Interfaces for remote access to JMX MBean servers.

 

Interfaces for remote access to JMX MBean servers. This package defines the essential interfaces for making a JMX MBean server manageable remotely. The specification of this functionality is completed by Part III of the JMX Specification, version 1.4 PDF document.

The JMX specification defines the notion of connectors. A connector is attached to a JMX API MBean server and makes it accessible to remote Java clients. The client end of a connector exports essentially the same interface as the MBean server, specifically the MBeanServerConnection interface.

A connector makes an MBean server remotely accessible through a given protocol. The JMX Remote API allows the use of different type of connectors:

• The JMX Remote API defines a standard connector, the RMI Connector, which provides remote access to an MBeanServer through RMI.
• The JMX Remote API also defines an optional connector called JMXMP Connector implementing the JMX Message Protocol (JMXMP). As it is optional, it is not part of this bundle (see note below).
• User-defined connector protocols are also possible using the JMXConnectorFactory and, optionally, the Generic Connector (not part of this bundle, see note below).

Note: the optional packages implementing the optional part of the JMX Remote API are not included in the Java SE Platform but are available from the JMX Remote API Reference Implementation.

Connector addresses

Typically, a connector server has an address, represented by the class JMXServiceURL. An address for the RMI Connector can look like this:

      service:jmx:rmi:///jndi/rmi://myhost:1099/myname
      

In this JMXServiceURL, the first rmi: specifies the RMI connector, while the second rmi: specifies the RMI registry into which the RMI connector server has stored its stub.

The example above shows only one form of address. An address for the RMI Connector can take several forms, as detailed in the documentation for the package javax.management.remote.rmi.

Creating a connector server

A connector server is created by constructing an instance of a subclass of JMXConnectorServer. Usually, this instance is created using the method JMXConnectorServerFactory.newJMXConnectorServer.

Typically, a connector server is associated with an MBean server either by registering it in that MBean server, or by supplying the MBean server as a parameter when creating the connector server.

Creating a connector client

A connector client is usually created by supplying the JMXServiceURL of the connector server to connect to to the JMXConnectorFactory.connect method.

For more specialized uses, a connector client can be created by directly instantiating a class that implements the JMXConnector interface, for example the class RMIConnector.

Additional client or server parameters

When creating a connector client or server, it is possible to supply an object of type Map that defines additional parameters. Each entry in this Map has a key that is a string and an associated value whose type is appropriate for that key. The standard keys defined by the JMX Remote API all begin with the string "jmx.remote.". The document JMX Remote API lists these standard keys.

Connection identifiers

Every connection opened by a connector server has a string identifier, called its connection id. This identifier appears in the JMXConnectionNotification events emitted by the connector server, in the list returned by getConnectionIds(), and in the value returned by the client's getConnectionId() method.

As an example, a connection ID can look something like this:

rmi://192.18.1.9 username 1
      

The formal grammar for connection ids that follow this convention is as follows (using the grammar notation from The Java Language Specification, Second Edition):

ConnectionId:
    Protocol : ClientAddressopt Space ClientIdopt Space ArbitraryText

ClientAddress:
    // HostAddress ClientPortopt

ClientPort
    : HostPort
      

The Protocol is a protocol that would be recognized by JMXConnectorFactory.

The ClientAddress is the address and port of the connecting client, if these can be determined, otherwise nothing. The HostAddress is the Internet address of the host that the client is connecting from, in numeric or DNS form. Numeric IPv6 addresses are enclosed in square brackets []. The HostPort is the decimal port number that the client is connecting from.

The ClientId is the identity of the client entity, typically a string returned by JMXPrincipal.getName(). This string must not contain spaces.

The ArbitraryText is any additional text that the connector server adds when creating the client id. At a minimum, it must be enough to distinguish this connection ID from the ID of any other connection currently opened by this connector server.