public MapperListener(Mapper mapper,
    Connector connector) 
{
        this.mapper = mapper;
        this.connector = connector;
}

Create mapper listener.

 public  void containerEvent(ContainerEvent event) 
{
        if (event.getType() == Host.ADD_ALIAS_EVENT) {
            mapper.addHostAlias(((Host) event.getSource()).getName(),
                    event.getData().toString());
        } else if (event.getType() == Host.REMOVE_ALIAS_EVENT) {
            mapper.removeHostAlias(event.getData().toString());
        }
}

 public  void destroy() 
{
        try {
            ObjectName objectName = new ObjectName(
                    "JMImplementation:type=MBeanServerDelegate");
            mBeanServer.removeNotificationListener(objectName, this);
        } catch (Exception e) {
            log.warn("Error unregistering MBeanServerDelegate", e);
        }
}

unregister this from JMImplementation:type=MBeanServerDelegate

 public String getDomain() 
{
        return domain;
}

 public String getEngine() 
{
        return engine;
}

 public  void handleNotification(Notification notification,
    Object handback) 
{
        if (notification instanceof MBeanServerNotification) {
            ObjectName objectName = 
                ((MBeanServerNotification) notification).getMBeanName();
            String j2eeType = objectName.getKeyProperty("j2eeType");
            String engineName = null;
            if (j2eeType != null) {
                if ((j2eeType.equals("WebModule")) || 
                    (j2eeType.equals("Servlet"))) {
                    if (mBeanServer.isRegistered(objectName)) {
                        try {
                            engineName = (String)
                                mBeanServer.getAttribute(objectName, "engineName");
                        } catch (Exception e) {
                            // Ignore  
                        }
                    }
                }
            }
            // At deployment time, engineName is always = null.
            if ( (!"*".equals(domain)) &&
                 ( !domain.equals(objectName.getDomain()) ) &&
                 ( (!domain.equals(engineName) ) &&
                   (engineName != null) ) )  {
                return;
            }
            if(log.isDebugEnabled())
                log.debug( "Handle " + objectName  + " type : " + notification.getType());    
            if (notification.getType().equals
                (MBeanServerNotification.REGISTRATION_NOTIFICATION)) {
                String type=objectName.getKeyProperty("type");
                if( "Host".equals( type ) && domain.equals(objectName.getDomain())) {
                    try {
                        registerHost(objectName);
                    } catch (Exception e) {
                        log.warn("Error registering Host " + objectName, e);  
                    }
                }
                if (j2eeType != null) {
                    if (j2eeType.equals("WebModule")) {
                        try {
                            registerContext(objectName);
                        } catch (Throwable t) {
                            log.warn("Error registering Context " + objectName,t);
                        }
                    } else if (j2eeType.equals("Servlet")) {
                        try {
                            registerWrapper(objectName);
                        } catch (Throwable t) {
                            log.warn("Error registering Wrapper " + objectName,t);
                        }
                    }
                }
            } else if (notification.getType().equals
                       (MBeanServerNotification.UNREGISTRATION_NOTIFICATION)) {
                String type=objectName.getKeyProperty("type");
                if( "Host".equals( type )&& domain.equals(objectName.getDomain())) {
                    try {
                        unregisterHost(objectName);
                    } catch (Exception e) {
                        log.warn("Error unregistering Host " + objectName,e);  
                    }
                }
                if (j2eeType != null) {
                    if (j2eeType.equals("WebModule")) {
                        try {
                            unregisterContext(objectName);
                        } catch (Throwable t) {
                            log.warn("Error unregistering webapp " + objectName,t);
                        }
                    }
                }
            }
        }
}

 public  void init() 
{
        try {
            mBeanServer = Registry.getRegistry(null, null).getMBeanServer();
            registerEngine();
            // Query hosts
            String onStr = domain + ":type=Host,*";
            ObjectName objectName = new ObjectName(onStr);
            Set set = mBeanServer.queryMBeans(objectName, null);
            Iterator iterator = set.iterator();
            while (iterator.hasNext()) {
                ObjectInstance oi = (ObjectInstance) iterator.next();
                registerHost(oi.getObjectName());
            }
            // Query contexts
            onStr = "*:j2eeType=WebModule,*";
            objectName = new ObjectName(onStr);
            set = mBeanServer.queryMBeans(objectName, null);
            iterator = set.iterator();
            while (iterator.hasNext()) {
                ObjectInstance oi = (ObjectInstance) iterator.next();
                registerContext(oi.getObjectName());
            }
            // Query wrappers
            onStr = "*:j2eeType=Servlet,*";
            objectName = new ObjectName(onStr);
            set = mBeanServer.queryMBeans(objectName, null);
            iterator = set.iterator();
            while (iterator.hasNext()) {
                ObjectInstance oi = (ObjectInstance) iterator.next();
                registerWrapper(oi.getObjectName());
            }
            onStr = "JMImplementation:type=MBeanServerDelegate";
            objectName = new ObjectName(onStr);
            mBeanServer.addNotificationListener(objectName, this, null, null);
        } catch (Exception e) {
            log.warn("Error registering contexts",e);
        }
}

Initialize associated mapper.

 public  void setDomain(String domain) 
{
        this.domain = domain;
}

 public  void setEngine(String engine) 
{
        this.engine = engine;
}