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Generally, every MBean that is not a singleton, should be mapped (or modeled) to (as) a SNMP table. MBeans that contain lists of other MBeans or Java objects should be mapped to several SNMP tables that share a common base index (i.e., the index of the master MBean/table).

The following steps describe how a MBean can be descriptively mapped to a table:

First of all, you need a JMXTableSupport instance which is registered with the MBean server:

Code Block
final MBeanServerConnection server = ManagementFactory.getPlatformMBeanServer(); final MBeanAttributeMOTableSupport tableSupport = new MBeanAttributeMOTableSupport(server);

Next you need to define how the index of the SNMP table is mapped from MBean data or autogenerated. The mapping is done bidirectional by mapping a MBean to a key uniquely identifying the MBean and an Index (OID) uniquely defining the SNMP table row(MOTableRow). The JMXIndexSupport knows about Key and Index and thus provides the mapping.

Code Block

language	java

tableSupport.add(oidJvmThreadInstanceEntry,
          new MBeanAttributeMOTableInfo(onameJvmThreading,

// The key provider retrieves all available keys (thus all available MBean instances:
          new MBeanInvokationKeyProvider(onameJvmThreading,
                                         new TypedAttribute("AllThreadIds", long.class),
                                         "getThreadInfo", true),
...
          new String[] { "ThreadId" },

// The JMX index support maps from rowIdentidier (= Key) to MBean objectname and ...
          new JMXIndexSupport() {
        public ObjectName mapToRowMBean(Object rowIdentifier) {
          return null;
        }

// from rowIdentfier to index OID and ...
        public OID mapToIndex(Object rowIdentifier) {
          Long l = (Long)rowIdentifier;
          return OctetString.fromHexString(Long.toHexString(l)).toSubIndex(true);
        }

// maps native row ID (key used by MBean) or index to rowIdentifier ...
        public Object getRowIdentifier(Object nativeRowId, int nativeIndex) {
          return nativeRowId;
        }

// maps index OID to rowIdentifier (= Key)
        public Object mapToRowIdentifier(OID rowIndex) {
          if (rowIndex == null) {
            return null;
          }
          OctetString os = new OctetString();
          os.fromSubIndex(rowIndex, true);
          String hexString = os.toHexString();
          return Long.parseLong(hexString, 16);
        }
      }));

Next, each column of the SNMP table needs to be mapped to a MBean attribute or action:

Code Block

language	java

tableSupport.add(oidJvmThreadInstanceEntry,
          new MBeanAttributeMOTableInfo(onameJvmThreading,
          new MBeanInvokationKeyProvider(onameJvmThreading,
                                         new TypedAttribute("AllThreadIds", long.class),
                                         "getThreadInfo", true),
          new TypedAttribute[] {
          new TypedCompositeDataAttribute(new TypedAttribute("threadId", Long.class)),
          new CombinedBitsType(new TypedAttribute[] {
                               new EnumBitsType("threadState", Thread.State.class, Thread.State.values(), 3),
                               new BooleanBitsType("inNative", 1),
                               new BooleanBitsType("suspended", 2)}),
          new TypedCompositeDataAttribute(new TypedAttribute("blockedCount", Long.class)),
          new TypedCompositeDataAttribute(new TypedAttribute("blockedTime", Long.class)),
          new TypedCompositeDataAttribute(new TypedAttribute("waitedCount", Long.class)),
          new TypedCompositeDataAttribute(new TypedAttribute("waitedTime", Long.class)),
          new MBeanProxyType(server, onameJvmThreading, Long.class,
                             "getThreadUserTime",
                             new TypedCompositeDataAttribute(new TypedAttribute("threadId", long.class))) {
            public Object transformFromNative(Object nativeValue, ObjectName objectName) {
              Long result = (Long) super.transformFromNative(nativeValue, objectName);
              if ((result == null) || (result < 0)) {
                return 0L;
              }
              return result;
            }
          },
          new TypedCompositeDataAttribute(new TypedAttribute("threadName", String.class)),
          new TypedCompositeDataAttribute(new TypedAttribute("lockOwnerName", String.class)),
          new TypedCompositeDataAttribute(new TypedAttribute("lockOwnerId", Long.class)) {
            public Object transformFromNative(Object nativeValue, ObjectName objectName) {
              Long result = (Long)super.transformFromNative(nativeValue, objectName);
              if ((result == null) || (result < 0)) {
                return "0.0";
              }
              OID rowPointer = new OID(JvmManagementMib.oidJvmThreadInstanceEntry);
              rowPointer.append(JvmManagementMib.colJvmThreadInstId);
              String index = Long.toHexString(result);
              OctetString os = OctetString.fromHexString(index);
              rowPointer.append(os.toSubIndex(true));
              return rowPointer.toString();
            }
          }},
          new String[] { "ThreadId" },
          new JMXIndexSupport() {
        public ObjectName mapToRowMBean(Object rowIdentifier) {
          return null;
        }

        public Object getRowIdentifier(Object nativeRowId, int nativeIndex) {
          return nativeRowId;
        }

        public OID mapToIndex(Object rowIdentifier) {
          Long l = (Long)rowIdentifier;
          return OctetString.fromHexString(Long.toHexString(l)).toSubIndex(true);
        }

        public Object mapToRowIdentifier(OID rowIndex) {
          if (rowIndex == null) {
            return null;
          }
          OctetString os = new OctetString();
          os.fromSubIndex(rowIndex, true);
          String hexString = os.toHexString();
          return Long.parseLong(hexString, 16);
        }
}));

Finally, the table model of the MOTable has been set to the JMXTableModel bound to the table support and table OID created in the previous steps:

Code Block

JMXTableModel jvmMemMgrPoolRelEntryModel =
    JMXTableModel.getDefaultInstance(oidJvmMemMgrPoolRelEntry,
                          tableSupport,
                          super.getJvmMemMgrPoolRelEntry().getColumns());
((MOTableJMX)super.getJvmMemMgrPoolRelEntry()).
    setModel(jvmMemMgrPoolRelEntryModel);

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