Sun Java System Application Server Enterprise Edition 8.1 2005Q2 Developer's Guide

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# AMX MBeans

All AMX MBeans are represented as interfaces in a subpackage of `com.sun.appserv.management` and are implemented by dynamic proxies on the client-side. While you can access AMX MBeans directly through standard JMX APIs, most users find the use of AMX interface (proxy) classes to be most convenient.

An AMX MBean belongs to an application server domain. There is exactly one domain per DAS. Thus all MBeans accessible through the DAS belong to a single Application Server administrative domain. All MBeans in an Application Server administrative domain, and hence within the DAS, belong to the JMX domain `amx`. Any MBeans that do not have the JMX domain `amx` are not part of AMX, and are neither documented nor supported for use by clients. All AMX MBeans can be reached navigationally through the `DomainRoot`.

AMX defines different types of MBean, namely, configuration MBeans, monitoring MBeans, utility MBeans and J2EE management (JSR 77) MBeans. These MBeans are logically related in the following ways:

- They all implement the `com.sun.appserv.management.base.AMX` interface.

- They all have a `j2eeType` and `name` property within their `ObjectName` (see `com.sun.appserv.management.base.XTypes` and `com.sun.appserv.management.j2ee.J2EETypes` for the available values of the `j2eeType` property).

- All MBeans that logically contain other MBeans implement the `com.sun.appserv.management.base.Container` interface.

- JSR 77 MBeans that have a corresponding configuration or monitoring peer expose it via `getConfigPeer()` or `getMonitoringPeer()`. However, there are many configuration and monitoring MBeans that do not correspond to JSR 77 MBeans.

## Configuration MBeans

Configuration information for a given Application Server domain is stored in a central repository that is shared by all instances in that domain. The central repository can only be written to by the DAS. However, configuration information in the central repository is made available to administration clients via AMX MBeans.

The configuration MBeans are those that modify the underlying `domain.xml` or related files. Collectively, they form a model representing the configuration and deployment repository and the operations that can be performed on them.

The `Group` Attribute of configuration MBeans, obtained from `getGroup()`, has a value of `com.sun.appserv.management.base.AMX.GROUP_CONFIGURATION`.

## Monitoring MBeans

Monitoring MBeans provide transient monitoring information about all the vital components of the Application Server.

The `Group` Attribute of monitoring MBeans, obtained from `getGroup()`, has a value of `com.sun.appserv.management.base.AMX.GROUP_MONITORING`.

## Utility MBeans

Utility MBeans provide commonly used services to the Application Server.

The `Group` Attribute of utility MBeans, obtained from `getGroup()`, has a value of `com.sun.appserv.management.base.AMX.GROUP_UTILITY`.

## J2EE Management MBeans

The J2EE management MBeans implement, and in some cases extend, the management hierarchy as defined by JSR 77, which specifies the management model for the whole J2EE platform. One of the management APIs implemented in JSR 77 is the JMX API.

The implementation of JSR 77 in AMX offers access to and monitoring of MBeans via J2EE management MBeans, by using the `getMonitoringPeer()` and `getConfigPeer()` methods.

The J2EE management MBeans can be thought of as the central hub from which other MBeans are obtained.

The `Group` Attribute of J2EE management MBeans, obtained from `getGroup()`, has a value of `com.sun.appserv.management.base.AMX.GROUP_JSR77`.

## Other MBeans

MBeans that do not fit into one of the above four categories have the value `com.sun.appserv.management.base.AMX.GROUP_OTHER`. One such example is `com.sun.appserv.management.deploy.DeploymentMgr`.

## MBean Notifications

All AMX MBeans that emit Notifications place a `java.util.Map` within the `userData` field of a standard Notification, which can be obtained via `Notification.getUserData()`. Within the map are zero or more items, which vary according to the Notification type. Each Notification type, and the data available within the Notification, is defined in its respective MBean or in an appropriate place.

Note that certain standard Notifications, such as `javax.management.AttributeChangeNotification` do not and cannot follow this behavior.

## Access to MBean Attributes

An AMX MBean `Attribute` is accessible in three ways:

- Dotted names via `MonitoringDottedNames` and `ConfigDottedNames`

- Attributes on MBeans via `getAttribute(s)` and `setAttributes(s)` (from the standard JMX API)

- Getters/setters within the MBean’s interface class, for example, `getPort()`, `setPort()`, and so on.

All dotted names that are accessible via the command line interface are available as Attributes within a single MBean. This includes properties, which are Attributes beginning with the prefix `property.`, for example, `server.property.myproperty`.

Note –

Certain attributes that may be of a specific type, such as `int`, are declared as `java.lang.String`. This is because the value of the attribute may be a template of a form such as `${HTTP_LISTENER_PORT}`.

Note –

An application or module MBean has two `enabled` attributes. Which `enabled` attribute to look up for the state of the application or module depends on the target. If the target is `domain`, look up the attribute under application or module itself. If the target is not domain, look up the attribute under the `application-ref`.

To look up an application in JConsole, select the following:

`com.sun.appserv` -> `j2ee-application` -> app-name -> `server` -> `config`

To look up a module in JConsole, select the following:

`com.sun.appserv` -> module-type -> module-name -> `server` -> `config`

To look up an `application-ref` in JConsole, select the following:

`com.sun.appserv` -> `application-ref` -> app-or-module-name -> `server` -> `config`

The attributes, including `enabled`, are listed under `config`.

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