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Controller.javaAPI DocExample15430Thu May 23 09:32:50 BST 2002 sample.loading

Controller

public class Controller extends sample.standard.Basic implements ControllerMBean, NotificationListener
Controls and coordinates all activities in the sample application. Implemented as a standard MBean. This class is also a notification listener (i.e., it implements the NotificationListener interface).
author
Steve Perry

Fields Summary
public static final String
CONTROLLER_OBJECT_NAME
public static final String
BASE_URL
private MBeanServer
_server
private ObjectName
_queue
private sample.standard.Queue
_theQueue
private HtmlAdaptorServer
_html
private MLet
_mlet
private ArrayList
_mbeans
List of the registered MBeans. Used so that all MBeans can be deregistered when the application terminates.
sample.utility.MessageLog
_logger
Constructors Summary
Methods Summary
private voidcreateHTMLAdapter()
Creates the HTML adapter server and starts it running on its own thread of execution.

        int portNumber = 8090;
        _html = new HtmlAdaptorServer(portNumber);
        ObjectName html_name = null;
        try {
            html_name = new ObjectName("Adaptor:name=html,port=" + portNumber);
            _server.registerMBean(_html, html_name);
        } catch (Exception e) {
            trace("\t!!! Could not create the HTML adaptor !!!");
            e.printStackTrace();
            return;
        }
        _html.start();
public voidcreateWorker(java.lang.String role, int workFactor)

        // Create the Worker and register it with the MBean server.
        ObjectName objName = null;
        try {
            // use the role name to build out the mlet file name
            /// located at the baseUrl...
            Set loadedBeans = loadMBeans(BASE_URL + role + ".txt");
            if (loadedBeans.size() > 1)
                trace("Controller.init(): ERROR: " + "Too many items (" + loadedBeans.size()
                        + ") in the returned set from loadMBeans()!");
            // Grab the ObjectName from the returned set of ObjectInstances
            Iterator iter = loadedBeans.iterator();
            while (iter.hasNext()) {
                Object obj = iter.next();
                if (obj instanceof Throwable) {
                    Throwable e = (Throwable)obj;
                    trace("Controller.createWorker(): ERROR: " + "Error occurred attempting to load the Worker MBeans.");
                    trace("Controller.createWorker(): EXCEPTION INFORMATION: " + e.toString());
                    trace(e);
                    e.printStackTrace();
                } 
                else {
                    objName = ((ObjectInstance)obj).getObjectName();
                    trace("Controller.createWorker(): INFO: Loaded MBean \'" + objName
                            + "\'");
                    //
                    // Set the queue and work factor
                    //
                    try {
                        Attribute attribute = new Attribute("Queue", _theQueue);
                        _server.setAttribute(objName, attribute);
                        attribute = new Attribute("WorkFactor", new Integer(workFactor));
                        _server.setAttribute(objName, attribute);
                    } catch (Exception e) {
                        trace(e);
                        e.printStackTrace();
                    }
                    // Get a reference to the MBean, cast it to a Runnable and
                    /// create a new Thread object. This will start the worker
                    /// thread...
                    Object worker = _server.getAttribute(objName, "Me");
                    Thread t = new Thread((Runnable)worker);
                    t.start();
                }
            }
        } catch (Exception e) {
            trace("Controller.createWorker(): ERROR: " + "Could not register the MBean! Stack trace follows...");
            trace(e);
            return;
        }
javax.management.MBeanServergetMBeanServer()
Obtains a reference to the MBean server. If at least one MBean server already exists, then a reference to that MBean server is returned. Otherwise a new instance is created.

        if (_server == null) {
            ArrayList mbeanServers = MBeanServerFactory.findMBeanServer(null);
            Iterator iter = mbeanServers.iterator();
            int aa = 1;
            while (iter.hasNext()) {
                MBeanServer mbs = (MBeanServer)iter.next();
                trace("QueueAgent.main(): INFO: " + "MBean server no. " + aa
                        + ":");
                Set set = mbs.queryMBeans(null, null);
                Iterator iter2 = set.iterator();
                while (iter2.hasNext()) {
                    ObjectInstance obji = (ObjectInstance)iter2.next();
                    trace("\tCLASSNAME={" + obji.getClassName() + "}, OBJECTNAME={"
                            + obji.getObjectName() + "}");
                }
                aa++;
            }
            _server = (mbeanServers.size() > 0) ? (MBeanServer)mbeanServers.get(0) :
                    MBeanServerFactory.createMBeanServer();
        }
        return  _server;
public java.lang.ObjectgetMe()

        return  this;
public voidhandleNotification(javax.management.Notification notification, java.lang.Object handback)
Invoked when a JMX notification occurs. The implementation of this method should return as soon as possible, to avoid blocking its notification broadcaster.

param
notification The notification.
param
handback An opaque object which helps the listener to associate information regarding the MBean emitter. This object is passed to the MBean during the addListener call and resent, without modification, to the listener. The MBean object should not use or modify the object.


                                                                                      
           
        String notificationType = notification.getType();
        Object source = notification.getSource();
        long sequenceNumber = notification.getSequenceNumber();
        Date timeStamp = new Date(notification.getTimeStamp());
        try {
            if (handback instanceof Properties) {
                Properties props = (Properties)handback;
                String response = (String)props.get("response");
                if (response.equals("email")) {
                // send an email, using the properties set in the
                /// handback object. . .
                } 
                else if (response.equals("consoleMessage")) {
                    trace("Controller: NOTIFICATION: response=consoleMessage: "
                            + "Received from: " + source.getClass().getName()
                            + " at " + timeStamp);
                    trace("\tof type \'" + notificationType + "\': " + "sequence no. "
                            + sequenceNumber);
                } 
                else {
                    System.out.println("handleNotification: ERROR: " + "Unexpected response type \'"
                            + response + "\'.");
                }
            } 
            else {
                if (notification instanceof TraceNotification) {
                    TraceNotification notif = (TraceNotification)notification;
                    trace("Controller.handleNotification: TRACE NOTIFICATION: "
                            + "info: " + notif.info + ", class: " + notif.className
                            + ", methodName: " + notif.methodName + ", sequenceNumber: "
                            + notif.sequenceNumber + ", globalSequenceNumber: "
                            + notif.globalSequenceNumber + ", type: " + notif.type
                            + ", level: " + notif.level + ", exception: \'"
                            + notif.exception + "\'.");
                } 
                else if (notificationType.equals(MBeanServerNotification.REGISTRATION_NOTIFICATION)) {
                    ObjectName objName = ((MBeanServerNotification)notification).getMBeanName();
                    trace("Controller.handleNotification: REGISTRATION NOTIFICATION: "
                            + "OBJECT_NAME = " + objName);
                    _mbeans.add(objName);
                } 
                else {
                    trace("Controller: NOTIFICATION: \'" + notification.getMessage()
                            + "', received from: " + source.getClass().getName()
                            + " at " + timeStamp + " of type \'" + notificationType
                            + "\': " + "sequence no. " + sequenceNumber);
                }
            }
        } catch (Exception e) {
        // handle possible exceptions . . .
        }
private voidinit()
Initialization. Creates and registers the Queues and performs initialization to get the controller up and running.

        // find reference to (or create) MBean server
        MBeanServer mbs = this.getMBeanServer();
        try {
            // Create and register the mlet service
            ObjectName mletObjName = new ObjectName("DynamicLoader:type=m-let");
            _mlet = new MLet();
            mbs.registerMBean(_mlet, mletObjName);
            _theQueue = new Queue();
            _queue = new ObjectName(_server.getDefaultDomain() + ":name=Queue");
            mbs.registerMBean(_theQueue, _queue);
        } catch (Exception e) {
            trace(e);
            return;
        }
        // Create the HTML adapter
        this.createHTMLAdapter();
private java.util.SetloadMBeans(java.lang.String url)

        Set ret = null;
        trace("Controller.loadMBeans(): INFO: Loading MBeans from URL \'" + 
                url + "\'.");
        try {
            //        ret = _mlet.getMBeansFromURL(url);
            ret = _mlet.getMBeansFromURL(new java.net.URL(url));
        } catch (Exception e) {
            trace("Controller.loadMBeans(): ERROR: " + "Error getting MBeans from URL \'"
                    + url + "\'.");
            trace(e);
        }
        return  ret;
public static voidmain(java.lang.String[] args)
The main method.

param
args String array containing arguments

        // Must contain supplier work factor, followed by consumer
        /// work factor.
        if (args.length == 2) {
            //
            // This m-let stuff gets tricky. It's nice to see
            /// what's going on under the hood sometimes...
            try {
                Trace.parseTraceProperties();
            } catch (java.io.IOException e) {
                MessageLog log = new MessageLog();
                log.write(e);
            }
            int supplierWorkFactor = Integer.parseInt(args[0]);
            int consumerWorkFactor = Integer.parseInt(args[1]);
            System.out.println("Controller.main(): INFO: " + "supplierWorkFactor="
                    + supplierWorkFactor + ", consumerWorkFactor=" + consumerWorkFactor);
            // Create and initialize the controller
            Controller controller = new Controller();
            controller.enableTracing();
            Trace.addNotificationListener(controller, null, null);
            // Register the controller as an MBean
            ObjectName objName = null;
            // obtain a reference to the MBean server
            MBeanServer server = controller.getMBeanServer();
            try {
                ObjectName delegateObjName = new ObjectName("JMImplementation:type=MBeanServerDelegate");
                server.addNotificationListener(delegateObjName, controller, 
                        null, null);
                controller.init();
                objName = new ObjectName(Controller.CONTROLLER_OBJECT_NAME);
                server.registerMBean(controller, objName);
                // Load the worker MBeans
                controller.createWorker("Supplier", supplierWorkFactor);
                controller.createWorker("Consumer", consumerWorkFactor);
                boolean queueEOF = ((Boolean)server.getAttribute(controller._queue, 
                        "EndOfInput")).booleanValue();
                boolean queueEmpty = ((Boolean)server.getAttribute(controller._queue, 
                        "QueueEmpty")).booleanValue();
                while (!(queueEOF && queueEmpty)) {
                    Thread.sleep(5000);
                    queueEOF = ((Boolean)server.getAttribute(controller._queue, 
                            "EndOfInput")).booleanValue();
                    queueEmpty = ((Boolean)server.getAttribute(controller._queue, 
                            "QueueEmpty")).booleanValue();
                }
            } catch (Exception e) {
                System.out.println("Controller.main(): ERROR: " + "Could not register the Controller MBean! Stack trace follows...");
                MessageLog log = new MessageLog();
                log.write(e);
                return;
            }
            // We're done, unregister all MBeans
            controller._html.stop();
            Iterator iter = controller._mbeans.iterator();
            while (iter.hasNext()) {
                objName = (ObjectName)iter.next();
                String message = "Controller.main(): INFO: " + "Unregistering MBean \'"
                        + objName.toString() + "\'.";
                System.out.println(message);
                MessageLog log = new MessageLog();
                log.write(message);
                try {
                    server.unregisterMBean(objName);
                } catch (Exception e) {
                    System.out.println("Controller.main(): ERROR: " + "Error unregistering MBean!");
                    log.write(e);
                }
            }
        } 
        else {
            System.out.println("Controller.main(): ERROR: Usage: " + "Controller supplier-weight consumer-weight");
        }
public voidreset()

    // nothing to do
private voidtrace(java.lang.Throwable t)

        traceLog(t);
private voidtrace(java.lang.String message)
Provides an abstraction mechanism for tracing.

param
message String containing the message to be written to the trace facility.

        if (isTraceOn()) {
            System.out.println(message);
        }
        traceLog(message);
private voidtraceLog(java.lang.Throwable t)

        if (isTraceOn()) {
            _logger.write(t);
        }
private voidtraceLog(java.lang.String message)


         
        if (isTraceOn()) {
            _logger.write(message);
        }