Value
CreateCount	R	int	MBean Attribute.	0
InvokeStats	R	org.jboss.ejb3.statistics.InvocationStatistics	MBean Attribute.	InvocationStatistics concurrentCalls='0'
CurrentSize	R	int	MBean Attribute.	0
RemoveCount	R	int	MBean Attribute.	0
MaxSize	R	int	MBean Attribute.	0
AvailableCount	R	int	MBean Attribute.	0

Operation	Return Type	Description	Parameters
getTimerService	javax.ejb.TimerService	MBean Operation.	p1 java.lang.Object (no description)

Coudl someone please suggest why the timer is not getting executed and if i need to configure anything inside jmx-console?

Thanks.

[sbutt]

any help, people?