Java Management Extensions

Open MBean Metadata Classes

Now that we’ve seen how open MBean types work and how they are defined, let’s take a look at creating the metadata classes that describe resources that are instrumented as open MBeans. We will start by seeing how to describe parameters, attributes, constructors, operations, notifications, and finally OpenMBeanInfo. Each of these is described by an interface and implemented by a support class. This is similar to model MBeans—the focus of the previous chapter—and the open MBean types we looked at earlier in this chapter.

As with the open MBean type classes, when we talk about an object that implements the interface (e.g., an OpenMBeanParameterInfo object) we have presupposed the creation of the object using a support class. This is because we generally work with a particular open MBean metadata type through its interface and use the corresponding support class only to create instances of those objects.

A common theme for all of the OpenMBean*Info objects (where * is Parameter, Attribute, etc.) is that the support classes provided extend their javax.management.MBean*Info counterparts—for example, OpenMBeanParameterInfoSupport extends MBeanParameterInfo. The relationships between the open MBean classes are shown in Figure 5-1.

Figure 5-1. Relationships between the open MBean metadata classes

As we saw with dynamic MBeans in Figure 3-1, a single instance of ...