FileDocCategorySizeDatePackage
Controller.javaAPI DocExample19356Thu May 23 09:32:50 BST 2002 sample.dynamic

Controller

public class Controller extends Basic implements DynamicMBean
Controls and coordinates all activities in the sample application. Implemented as a dynamic MBean.

Fields Summary
public static final String
CONTROLLER_OBJECT_NAME
private MBeanServer
_server
private Queue
_queue
private int
_numberOfSuppliers
private int
_numberOfConsumers
private MBeanInfo
_MBeanInfo
MessageLog
_logger
Constructors Summary
public Controller()
Constructor. Creates and registers the Queues and performs initialization to get the controller up and running.

        super();
        //
        // Get the metadata from the parent class. We will then make
        /// copies of the metadata from the parent in order to implement 
        /// inheritance for this dynamic MBean. In our implementation of
        /// the DynamicMBean interface, we will delegate attributes and
        /// operations asked for but not located on this class to the
        /// parent class (parent class delegation).
        //
        MBeanInfo parentInfo = super.getMBeanInfo();
        //
        // Create attribute metadata:
        // - ConsumerQueue
        // - SupplierQueue
        //
        MBeanAttributeInfo[] parentAttributes = parentInfo.getAttributes();
        int numParentAtts = parentAttributes.length;
        MBeanAttributeInfo[] attributeInfo = new MBeanAttributeInfo[numParentAtts + 1];
        System.arraycopy(parentAttributes, 0, attributeInfo, 0, numParentAtts);
        //
        // Add one attribute: the Queue that holds the WorkUnit objects
        /// that are exchanged between consumer and supplier. The Queue
        /// object type is not supported by the HtmlAdaptorServer.
        //
        attributeInfo[numParentAtts + 0] = new MBeanAttributeInfo(
            "ConsumerSupplierQueue",// name
            "sample.dynamic.Queue", // type
            "The Queue.",           // description
            true,                   // isReadable?
            false,                  // isWritable?
            false                   // isIs?
        );
        //
        // Create constructor metadata
        //
        Constructor[] constructors = this.getClass().getConstructors();
        MBeanConstructorInfo[] constructorInfo = new MBeanConstructorInfo[constructors.length];
        for (int aa = 0; aa < constructors.length; aa++) {
            constructorInfo[aa] = new MBeanConstructorInfo(
                "Constructs a Controller MBean.",   // description
                constructors[aa]                    // java.lang.reflect.Constructor
            );
        }
        MBeanOperationInfo[] parentOperations = parentInfo.getOperations();
        int numParentOps = parentOperations.length;
        MBeanOperationInfo[] operationInfo = new MBeanOperationInfo[numParentOps + 1];
        System.arraycopy(parentOperations, 0, operationInfo, 0, numParentOps);
        //
        // Create operation info:
        // - createWorker
        //
        MBeanParameterInfo[] signature = new MBeanParameterInfo[2];
        signature[0] = new MBeanParameterInfo(
            "role",             // name
            "java.lang.String", // type
            "The role this new worker thread will take on."         // description
        );
        signature[1] = new MBeanParameterInfo(
            "workFactor", Integer.TYPE.getName(), 
            "The weighted work factor for this new worker thread."
        );
        operationInfo[numParentOps + 0] = new MBeanOperationInfo(
            "createWorker",             // name
            "Creates a new Worker thread.",         // description
            signature,                  // MBeanParameterInfo[]
            Void.TYPE.getName(),        // return type
            MBeanOperationInfo.ACTION   // impact
        );
        //
        // Create Notification metadata:
        // - none
        //
        MBeanNotificationInfo[] parentNotifications = parentInfo.getNotifications();
        int numParentNots = parentNotifications.length;
        MBeanNotificationInfo[] notificationInfo = new MBeanNotificationInfo[
                numParentNots + 0];
        System.arraycopy(parentNotifications, 0, notificationInfo, 0, numParentNots);
        //
        // Now (finally!) create the MBean info metadata object
        //
        _MBeanInfo = new MBeanInfo(
            this.getClass().getName(),  // DynamicMBean implementing class name
            "Controller Dynamic MBean.",// description
            attributeInfo,              // MBeanAttributeInfo[]
            constructorInfo,            // MBeanConstructorInfo[]
            operationInfo,              // MBeanOperationInfo[]
            notificationInfo            // MBeanNotificationInfo[]
        );
        // find reference to (or create) MBean server
        this.getMBeanServer();
        // Create the queues
        _queue = new Queue();
        // Register the queue as an MBean
        ObjectName objName = null;
        try {
            objName = new ObjectName(_server.getDefaultDomain() + ":name=Queue");
            trace("\tOBJECT NAME = " + objName);
            _server.registerMBean(_queue, objName);
        } catch (Exception e) {
            e.printStackTrace();
            trace(e);
            return;
        }
        // Create the HTML adapter
        this.createHTMLAdapter();
Methods Summary
protected java.lang.StringbuildWorkerKey(java.lang.String role)
Builds the worker key from the role name

        StringBuffer buf = new StringBuffer();
        buf.append(Worker.OBJECT_NAME);
        buf.append(",role=");
        buf.append(role);
        return  buf.toString();
private voidcreateHTMLAdapter()
Creates the HTML adapter server and starts it running on its own thread of execution.

        int portNumber = 8090;
        HtmlAdaptorServer html = new HtmlAdaptorServer(portNumber);
        ObjectName html_name = null;
        try {
            html_name = new ObjectName("Adaptor:name=html,port=" + portNumber);
            trace("\tOBJECT NAME = " + html_name);
            _server.registerMBean(html, html_name);
        } catch (Exception e) {
            trace("\t!!! Could not create the HTML adaptor !!!");
            e.printStackTrace();
            trace(e);
            return;
        }
        html.start();
protected voidcreateNewWorker(java.lang.String role, int workFactor, int instanceId)
Creates and registers a worker MBean of the specified type.

        // Create the Worker and register it with the MBean server.
        Worker worker = null;
        ObjectName objName = null;
        StringBuffer buf = new StringBuffer();
        try {
            buf.append(buildWorkerKey(role));
            buf.append(",instanceId=");
            buf.append(instanceId);
            if (role.equalsIgnoreCase(Supplier.ROLE)) {
                worker = new Supplier(_queue, workFactor);
            } 
            else if (role.equalsIgnoreCase(Consumer.ROLE)) {
                worker = new Consumer(_queue, workFactor);
            }
            objName = new ObjectName(buf.toString());
            trace("\tOBJECT NAME = " + objName);
            _server.registerMBean(worker, objName);
            Thread t = new Thread(worker);
            t.start();
            if (role.equalsIgnoreCase(Supplier.ROLE)) {
                _numberOfSuppliers++;
            } 
            else if (role.equalsIgnoreCase(Consumer.ROLE)) {
                _numberOfConsumers++;
            }
        } catch (Exception e) {
            trace("Controller.main(): ERROR: " + "Could not register the Supplier MBean! Stack trace follows...");
            e.printStackTrace();
            trace(e);
            return;
        }
public voidcreateWorker(java.lang.String role, int workFactor)
Creates and starts a worker thread

        int index = getNumberOfWorkers(role);
        createNewWorker(role, workFactor, index + 1);
public java.lang.ObjectgetAttribute(java.lang.String attributeName)
Obtains the value of a specific attribute of the Dynamic MBean.

param
attribute The name of the attribute to be retrieved
return
The value of the attribute retrieved.
exception
AttributeNotFoundException
exception
MBeanException Wraps a java.lang.Exception thrown by the MBean's getter.
exception
ReflectionException Wraps a java.lang.Exception thrown while trying to invoke the getter.

        Object ret = null;
        if (attributeName.equals("ConsumerSupplierQueue")) {
            ret = this.getConsumerSupplierQueue();
        } 
        else 
            ret = super.getAttribute(attributeName);
        return  ret;
public javax.management.AttributeListgetAttributes(java.lang.String[] attributeNames)
Enables the values of several attributes of the Dynamic MBean.

param
attributes A list of the attributes to be retrieved.
return
The list of attributes retrieved.

        // no attributes...delegate to parent class
        return  super.getAttributes(attributeNames);
public java.util.QueuegetConsumerSupplierQueue()
Retrieves a reference to the Queue.

        return  _queue;
public javax.management.MBeanInfogetMBeanInfo()
Provides the exposed attributes and actions of the Dynamic MBean using an MBeanInfo object.

return
An instance of MBeanInfo allowing all attributes and actions exposed by this Dynamic MBean to be retrieved.

        return  (_MBeanInfo);
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;
protected intgetNumberOfWorkers(java.lang.String role)
Returns the number of workers of each type

        int ret = 0;
        if (role.equalsIgnoreCase(Supplier.ROLE)) {
            ret = _numberOfSuppliers;
        } 
        else if (role.equalsIgnoreCase(Consumer.ROLE)) {
            ret = _numberOfConsumers;
        } 
        else {
            throw  new RuntimeMBeanException(new IllegalArgumentException("Controller.getNumberOfWorkers(): ERROR: "
                    + "Unknown role name \'" + role + "\'."));
        }
        return  ret;
public java.lang.Objectinvoke(java.lang.String operationName, java.lang.Object[] params, java.lang.String[] signature)
Allows an action to be invoked on the Dynamic MBean.

param
actionName The name of the action to be invoked.
param
params An array containing the parameters to be set when the action is invoked.
param
signature An array containing the signature of the action. The class objects will be loaded through the same class loader as the one used for loading the MBean on which the action is invoked.
return
The object returned by the action, which represents the result of invoking the action on the MBean specified.
exception
MBeanException Wraps a java.lang.Exception thrown by the MBean's invoked method.
exception
ReflectionException Wraps a 

        Object ret = Void.TYPE;
        //
        // Turn the signature into a Class array so we can get the Method
        /// object and invoke the method, passing params
        //
        try {
            Class[] sign = new Class[signature.length];
            for (int aa = 0; aa < signature.length; aa++) {
                try {
                    sign[aa] = this.getClassFromString(signature[aa]);
                } catch (ClassNotFoundException e) {
                    throw  new RuntimeOperationsException(new IllegalArgumentException(
                            "Controller.invoke(): ERROR: " + "Bad argument \'"
                            + sign[aa] + " found when attempting to invoke operation \'"
                            + operationName + "\'!"));
                }
            }
            Method theMethod = this.getClass().getMethod(operationName, sign);
            //
            // If we got this far, then the requested method is on the
            /// Class, but is it on the management interface?
            //
            if (operationName.equals("createWorker")) {
                theMethod.invoke(this, params);
            } 
            else {
                // delegate to parent class
                ret = super.invoke(operationName, params, signature);
            }
        } catch (NoSuchMethodException e) {
            throw  new ReflectionException(e, e.getClass().getName());
        } catch (IllegalAccessException e) {
            throw  new ReflectionException(e, e.getClass().getName());
        } catch (InvocationTargetException e) {
            throw  new ReflectionException(e, e.getClass().getName());
        }
        return  ret;
public static voidmain(java.lang.String[] args)
This block of code acts as the JMX agent for the sample application.


                      
          
        MessageLog log = new MessageLog();
        if (args.length == 2) {
            int supplierWorkFactor = Integer.parseInt(args[0]);
            int consumerWorkFactor = Integer.parseInt(args[1]);
            System.out.println("Controller.main(): INFO: " + "supplierWorkFactor="
                    + supplierWorkFactor + ", consumerWorkFactor=" + consumerWorkFactor);
            log.write("Controller.main(): INFO: " + "supplierWorkFactor=" + 
                    supplierWorkFactor + ", consumerWorkFactor=" + consumerWorkFactor);
            Controller controller = new Controller();
            controller.enableTracing();
            MBeanServer server = controller.getMBeanServer();
            // Register the controller as an MBean
            ObjectName objName = null;
            try {
                objName = new ObjectName(Controller.CONTROLLER_OBJECT_NAME);
                System.out.println("\tOBJECT NAME = " + objName);
                log.write("\tOBJECT NAME = " + objName);
                server.registerMBean(controller, objName);
            } catch (Exception e) {
                System.out.println("Controller.main(): ERROR: " + "Could not register the Controller MBean! Stack trace follows...");
                log.write("Controller.main(): ERROR: " + "Could not register the Controller MBean! Stack trace follows...");
                e.printStackTrace();
                log.write(e);
                return;
            }
            controller.createWorker(Supplier.ROLE, supplierWorkFactor);
            controller.createWorker(Consumer.ROLE, consumerWorkFactor);
        } 
        else {
            System.out.println("Controller.main(): ERROR: Usage: " + "Controller supplier-weight consumer-weight");
            log.write("Controller.main(): ERROR: Usage: " + "Controller supplier-weight consumer-weight");
        }
public voidreset()

    // nothing to do, have to implement, though...
public voidsetAttribute(javax.management.Attribute attribute)
Sets the value of a specific attribute of the Dynamic MBean

param
attribute The identification of the attribute to be set and the value it is to be set to.
exception
AttributeNotFoundException
exception
InvalidAttributeValueException
exception
MBeanException Wraps a java.lang.Exception thrown by the MBean's setter.
exception
ReflectionException Wraps a java.lang.Exception thrown while trying to invoke the MBean's setter.

        //
        // No writeable attributes on the management interface.
        // Delegate to parent class to implement management interface
        /// inheritance.
        //
        super.setAttribute(attribute);
public javax.management.AttributeListsetAttributes(javax.management.AttributeList attributes)
Sets the values of several attributes of the Dynamic MBean

param
name The object name of the MBean within which the attributes are to be set.
param
attributes A list of attributes: The identification of the attributes to be set and the values they are to be set to.
return
The list of attributes that were set, with their new values.

        //
        // No writeable attributes on the management interface...
        // Delegate to parent class.
        //
        return  super.setAttributes(attributes);
private voidtrace(java.lang.String message)

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

        traceLog(t);
private voidtraceLog(java.lang.Throwable t)

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


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