Java Reference
In-Depth Information
Protocol adapters and connectors
Protocol adapters and connectors are objects residing within a
JMX
agent that
expose the agent to management application and protocols. For example,
SNMP
could be mapped into a
JMX
agent using an
SNMP
adapter object of the agent.
In addition, an agent could have an
RMI
connector that opens it up for manage-
ment applications that use
RMI
clients. Protocol adapters consist of a single
object within an agent, whereas connectors have both an object in the agent and
an object used by a client.
An agent can have any number of adapters and connectors, essentially giving
you the ability to reach the agent using new tools or existing management proto-
cols and applications. Not only does your agent have the flexibility to be man-
aged by many applications, but you also have a mechanism for distributing
agents across a network.
Management application
A management application is any user application that is used to interface to any
number of
JMX
agents.
JMX
agents can work with management applications
designed to work with
JMX
technology or those that are not. A compatible
JMX
management application will be able to take advantage of
JMX
's advanced fea-
tures. You can provide a
JMX
agent with the ability to interact with existing (non-
JMX
) managers by writing custom adapters and connectors. For instance, an
SNMP
manager can be used to work with
JMX
agents by creating an
SNMP
adapter. Later in this topic, we will work with connectors and adapters covering
RMI
, Jini, and
TCP
.
Notification
Notifications are Java objects emitted by MBeans and the MBean server to
encapsulate events, alerts, or general information. Other MBeans or Java objects
can register as listeners to receive notifications. In fact, the
JMX
notification
model is similar to the Java event model, as you will see in chapter 6.
Instrumentation
Instrumentation is the process of exposing a manageable resource using an
MBean (or set of MBeans). Instrumentation of an application can take place
alongside development, or developers can work to create MBeans that use exist-
ing
API
s of currently active systems. You will discover that with several types of
MBeans from which to choose, you will be able to find an easy way to expose
parts of your applications and resources to
JMX
.
