18.3.1 Classes Generated by mibgen

Before you can proceed with this example, you need to generate the JMX-MBEAN-SERVER-MIB and it's associated classes, by using the mibgen compiler supplied with Java DMK. For details of the mibgen compiler, see the Java Dynamic Management Kit 5.1 Tools Reference Guide.

To Generate the JMX-MBEAN-SERVER-MIB

The example MIB is contained in the configuration file JMX-MBEAN-SERVER-MIB.mib, which is found in examplesDir/current/Snmp/MBeanVirtualTable. You should run the example from within this directory.

1. Ensure that your PATH environment variable knows where to find mibgen.

   In a default installation, mibgen is found in installDir/bin.

2. Create a new directory, generated, inside examplesDir/current/Snmp/MBeanVirtualTable.

   $ mkdir generated

   This directory is where mibgen generates the classes associated with JMX-MBEAN-SERVER-MIB.mib.

3. Run the mibgen compiler.

   $ mibgen -X:use-display-hint -X:no-table-access -X:abstract-mib \ -d generated JMX-MBEAN-SERVER-MIB.mib

   The advanced mibgen option use-display-hint instructs mibgen to generate an attribute of type String for any object using a textual convention whose DISPLAY-HINT is 255a. This option is used because JMX-MBEAN-SERVER-MIB defines textual conventions (for example, JmxMBeanObjectNameTC) which must be translated into java.lang.String attributes, rather than the default Byte[] attributes.

   The -X:no-table-access option instructs mibgen not to generate a table accessor in the group MBean interfaces. The effect of this is that the accessors used to return the TableJmxMBeanTable and TableJmxMBeanAttrTable table objects are not created.

   The -X:abstract-mib option, as the name suggests, generates an abstract MIB. In this case, the MIB class is an abstract class, in which the MBean factory methods are also abstract.

   The -d generated option sends the output of mibgen to the newly created generated directory

   Using the first two options makes it possible to get rid of any references to the default JmxMBeanServer class, as well as to its associated Table* objects. These classes are still generated, but our customer implementation no longer references them.

The MIB used in this example is the same as the one used in the SNMP table instrumentation example. Consequently, mibgen generates the same files in the generated directory as were generated in the table instrumentation example. The differences between this example and the instrumentation example are found in the customized classes, that are used to extend the generated classes.