Advanced MBean loading - JMX in Action - page 243

Looking over the code for the notification class, you can see that it does not con-
tain anything complex. It declares the three notification types as public static
final member variables for convenience. In addition, it adds methods for setting
and getting a URL and an ObjectInstance object. The URL methods allow the
MLetWrapper MBean to send the URL that was added successfully or that caused
an error. The ObjectInstance variable will be set whenever an MBean is created
successfully using the M-let service.

10.4.2 Writing the MLetWrapper MBean

Now that the notification is defined, you can move on to the MLetWrapper MBean
class. This MBean is a Standard MBean (look back at chapter 3 for more informa-
tion about Standard MBeans); because you will wrap the M-let service entirely, the
new MLetWrapper MBean class will have the same management interface as the
MLet MBean.
The MLetWrapper MBean class implements the MBean interface jmx-
book.ch10.MLetWrapperMBean . This MBean interface extends the javax.man-
agement.loading.MLetMBean interface. Thus an implementing MBean has the
same interface as the M-let service, ensuring that it has the same attributes
and operations.
In addition, the MLetWrapper MBean class implements the MBeanRegistration
interface to interact with the M-let service and extends the NotificationBroad-
casterSupport class to provide support for sending notifications.
The following code shows the MLetWrapperMBean interface:

package jmxbook. ch10;

import javax.management.loading.*;

public interface MLetWrapperMBean extends MLetMBean
{
}
The MLetWrapper MBean will emit notifications for every MBean it creates and
for every URL that is added. The basic behavior of the MBean is to delegate all
method calls to the M-let service and capture return values in order to generate
notifications. Listing 10.3 shows the MLetWrapper class.

Listing 10.3 MLetWrapper.java

package jmxbook.ch10;

import javax.management.*;
import javax.management.loading.*;