javax.management.monitor
Class CounterMonitor

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

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).

Version:

1.15

Author:

Max Parlione, Maurizio Simeoni, Massimo Tarquini

See Also:

Serialized Form

Fields inherited from class javax.management.monitor.Monitor
alreadyNotified, dbgTag, OBSERVED_ATTRIBUTE_ERROR_NOTIFIED, OBSERVED_ATTRIBUTE_TYPE_ERROR_NOTIFIED, OBSERVED_OBJECT_ERROR_NOTIFIED, RESET_FLAGS_ALREADY_NOTIFIED, RUNTIME_ERROR_NOTIFIED, server
 

 

Constructor Summary
CounterMonitor()
    Default constructor.
 

 

Method Summary
 java.lang.Number getDerivedGauge()
    Gets the derived gauge.
 long getDerivedGaugeTimeStamp()
    Gets the derived gauge timestamp.
 boolean getDifferenceMode()
    Gets the difference mode flag value.
 java.lang.Number getModulus()
    Gets the modulus value.
 MBeanNotificationInfo[] getNotificationInfo()
    Returns a NotificationInfo object containing the name of the Java class of the notification and the notification types sent by the counter monitor.
 boolean getNotify()
    Gets the notification's on/off switch value.
 java.lang.Number getOffset()
    Gets the offset value.
 java.lang.Number getThreshold()
    Gets the threshold value.
 void preDeregister()
    Allows the counter monitor MBean to perform any operations it needs before being de-registered by the MBean server.
 void setDifferenceMode(boolean differenceMode)
    Sets the difference mode flag value.
 void setModulus(java.lang.Number modulus)
    Sets the modulus value.
 void setNotify(boolean notify)
    Sets the notification's on/off switch value.
 void setOffset(java.lang.Number offset)
    Sets the offset value.
 void setThreshold(java.lang.Number threshold)
    Sets the threshold value.
 void start()
    Starts the counter monitor.
 void stop()
    Stops the counter monitor.
 
Methods inherited from class javax.management.monitor.Monitor
getGranularityPeriod, getObservedAttribute, getObservedObject, isActive, postDeregister, postRegister, preRegister, setGranularityPeriod, setObservedAttribute, setObservedObject
 
Methods inherited from class javax.management.NotificationBroadcasterSupport
addNotificationListener, removeNotificationListener, sendNotification
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

 

Constructor Detail

CounterMonitor

public CounterMonitor()

Default constructor.

 

Method Detail

preDeregister

public void preDeregister()
                   throws java.lang.Exception

Allows the counter monitor MBean to perform any operations it needs before being de-registered by the MBean server. Resets the threshold values.

Overrides:

preDeregister in class Monitor

 

Throws:

java.lang.Exception -  

getDerivedGauge

public java.lang.Number getDerivedGauge()

Gets the derived gauge.

Specified by:

getDerivedGauge in interface CounterMonitorMBean

 

Returns:

The derived gauge.

getDerivedGaugeTimeStamp

public long getDerivedGaugeTimeStamp()

Gets the derived gauge timestamp.

Specified by:

getDerivedGaugeTimeStamp in interface CounterMonitorMBean

 

Returns:

The derived gauge timestamp.

getDifferenceMode

public boolean getDifferenceMode()

Gets the difference mode flag value.

Specified by:

getDifferenceMode in interface CounterMonitorMBean

 

Returns:

True if the difference mode is used, false otherwise.

getModulus

public java.lang.Number getModulus()

Gets the modulus value.

Specified by:

getModulus in interface CounterMonitorMBean

 

Returns:

The modulus value.

getNotificationInfo

public MBeanNotificationInfo[] getNotificationInfo()

Returns a NotificationInfo object containing the name of the Java class of the notification and the notification types sent by the counter monitor.

Overrides:

getNotificationInfo in class NotificationBroadcasterSupport

getNotify

public boolean getNotify()

Gets the notification's on/off switch value.

Specified by:

getNotify in interface CounterMonitorMBean

 

Returns:

True if the counter monitor notifies when exceeding the threshold, false otherwise.

getOffset

public java.lang.Number getOffset()

Gets the offset value.

Specified by:

getOffset in interface CounterMonitorMBean

 

Returns:

The offset value.

getThreshold

public java.lang.Number getThreshold()

Gets the threshold value.

Specified by:

getThreshold in interface CounterMonitorMBean

 

Returns:

The threshold value.

setDifferenceMode

public void setDifferenceMode(boolean differenceMode)

Sets the difference mode flag value.

Specified by:

setDifferenceMode in interface CounterMonitorMBean

 

Parameters:

differenceMode -  

setModulus

public void setModulus(java.lang.Number modulus)
                throws java.lang.IllegalArgumentException

Sets the modulus value.

Specified by:

setModulus in interface CounterMonitorMBean

 

Parameters:

modulus - the new modulus value

setNotify

public void setNotify(boolean notify)

Sets the notification's on/off switch value.

Specified by:

setNotify in interface CounterMonitorMBean

 

Parameters:

notify - the on/off flag

setOffset

public void setOffset(java.lang.Number offset)
               throws java.lang.IllegalArgumentException

Sets the offset value.

Specified by:

setOffset in interface CounterMonitorMBean

 

Parameters:

offset - the new offset

setThreshold

public void setThreshold(java.lang.Number threshold)
                  throws java.lang.IllegalArgumentException

Sets the threshold value. The internal algorithm is reset if it is active.

Specified by:

setThreshold in interface CounterMonitorMBean

 

Parameters:

threshold - the new threshold

start

public void start()

Starts the counter monitor. The error notification hysteresis mechanism is reset.

Overrides:

start in class Monitor

stop

public void stop()

Stops the counter monitor.

Overrides:

stop in class Monitor