Sun Java System Application Server Enterprise Edition 8.1 2005Q2 Developer's Guide

- Previous: Connecting to the Domain Administration Server
- Next: Running the AMX Samples

# Examining AMX Code Samples

The following example uses of AMX are discussed in this document:

- Starting an Application Server

- Deploying an Archive

- Displaying the AMX MBean Hierarchy

- Setting Monitoring States

- Accessing AMX MBeans

- Accessing and Displaying the Attributes of an AMX MBean

- Listing AMX MBean Properties

- Querying

- Monitoring Attribute Changes

- Undeploying Modules

- Stopping an Application Server

## Connecting to the DAS

The connection to the DAS is shown in the following code.

##### Example 16–1 Connecting to the DAS

    [...]
    public static AppserverConnectionSource
        connect(
            final String host,
            final int port,
            final String user,
            final String password,
            final TLSParams tlsParams )
            throws IOException
            {
                final String info = "host=" + host + ", port=" + port +
                    ", user=" + user + ", password=" + password +
                    ", tls=" + (tlsParams != null);

                SampleUtil.println( "Connecting...:" + info );

                final AppserverConnectionSource conn    =
                    new AppserverConnectionSource(
                        AppserverConnectionSource.PROTOCOL_RMI,
                        host, port, user, password, tlsParams, null);

                conn.getJMXConnector( false );

                SampleUtil.println( "Connected: " + info );

                return( conn );
            }
    [...]

A connection to the DAS is obtained via an instance of the `com.sun.appserv.management.client.AppserverConnectionSource` class. For the connection to be established, you must know the name of the host and port number on which the DAS is running, and have the correct user name, password and TLS parameters.

Once the connection to the DAS is established, `DomainRoot` is obtained as follows:

    DomainRoot domainRoot = appserverConnectionSource.getDomainRoot();

This `DomainRoot` instance is a client-side dynamic proxy to the MBean `amx:j2eeType=X-DomainRoot,name=amx`.

See the API documentation for `com.sun.appserv.management.client.AppserverConnectionSource` for further details about connecting to the DAS using the `AppserverConnectionSource` class`.`

However, if you prefer to work with standard JMX, instead of getting `DomainRoot`, you can get the `MBeanServerConnection` or `JMXConnector`, as shown:

    MBeanServerConnection conn =
    appserverConnectionSource.getMBeanServerConnection( false );
    JMXConnector jmxConn =
    appserverConnectionSource.getJMXConnector( false );

## Starting an Application Server

The `startServer()` method demonstrates how to start an Application Server.

##### Example 16–2 Starting an Application Server

    [...]
    startServer( final String serverName )
    {
        final J2EEServer server    = getJ2EEServer( serverName );

        server.start();
    }
    [...]

This method retrieves and starts an application server instance named `server`. The `server` is an instance of the `com.sun.appserv.management.j2see.J2EEServer` interface, and is obtained by calling another method, `getJ2EEServer()`, shown in the following code.

##### Example 16–3 Obtaining a Named J2EE server instance

    [...]
    getJ2EEServer( final String serverName )
    {
        final J2EEDomain j2eeDomain = getDomainRoot().getJ2EEDomain();
        final Map servers = j2eeDomain.getServerMap();
        final J2EEServer server = (J2EEServer)servers.get( serverName );
            if ( server == null )
            {
                throw new IllegalArgumentException( serverName );
            }
        return( server );
    }
    [...]

To obtain a J2EE server instance, the `getJ2EEServer()` method first of all obtains an instance of the `J2EEDomain` interface by calling the `com.sun.appserv.management.base.AMX.getDomainRoot()` and `com.sun.appserv.management.DomainRoot.getJ2EEDomain()` methods. The two methods called establish the following:

- `AMX.getDomainRoot()` obtains the Application Server domain to which `j2eeDomain` belongs.

- `DomainRoot.getJ2EEDomain()` obtains the J2EE domain for `j2eeDomain`.

The `J2EEServer` instance is then started by a call to the `start()` method. The `com.sun.appserv.management.j2ee.StateManageable.start()` method can be used to start any state manageable object.

## Deploying an Archive

The `uploadArchive()` and `deploy()` methods demonstrate how to upload and deploy a J2EE archive file.

##### Example 16–4 Uploading an archive

    [...]
    uploadArchive ( final File archive  ) throws IOException
    {
        final FileInputStream input = new FileInputStream( archive );
        final long length = input.available();
        final DeploymentMgr mgr = getDomainRoot().getDeploymentMgr();
        final Object uploadID = mgr.initiateFileUpload( length );
        try
        {
            [...]
        }
        finally
        {
            input.close();
        }
        return( uploadID );
    }
    [...]

The `uploadArchive()` method creates a standard Java `FileInputStream` instance called `input`, to upload the archive `archive`. It then obtains the AMX deployment manager running in the application server domain, by calling the `DomainRoot.getDeploymentMgr()` method.

A call to `com.sun.appserv.management.deploy.initiateFileUpload` starts the upload of `archive`. The `initiateFileUpload()` method automatically issues an upload ID, that `uploadArchive()` returns when it is called by `deploy()`.

##### Example 16–5 Deploying an archive

    [...]
    deploy ( final File archive ) throws IOException
    {
        final Object uploadID = uploadArchive(archive);
        final DeploymentMgr mgr    = getDomainRoot().getDeploymentMgr();
        final Object deployID = mgr.initDeploy( );
        final DeployNotificationListener myListener =
            new DeployNotificationListener( deployID);
        mgr.addNotificationListener( myListener, null, null);
        try
        {
            final Map    options  = new HashMap();
            options.put( DeploymentMgr.DEPLOY_OPTION_VERIFY_KEY,
                Boolean.TRUE.toString() );
            options.put( DeploymentMgr.DEPLOY_OPTION_DESCRIPTION_KEY,
                "description" );
            mgr.startDeploy( deployID, uploadID, null, null);
            while ( ! myListener.isCompleted() )
            {
                try
                {
                    println( "deploy: waiting for deploy of " + archive);
                    Thread.sleep( 1000 );
                }
                catch( InterruptedException e )
                {
                }
            }
            final DeploymentStatus status = myListener.getDeploymentStatus();
            println( "Deployment result: " + getStageStatusString(
                status.getStageStatus() ) );
            if ( status.getStageThrowable() != null )
            {
                status.getStageThrowable().printStackTrace();
            }
        }
        finally
        {
            try
            {
                mgr.removeNotificationListener( myListener );
            }
            catch( Exception e )
            {
            }
        }
    }
    [...]

The `deploy()` method calls `uploadArchive` to get the upload ID for `archive`. It then identifies the deployment manager by calling `DomainRoot.getDeploymentMgr()`. A call to `DeploymentMgr.initDeploy()` initializes the deployment and obtains a deployment ID, which is used to track the progress of the deployment.

A JMX notification listener, `myListener`, is created and activated to listen for notifications regarding the deployment of `deployID`.

Deployment is started by calling the `DeploymentMgr.startDeploy()` method and providing it with the `deployID` and `uploadID`.

While the deployment is continuing, `myListener` listens for the completion notification and `DeploymentStatus` keeps you informed of the status of the deployment by regularly calling its `getStageStatus()` method. Once the deployment is complete, the listener is closed down.

Caution –

Some of the behavior of the `com.sun.appserv.management.deploy` API is unpredictable, and it should be used with caution.

## Displaying the AMX MBean Hierarchy

The `displayAMX()` method demonstrates how to display the AMX MBean hierarchy.

##### Example 16–6 Displaying the AMX MBean Hierarchy

    [...]
    displayAMX(
        final AMX amx,
        final int indentCount )
    {
        final String indent = getIndent( indentCount );
        final String j2eeType = amx.getJ2EEType();
        final String name = amx.getName();
        if ( name.equals( AMX.NO_NAME ) )
        {
            println( indent + j2eeType );
        }
        else
        {
            println( indent + j2eeType + "=" + name );
        }
    }
    private void
    displayHierarchy(
        final Collection amxSet,
        final int indentCount )
    {
        final Iterator    iter    = amxSet.iterator();
        while ( iter.hasNext() )
        {
            final AMX amx = (AMX)iter.next();
            displayHierarchy( amx, indentCount );
        }
    }
    public void
    displayHierarchy(
        final AMX amx,
        final int    indentCount )
    {
        displayAMX( amx, indentCount );
        if ( amx instanceof Container )
        {
            final Map m = ((Container)amx).getMultiContaineeMap( null );
            final Set deferred = new HashSet();
            final Iterator mapsIter = m.values().iterator();
            while ( mapsIter.hasNext() )
            {
                final Map instancesMap = (Map)mapsIter.next();
                final AMX first = (AMX)instancesMap.values().iterator().next();
                if ( first instanceof Container )
                {
                    deferred.add( instancesMap );
                }
                else
                {
                    displayHierarchy( instancesMap.values(), indentCount + 2);
                }
            }
            // display deferred items
            final Iterator iter = deferred.iterator();
            while ( iter.hasNext() )
            {
                final Map instancesMap = (Map)iter.next();
                displayHierarchy( instancesMap.values(), indentCount + 2);
            }
        }
    }
    public void displayHierarchy()
    {
        displayHierarchy( getDomainRoot(), 0);
    }
    public void
    displayHierarchy( final String j2eeType )
    {
        final Set items = getQueryMgr().queryJ2EETypeSet( j2eeType );
        if ( items.size() == 0 )
        {
            println( "No {@link AMX} of j2eeType "
                + SampleUtil.quote( j2eeType ) + " found" );
        }
        else
        {
            displayHierarchy( items, 0);
        }
    }
    [...]

The `displayAMX()` method obtains the J2EE type and the name of an AMX MBean by calling `AMX.getJ2EEType` and `AMX.getName` respectively.

The `displayHierarchy()` method defines a standard Java `Collection` instance, `amxSet`, which collects instances of AMX MBeans.

To display the hierarchy of MBeans within a particular MBean in the collection, `displayHierarchy()` checks whether the MBean is an instance of `Container`. If so, it creates a set of the MBeans it contains by calling the `com.sun.appserv.management.base.Container.getMultiContaineeMap()` method.

The MBean hierarchy for a particular J2EE type is displayed by calling the `com.sun.appserv.management.base.QueryMgr.queryJ2EETypeSet()`, and passing the result to `displayHierarchy()`.

To display the entire AMX MBean hierarchy in a domain, `displayHierarchy()` calls `getDomainRoot()` to obtain the root AMX MBean in the domain.

## Setting Monitoring States

The `setMonitoring()` method demonstrates how to set monitoring states.

##### Example 16–7 Setting Monitoring States

    [...]
    private static final Set LEGAL_MON =
        Collections.unmodifiableSet( SampleUtil.newSet( new String[]
    {
        ModuleMonitoringLevelValues.HIGH,
        ModuleMonitoringLevelValues.LOW,
        ModuleMonitoringLevelValues.OFF,
    } ));
    public void setMonitoring(
        final String configName,
        final String state )
    {
        if ( ! LEGAL_MON.contains( state ) )
        {
            throw new IllegalArgumentException( state );
        }
        final ConfigConfig config =
            (ConfigConfig)getDomainConfig().
            getConfigConfigMap().get( configName );
        final ModuleMonitoringLevelsConfig mon =
            config.getMonitoringServiceConfig().
            getModuleMonitoringLevelsConfig();
        mon.setConnectorConnectionPool( state );
        mon.setThreadPool( state );
        mon.setHTTPService( state );
        mon.setJDBCConnectionPool( state );
        mon.setORB( state );
        mon.setTransactionService( state );
        mon.setWebContainer( state );
        mon.setEJBContainer( state );
    }
    [...]

The AMX API defines three levels of monitoring in `com.sun.appserv.management.config.ModuleMonitoringLevelValues`, namely, `HIGH`, `LOW`, and `OFF`.

In this example, the configuration element being monitored is named `configName`. The `com.sun.appserv.management.config.ConfigConfig` interface is used to configure the `config` element for `configName` in the `domain.xml` file.

An instance of `com.sun.appserv.management.config.ModuleMonitoringLevelsConfig` is created to configure the `module-monitoring-levels` element for `configName` in the `domain.xml` file.

The `ModuleMonitoringLevelsConfig` instance created then calls each of its set methods to change their states to `state`.

The above is performed by running the `set-monitoring` command when you run `SimpleMain`, stating the name of the configuration element to be monitored and the monitoring `state` to one of `HIGH`, `LOW` or `OFF`.

## Accessing AMX MBeans

The `handleList()` method demonstrates how to access many (but not all) configuration elements.

##### Example 16–8 Accessing AMX MBeans

    [...]
    handleList()
    {
        final DomainConfig dcp = getDomainConfig();
        println( "\n--- Top-level --- \n" );
        displayMap( "ConfigConfig", dcp.getConfigConfigMap() );
        displayMap( "ServerConfig", dcp.getServerConfigMap() );
        displayMap( "StandaloneServerConfig",
            dcp.getStandaloneServerConfigMap() );
        displayMap( "ClusteredServerConfig",
            dcp.getClusteredServerConfigMap() );
        displayMap( "ClusterConfig", dcp.getClusterConfigMap() );
        println( "\n--- DeployedItems --- \n" );
        displayMap( "J2EEApplicationConfig",
            dcp.getJ2EEApplicationConfigMap() );
        displayMap( "EJBModuleConfig",
            dcp.getEJBModuleConfigMap() );
        displayMap( "WebModuleConfig",
            dcp.getWebModuleConfigMap() );
        displayMap( "RARModuleConfig",
            dcp.getRARModuleConfigMap() );
        displayMap( "AppClientModuleConfig",
            dcp.getAppClientModuleConfigMap() );
        displayMap( "LifecycleModuleConfig",
            dcp.getLifecycleModuleConfigMap() );
        println( "\n--- Resources --- \n" );
        displayMap( "CustomResourceConfig",
            dcp.getCustomResourceConfigMap() );
        displayMap( "PersistenceManagerFactoryResourceConfig",
            dcp.getPersistenceManagerFactoryResourceConfigMap() );
        displayMap( "JNDIResourceConfig",
            dcp.getJNDIResourceConfigMap() );
        displayMap( "JMSResourceConfig",
            dcp.getJMSResourceConfigMap() );
        displayMap( "JDBCResourceConfig",
            dcp.getJDBCResourceConfigMap() );
        displayMap( "ConnectorResourceConfig",
            dcp.getConnectorResourceConfigMap() );
        displayMap( "JDBCConnectionPoolConfig",
            dcp.getJDBCConnectionPoolConfigMap() );
        displayMap( "PersistenceManagerFactoryResourceConfig",
            dcp.getPersistenceManagerFactoryResourceConfigMap() );
        displayMap( "ConnectorConnectionPoolConfig",
            dcp.getConnectorConnectionPoolConfigMap() );
        displayMap( "AdminObjectResourceConfig",
            dcp.getAdminObjectResourceConfigMap() );
        displayMap( "ResourceAdapterConfig",
            dcp.getResourceAdapterConfigMap() );
        displayMap( "MailResourceConfig",
            dcp.getMailResourceConfigMap() );
        final ConfigConfig config =
            (ConfigConfig)dcp.getConfigConfigMap().get( "server-config" );
        println( "\n--- HTTPService --- \n" );
        final HTTPServiceConfig httpService = config.getHTTPServiceConfig();
        displayMap( "HTTPListeners",
            httpService.getHTTPListenerConfigMap() );
        displayMap( "VirtualServers",
            httpService.getVirtualServerConfigMap() );
    }
    [...]

The `handleList()` method makes use of the `displayMap()` method, which simply prints out the key value pairs.

The `handleList()` method identifies the configuration for a domain by calling the `DomainRoot.getDomainConfig()` method. This `DomainConfig` instance then calls each of its `getXXXMap()` methods in turn, to obtain a `Map` for each type of AMX MBean. The `Map` returned by each getter is displayed by `displayMap()`.

Similarly, the AMX MBeans representing the `http-service` element are displayed as `Maps` by calling the `getXXXMap()` methods of the `com.sun.appserv.management.config.HTTPServiceConfig` interface, and passing them to `displayMap()`.

## Accessing and Displaying the Attributes of an AMX MBean

The `displayAllAttributes()` method demonstrates how to access and display the attributes of an AMX MBean.

##### Example 16–9 Accessing and Displaying the Attributes of an AMX MBean

    [...]
    displayAllAttributes( final AMX item )
    {
        println( "\n--- Attributes for " + item.getJ2EEType() +
            "=" + item.getName() + " ---" );
        final Extra extra = Util.getExtra( item );
        final Map attrs    = extra.getAllAttributes();
        final Iterator iter = attrs.keySet().iterator();
        while ( iter.hasNext() )
        {
            final String name = (String)iter.next();
            final Object value = attrs.get( name );
            println( name + "=" + toString( value ) );
        }
    }
    public void
    displayAllAttributes( final String j2eeType )
    {
        final Set items = queryForJ2EEType( j2eeType );
        if ( items.size() == 0 )
        {
            println( "No {@link AMX} of j2eeType "
                + SampleUtil.quote( j2eeType ) + " found" );
        }
        else
        {
            final Iterator iter= items.iterator();
            while ( iter.hasNext() )
            {
                final AMX amx = (AMX)iter.next();
                displayAllAttributes( amx );
                println( "" );
            }
        }
    }
    [...]

The `displayAllAttributes()` method calls the `AMX.getName()` and `AMX.getJ2EEType()` methods for an AMX MBean and prints the results onscreen. It then gets all the attributes for that MBean by calling `com.sun.appserv.management.base.Extra.getAllAttributes()` on the `Extra` instance returned by `com.sun.appserv.management.base.Util.getExtra()`. This is repeated for every MBean.

The attributes of AMX MBeans of a certain J2EE type can be displayed by specifying the J2EE type when the command is run. In this case, `displayAllAttributes()` calls `queryForJ2EEType()`. The `queryForJ2EEType()` method calls the `com.sun.appserv.management.base.QueryManager.queryPropSet()` method on the specified J2EE type to identify all elements of that type in the domain.

## Listing AMX MBean Properties

The `displayAllProperties()` demonstrates how to list AMX MBean properties.

##### Example 16–10 Listing AMX MBean Properties

    [...]
    getProperties( final PropertiesAccess pa )
    {
        final HashMap m = new HashMap();
        final String[] names = pa.getPropertyNames();
        for( int i = 0; i < names.length; ++i )
        {
            m.put( names[ i ], pa.getPropertyValue( names[ i ] ) );
        }
        return( m );
    }
    public void
    displayAllProperties( )
    {
        final Iterator iter    = getQueryMgr().queryAllSet().iterator();
        while ( iter.hasNext() )
        {
            final AMX amx = (AMX)iter.next();
            if ( amx instanceof PropertiesAccess )
            {
                final PropertiesAccess pa = (PropertiesAccess)amx;
                final Map    props    = getProperties( pa );
                if ( props.keySet().size() != 0 )
                {
                    println( "\nProperties for:
                        " + Util.getObjectName( AMX)pa ) );
                    println( SampleUtil.mapToString(getProperties(pa), "\n") );
                }
            }
        }
    }
    [...]

The `displayAllProperties()` method uses another `Samples` method, `getProperties()`. This method creates an instance of the `com.sun.appserv.management.config.PropertiesAccess` interface, and calls its `getPropertyNames()` method to obtain the names of all the properties for a given AMX MBean. For each property name obtained, its corresponding value is obtained by calling `PropertiesAccess.getPropertyValue()`.

The `displayAllProperties()` method calls the `com.sun.appserv.management.base.QueryMgr.queryAllSet()` method to obtain a set of all the AMX MBeans present in the domain. All AMX MBeans that have properties obligatorily extend the `PropertiesAccess` interface. Any MBean found to extend `PropertiesAccess` is passed to the `getProperties()` method, and the list of property values returned is printed onscreen.

## Querying

The ```demoQuery()` method demonstrates how to issue queries.

The `demoQuery()` method uses other methods that are defined by `Samples`, namely `displayWild()`, and `displayJ2EEType()`. The `displayWild()` method is shown in the following code.

##### Example 16–11 Querying and displaying wild cards

    [...]
    queryWild(
        final String propertyName,
        final String propertyValue)
    {
        final String[] propNames = new String[] { propertyName };
        final String[] propValues = new String[]{ propertyValue };
        final Set amxs = getQueryMgr().queryWildSet( propNames, propValues );
        return( amxs );
    }
    public Set
    displayWild(
        final String propertyName,
        final String propertyValue)
    {
        final Set items = queryWild( propertyName, propertyValue );
        println( "\n--- Queried for " + propertyName + "="
            + propertyValue + " ---" );
        final Iterator    iter    = items.iterator();
        while ( iter.hasNext() )
        {
            final AMX    item    = (AMX)iter.next();
            println( "j2eeType=" + item.getJ2EEType() + ",
                " + "name=" + item.getName() );
        }
    }
    [...]

The `displayWild()` method calls `queryWild()`, to obtain all the AMX MBeans that have object names matching `propertyName` and `propertyValue`. To do so, `queryWild()` calls the `com.sun.appserv.management.base.QueryMgr.queryWildSet()` method. The `queryWildSet()` method returns the list of AMX MBeans with object names matching the wild card strings.

For each MBean returned, the `displayWild()` calls `AMX.getJ2EEType()` to identify its J2EE type, and prints the result onscreen.

In code that is not shown here, the `displayJ2EEType()` method calls the `queryForJ2EEType()` method, which was seen in Accessing and Displaying the Attributes of an AMX MBean, to identify MBeans of a certain J2EE type and print their object names onscreen.

##### Example 16–12 Querying

    [...]
    demoQuery()
    {
        displayWild( AMX.J2EE_TYPE_KEY, "X-*ResourceConfig" );
        displayWild( AMX.J2EE_TYPE_KEY, "X-*ServerConfig" );
        displayJ2EEType( XTypes.SSL_CONFIG );
        displayJ2EEType( XTypes.CLUSTER_CONFIG );
    }
    [...]

In the `demoQuery()` method, the `displayWild()` and `displayJ2EEType()` methods are called to find the following MBeans:

- `J2EE_TYPE_KEY` MBeans called `ResourceConfig`

- `J2EE_TYPE_KEY` MBeans called `ServerConfig`

- All `SSL_CONFIG` MBeans

- All `CLUSTER_CONFIG` MBeans

## Monitoring Attribute Changes

The `demoJMXMonitor()` demonstrates how to monitor attribute changes.

##### Example 16–13 Monitoring Attribute Changes

    [...]
    demoJMXMonitor() throws InstanceNotFoundException, IOException
    {
        final JMXMonitorMgr mgr = getDomainRoot().getJMXMonitorMgr();
        final String attrName = "SampleString";
        final String attrValue = "hello";
        final SampleListener sampleListener = new SampleListener();
        final MBeanServerConnection conn =
            Util.getExtra( mgr ).getConnectionSource()
            .getExistingMBeanServerConnection();
        conn.addNotificationListener(
            getMBeanServerDelegateObjectName(),
            sampleListener, null, null );
        final Sample sample = (Sample)getDomainRoot()
            .getContainee( XTypes.SAMPLE );
        final String monitorName = "SampleStringMonitor";
        AMXStringMonitor mon = null;
        try
        {
            try { mgr.remove( monitorName ); }
            catch( Exception e ) {}
            mon = mgr.createStringMonitor( monitorName );
            waitMBeanServerNotification( sampleListener,
                MBeanServerNotification.REGISTRATION_NOTIFICATION,
                Util.getObjectName( mon ) );
            sample.addAttribute( attrName, attrValue );
            mon.addNotificationListener( sampleListener, null, null);
            mon.setObservedAttribute( attrName );
            mon.setStringToCompare( attrValue );
            mon.setNotifyDiffer( true );
            mon.setNotifyMatch( true );
            mon.addObservedObject( Util.getObjectName( sample ) );
            final StdAttributesAccess attrs = Util.getExtra( sample);
            attrs.setAttribute( new Attribute(attrName, "goodbye") );
            attrs.setAttribute( new Attribute(attrName, attrValue) );
            sample.removeAttribute( attrName );
            final Map notifs = sampleListener.getNotifsReceived();
            waitNumNotifs( notifs,
                AttributeChangeNotification.ATTRIBUTE_CHANGE, 4 );
        }
        catch( Throwable t )
        {
            t.printStackTrace();
        }
        finally
        {
            try
            {
                mon.removeNotificationListener( sampleListener );
                if ( mon != null )
                {
                    mgr.remove( mon.getName() );
                    waitMBeanServerNotification( sampleListener,
                        MBeanServerNotification
                        .UNREGISTRATION_NOTIFICATION,
                        Util.getObjectName( mon ) );
                }
                conn.removeNotificationListener(
                getMBeanServerDelegateObjectName(),
                sampleListener );
            }
            catch( ListenerNotFoundException e )
            {
            }
        }
    }
    [...]

The `demoJmx()` method demonstrates the implementation of a JMX monitor MBean, that listens for changes in a certain attribute. This is achieved in the following stages:

1. A `com.sun.appserv.management.monitor.JMXMonitorMgr` instance is obtained using the `DomainRoot.getJMXMonitorMgr()` method.

2. A `SampleListener` JMX notification listener that is provided in the sample package is instantiated.

3. A connection to the domain’s MBean server is obtained by calling `com.sun.appserv.management.client.ConnectionSource`. `getExistingMBeanServerConnection()` on the `JMXMonitorMgr` instance’s `Extra` information.

4. The `SampleListener` notification listener is added to the MBean server connection, with an MBean server delegate obtained from `getMBeanServerDelegateObject()`. The notification listener is now in place on the MBean server connection.

5. An AMX MBean, `sample`, of the type `SAMPLE` is obtained by calling the `com.sun.appserv.management.base.Container.getContainee()` method on an instance of the `Sample` interface. The `Sample` interface defines a basic AMX MBean.

6. An `AMXStringMonitor`, an AMX-compatible JMX `StringMonitorMBean`, is instantiated by calling `createStringMonitor` on the `JMXMonitorMgr` instance created above. The `AMXStringMonitor` instance then calls `waitMBeanServerNotification()`. The `waitMBeanServerNotification()` method waits for MBean server notifications of the type `REGISTRATION_NOTIFICATION` from the `SampleListener` instance that is listening on the MBean server connection.

7. An attribute of name `attrName` and value `attrValue` is added to the AMX MBean `sample`.

8. Various methods of the `AMXStringMonitor` instance are called, to add a listener, and to set the value to be observed, the object to be observed, and so on.

9. Access to the `sample` MBean’s attributes is obtained by passing the `sample` MBean’s `Extra` information to an instance of `com.sun.appserv.management.base.StdAttributesAccess`. The `StdAttributesAccess.setAttribute()` method is then called to change the values of these attributes.

10. The `AMXStringMonitor` then calls the sample notification listener’s `getNotifsReceived()` method to retrieve the notifications that resulted from the calls to `setAttribute()` above. The `waitNumNotifs()` method waits until four `ATTRIBUTE_CHANGE` notifications have been received before exiting.

11. The notification listener is then removed and the monitor is closed down.

## Undeploying Modules

The `undeploy()` method demonstrates how to undeploy a module.

##### Example 16–14 Undeploying Modules

    [...]
    undeploy ( final String moduleName ) throws IOException
    {
        final DeploymentMgr mgr = getDomainRoot().getDeploymentMgr();

        final Map statusData = mgr.undeploy( moduleName, null );
        final DeploymentStatus status =
            DeploymentSupport.mapToDeploymentStatus( statusData );
        println( "Undeployment result: "
            + getStageStatusString(status.getStageStatus()));
        if ( status.getStageThrowable() != null )
        {
            status.getStageThrowable().printStackTrace();
        }
    }
    [...]

The `undeploy()` method obtains the `DeploymentMgr` instance for the domain in the same way that `deploy()` does so. It then calls the `DeploymentMgr.undeploy()` method for a named module.

## Stopping an Application Server

The `stopServer()` method demonstrates how to stop an application server. The `stopServer()` method simply calls the `getJ2EEServer()` method on a given server instance, and then calls `J2EEServer.stop()`.

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