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Worker.javaAPI DocExample15753Thu May 23 09:32:50 BST 2002 sample.dynamic

Worker

public abstract class Worker extends Basic implements DynamicMBean, Runnable
Base class for the workers in the sample application.

Fields Summary
public static final String
OBJECT_NAME
Queue
_queue
int
_workFactor
long
_numberOfUnitsProcessed
long
_totalProcessingTime
boolean
_stopCalled
boolean
_suspended
private MBeanInfo
_MBeanInfo
Constructors Summary
public Worker(Queue queue, int workFactor)


          
        super();
        _queue = queue;
        _workFactor = workFactor;
        MBeanInfo parentInfo = super.getMBeanInfo();
        // Attributes
        MBeanAttributeInfo[] attributeInfo = new MBeanAttributeInfo[7];
        attributeInfo[0] = new MBeanAttributeInfo(
            "WorkFactor",               // name
            Integer.TYPE.getName(),     // type
            "The amount of work to do.",// description
            true,                       // isReadable?
            false,                      // isWritable?
            false                       // isIs?
        );
        attributeInfo[1] = new MBeanAttributeInfo(
            "NumberOfUnitsProcessed",   // name
            Long.TYPE.getName(),        // type
            "The number of units processed.",       // description
            true,                       // isReadable?
            false,                      // isWritable?
            false                       // isIs?
        );
        attributeInfo[2] = new MBeanAttributeInfo(
            "AverageUnitProcessingTime",// name
            Float.TYPE.getName(),       // type
            "Avg. no. milliseconds to process each work unit.",                     // description
            true,                       // isReadable?
            false,                      // isWritable?
            false                       // isIs?
        );
        attributeInfo[3] = new MBeanAttributeInfo(
            "Suspended",            // name
            Boolean.TYPE.getName(), // type
            "Whether or not this thread is suspended.",             // description
            true,                   // isReadable?
            false,                  // isWritable?
            true                    // isIs?
        );
        attributeInfo[4] = new MBeanAttributeInfo(
            "NumberOfResets",       // name
            Integer.TYPE.getName(), // type
            "The number of times this MBean has been reset.",       // description
            true,                   // isReadable?
            false,                  // isWritable?
            false                   // isIs?
        );
        attributeInfo[5] = new MBeanAttributeInfo(
            "TraceOn",              // name
            Boolean.TYPE.getName(), // type
            "Whether or not tracing is on.",        // description
            true,                   // isReadable?
            false,                  // isWritable?
            true                    // isIs?
        );
        attributeInfo[6] = new MBeanAttributeInfo(
            "DebugOn",              // name
            Boolean.TYPE.getName(), // type
            "Whether or not debugging is on.",        // description
            true,                   // isReadable?
            false,                  // isWritable?
            true                    // isIs?
        );
        // Constructors
        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 Worker MBean.",        // description
                constructors[aa]                    // java.lang.reflect.Constructor
            );
        }
        // Operations
        MBeanOperationInfo[] parentOperations = parentInfo.getOperations();
        int numParentOps = parentOperations.length;
        MBeanOperationInfo[] operationInfo = new MBeanOperationInfo[numParentOps + 3];
        System.arraycopy(parentOperations, 0, operationInfo, 0, numParentOps);
        operationInfo[numParentOps + 0] = new MBeanOperationInfo(
            "stop",                     // name
            "Stops this Worker thread.",// description
            null,                       // MBeanParameterInfo[]
            Void.TYPE.getName(),        // return type
            MBeanOperationInfo.ACTION   // impact
        );
        operationInfo[numParentOps + 1] = new MBeanOperationInfo(
            "suspend",                  // name
            "Suspends this Worker thread.",         // description
            null,                       // MBeanParameterInfo[]
            Void.TYPE.getName(),        // return type
            MBeanOperationInfo.ACTION   // impact
        );
        operationInfo[numParentOps + 2] = new MBeanOperationInfo(
            "resume",                   // name
            "Resumes this Worker thread.",          // description
            null,                       // MBeanParameterInfo[]
            Void.TYPE.getName(),        // return type
            MBeanOperationInfo.ACTION   // impact
        );
        // Notifications - NONE
        // MBeanInfo!
        _MBeanInfo = new MBeanInfo(
            this.getClass().getName(),  // DynamicMBean implementing class name
            "Worker Dynamic MBean.",    // description
            attributeInfo,              // MBeanAttributeInfo[]
            constructorInfo,            // MBeanConstructorInfo[]
            operationInfo,              // MBeanOperationInfo[]
            null                        // MBeanNotificationInfo[]
        );
Methods Summary
voidcalculatePrimes(int numberOfPrimesToCalculate)
In this method is where the "work" takes place. We need a way to simulate the application doing something, so we calculate the first workFactor primes, starting with zero. So, the work factor is equal to the number of primes that are calculated.

        // There is probably an easier way to do this,
        /// but it seemed a good way to chew up some CPU
        long startTime = System.currentTimeMillis();
        long number = 1;
        int numberOfPrimesCalculated = 0;
        while (numberOfPrimesCalculated < numberOfPrimesToCalculate) {
            long currentNumber = 1;             // start with 1
            long numberOfFactors = 0;
            while (currentNumber <= number) {
                if ((number%currentNumber) == 0) {
                    // This is *definitely* the long way around, but
                    /// remember, we *want* to eat up lots of CPU...
                    numberOfFactors++;
                }
                currentNumber++;
            }
            // The number is prime if it only has two factors
            /// (i.e., itself and 1)
            if (numberOfFactors == 2) {
                numberOfPrimesCalculated++;
                //                System.out.println("Supplier.calculatePrimes(): INFO: " +
                //                    "Prime number found - " + number);
            }
            number++;
        }
        _totalProcessingTime += (System.currentTimeMillis() - startTime);
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;
        //
        // Using exlicit superclass exposure as the means of
        /// management interface inheritance.
        //
        if (attributeName.equals("WorkFactor")) {
            ret = new Integer(getWorkFactor());
        } 
        else if (attributeName.equals("NumberOfUnitsProcessed")) {
            ret = new Long(getNumberOfUnitsProcessed());
        } 
        else if (attributeName.equals("AverageUnitProcessingTime")) {
            ret = new Float(getAverageUnitProcessingTime());
        } 
        else if (attributeName.equals("Suspended")) {
            ret = new Boolean(isSuspended());
        } 
        else if (attributeName.equals("NumberOfResets")) {
            ret = new Integer(getNumberOfResets());
        } 
        else if (attributeName.equals("TraceOn")) {
            ret = new Boolean(isTraceOn());
        } 
        else if (attributeName.equals("DebugOn")) {
            ret = new Boolean(isDebugOn());
        } 
        else 
            throw  new AttributeNotFoundException("Worker.getAttribute(): ERROR: "
                    + "Attribute \'" + attributeName + "\' not found.");
        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.

        AttributeList ret = new AttributeList();
        for (int aa = 0; aa < attributeNames.length; aa++) {
            try {
                Object value = getAttribute((String)attributeNames[aa]);
                ret.add(new Attribute(attributeNames[aa], value));
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
        return  ret;
public floatgetAverageUnitProcessingTime()

        return  (_numberOfUnitsProcessed > 0) ? (float)_totalProcessingTime/(float)_numberOfUnitsProcessed :
                0.0f;
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);
public longgetNumberOfUnitsProcessed()

        return  _numberOfUnitsProcessed;
public intgetWorkFactor()

        return  _workFactor;
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("stop") || operationName.equals("suspend")
                    || operationName.equals("resume")) {
                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 booleanisSuspended()

        return  _suspended;
public voidreset()

        setNumberOfUnitsProcessed(0);
        setNumberOfResets(getNumberOfResets() + 1);
public synchronized voidresume()

        _suspended = false;
        notifyAll();
public abstract voidrun()

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.
    //
    
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...
        //
        AttributeList ret = new AttributeList();
        return  ret;
    
public voidsetNumberOfUnitsProcessed(long value)
        _numberOfUnitsProcessed = value;
    
public synchronized voidstop()
        _stopCalled = true;
    
public synchronized voidsuspend()
        _suspended = true;