API java : MBeanServerInvocationHandler

javax.management
Class MBeanServerInvocationHandler

java.lang.Object
  javax.management.MBeanServerInvocationHandler

All Implemented Interfaces:

InvocationHandler

public class MBeanServerInvocationHandler
extends Object
implements InvocationHandler

InvocationHandler that forwards methods in an MBean's management interface through the MBean server to the MBean.

Given an MBeanServerConnection, the ObjectName of an MBean within that MBean server, and a Java interface Intf that describes the management interface of the MBean using the patterns for a Standard MBean, this class can be used to construct a proxy for the MBean. The proxy implements the interface Intf such that all of its methods are forwarded through the MBean server to the MBean.

If you have an MBean server mbs containing an MBean with ObjectName name, and if the MBean's management interface is described by the Java interface Intf, you can construct a proxy for the MBean like this:

Intf proxy = (Intf)
     MBeanServerInvocationHandler.newProxyInstance(mbs,
                                                   name,
                                                   Intf.class,
                                                   false);

Suppose, for example, Intf looks like this:

public interface Intf {
     public String getSomeAttribute();
     public void setSomeAttribute(String value);
     public void someOperation(String param1, int param2);
 }

Then you can execute:

• proxy.getSomeAttribute() which will result in a call to mbs.getAttribute(name, "SomeAttribute").
• proxy.setSomeAttribute("whatever") which will result in a call to mbs.setAttribute(name, new Attribute("SomeAttribute", "whatever")).
• proxy.someOperation("param1", 2) which will be translated into a call to mbs.invoke(name, "someOperation", <etc>).

If the last parameter to newProxyInstance is true, then the MBean is assumed to be a NotificationBroadcaster or NotificationEmitter and the returned proxy will implement NotificationEmitter. A call to NotificationBroadcaster.addNotificationListener(javax.management.NotificationListener, javax.management.NotificationFilter, java.lang.Object) on the proxy will result in a call to MBeanServerConnection.addNotificationListener(ObjectName, NotificationListener, NotificationFilter, Object), and likewise for the other methods of NotificationBroadcaster and NotificationEmitter.

The methods Object.toString(), Object.hashCode(), and Object.equals(Object), when invoked on a proxy using this invocation handler, are forwarded to the MBean server as methods on the proxied MBean. This will only work if the MBean declares those methods in its management interface.

Since:

1.5

Constructor Summary
MBeanServerInvocationHandler(MBeanServerConnection connection, ObjectName objectName)           Invocation handler that forwards methods through an MBean server.

 

Method Summary
Object	invoke(Object proxy, Method method, Object[] args)           Processes a method invocation on a proxy instance and returns the result.
static Object	newProxyInstance(MBeanServerConnection connection, ObjectName objectName, Class interfaceClass, boolean notificationBroadcaster)           Return a proxy that implements the given interface by forwarding its methods through the given MBean server to the named MBean.

 

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

 

Constructor Detail

MBeanServerInvocationHandler

public MBeanServerInvocationHandler(MBeanServerConnection connection,
                                    ObjectName objectName)

Invocation handler that forwards methods through an MBean server. This constructor may be called instead of relying on newProxyInstance(javax.management.MBeanServerConnection, javax.management.ObjectName, java.lang.Class, boolean), for instance if you need to supply a different ClassLoader to Proxy.newProxyInstance.

Parameters:

connection - the MBean server connection through which all methods of a proxy using this handler will be forwarded.

objectName - the name of the MBean within the MBean server to which methods will be forwarded.

newProxyInstance

public static Object newProxyInstance(MBeanServerConnection connection,
                                      ObjectName objectName,
                                      Class interfaceClass,
                                      boolean notificationBroadcaster)

Return a proxy that implements the given interface by forwarding its methods through the given MBean server to the named MBean.

This method is equivalent to Proxy.newProxyInstance(interfaceClass.getClassLoader(), interfaces, handler). Here handler is the result of new MBeanServerInvocationHandler(connection, objectName), and interfaces is an array that has one element if notificationBroadcaster is false and two if it is true. The first element of interfaces is interfaceClass and the second, if present, is NotificationEmitter.class.

Parameters:

connection - the MBean server to forward to.

objectName - the name of the MBean within connection to forward to.

interfaceClass - the management interface that the MBean exports, which will also be implemented by the returned proxy.

notificationBroadcaster - make the returned proxy implement NotificationEmitter by forwarding its methods via connection.

Returns:

the new proxy instance.

invoke

public Object invoke(Object proxy,
                     Method method,
                     Object[] args)
              throws Throwable

Description copied from interface: InvocationHandler

Processes a method invocation on a proxy instance and returns the result. This method will be invoked on an invocation handler when a method is invoked on a proxy instance that it is associated with.

Specified by:

invoke in interface InvocationHandler

Parameters:

proxy - the proxy instance that the method was invoked on

method - the Method instance corresponding to the interface method invoked on the proxy instance. The declaring class of the Method object will be the interface that the method was declared in, which may be a superinterface of the proxy interface that the proxy class inherits the method through.

args - an array of objects containing the values of the arguments passed in the method invocation on the proxy instance, or null if interface method takes no arguments. Arguments of primitive types are wrapped in instances of the appropriate primitive wrapper class, such as java.lang.Integer or java.lang.Boolean.

Returns:

the value to return from the method invocation on the proxy instance. If the declared return type of the interface method is a primitive type, then the value returned by this method must be an instance of the corresponding primitive wrapper class; otherwise, it must be a type assignable to the declared return type. If the value returned by this method is null and the interface method's return type is primitive, then a NullPointerException will be thrown by the method invocation on the proxy instance. If the value returned by this method is otherwise not compatible with the interface method's declared return type as described above, a ClassCastException will be thrown by the method invocation on the proxy instance.

Throws:

Throwable - the exception to throw from the method invocation on the proxy instance. The exception's type must be assignable either to any of the exception types declared in the throws clause of the interface method or to the unchecked exception types java.lang.RuntimeException or java.lang.Error. If a checked exception is thrown by this method that is not assignable to any of the exception types declared in the throws clause of the interface method, then an UndeclaredThrowableException containing the exception that was thrown by this method will be thrown by the method invocation on the proxy instance.

See Also:

UndeclaredThrowableException