CounterMonitor

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javax.management.monitor
Class CounterMonitor

java.lang.Object
  |
  +--javax.management.NotificationBroadcasterSupport
        |
        +--javax.management.monitor.Monitor
              |
              +--javax.management.monitor.CounterMonitor

All Implemented Interfaces:: CounterMonitorMBean, MBeanRegistration, MonitorMBean, NotificationBroadcaster, NotificationEmitter

public class CounterMonitor
extends Monitor
implements CounterMonitorMBean

Defines a monitor MBean designed to observe the values of a counter attribute.

A counter monitor sends a threshold notification when the value of the counter reaches or exceeds a threshold known as the comparison level. The notify flag must be set to true.
In addition, an offset mechanism enables particular counting intervals to be detected.

If the offset value is not zero, whenever the threshold is triggered by the counter value reaching a comparison level, that comparison level is incremented by the offset value. This is regarded as taking place instantaneously, that is before the count is incremented. Thus, for each level, the threshold triggers an event notification every time the count increases by an interval equal to the offset value.

If the counter can wrap around its maximum value, the modulus needs to be specified. The modulus is the value at which the counter is reset to zero.

If the counter difference mode is used, the value of the derived gauge is calculated as the difference between the observed counter values for two successive observations. If this difference is negative, the value of the derived gauge is incremented by the value of the modulus.
The derived gauge value (V[t]) is calculated using the following method:

if (counter[t] - counter[t-GP]) is positive then V[t] = counter[t] - counter[t-GP]
if (counter[t] - counter[t-GP]) is negative then V[t] = counter[t] - counter[t-GP] + MODULUS

This implementation of the counter monitor requires the observed attribute to be of the type integer (Byte, Integer, Short, Long).

Author:: Young Yang

Field Summary

Fields inherited from class javax.management.monitor.Monitor

observedObjects

Constructor Summary

CounterMonitor()


Method Summary

void addObservedObject(ObjectName objectName)
          Adds the specified object in the set of observed MBeans.

protected void doMonitor(ObjectName observedObject, java.lang.Object value)


java.lang.Number getDerivedGauge(ObjectName observedObjectName)
          Gets the derived gauge for the specified MBean.

long getDerivedGaugeTimeStamp(ObjectName observedObjectName)
          Gets the derived gauge timestamp for the specified MBean.

boolean getDifferenceMode()
          Gets the difference mode flag value.

java.lang.Number getInitThreshold()
          Gets the initial threshold value common to all observed objects.

java.lang.Number getModulus()
          Gets the modulus value.

MBeanNotificationInfo[] getNotificationInfo()
          Returns a NotificationInfo object contaning the name of the Java class of the notification and the notification types sent.

boolean getNotify()
          Gets the notification's on/off switch value.

java.lang.Number getOffset()
          Gets the offset value.

java.lang.Number getThreshold(ObjectName observedObjectName)
          Gets the threshold value for the specified MBean.

void setDifferenceMode(boolean value)
          Sets the difference mode flag value.

void setInitThreshold(java.lang.Number value)
          Sets the initial threshold value common to all observed MBeans.

void setModulus(java.lang.Number value)
          Sets the modulus value.

void setNotify(boolean value)
          Sets the notification's on/off switch value.

void setOffset(java.lang.Number value)
          Sets the offset value.

void start()


void stop()


Methods inherited from class javax.management.monitor.Monitor

_start, _stop, containsObservedObject, getGranularityPeriod, getMonitorData, getObservedAttribute, getObservedObjects, isActive, postDeregister, postRegister, preDeregister, preRegister, removeObservedObject, sendNotification, setGranularityPeriod, setObservedAttribute

Methods inherited from class javax.management.NotificationBroadcasterSupport

addNotificationListener, handleNotification, removeNotificationListener, removeNotificationListener, sendNotification

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface javax.management.monitor.MonitorMBean

containsObservedObject, getGranularityPeriod, getObservedAttribute, getObservedObjects, isActive, removeObservedObject, setGranularityPeriod, setObservedAttribute

Constructor Detail

CounterMonitor

public CounterMonitor()

Method Detail

start

public void start()

Specified by:: start in class Monitor

stop

public void stop()

Specified by:: stop in class Monitor