Use the JMX interface to develop your own monitoring application

You can use AdminClient API to get Performance Monitoring Infrastructure (PMI) data by using either PerfMBean or individual MBeans. You can invoke methods on MBeans through the AdminClient Java Management Extension (JMX) interface. You can use AdminClient API to get Performance Monitoring Infrastructure (PMI) data by using either PerfMBean or individual MBeans. See information about using individual MBeans at bottom of this article.

Individual MBeans provide the Stats attribute from which you can get PMI data. The PerfMBean provides extended methods for PMI administration and more efficient ways to access PMI data. To set the PMI module instrumentation level, invoke methods on PerfMBean. To query PMI data from multiple MBeans, it is faster to invoke the getStatsArray method in PerfMBean than to get the Stats attribute from multiple individual MBeans. Perf MBean can provide PMI data from multiple MBeans using a single JMX call, but multiple JMX calls have to be made through individual MBeans.

See the topic "Developing an administrative client program" for more information on AdminClient JMX.

Overview

After the performance monitoring service is enabled and the appserver is started or restarted, a PerfMBean is located in each appserver giving access to PMI data. To use PerfMBean:

Procedure

Create an instance of AdminClient. When using AdminClient API, first create an instance of AdminClient by passing the host name, port number and connector type. The example code is:

        AdminClient ac = null;
        java.util.Properties props = new java.util.Properties();
        props.put(AdminClient.CONNECTOR_TYPE, connector);
        props.put(AdminClient.CONNECTOR_HOST, host);
        props.put(AdminClient.CONNECTOR_PORT, port);
        try {
            ac = AdminClientFactory.createAdminClient(props);
        }
        catch(Exception ex) {
            failed = true;
            new AdminException(ex).printStackTrace();
            System.out.println("getAdminClient: exception");
        }

Use AdminClient to query the MBean ObjectNames Once you get the AdminClient instance, you can call queryNames to get a list of MBean ObjectNames depending on your query string. To get all the ObjectNames, you can use the following example code. If you have a specified query string, you will get a subset of ObjectNames.

javax.management.ObjectName on = new javax.management.ObjectName("WebSphere:*");
     Set objectNameSet= ac.queryNames(on, null);
  // you can check properties like type, name, and process to find a specified ObjectName

After you get all the ObjectNames, you can use the following example code to get all the node names:

    HashSet nodeSet = new HashSet();
         for(Iterator i = objectNameSet.iterator(); i.hasNext(); on =  (ObjectName)i.next()) {
            String type = on.getKeyProperty("type");
            if(type != null && type.equals("Server")) {
    nodeSet.add(servers[i].getKeyProperty("node"));
            }
  }

Note, this will only return nodes that are started. To list running servers on the node, you can either check the node name and type for all the ObjectNames or use the following example code:

     StringBuffer oNameQuery= new StringBuffer(41);
        oNameQuery.append("WebSphere:*");
        oNameQuery.append(",type=").append("Server");
        oNameQuery.append(",node=").append(mynode);

        oSet= ac.queryNames(new ObjectName(oNameQuery.toString()), null);
         Iterator i = objectNameSet.iterator ();
        while (i.hasNext ()) {
        on=(objectName) i.next();
      String process= on[i].getKeyProperty("process");
      serversArrayList.add(process);
    }

Get the PerfMBean ObjectName for the appserver from which you want to get PMI data. Use this example code:

for(Iterator i = objectNameSet.iterator(); i.hasNext(); on = (ObjectName)i.next()) {
      // First make sure the node name and server name is what you want
      // Second, check if the type is Perf
            String type = on.getKeyProperty("type");
      String node = on.getKeyProperty("node");
      String process= on.getKeyProperty("process");
            if (type.equals("Perf") && node.equals(mynode) &
& server.equals(myserver)) {
    perfOName = on;
            }
  }

Invoke operations on PerfMBean through the AdminClient. Once you get the PerfMBean(s) in the appserver from which you want to get PMI data, you can invoke the following operations on the PerfMBean through AdminClient API:

- setStatisticSet: Enable PMI data using the pre-defined statistic sets.
  Object[] params = new Object[] { com.ibm.websphere.pmi.stat.StatConstants.STATISTIC_SET_EXTENDED};
  String[] signature = new String[] {"java.lang.String"};
  ac.invoke (perfOName, "setStatisticSet", params, signature);

- getStatisticSet: Returns the current statistic set.
  String setname = (String) ac.invoke (perfOName, "getStatisticSet", null, null);

- setCustomSetString: Customizing PMI data that is enabled using fine-grained control. 
This method allows to enable or disable statistics selectively. The format of the custom  set specification string is STATS_NAME=ID1,ID2,ID3 seperated by ':', where STATS_NAME  and IDs are defined in WS*Stat interfaces in com.ibm.websphere.pmi.stat package.
  params[0] = new String (WSJVMStats.NAME + "=" + WSJVMStats.HeapSize);
  params[1] = new Boolean (false);
  signature = new String[] {"java.lang.String", "java.lang.Boolean"};
  ac.invoke (perfOName, "setCustomSetString", params, signature);

 
 Statistics that are not listed in the set string are not changed.
 
- getCustomSetString: Returns the current custom set specification as a string
  String setstring = (String) ac.invoke (perfOName, "getCustomSetString", null, null);


- setInstrumentationLevel: set the instrumentation level
            params[0] = new MBeanLevelSpec(objectName, new int[]{WSJVMStats.HEAPSIZE});
            params[1] = new Boolean(true);
            signature= new String[]{ "com.ibm.websphere.pmi.stat.MBeanLevelSpec", 
"java.lang.Boolean"};
            ac.invoke(perfOName, "setInstrumentationLevel", params, signature);

- getInstrumentationLevel: get the instrumentation level
            params[0] = objectName;
            params[1] = new Boolean(recursive);
            String[] signature= new String[]{ 
"javax.management.ObjectName", "java.lang.Boolean"};
            MBeanLevelSpec[] mlss = (MBeanLevelSpec[])ac.invoke(perfOName, 
          "getInstrumentationLevel", params, signature);

- setInstrumentationLevel: set the instrumentation level (deprecated in V6.0)
            params[0] = new MBeanLevelSpec(objectName, optionalSD, level);
            params[1] = new Boolean(true);
            signature= new String[]{ "com.ibm.websphere.pmi.stat.MBeanLevelSpec", 
          "java.lang.Boolean"};
            ac.invoke(perfOName, "setInstrumentationLevel", params, signature);

- getInstrumentationLevel: get the instrumentation level (deprecated in V6.0)
            Object[] params = new Object[2];
            params[0] = new MBeanStatDescriptor(objectName, optionalSD);
            params[1] = new Boolean(recursive);
            String[] signature= new String[]{ 
          "com.ibm.websphere.pmi.stat.MBeanStatDescriptor", "java.lang.Boolean"};
            MBeanLevelSpec[] mlss = (MBeanLevelSpec[])ac.invoke(perfOName, 
          "getInstrumentationLevel", params, signature);

- getConfigs: get PMI static config info for all the MBeans
            configs = (PmiModuleConfig[])ac.invoke(perfOName, "getConfigs", null, null);

- getConfig: get PMI static config info for a specific MBean
      ObjectName[] params = {objectName};
      String[] signature= { "javax.management.ObjectName" };
            config = (PmiModuleConfig)ac.invoke(perfOName, "getConfig", params,  signature);

- getStatsObject: you can use either ObjectName or MBeanStatDescriptor 
            Object[] params    = new Object[2];
            params[0] = objectName;  // either ObjectName or or MBeanStatDescriptor
            params[1] = new Boolean(recursive);
            String[] signature = new String[] { "javax.management.ObjectName", 
          "java.lang.Boolean"};
            Stats stats  = (Stats)ac.invoke(perfOName, "getStatsObject", params, 
          signature);

 
 The returned data only have dynamic information (value and time stamp). 
See PmiJmxTest.java for additional code to link the configuration information with the  returned data.

- getStatsArray: you can use either ObjectName or MBeanStatDescriptor   
            ObjectName[] onames = new ObjectName[]{objectName1, objectName2};
            Object[] params = new Object[]{onames, new Boolean(true)};
            String[] signature = new String[]{"[Ljavax.management.ObjectName;", 
          "java.lang.Boolean"};
            Stats[] statsArray = (Stats[])ac.invoke(perfOName, "getStatsArray", 
          params, signature);

 
 The returned data only have dynamic information (value and time stamp). 
See PmiJmxTest.java for additional code to link the configuration information with the  returned data.

- listStatMembers: navigate the PMI module trees 

            Object[] params = new Object[]{mName};
            String[] signature= new String[]{"javax.management.ObjectName"};
            MBeanStatDescriptor[] msds = (MBeanStatDescriptor[])ac.invoke(perfOName, 
          "listStatMembers", params, signature);
 or,

            Object[] params = new Object[]{mbeanSD};
            String[] signature= new String[]
{"com.ibm.websphere.pmi.stat.MBeanStatDescriptor"};
            MBeanStatDescriptor[] msds = (MBeanStatDescriptor[])ac.invoke (perfOName, "listStatMembers", params, signature);

Refer the API documentation for deprecated classes

Repeated calls to retrieve PMI data might return references to the same objects. To compare values over time, save the actual data and not references to the PMI objects containing the data. For example, if you have a WSCountStatistic object, call getCount() and save the result for later comparison, instead of saving a reference to the object.

To use an individual MBean: We need to get the AdminClient instance and the ObjectName for the individual MBean. Then you can simply get the Stats attribute on the MBean.

Example: Administering Java Management Extension-based interface