Provides the definition of the ModelMBean classes. A Model + MBean is an MBean that acts as a bridge between the management + interface and the underlying managed resource. Both the + management interface and the managed resource are specified as + Java objects. The same Model MBean implementation can be + reused many times with different management interfaces and + managed resources, and it can provide common functionality + such as persistence and caching.
+ +A Model MBean implements the {@link + javax.management.modelmbean.ModelMBean ModelMBean} interface. + It is a {@link javax.management.DynamicMBean DynamicMBean} + whose {@link javax.management.DynamicMBean#getMBeanInfo() + getMBeanInfo} method returns an object implementing {@link + javax.management.modelmbean.ModelMBeanInfo + ModelMBeanInfo}.
+ +Every MBean has an {@link javax.management.MBeanInfo
+ MBeanInfo} with information about the MBean itself, and its
+ attributes, operations, constructors, and notifications. A
+ Model MBean augments this MBeanInfo with {@link
+ javax.management.Descriptor Descriptor}s that encode
+ additional information in the form of (key,value) pairs.
+ Usually, Descriptors are instances of {@link
+ javax.management.modelmbean.DescriptorSupport
+ DescriptorSupport}.
The class {@link + javax.management.modelmbean.RequiredModelMBean + RequiredModelMBean} provides a standard Model MBean + implementation.
+ +The following example shows a Model MBean being used to make
+ the get method of a HashMap
+ available for management through an MBean server. No other
+ methods are available through the MBean server. There is
+ nothing special about HashMap here. Public
+ methods from any public class can be exposed for management in
+ the same way.
+import java.lang.reflect.Method;
+import java.util.HashMap;
+import javax.management.*;
+import javax.management.modelmbean.*;
+
+// ...
+
+MBeanServer mbs = MBeanServerFactory.createMBeanServer();
+// The MBean Server
+
+HashMap map = new HashMap();
+// The resource that will be managed
+
+// Construct the management interface for the Model MBean
+Method getMethod = HashMap.class.getMethod("get", new Class[] {Object.class});
+ModelMBeanOperationInfo getInfo =
+ new ModelMBeanOperationInfo("Get value for key", getMethod);
+ModelMBeanInfo mmbi =
+ new ModelMBeanInfoSupport(HashMap.class.getName(),
+ "Map of keys and values",
+ null, // no attributes
+ null, // no constructors
+ new ModelMBeanOperationInfo[] {getInfo},
+ null); // no notifications
+
+// Make the Model MBean and link it to the resource
+ModelMBean mmb = new RequiredModelMBean(mmbi);
+mmb.setManagedResource(map, "ObjectReference");
+
+// Register the Model MBean in the MBean Server
+ObjectName mapName = new ObjectName(":type=Map,name=whatever");
+mbs.registerMBean(mmb, mapName);
+
+// Resource can evolve independently of the MBean
+map.put("key", "value");
+
+// Can access the "get" method through the MBean Server
+mbs.invoke(mapName, "get", new Object[] {"key"}, new String[] {Object.class.getName()});
+// returns "value"
+
+
+