Getting Started with the Java Dynamic Management Kit 4.2

Protocol Adaptors

Protocol adaptors only have a server component and provide a view of an agent and its MBeans through a different protocol. They may also translate requests formulated in this protocol into management request on the JMX agent. The view of the agent and the range of possible requests depends upon the given protocol.

For example, the Java Dynamic Management Kit provides an HTML adaptor which presents the agent and its MBeans as HTML pages viewable in any web browser. Because the HTML protocol is text based, only data types which have a string representation may be viewed through the HTML adaptor. However, this is sufficient to access most MBeans, view their attributes and invoke their operations.

Due to limitations of the chosen protocol, adaptors have the following limitations:

Not all data types are necessarily supported.
Not all management requests are necessarily supported, as some requests may rely on unsupported data types.
Notifications from a broadcaster MBean may not be supported.
A given protocol adaptor may require private data structures or helper MBeans in order to respond to requests.

The SNMP adaptor provided in the Java Dynamic Management Kit is limited by the constraints of SNMP. The richness of the JMX architecture cannot be translated into SNMP, but all of the operations of SNMP can be imitated by methods of the MBean server. This translation requires a structure of MBeans that imitates the MIB. While an SNMP manager cannot access the full potential of the JMX agent, the MBeans representing the MIB are available for other managers to access and incorporate into their management systems.

In general, a protocol adaptor tries to map the elements of the JMX architecture into the structures provided by the given protocol. There is no guarantee that this mapping is complete or fully accurate. However, specification efforts are currently underway to fully define and standardize the mappings between the JMX architecture and the most widespread management protocols such as SNMP, CORBA, and TMN. Please see the Java Community Process^SM web site (http://java.sun.com/aboutJava/communityprocess/) for more details.