What is wrong with ModelMBean and what is the difference wit
I am using JBoss 3.0.6.
I am trying to implement the same MBean as DynamicMBean and as ModelMBean.
I call it both times the same way from my code:
String pulsarName = "com.peerdirect.rmapplications.master.jmx.PulsarStandard" ;
Object pulsar = Class.forName (pulsarName).newInstance();
String name = myMBeanServer.getDefaultDomain() + ":type=" + pulsarName;
myMBeanServer.registerMBean (pulsar, new ObjectName(name)); // line 67
When I implement it as a DynamicMBean, it works OK.
Here is the implementation:
------------- start of implementation -------------------
package com.peerdirect.rmapplications.master.jmx;
import com.peerdirect.rmapplications.master.jms.StatusNotificationClient;
import javax.management.*;
import javax.management.modelmbean.*;
import java.util.Iterator;
import java.lang.Runnable;
import java.io.*;
import org.jboss.mx.modelmbean.*;
import org.jboss.mx.modelmbean.ModelMBeanConstants.*;
public class PulsarStandard extends NotificationBroadcasterSupport
implements DynamicMBean, Runnable
{
// support for generic notification listeners
private NotificationBroadcasterSupport notifier = new NotificationBroadcasterSupport();
// sequence numbers for notifications
protected long notifierSequence = 0;
protected long attrNotifierSequence = 0;
// mgmt attribute name constants
final static String PULSE_PERIOD = "PulsePeriodInMills";
final static String IF_STARTED = "Started";
// mgmt operation name constants
final static String START_PULSE = "startPulse";
final static String STOP_PULSE = "stopPulse";
// fields for attribute values
private static final int DEFAULT_PULSE_PERIOD = 1000;
private static final boolean DEFAULT_STARTED= false;
private int mPulsePeriod = 0;
private boolean mStarted = false;
private StatusNotificationClient mSNC = null;
private Thread mThread = null;
// getAttribute implementation
public PulsarStandard () throws MBeanException
{
System.out.println ("PulsarStandard");
mPulsePeriod = DEFAULT_PULSE_PERIOD;
mStarted = DEFAULT_STARTED;
mSNC = new StatusNotificationClient ();
mThread = new Thread (this);
startPulse () ;
}
public Object getAttribute(String attribute) throws AttributeNotFoundException, MBeanException, ReflectionException
{
System.out.println ("getAttribute");
if (attribute == null || attribute.equals(""))
throw new IllegalArgumentException("null or empty attribute name");
// map the named attributes to fields
if (attribute.equals(PULSE_PERIOD))
return new Integer (mPulsePeriod);
else if (attribute.equals(IF_STARTED))
return new Boolean (mStarted);
throw new AttributeNotFoundException("Attribute " + attribute + " not found.");
}
// getAttributes implementation
public AttributeList getAttributes (String[] attributes)
{
System.out.println ("getAttributes");
if (attributes == null)
throw new IllegalArgumentException("null array");
AttributeList list = new AttributeList();
for (int i = 0; i < attributes.length; ++i)
{
try
{
list.add (new Attribute (attributes, getAttribute(attributes)));
}
catch (JMException ignored)
{
// if the attribute could not be retrieved, skip it
}
}
return list;
}
// setAttribute implementation
public void setAttribute (Attribute attribute) throws AttributeNotFoundException, InvalidAttributeValueException,
MBeanException, ReflectionException
{
System.out.println ("setAttribute");
if (attribute == null) throw new
AttributeNotFoundException("null attribute");
// map attributes to fields
try
{
if (attribute.getName().equals(PULSE_PERIOD))
this.mPulsePeriod = ((Integer)attribute.getValue()).intValue();
else if (attribute.getName().equals(IF_STARTED))
this.mStarted = ((Boolean)attribute.getValue()).booleanValue();
else
throw new AttributeNotFoundException("attribute " + attribute.getName() + " not found.");
}
catch (ClassCastException e)
{
throw new InvalidAttributeValueException("Invalid attribute type " + attribute.getValue().getClass().getName());
}
}
// setAttributes implementation
public AttributeList setAttributes (AttributeList list)
{
System.out.println ("setAttributes");
if (list == null)
throw new IllegalArgumentException("null list");
AttributeList results = new AttributeList();
Iterator it = list.iterator();
while (it.hasNext())
{
try
{
Attribute attr = (Attribute)it.next();
setAttribute(attr);
results.add(attr);
}
catch (JMException ignored)
{
// if unable to set the attribute, skip it
}
}
return results;
}
// invoke implementation
public Object invoke(String actionName,
Object[] params,
String[] signature) throws MBeanException, ReflectionException {
System.out.println ("invoke");
if (actionName == null || actionName.equals(""))
throw new IllegalArgumentException("no operation");
// map operation names to methods
if (actionName.equals(START_PULSE))
{
startPulse();
return null;
}
else if (actionName.equals(STOP_PULSE))
{
stopPulse ();
return null;
}
else
throw new UnsupportedOperationException("unknown operation " + actionName);
}
// getMBeanInfo implementation
/*public static MBeanInfo getMBeanInfo()
{
return getMBeanInfo1();
}*/
public MBeanInfo getMBeanInfo()
{
System.out.println ("getMBeanInfo");
final boolean IS_READABLE = true;
final boolean IS_WRITABLE = true;
final boolean IS_IS = true;
// MBean class and description
//String className = getClass().getName();
String className = PulsarStandard.class.getName();
String description =
"User resource with dynamic management interface";
// meta data for 'PULSE_PERIOD' attribute.
MBeanAttributeInfo mPulsePeriod = new MBeanAttributeInfo(
PULSE_PERIOD, // name
int.class.getName(), // type
"Pulse Period", // description
IS_READABLE, IS_WRITABLE, !IS_IS // access
);
// meta data for 'IF_STARTED' attribute.
MBeanAttributeInfo mStarted = new MBeanAttributeInfo(
IF_STARTED, // name
boolean.class.getName(), // type
"If the Pulser has Started", // description
IS_READABLE, !IS_WRITABLE, !IS_IS // access
);
// meta data for 'startPulse' operation
MBeanOperationInfo startPulse = new MBeanOperationInfo(
START_PULSE, // name
"Start the pulsar", // description
null, // signature
void.class.getName(), // return type
MBeanOperationInfo.ACTION // impact
);
// meta data for 'stopPulse' operation
MBeanOperationInfo stopPulse = new MBeanOperationInfo(
STOP_PULSE, // name
"Stop the pulsar", // description
null, // signature
void.class.getName(), // return type
MBeanOperationInfo.ACTION // impact
);
// mbean constructors
MBeanConstructorInfo defaultConstructor =
new MBeanConstructorInfo(
"Default Constructor",
"Creates a new Pulsar", null
);
// attribute, constructor and operation lists
MBeanAttributeInfo[] attributes = new MBeanAttributeInfo[] {mPulsePeriod, mStarted};
MBeanConstructorInfo[] constructors = new MBeanConstructorInfo[] {defaultConstructor};
MBeanOperationInfo[] operations = new MBeanOperationInfo[] {startPulse, stopPulse};
// return the MBeanInfo
return new MBeanInfo (className, description, attributes, constructors, operations, null);
}
public void startPulse ()
{
System.out.println ("startPulse");
mThread.start ();
try
{
mSNC.connect();
mStarted = true ;
}
catch (Exception e)
{
mStarted = false ;
}
}
public void stopPulse ()
{
System.out.println ("stopPulse");
mThread.stop ();
mSNC.disconnect();
mStarted = false ;
}
public void run ()
{
System.out.println ("run");
try
{
while (true)
{
mThread.sleep (mPulsePeriod);
if (mStarted)
{
System.out.println("Pulsing");
mSNC.sendPulse();
}
}
}
catch (Exception ex)
{
ex.printStackTrace();
}
}
}
//////////////////////////////////////////////////////////////////////////////////////
//////////////////////////////////////////////////////////////////////////////////////
//////////////////////////////////////////////////////////////////////////////////////
----------------- end of implementation ---------------
However, whan I implement it as a ModelMBean (not directly ModelMBean, because I need to use PersistPolicy; I tried to implement it as ModelBase or as XMBean - both times) it does not wortk - it bring out an exception (which is not brough out when I use DynamicMBean implementation of the same Mbean):
MBeanException: preRegister() failed
[ObjectName='DefaultDomain:type=com.peerdirect.rmapplications.master.jmx.PulsarStandard',Class=com.peerdirect.rmapplications.master.jmx.PulsarStandard
(com.peerdirect.rmapplications.master.jmx.PulsarStandard@5bdc50)]
Cause: java.lang.NullPointerException
at
org.jboss.mx.server.registry.BasicMBeanRegistry.registerMBean(BasicMBeanRegistry.java:187)
at org.jboss.mx.server.MBeanServerImpl.registerMBean(MBeanServerImpl.java:975)
at org.jboss.mx.server.MBeanServerImpl.registerMBean(MBeanServerImpl.java:302)
at com.peerdirect.rmapplications.agent.BaseAgent.(BaseAgent.java:67)
at com.peerdirect.rmapplications.agent.MasterAgent.(MasterAgent.java:5)
at com.peerdirect.rmapplications.agent.MasterAgent.main(MasterAgent.java:15)
Here is my implementation as ModelBase (absolutely the same thing happens when I use XMBean instead of ModelBase):
--------------------- start of implementation --------
package com.peerdirect.rmapplications.master.jmx;
import com.peerdirect.rmapplications.master.jms.StatusNotificationClient;
import javax.management.*;
import javax.management.modelmbean.*;
import java.util.Iterator;
import java.lang.Runnable;
import java.io.*;
import org.jboss.mx.modelmbean.*;
import org.jboss.mx.modelmbean.ModelMBeanConstants.*;
public class PulsarStandard extends ModelBase
implements Runnable
{
// support for generic notification listeners
private NotificationBroadcasterSupport notifier = new NotificationBroadcasterSupport();
// sequence numbers for notifications
protected long notifierSequence = 0;
protected long attrNotifierSequence = 0;
// mgmt attribute name constants
final static String PULSE_PERIOD = "PulsePeriodInMills";
final static String IF_STARTED = "Started";
// mgmt operation name constants
final static String START_PULSE = "startPulse";
final static String STOP_PULSE = "stopPulse";
// fields for attribute values
private static final int DEFAULT_PULSE_PERIOD = 1000;
private static final boolean DEFAULT_STARTED= false;
private int mPulsePeriod = 0;
private boolean mStarted = false;
private StatusNotificationClient mSNC = null;
private Thread mThread = null;
protected ModelMBeanInfo metadata = null;
protected Object resource = null;
protected String resourceType = null;
public boolean isSupportedResourceType(String resourceType)
{
System.out.println("isSupportedResourceType");
return true;
}
// getAttribute implementation
public PulsarStandard () throws MBeanException
{
super ();
System.out.println ("PulsarStandard");
mPulsePeriod = DEFAULT_PULSE_PERIOD;
mStarted = DEFAULT_STARTED;
mSNC = new StatusNotificationClient ();
mThread = new Thread (this);
startPulse () ;
}
public Object getAttribute(String attribute) throws AttributeNotFoundException, MBeanException, ReflectionException
{
System.out.println ("getAttribute");
if (attribute == null || attribute.equals(""))
throw new IllegalArgumentException("null or empty attribute name");
// map the named attributes to fields
if (attribute.equals(PULSE_PERIOD))
return new Integer (mPulsePeriod);
else if (attribute.equals(IF_STARTED))
return new Boolean (mStarted);
throw new AttributeNotFoundException("Attribute " + attribute + " not found.");
}
// getAttributes implementation
public AttributeList getAttributes (String[] attributes)
{
System.out.println ("getAttributes");
if (attributes == null)
throw new IllegalArgumentException("null array");
AttributeList list = new AttributeList();
for (int i = 0; i < attributes.length; ++i)
{
try
{
list.add (new Attribute (attributes, getAttribute(attributes)));
}
catch (JMException ignored)
{
// if the attribute could not be retrieved, skip it
}
}
return list;
}
// setAttribute implementation
public void setAttribute (Attribute attribute) throws AttributeNotFoundException, InvalidAttributeValueException,
MBeanException, ReflectionException
{
System.out.println ("setAttribute");
if (attribute == null) throw new
AttributeNotFoundException("null attribute");
// map attributes to fields
try
{
if (attribute.getName().equals(PULSE_PERIOD))
this.mPulsePeriod = ((Integer)attribute.getValue()).intValue();
else if (attribute.getName().equals(IF_STARTED))
this.mStarted = ((Boolean)attribute.getValue()).booleanValue();
else
throw new AttributeNotFoundException("attribute " + attribute.getName() + " not found.");
}
catch (ClassCastException e)
{
throw new InvalidAttributeValueException("Invalid attribute type " + attribute.getValue().getClass().getName());
}
}
// setAttributes implementation
public AttributeList setAttributes (AttributeList list)
{
System.out.println ("setAttributes");
if (list == null)
throw new IllegalArgumentException("null list");
AttributeList results = new AttributeList();
Iterator it = list.iterator();
while (it.hasNext())
{
try
{
Attribute attr = (Attribute)it.next();
setAttribute(attr);
results.add(attr);
}
catch (JMException ignored)
{
// if unable to set the attribute, skip it
}
}
return results;
}
// invoke implementation
public Object invoke(String actionName,
Object[] params,
String[] signature) throws MBeanException, ReflectionException {
System.out.println ("invoke");
if (actionName == null || actionName.equals(""))
throw new IllegalArgumentException("no operation");
// map operation names to methods
if (actionName.equals(START_PULSE))
{
startPulse();
return null;
}
else if (actionName.equals(STOP_PULSE))
{
stopPulse ();
return null;
}
else
throw new UnsupportedOperationException("unknown operation " + actionName);
}
// getMBeanInfo implementation
/*public static MBeanInfo getMBeanInfo()
{
return getMBeanInfo1();
}*/
public MBeanInfo getMBeanInfo()
{
System.out.println ("getMBeanInfo");
//final boolean IS_READABLE = true;
//final boolean IS_WRITABLE = true;
//final boolean IS_IS = true;
// MBean class and description
//String className = getClass().getName();
String className = PulsarStandard.class.getName();
String description =
"User resource with model management interface";
// build 'RoomName' read-write attribute
/*Descriptor descr_my = new DescriptorSupport();
descr_my.setField(PERSIST_POLICY, "OnUpdate");
descr_my.setField(PERSIST_LOCATION, "c:\\aa");
descr_my.setField(PERSIST_NAME, "storage.txt");
System.out.println ("Valid " + descr_my.isValid());*/
// meta data for 'PULSE_PERIOD' attribute.
ModelMBeanAttributeInfo mPulsePeriod = new ModelMBeanAttributeInfo(
PULSE_PERIOD, // name
int.class.getName(), // type
"Pulse Period", // description
IS_READABLE, IS_WRITABLE, !IS_IS//, // access
//descr_my
);
// meta data for 'IF_STARTED' attribute.
ModelMBeanAttributeInfo mStarted = new ModelMBeanAttributeInfo(
IF_STARTED, // name
boolean.class.getName(), // type
"If the Pulser has Started", // description
IS_READABLE, !IS_WRITABLE, !IS_IS // access
);
// meta data for 'startPulse' operation
ModelMBeanOperationInfo startPulse = new ModelMBeanOperationInfo(
START_PULSE, // name
"Start the pulsar", // description
null, // signature
void.class.getName(), // return type
MBeanOperationInfo.ACTION // impact
);
// meta data for 'stopPulse' operation
ModelMBeanOperationInfo stopPulse = new ModelMBeanOperationInfo(
STOP_PULSE, // name
"Stop the pulsar", // description
null, // signature
void.class.getName(), // return type
MBeanOperationInfo.ACTION // impact
);
// mbean constructors
ModelMBeanConstructorInfo defaultConstructor =
new ModelMBeanConstructorInfo(
"Default Constructor",
"Creates a new Pulsar", null
);
// attribute, constructor and operation lists
ModelMBeanAttributeInfo[] attributes = new ModelMBeanAttributeInfo[] {mPulsePeriod, mStarted};
ModelMBeanConstructorInfo[] constructors = new ModelMBeanConstructorInfo[] {defaultConstructor};
ModelMBeanOperationInfo[] operations = new ModelMBeanOperationInfo[] {startPulse, stopPulse};
// return the MBeanInfo
return new ModelMBeanInfoSupport (className, description, attributes, constructors, operations, null);
}
// RW attributes
/*
public int getPulsePeriodInMills ()
{
return mPulsePeriod;
}
public void setPulsePeriodInMills (int pPulsePeriod)
{
mPulsePeriod = pPulsePeriod ;
}
public boolean getStarted ()
{
return mStarted;
}
*/
public void startPulse ()
{
System.out.println ("startPulse");
mThread.start ();
try
{
mSNC.connect();
mStarted = true ;
}
catch (Exception e)
{
mStarted = false ;
}
}
public void stopPulse ()
{
System.out.println ("stopPulse");
mThread.stop ();
mSNC.disconnect();
mStarted = false ;
}
public void run ()
{
System.out.println ("run");
try
{
while (true)
{
mThread.sleep (mPulsePeriod);
if (mStarted)
{
System.out.println("Pulsing");
mSNC.sendPulse();
}
}
}
catch (Exception ex)
{
ex.printStackTrace();
}
}
}
//////////////////////////////////////////////////////////////////////////////////////
//////////////////////////////////////////////////////////////////////////////////////
//////////////////////////////////////////////////////////////////////////////////////
--------------------- end of implementation --------
