• Operation of the Adaptor Clients -- page 79
• The adaptorMO Interface -- page 79
• Supported Protocols -- page 82
• Initializing an Adaptor Client -- page 83
• Required Services -- page 86
• Operations on an Agent -- page 88

Two levels exist within the adaptorMO interface:

• Low-level, where each m-bean in a remote agent is accessed through its object name

• High-level, where each m-bean in a remote agent is accessed through a c-bean, which provides a local view of the m-bean

Use of C-Beans by the adaptorMO Interface

• A Java interface (MO) that defines which of the methods of an m-bean are accessible to a Java management application

• A Java stub (MOStub) that implements the methods defined in the Java interface MO

The mogen compiler enables you to generate a c-bean automatically from an m-bean. It enables you to generate several different c-beans from the same m-bean. This enables different representations of the same m-bean to be presented to different Java managers. For information on how to use the mogen compiler, refer to Chapter 6.

• RMI
• HTTP/TCP
• HTTP/UDP
• HTTP/SSL
• IIOP

HTTP/TCP Adaptor Client

HTTP/UDP Adaptor Client

HTTP/SSL Adaptor Client

IIOP Adaptor Client

• Adding the adaptor client to the manager
• Connecting the adaptor client to an agent

The constructor of each of these classes is a public constructor that takes no parameters. This enables you to instantiate an adaptor client without hard-coding its Java class. CODE EXAMPLE 7-1 shows how to do this. In this example, the class of the adaptor client to be instantiated is specified as a hard-coded string. Such information can be provided by a command-line argument, a name server, or a directory service.

If you want to use more than one RMI adaptor per client (or agent), you must run the rmiregistry command, specifying the port number that the new adaptor is going to use:  

portNumber

This refers to the port number for the new RMI adaptor.

Connecting an Adaptor Client

• The authentication information (HTTP adaptors only). Specify null for RMI and IIOP adaptors.
• The host name of the machine where the agent is running
• The port number that this machine listens on for incoming requests
• A logical name associated with the agent, which depends on the communication mechanism

When a manager invokes the connect method, it is possible that no messages are exchanged between the adaptor client and the agent. Whether this happens depends on the underlying communication mechanism used by the adaptor client.

Authentication

The client sends a request to the server to login to the server. If login/password information is defined for the adaptor server (see page 58) the server responds with a request for login/password information. The client sends its login/password information, which is compared by the server with the information for users with login/passwords authenticated by the server.

To add an adaptor client with login/password information to a manager, create an instance of the Java class that implements the adaptor. The classes are shown on page 83. To add login/password authentication, create an instance of the AuthInfo class. CODE EXAMPLE 7-3 shows the instantiation of an HTTP/TCP adaptor client and an authentication information object.  

If the server has no login/password information defined, client authentication is not performed. Where authentication is not performed, any client is able to connect to the server. 

• A mapping service
• A class loader

• The Java class of an m-bean when it is not specified
• The Java class of a c-bean

Class Loader

When you add a class loader to a manager, you must assign it an object name. The object name you assign to a class loader must contain configuration information that the class loader requires. For more information, refer to "Object Name of an RMI Network Class Loader" on page 150.

To add the supplied class loader to a manager, include in the manager the code required for instantiating the com.sun.jaw.impl.agent.services.loader.rmi.NetClassLoader class. If you add this class loader, the Java classes it loads must be present on a machine on which the class and library server is running. For more information, refer to "Class and Library Server" on page 147.

CODE EXAMPLE 7-4 shows how to add a network class loader to a manager. The newly instantiated class loader obtains classes and libraries from an RMI server that has the URL rmi://sky:1099/NetClassServer.

After you have added a class loader to a manager, register the class loader with the adaptor client. To register the class loader, set the ClassLoader property of the adaptor client as illustrated in CODE EXAMPLE 7-5.

For information on how to use an adaptor client to instantiate a class loader in an agent, refer to "Adding an RMI Network Class Loader Through a Manager" on page 151.

• Retrieving m-beans
• Getting properties of m-beans
• Setting properties of m-beans
• Instantiating m-beans
• Transferring m-bean instances
• Deleting m-bean instances

Retrieving M-Beans

• A list of object names represented by a vector is returned if you use the low-level interface.
• A list of c-beans is returned if you use the high-level interface. For each object name retrieved the adaptor client instantiates a c-bean.

Using the High-Level Interface to Retrieve C-Beans

CODE EXAMPLE 7-8 shows how to retrieve a specific c-bean. Retrieving a specific c-bean enables a manager to invoke methods defined in the SimpleMO interface directly for performing management operations on the Simple m-bean.

Getting All Objects by Using an Adaptor Client

• Invoking getObject with null arguments for the object name and query, and then using a filter to exclude unwanted objects

• Invoking getOnlyNames to get all the object names and then invoking getObject with the names of the objects you want

Using the Low-Level Interface to Get a Property

Using the Low-Level Interface to Get Several Properties

Using the High-Level Interface to Get a Property

1. Getting a c-bean, as explained in "Using the High-Level Interface to Retrieve C-Beans" on page 89.

2. Invoking the getter associated with the property as illustrated in CODE EXAMPLE 7-11, which shows how to retrieve a property called State through a c-bean.

---

CODE  EXAMPLE  7-11     Getting a Property Value Through a C-Bean

ObjectName name= new ObjectName("sky:SimpleMO");

Vector result= MOFactory.getObject(name, null);

if (result.isEmpty()) {

return;

}

SimpleMO cbean= (SimpleMO) result.firstElement();

String value= cbean.getState();

---

Getting all of the properties of a c-bean involves:

• Generating the stubs of the c-bean by using mogen
• Using the high-level interface to get the c-bean
• Invoking the readAll method to retrieve all properties from the remote agent
• Setting the GroupOper property of the c-bean to true
• Invoking getter methods on the c-bean to retrieve property values stored in a cache within the c-bean

Getting a subset of the properties of a c-bean involves:

• Generating the stubs of the c-bean by using mogen
• Using the high-level interface to get the c-bean
• Setting the GroupOper property of the c-bean to true
• Invoking the getters for all the properties to be retrieved
• Invoking the readObject method to retrieve all the requested properties from the remote agent
• Invoking getter methods on the c-bean to retrieve property values stored in a cache within the c-bean

Setting Properties of M-Beans

Using the Low-Level Interface to Set a Property

The Java Dynamic Management Kit enables you to specify the name of an operator class when setting a property. The framework instantiates the specified operator and invokes it to set the property value.

Using the Low-Level Interface to Set Several Properties

• To represent a list of modifications, instantiate the com.sun.jaw.reference.common.ModificationList Java class.
• To represent a modification in the list, instantiate the com.sun.jaw.reference.common.Modification Java class.

Using the High-Level Interface to Set a Property

1. Getting a c-bean, as explained in "Using the High-Level Interface to Retrieve C-Beans" on page 89

2. Invoking the setter associated with the property as illustrated in CODE EXAMPLE 7-16

---

CODE  EXAMPLE  7-16     Setting a Property Value Through a C-Bean

ObjectName name= new ObjectName("sky:SimpleMO");

Vector result= MOFactory.getObject(name, null);

if (result.isEmpty()) {

return;

}

SimpleMO cbean= (SimpleMO) result.firstElement();

cbean.setState("OK");

---

• Generating the stubs of the c-bean by using mogen
• Using the high-level interface to get the c-bean
• Setting the GroupOper property of the c-bean to true
• Invoking setter methods on the c-bean to provide the values for the properties to be set
• Invoking the modifyObject method to set all the requested properties in the remote agent and update the cache of the c-bean

Instantiating M-Beans

When requesting that m-beans be instantiated, it is possible to specify the class loader the agent must use to load the new class to instantiate. The class loader is specified using its object name. If no class loader is specified, the agent uses its default class loader.

When instantiating a remote m-bean, you can directly obtain a c-bean to represent the newly created m-bean. This is illustrated in CODE EXAMPLE 7-18.

In this example, the name of the Java class to be instantiated in the agent is specified explicitly. If you do not specify the Java class name explicitly, you can use the mapping service to enable the adaptor to obtain the name of the Java class to be instantiated in the agent. If you do not specify the Java class name explicitly, and do not use the mapping service, you must ensure that the agent includes the code required to determine the Java class name of the class to be instantiated.

When instantiating an m-bean in the agent, you can explicitly request the object to be persistent using the cb_newDBMO method.

Transferring M-Bean Instances

Deleting M-Bean Instances

CODE EXAMPLE 7-19 shows how to use the low-level interface of an adaptor client to delete an m-bean from the repository.

CODE EXAMPLE 7-20 shows how to use the high-level interface of an adaptor client to delete an m-bean from the repository.