Tushar Khairnar's Tech Blog: JAMon Data for Java Applications

Saturday, September 6, 2008

JAMon Data for Java Applications

Recently i used JAMon for gathering important metric in one application which was not j2ee application. For JDK based application how do you get information in absence of JAMon Web Interface. I asked about it to Steve Souza who imeedaitedly returned with answer : MonitorFactory.getData() and MonitorFactory.getHeader(). Based on this data jsmons.jsp is written. For JDK based application i thought we can give same information via JMX. Below is small wrapeer to do


   JAMonMBean mbean = new JAMon();
   ObjectName name = new ObjectName("jamon.perf:type=JAMonBean");
   MBeanServer mbs = ManagementFactory.getPlatformMBeanServer();
   mbs.registerMBean(mbean, name);

JAMon Client


   ObjectName name = new ObjectName("jamon.perf:type=JAMonBean");
   MBeanServer mbs = ManagementFactory.getPlatformMBeanServer();
   String arr[] = {key};
   String[] signature = new String[] { "java.lang.String" };
   obj = mbs.invoke(name,operationName, arr,signature );

Start background thread to store information in file


   Object[][] data= client.getData();   
   // record format date : label : Hits : Avg : Total : StdDev
   String timestamp = "" + System.currentTimeMillis();
   if(data!=null)
   {
    for(int i=0;i<data.length;i++)
    {
     StringBuilder sb = new StringBuilder();
     sb.append(timestamp).append(" : ");
     sb.append(data[i][0]).append(" : ");
     sb.append(data[i][1]).append(" : ");
     sb.append(data[i][2]).append(" : ");
     sb.append(data[i][3]).append(" : ");
     sb.append(data[i][4]);
     pw.println(sb.toString());
     pw.flush();
     //System.out.println(sb.toString());
    }
   }

Equipped with above, I have also written a small utility which outputs information of all counters periodically in the format

timestamp : label : avg. response time : hits : std. deviation

I have uploaded code used to demonstrate the JAMon Bean have been uploaded at http://tushar.khairnar.googlepages.com/perf-sample.zip.

Please see Sample Program for the same.

2 comments:

Unknown said...: How did you create your JAMon MBean?; November 11, 2008 at 5:36 AM
Tushar Khairnar said...: Hi,

Any class can be registered as mbean to Platform mbean or other mbean servers. Below is small example of Hello Mbean.

public interface HelloMBean {
// operations

public void sayHello();

// a read-write attribute called CacheSize of type int
public int getCacheSize();
public void setCacheSize(int size);

}

public class Hello implements HelloMBean {

public void sayHello() {
System.out.println("hello, world");
}

public int getCacheSize() {
return this.cacheSize;
}

/* Setter for the CacheSize attribute. To avoid problems with
stale values in multithreaded situations, it is a good idea
for setters to be synchronized. */
public synchronized void setCacheSize(int size) {
}

}

Sample Code for Creatring and Registering above Hello MBean.

MBeanServer mbs = ManagementFactory.getPlatformMBeanServer();

// Create the Hello World MBean
Hello mbean = new Hello();
mbean.setCacheSize(150);

try {
// Construct the ObjectName for the MBean we will register
ObjectName name = new ObjectName("com.sun.example:type=Hello");

// Register the Hello World MBean
mbs.registerMBean(mbean, name);
} catch (MalformedObjectNameException e) {
e.printStackTrace();
System.exit(0);
} catch (InstanceAlreadyExistsException e) {
e.printStackTrace();
System.exit(0);
} catch (MBeanRegistrationException e) {
e.printStackTrace();
System.exit(0);
}

I have uploaded code used to demonstrate the JAMon Bean have been uploaded at http://tushar.khairnar.googlepages.com/perf-sample.zip. Please see Sample Program for the same.

Hope you find it useful.

Thanks and Regards,
Tushar; November 11, 2008 at 12:11 PM