Java Reference
In-Depth Information
to provide some measure of assistance to management users. The description
should provide meaningful information such as the possible values of an attribute
or the effect of an operation.
The following sections provide more detail about each of the support classes
that implement the interfaces listed in table A.1.
A.5.1
The OpenMBeanInfoSupport class
The OpenMBeanInfoSupport class implements the OpenMBeanInfo interface and
extends the MBeanInfo class. Toward this end, it inherits the name and descrip-
tion methods used to describe the overall MBean.
The support class overrides the methods that return arrays of metadata objects
for attributes, operations, and constructors. It does so in order to return the
appropriate Open MBean metadata objects instead of the usual metadata. Open
MBeans use the normal MBeanNotificationInfo object to describe notifications,
so no new implementation is provided in the support class.
A.5.2
The OpenMBeanOperationSupport and
OpenMBeanConstructorSupport classes
These two subclasses represent operations and constructors, respectively. Both
classes override the getSignature() method in order to provide the correct Open
MBean metadata return type.
The OpenMBeanOperationSupport class adds an additional method, getReturn-
OpenType() , which returns the open type descriptor object that describes the object
being returned from an operation. In addition, the getImpact() method of the
OpenMBeanOperationSupport class must return anything except UNKNOWN (see the
MBeanOperationInfo class in chapter 5 for more details).
A.5.3
The OpenMBeanAttributeSupport and
OpenMBeanParameterSupport classes
Like the OpenMBeanOperationSupport class, both the OpenMBeanAttributeSupport
and OpenMBeanParameterSupport classes provide a new method, getOpenType() ,
which is used to describe the type of parameter or attribute they represent. The
return type of the getOpenType() method is one of the four open-type classes pre-
viously described.
In addition, both classes implement the getDefaultValue() and getLegalVal-
ues() methods. The getDefaultValue() method returns a value that is applicable
to the type returned by the getType() method of each class. The getLegalVal-
ues() method returns an array of objects that must be compatible with the type
Search WWH ::




Custom Search