JMX

The JMX technology provides a simple, standard way of managing resources such as applications

Using the JMX technology, a given resource is instrumented by one or more Java objects known as Managed Beans, or MBeans. These MBeans are registered in a core-managed object server, known as an MBean server. The MBean server acts as a management agent and can run on most devices that have been enabled for the Java programming language.

# * Server.java: creates an MBeanServer,

# registers a SimpleStandard MBean on the local MBeanServer,

# registers a SimpleDynamic MBean on the local MBeanServer,

# performs local operations on both MBeans,

# creates and starts an RMI connector server (JRMP).

# * Client.java: creates an RMI connector (JRMP),

# registers a SimpleStandard MBean on the remote MBeanServer,

# registers a SimpleDynamic MBean on the remote MBeanServer,

# performs remote operations on both MBeans,

# closes the RMI connector.

# * ClientListener.java: implements a generic notification listener.

# * SimpleStandard.java: implements the Simple standard MBean.

# * SimpleStandardMBean.java: the management interface exposed

# by the Simple standard MBean.

# * SimpleDynamic.java: implements the Simple dynamic MBean.

public class Server {

public static void main(String[] args) {

try {

// Instantiate the MBean server

echo("\n>>> Create the MBean server");

MBeanServer mbs = MBeanServerFactory.createMBeanServer();

waitForEnterPressed();

// Get default domain

echo("\n>>> Get the MBean server's default domain");

String domain = mbs.getDefaultDomain();

echo("\tDefault Domain = " + domain);

waitForEnterPressed();

// Create and register the SimpleStandard MBean

String mbeanClassName = "SimpleStandard";

String mbeanObjectNameStr =

domain + ":type=" + mbeanClassName + ",name=1";

ObjectName mbeanObjectName =

createSimpleMBean(mbs, mbeanClassName, mbeanObjectNameStr);

waitForEnterPressed();

// Get and display the management information exposed by the

// SimpleStandard MBean

printMBeanInfo(mbs, mbeanObjectName, mbeanClassName);

waitForEnterPressed();

// Manage the SimpleStandard MBean

manageSimpleMBean(mbs, mbeanObjectName, mbeanClassName);

waitForEnterPressed();

// Create and register the SimpleDynamic MBean

mbeanClassName = "SimpleDynamic";

mbeanObjectNameStr =

domain + ":type=" + mbeanClassName + ",name=1";

mbeanObjectName =

createSimpleMBean(mbs, mbeanClassName, mbeanObjectNameStr);

waitForEnterPressed();

// Get and display the management information exposed by the

// SimpleDynamic MBean

printMBeanInfo(mbs, mbeanObjectName, mbeanClassName);

waitForEnterPressed();

// Manage the SimpleDynamic MBean

manageSimpleMBean(mbs, mbeanObjectName, mbeanClassName);

waitForEnterPressed();

// Create an RMI connector server

echo("\nCreate an RMI connector server");

JMXServiceURL url = new JMXServiceURL(

"service:jmx:rmi:///jndi/rmi://localhost:9999/server");

JMXConnectorServer cs =

JMXConnectorServerFactory.newJMXConnectorServer(url, null, mbs);

// Start the RMI connector server

echo("\nStart the RMI connector server");

cs.start();

echo("\nThe RMI connector server successfully started");

echo("and is ready to handle incoming connections");

echo("\nStart the client on a different window and");

echo("press <Enter> once the client has finished");

waitForEnterPressed();

// Stop the RMI connector server

echo("\nStop the RMI connector server");

cs.stop();

System.out.println("\nBye! Bye!");

} catch (Exception e) {

e.printStackTrace();

}

private static ObjectName createSimpleMBean(MBeanServer mbs,

String mbeanClassName,

String mbeanObjectNameStr) {

echo("\n>>> Create the " + mbeanClassName +

" MBean within the MBeanServer");

echo("\tObjectName = " + mbeanObjectNameStr);

try {

ObjectName mbeanObjectName =

ObjectName.getInstance(mbeanObjectNameStr);

mbs.createMBean(mbeanClassName, mbeanObjectName);

return mbeanObjectName;

} catch (Exception e) {

echo("\t!!! Could not create the " + mbeanClassName + " MBean !!!");

e.printStackTrace();

echo("\nEXITING...\n");

System.exit(1);

}

return null;

}

private static void printMBeanInfo(MBeanServer mbs,

ObjectName mbeanObjectName,

String mbeanClassName) {

echo("\n>>> Retrieve the management information for the " +

mbeanClassName);

echo(" MBean using the getMBeanInfo() method of the MBeanServer");

MBeanInfo info = null;

try {

info = mbs.getMBeanInfo(mbeanObjectName);

} catch (Exception e) {

echo("\t!!! Could not get MBeanInfo object for " +

mbeanClassName +" !!!");

e.printStackTrace();

return;

}

echo("\nCLASSNAME: \t" + info.getClassName());

echo("\nDESCRIPTION: \t" + info.getDescription());

echo("\nATTRIBUTES");

MBeanAttributeInfo[] attrInfo = info.getAttributes();

if (attrInfo.length > 0) {

for (int i = 0; i < attrInfo.length; i++) {

echo(" ** NAME: \t" + attrInfo[i].getName());

echo(" DESCR: \t" + attrInfo[i].getDescription());

echo(" TYPE: \t" + attrInfo[i].getType() +

"\tREAD: "+ attrInfo[i].isReadable() +

"\tWRITE: "+ attrInfo[i].isWritable());

}

} else echo(" ** No attributes **");

echo("\nCONSTRUCTORS");

MBeanConstructorInfo[] constrInfo = info.getConstructors();

for (int i=0; i<constrInfo.length; i++) {

echo(" ** NAME: \t" + constrInfo[i].getName());

echo(" DESCR: \t" + constrInfo[i].getDescription());

echo(" PARAM: \t" + constrInfo[i].getSignature().length +

" parameter(s)");

}

echo("\nOPERATIONS");

MBeanOperationInfo[] opInfo = info.getOperations();

if (opInfo.length > 0) {

for (int i = 0; i < opInfo.length; i++) {

echo(" ** NAME: \t" + opInfo[i].getName());

echo(" DESCR: \t" + opInfo[i].getDescription());

echo(" PARAM: \t" + opInfo[i].getSignature().length +

" parameter(s)");

}

} else echo(" ** No operations ** ");

echo("\nNOTIFICATIONS");

MBeanNotificationInfo[] notifInfo = info.getNotifications();

if (notifInfo.length > 0) {

for (int i = 0; i < notifInfo.length; i++) {

echo(" ** NAME: \t" + notifInfo[i].getName());

echo(" DESCR: \t" + notifInfo[i].getDescription());

String notifTypes[] = notifInfo[i].getNotifTypes();

for (int j = 0; j < notifTypes.length; j++) {

echo(" TYPE: \t" + notifTypes[j]);

}

} else echo(" ** No notifications **");

}

private static void manageSimpleMBean(MBeanServer mbs,

ObjectName mbeanObjectName,

String mbeanClassName) {

echo("\n>>> Manage the " + mbeanClassName +

" MBean using its attributes ");

echo(" and operations exposed for management");

try {

// Get attribute values

printSimpleAttributes(mbs, mbeanObjectName);

// Change State attribute

echo("\n Setting State attribute to value \"new state\"...");

Attribute stateAttribute = new Attribute("State","new state");

mbs.setAttribute(mbeanObjectName, stateAttribute);

// Get attribute values

printSimpleAttributes(mbs, mbeanObjectName);

// Invoking reset operation

echo("\n Invoking reset operation...");

mbs.invoke(mbeanObjectName, "reset", null, null);

// Get attribute values

printSimpleAttributes(mbs, mbeanObjectName);

} catch (Exception e) {

e.printStackTrace();

}

private static void printSimpleAttributes(MBeanServer mbs,

ObjectName mbeanObjectName) {

try {

echo("\n Getting attribute values:");

String State = (String) mbs.getAttribute(mbeanObjectName, "State");

Integer NbChanges =

(Integer) mbs.getAttribute(mbeanObjectName,"NbChanges");

echo("\tState = \"" + State + "\"");

echo("\tNbChanges = " + NbChanges);

} catch (Exception e) {

echo("\t!!! Could not read attributes !!!");

e.printStackTrace();

}

private static void echo(String msg) {

System.out.println(msg);

}

private static void sleep(int millis) {

try {

Thread.sleep(millis);

} catch (InterruptedException e) {

e.printStackTrace();

}

private static void waitForEnterPressed() {

try {

echo("\nPress <Enter> to continue...");

System.in.read();

} catch (IOException e) {

e.printStackTrace();

}

public class Client {

public static void main(String[] args) {

try {

// Create an RMI connector client and

// connect it to the RMI connector server

echo("\nCreate an RMI connector client and " +

"connect it to the RMI connector server");

JMXServiceURL url = new JMXServiceURL(

"service:jmx:rmi:///jndi/rmi://localhost:9999/server");

JMXConnector jmxc = JMXConnectorFactory.connect(url, null);

// Create listener

ClientListener listener = new ClientListener();

// Get an MBeanServerConnection

echo("\nGet an MBeanServerConnection");

MBeanServerConnection mbsc = jmxc.getMBeanServerConnection();

waitForEnterPressed();

// Get domains from MBeanServer

echo("\nDomains:");

String domains[] = mbsc.getDomains();

for (int i = 0; i < domains.length; i++) {

echo("\tDomain[" + i + "] = " + domains[i]);

}

waitForEnterPressed();

// Get MBeanServer's default domain

String domain = mbsc.getDefaultDomain();

// Create SimpleStandard MBean

ObjectName stdMBeanName =

new ObjectName(domain +":type=SimpleStandard,name=2");

echo("\nCreate SimpleStandard MBean...");

mbsc.createMBean("SimpleStandard", stdMBeanName, null, null);

waitForEnterPressed();

// Create SimpleDynamic MBean

ObjectName dynMBeanName =

new ObjectName(domain +":type=SimpleDynamic,name=2");

echo("\nCreate SimpleDynamic MBean...");

mbsc.createMBean("SimpleDynamic", dynMBeanName, null, null);

waitForEnterPressed();

// Get MBean count

echo("\nMBean count = " + mbsc.getMBeanCount());

// Query MBean names

echo("\nQuery MBeanServer MBeans:");

Set names = mbsc.queryNames(null, null);

for (Iterator i = names.iterator(); i.hasNext(); ) {

echo("\tObjectName = " + (ObjectName) i.next());

}

waitForEnterPressed();

// -------------------------------

// Manage the SimpleStandard MBean

// -------------------------------

echo("\n>>> Perform operations on SimpleStandard MBean <<<");

// Get State attribute in SimpleStandard MBean

echo("\nState = " + mbsc.getAttribute(stdMBeanName, "State"));

// Set State attribute in SimpleStandard MBean

mbsc.setAttribute(stdMBeanName,

new Attribute("State", "changed state"));

// Get State attribute in SimpleStandard MBean

// Another way of interacting with a given MBean is through a

// dedicated proxy instead of going directly through the MBean

// server connection

SimpleStandardMBean proxy = JMX.newMBeanProxy(

mbsc, stdMBeanName, SimpleStandardMBean.class, true);

echo("\nState = " + proxy.getState());

// Add notification listener on SimpleStandard MBean

echo("\nAdd notification listener...");

mbsc.addNotificationListener(stdMBeanName, listener, null, null);

// Invoke "reset" in SimpleStandard MBean

// Calling "reset" makes the SimpleStandard MBean emit a

// notification that will be received by the registered

// ClientListener.

echo("\nInvoke reset() in SimpleStandard MBean...");

mbsc.invoke(stdMBeanName, "reset", null, null);

// Sleep for 2 seconds in order to have time to receive the

// notification before removing the notification listener.

echo("\nWaiting for notification...");

sleep(2000);

// Remove notification listener on SimpleStandard MBean

echo("\nRemove notification listener...");

mbsc.removeNotificationListener(stdMBeanName, listener);

// Unregister SimpleStandard MBean

echo("\nUnregister SimpleStandard MBean...");

mbsc.unregisterMBean(stdMBeanName);

waitForEnterPressed();

// ------------------------------

// Manage the SimpleDynamic MBean

// ------------------------------

echo("\n>>> Perform operations on SimpleDynamic MBean <<<");

// Get State attribute in SimpleDynamic MBean

echo("\nState = " + mbsc.getAttribute(dynMBeanName, "State"));

// Set State attribute in SimpleDynamic MBean

mbsc.setAttribute(dynMBeanName,

new Attribute("State", "changed state"));

// Get State attribute in SimpleDynamic MBean

echo("\nState = " +

mbsc.getAttribute(dynMBeanName, "State"));

// Add notification listener on SimpleDynamic MBean

echo("\nAdd notification listener...");

mbsc.addNotificationListener(dynMBeanName, listener, null, null);

// Invoke "reset" in SimpleDynamic MBean

// Calling "reset" makes the SimpleDynamic MBean emit a

// notification that will be received by the registered

// ClientListener.

echo("\nInvoke reset() in SimpleDynamic MBean...");

mbsc.invoke(dynMBeanName, "reset", null, null);

// Sleep for 2 seconds in order to have time to receive the

// notification before removing the notification listener.

echo("\nWaiting for notification...");

sleep(2000);

// Remove notification listener on SimpleDynamic MBean

echo("\nRemove notification listener...");

mbsc.removeNotificationListener(dynMBeanName, listener);

// Unregister SimpleDynamic MBean

echo("\nUnregister SimpleDynamic MBean...");

mbsc.unregisterMBean(dynMBeanName);

waitForEnterPressed();

// Close MBeanServer connection

echo("\nClose the connection to the server");

jmxc.close();

echo("\nBye! Bye!");

} catch (Exception e) {

e.printStackTrace();

}

private static void echo(String msg) {

System.out.println(msg);

}

private static void sleep(int millis) {

try {

Thread.sleep(millis);

} catch (InterruptedException e) {

e.printStackTrace();

}

private static void waitForEnterPressed() {

try {

echo("\nPress <Enter> to continue...");

System.in.read();

} catch (IOException e) {

e.printStackTrace();

}

public class ClientListener implements NotificationListener {

public void handleNotification(Notification notification, Object handback) {

System.out.println("\nReceived notification: " + notification);

}

public class SimpleDynamic

extends NotificationBroadcasterSupport

implements DynamicMBean {

* -----------------------------------------------------

* CONSTRUCTORS

* -----------------------------------------------------

public SimpleDynamic() {

// Build the management information to be exposed by the dynamic MBean

buildDynamicMBeanInfo();

}

* -----------------------------------------------------

* IMPLEMENTATION OF THE DynamicMBean INTERFACE

* -----------------------------------------------------

/**

* Allows the value of the specified attribute of the Dynamic MBean to be

* obtained.

public Object getAttribute(String attribute_name)

throws AttributeNotFoundException,

MBeanException,

ReflectionException {

// Check attribute_name is not null to avoid NullPointerException

// later on

if (attribute_name == null) {

throw new RuntimeOperationsException(

new IllegalArgumentException("Attribute name cannot be null"),

"Cannot invoke a getter of " + dClassName +

" with null attribute name");

}

// Check for a recognized attribute_name and call the corresponding

// getter

if (attribute_name.equals("State")) {

return getState();

}

if (attribute_name.equals("NbChanges")) {

return getNbChanges();

}

// If attribute_name has not been recognized throw an

// AttributeNotFoundException

throw new AttributeNotFoundException("Cannot find " +

attribute_name +

" attribute in " +

dClassName);

}

/**

* Sets the value of the specified attribute of the Dynamic MBean.

public void setAttribute(Attribute attribute)

throws AttributeNotFoundException,

InvalidAttributeValueException,

MBeanException,

ReflectionException {

// Check attribute is not null to avoid NullPointerException later on

if (attribute == null) {

throw new RuntimeOperationsException(

new IllegalArgumentException("Attribute cannot be null"),

"Cannot invoke a setter of " + dClassName +

" with null attribute");

}

String name = attribute.getName();

Object value = attribute.getValue();

if (name == null) {

throw new RuntimeOperationsException(

new IllegalArgumentException("Attribute name cannot be null"),

"Cannot invoke the setter of " + dClassName +

" with null attribute name");

}

// Check for a recognized attribute name and call the corresponding

// setter

if (name.equals("State")) {

// if null value, try and see if the setter returns any exception

if (value == null) {

try {

setState( null );

} catch (Exception e) {

throw new InvalidAttributeValueException(

"Cannot set attribute " + name + " to null");

}

// if non null value, make sure it is assignable to the attribute

else {

try {

if (Class.forName("java.lang.String").isAssignableFrom(

value.getClass())) {

setState((String) value);

} else {

throw new InvalidAttributeValueException(

"Cannot set attribute " + name + " to a " +

value.getClass().getName() +

" object, String expected");

}

} catch (ClassNotFoundException e) {

e.printStackTrace();

}

// recognize an attempt to set "NbChanges" attribute (read-only):

else if (name.equals("NbChanges")) {

throw new AttributeNotFoundException(

"Cannot set attribute " + name + " because it is read-only");

}

// unrecognized attribute name:

else {

throw new AttributeNotFoundException("Attribute " + name +

" not found in " +

this.getClass().getName());

}

/**

* Enables the to get the values of several attributes of the Dynamic MBean.

public AttributeList getAttributes(String[] attributeNames) {

// Check attributeNames is not null to avoid NullPointerException

// later on

if (attributeNames == null) {

throw new RuntimeOperationsException(

new IllegalArgumentException("attributeNames[] cannot be null"),

"Cannot invoke a getter of " + dClassName);

}

AttributeList resultList = new AttributeList();

// If attributeNames is empty, return an empty result list

if (attributeNames.length == 0)

return resultList;

// Build the result attribute list

for (int i = 0 ; i < attributeNames.length ; i++) {

try {

Object value = getAttribute((String) attributeNames[i]);

resultList.add(new Attribute(attributeNames[i],value));

} catch (Exception e) {

e.printStackTrace();

}

return resultList;

}

/**

* Sets the values of several attributes of the Dynamic MBean, and returns

* the list of attributes that have been set.

public AttributeList setAttributes(AttributeList attributes) {

// Check attributes is not null to avoid NullPointerException later on

if (attributes == null) {

throw new RuntimeOperationsException(

new IllegalArgumentException(

"AttributeList attributes cannot be null"),

"Cannot invoke a setter of " + dClassName);

}

AttributeList resultList = new AttributeList();

// If attributeNames is empty, nothing more to do

if (attributes.isEmpty())

return resultList;

// For each attribute, try to set it and add to the result list if

// successfull

for (Iterator i = attributes.iterator(); i.hasNext();) {

Attribute attr = (Attribute) i.next();

try {

setAttribute(attr);

String name = attr.getName();

Object value = getAttribute(name);

resultList.add(new Attribute(name,value));

} catch(Exception e) {

e.printStackTrace();

}

return resultList;

}

/**

* Allows an operation to be invoked on the Dynamic MBean.

public Object invoke(String operationName,

Object params[],

String signature[])

throws MBeanException, ReflectionException {

// Check operationName is not null to avoid NullPointerException

// later on

if (operationName == null) {

throw new RuntimeOperationsException(

new IllegalArgumentException("Operation name cannot be null"),

"Cannot invoke a null operation in " + dClassName);

}

// Check for a recognized operation name and call the corresponding

// operation

if (operationName.equals("reset")) {

reset();

return null;

} else {

// Unrecognized operation name

throw new ReflectionException(

new NoSuchMethodException(operationName),

"Cannot find the operation " + operationName +

" in " + dClassName);

}

/**

* This method provides the exposed attributes and operations of the

* Dynamic MBean. It provides this information using an MBeanInfo object.

public MBeanInfo getMBeanInfo() {

// Return the information we want to expose for management:

// the dMBeanInfo private field has been built at instanciation time

return dMBeanInfo;

}

* -----------------------------------------------------

* OTHER PUBLIC METHODS

* -----------------------------------------------------

/**

* Getter: get the "State" attribute of the "SimpleDynamic" dynamic MBean.

public String getState() {

return state;

}

/**

* Setter: set the "State" attribute of the "SimpleDynamic" dynamic MBean.

public void setState(String s) {

state = s;

nbChanges++;

}

/**

* Getter: get the "NbChanges" attribute of the "SimpleDynamic" dynamic

* MBean.

public Integer getNbChanges() {

return new Integer(nbChanges);

}

/**

* Operation: reset to their initial values the "State" and "NbChanges"

* attributes of the "SimpleDynamic" dynamic MBean.

public void reset() {

AttributeChangeNotification acn =

new AttributeChangeNotification(this,

"NbChanges reset",

"NbChanges",

"Integer",

new Integer(nbChanges),

new Integer(0));

state = "initial state";

nbChanges = 0;

nbResets++;

sendNotification(acn);

}

/**

* Return the "NbResets" property.

* This method is not a Getter in the JMX sense because

* it is not returned by the getMBeanInfo() method.

public Integer getNbResets() {

return new Integer(nbResets);

}

* -----------------------------------------------------

* PRIVATE METHODS

* -----------------------------------------------------

/**

* Build the private dMBeanInfo field,

* which represents the management interface exposed by the MBean,

* that is, the set of attributes, constructors, operations and

* notifications which are available for management.

* A reference to the dMBeanInfo object is returned by the getMBeanInfo()

* method of the DynamicMBean interface. Note that, once constructed, an

* MBeanInfo object is immutable.

private void buildDynamicMBeanInfo() {

dAttributes[0] =

new MBeanAttributeInfo("State",

"java.lang.String",

"State string.",

true,

false);

dAttributes[1] =

new MBeanAttributeInfo("NbChanges",

"java.lang.Integer",

"Number of times the " +

"State string has been changed.",

true,

false,

false);

Constructor[] constructors = this.getClass().getConstructors();

dConstructors[0] =

new MBeanConstructorInfo("Constructs a " +

"SimpleDynamic object",

constructors[0]);

MBeanParameterInfo[] params = null;

dOperations[0] =

new MBeanOperationInfo("reset",

"reset State and NbChanges " +

"attributes to their initial values",

params ,

"void",

MBeanOperationInfo.ACTION);

dNotifications[0] =

new MBeanNotificationInfo(

new String[] { AttributeChangeNotification.ATTRIBUTE_CHANGE },

AttributeChangeNotification.class.getName(),

"This notification is emitted when the reset() method is called.");

dMBeanInfo = new MBeanInfo(dClassName,

dDescription,

dAttributes,

dConstructors,

dOperations,

dNotifications);

}

* -----------------------------------------------------

* PRIVATE VARIABLES

* -----------------------------------------------------

private String state = "initial state";

private int nbChanges = 0;

private int nbResets = 0;

private String dClassName = this.getClass().getName();

private String dDescription = "Simple implementation of a dynamic MBean.";

private MBeanAttributeInfo[] dAttributes =

new MBeanAttributeInfo[2];

private MBeanConstructorInfo[] dConstructors =

new MBeanConstructorInfo[1];

private MBeanNotificationInfo[] dNotifications =

new MBeanNotificationInfo[1];

private MBeanOperationInfo[] dOperations =

new MBeanOperationInfo[1];

private MBeanInfo dMBeanInfo = null;

}

public interface SimpleStandardMBean {

/**

* Getter: set the "State" attribute of the "SimpleStandard" standard

* MBean.

* @return the current value of the "State" attribute.

public String getState();

/**

* Setter: set the "State" attribute of the "SimpleStandard" standard

* MBean.

* @param <VAR>s</VAR> the new value of the "State" attribute.

public void setState(String s);

/**

* Getter: get the "NbChanges" attribute of the "SimpleStandard" standard

* MBean.

* @return the current value of the "NbChanges" attribute.

public int getNbChanges();

/**

* Operation: reset to their initial values the "State" and "NbChanges"

* attributes of the "SimpleStandard" standard MBean.

public void reset();

}

public class SimpleStandard

extends NotificationBroadcasterSupport

implements SimpleStandardMBean {

* -----------------------------------------------------

* CONSTRUCTORS

* -----------------------------------------------------

/* "SimpleStandard" does not provide any specific constructors.

* However, "SimpleStandard" is JMX compliant with regards to

* contructors because the default contructor SimpleStandard()

* provided by the Java compiler is public.

* -----------------------------------------------------

* IMPLEMENTATION OF THE SimpleStandardMBean INTERFACE

* -----------------------------------------------------

/**

* Getter: get the "State" attribute of the "SimpleStandard" standard MBean.

* @return the current value of the "State" attribute.

public String getState() {

return state;

}

/**

* Setter: set the "State" attribute of the "SimpleStandard" standard MBean.

* @param <VAR>s</VAR> the new value of the "State" attribute.

public void setState(String s) {

state = s;

nbChanges++;

}

/**

* Getter: get the "NbChanges" attribute of the "SimpleStandard" standard

* MBean.

* @return the current value of the "NbChanges" attribute.

public int getNbChanges() {

return nbChanges;

}

/**

* Operation: reset to their initial values the "State" and "NbChanges"

* attributes of the "SimpleStandard" standard MBean.

public void reset() {

AttributeChangeNotification acn =

new AttributeChangeNotification(this,

"NbChanges reset",

"NbChanges",

"Integer",

new Integer(nbChanges),

new Integer(0));

state = "initial state";

nbChanges = 0;

nbResets++;

sendNotification(acn);

}

* -----------------------------------------------------

* METHOD NOT EXPOSED FOR MANAGEMENT BY A JMX AGENT

* -----------------------------------------------------

/**

* Return the "NbResets" property.

* This method is not a Getter in the JMX sense because it

* is not exposed in the "SimpleStandardMBean" interface.

* @return the current value of the "NbResets" property.

public int getNbResets() {

return nbResets;

}

/**

* Returns an array indicating, for each notification this MBean

* may send, the name of the Java class of the notification and

* the notification type.</p>

* @return the array of possible notifications.

public MBeanNotificationInfo[] getNotificationInfo() {

return new MBeanNotificationInfo[] {

new MBeanNotificationInfo(

new String[] { AttributeChangeNotification.ATTRIBUTE_CHANGE },

AttributeChangeNotification.class.getName(),

"This notification is emitted when the reset() method is called.")

};

}

* -----------------------------------------------------

* ATTRIBUTES ACCESSIBLE FOR MANAGEMENT BY A JMX AGENT

* -----------------------------------------------------

private String state = "initial state";

private int nbChanges = 0;

* -----------------------------------------------------

* PROPERTY NOT ACCESSIBLE FOR MANAGEMENT BY A JMX AGENT

* -----------------------------------------------------

private int nbResets = 0;

}