Communicating with JMX agents - JMX in Action - page 219

Table 9.4 The possible commands used by the TCP client (continued)

TCPAdapter variable

Actual value

GET_ATTRIBUTE get attribute

SET_ATTRIBUTE set attribute

INVOKE invoke

SHUTDOWN shutdown

Not every message sent from a client will be one of the commands from table 9.4.
Other messages might be a classname or argument value, for instance. Table 9.5
lists the tasks the TCP adapter can perform, along with the messages needed to
perform the tasks. The messages and commands are listed in the order they
must be received. Messages in bold are expected values from the client (for
example, classname is an actual classname String ). Those in italic are optional.

Table 9.5 Commands to send to complete a function of the adapter

Adapter function Command order

Create an MBean

CREATE_MBEAN , classname , objectname , ARGS , arglist , siglist

Get attribute

GET_ATTRIBUTE , attname , objectname

Set attribute

SET_ATTRIBUTE , attname , objectname , ARGS , arglist , siglist

Invoke an operation

INVOKE , operation , objectname , ARGS , arglist , siglist

For each object name sent, the adapter expects the whole String value (such as a
String like JMXBookAgent:name=myValue ). The arglist and siglist messages are
expected to be comma-separated lists of arguments. The arglist parameters
must correspond to the types in the siglist message. In addition, each object
value being passed in the arglist must be able to create an Object from the
String value. This is similar to what the HTML adapter expects from clients.
Listing 9.9 shows the TCPAdapter class. After examining this class, you will
add the TCP adapter to your JMXBookAgent class and write a simple test program.

Listing 9.9 TCPAdapter.java

package jmxbook.ch9;

import java.net.*;
import javax.management.*;
import java.io.*;