org.objectweb.fractal.jmx.agent
Interface Admin

All Known Implementing Classes:

Agent

public interface Admin

A simple interface for MBean manipulation on the Fractal JMX agent side. This interface allows an agent component implementing this interface to register MBeans in its scope, where:

• the scope of the agent represents its super-components and all sub-components recursively enclosed in its super-components (or in itself if the agent has no super-components).
• the MBeans represent component server interfaces or standard JMX monitors for observing component attributes.

For example, in the architecture depicted below, where an agent is added to the composite B:

• The component B, C, D and Agent (itself) are in the agent scope and then candidate to expose MBeans representing their server interfaces or observer on their attributes.
• The component A is not in the agent scope, and then cannot be managed, since it is not a super-component of the agent.

Naming convention: In JMX, an ObjectName represents a reference to an MBean in the agent. It is unique within an MBeanServer and consists of two parts: the domain name and an unordered list of propert-value pairs. The string representation of an object name must follow the following syntax:

    [DomainName]:property=value[,property=value]*
 

In Fractal JMX, the object name of an MBean representing a component server interface uses this syntax as follows:

    FC/[path]component@id[shared]:itf=interface
 

where:

• component: is the name of the component, as returned by NameController.
• interface: is the name of a server interface of the component, as returned by InterfaceType.
• path: is a (slash separated) name sequence of the successive super-components of the component, in the reverse order.
• shared: is an optional field set to "-shared" if the component may be identified by several paths (i.e. if the component or some component, in its super-component hierarchy, is shared).
• id: is an inelegant, but unique, component identifier introduced to avoid JMX name clashes, since nothing prevents the same Fractal name sequence to identify several components.

For example, in the figure above, the MBean representing the interface I of the component D is identified by:

    FC/A/B/C/D@56e32:itf=I
 

where @56e32 is the unique identifier of component D. This identifier is generated by the agent and can be ignored.

This naming convention:

• requires components to have a NameController and to avoid (in component or interface names) characters interpreted in specific ways by ObjectName (e.g. ":", "*", "&"...).
• is used by the agent attributes to filter the relevant MBeans. Only the MBeans, whose ObjectName matches a pattern defined by these attributes, are registered in the agent. These MBeans represent either component server interfaces or monitors for observing component attributes. In the latter case, the naming convention used by the agent attributes considers some additional property-value pairs reserved for the configuration of JMX monitors.

Version:

0.1

Method Summary

void	expose() Registers MBeans in the agent.

Method Detail

expose

public void expose()
            throws JMException

Registers MBeans in the agent. This method allows the agent component (implementing this interface) to register MBeans in its scope, where:

• the scope of the agent represents its super-components and all sub-components recursively enclosed in its super-components (or in itself if the agent has no super-components).
• the MBeans represent component (server) interfaces or standard JMX monitors for observing component attributes.

This method:

• first unregisters (previously registered) MBeans in the agent.
• then registers MBeans in the scope that match the filter attributes of the agent.

Throws:

JMException - if a problem occurs during the MBean registration.