javax.management.monitor
Class GaugeMonitor

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

public class GaugeMonitor

extends Monitor

implements GaugeMonitorMBean

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

A gauge monitor observes an attribute that is continuously variable with time. A gauge monitor sends notifications as follows:

  • if the attribute value is increasing and becomes equal to or greater than the high threshold value, a threshold high notification is sent. The notify high flag must be set to true Subsequent crossings of the high threshold value do not cause further notifications unless the attribute value becomes equal to or less than the low threshold value.
  • if the attribute value is decreasing and becomes equal to or less than the low threshold value, a threshold low notification is sent. The notify low flag must be set to true. Subsequent crossings of the low threshold value do not cause further notifications unless the attribute value becomes equal to or greater than the high threshold value.

This provides a hysteresis mechanism to avoid repeated triggering of notifications when the attribute value makes small oscillations around the high or low threshold value.

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

  • V[t] = gauge[t] - gauge[t-GP]

This implementation of the gauge monitor requires the observed attribute to be of the type integer or floating-point (Byte,Integer,Short,Long,Float,Double).

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
GaugeMonitor()
    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 getHighThreshold()
    Gets the high threshold value.
 java.lang.Number getLowThreshold()
    Gets the low threshold 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 getNotifyHigh()
    Gets the high notification's on/off switch value.
 boolean getNotifyLow()
    Gets the low notification's on/off switch value.
 void setDifferenceMode(boolean value)
    Sets the difference mode flag value.
 void setNotifyHigh(boolean value)
    Sets the high notification's on/off switch value.
 void setNotifyLow(boolean value)
    Sets the low notification's on/off switch value.
 void setThresholds(java.lang.Number highValue, java.lang.Number lowValue)
    Sets the high and the low threshold values.
 void start()
    Starts the gauge monitor.
 void stop()
    Stops the gauge monitor.
 
Methods inherited from class javax.management.monitor.Monitor
getGranularityPeriod, getObservedAttribute, getObservedObject, isActive, postDeregister, postRegister, preDeregister, 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

GaugeMonitor

public GaugeMonitor()

Default constructor.

 

Method Detail

getDerivedGauge

public java.lang.Number getDerivedGauge()

Gets the derived gauge.

Specified by:

getDerivedGauge in interface GaugeMonitorMBean

 

Returns:

The derived gauge.

getDerivedGaugeTimeStamp

public long getDerivedGaugeTimeStamp()

Gets the derived gauge timestamp.

Specified by:

getDerivedGaugeTimeStamp in interface GaugeMonitorMBean

 

Returns:

The derived gauge timestamp.

getDifferenceMode

public boolean getDifferenceMode()

Gets the difference mode flag value.

Specified by:

getDifferenceMode in interface GaugeMonitorMBean

 

Returns:

true if the difference mode is used, false otherwise.

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

getNotifyHigh

public boolean getNotifyHigh()

Gets the high notification's on/off switch value.

Specified by:

getNotifyHigh in interface GaugeMonitorMBean

 

Returns:

true if the gauge monitor notifies when exceeding the high threshold, false otherwise.

getNotifyLow

public boolean getNotifyLow()

Gets the low notification's on/off switch value.

Specified by:

getNotifyLow in interface GaugeMonitorMBean

 

Returns:

true if the gauge monitor notifies when exceeding the low threshold, false otherwise.

getHighThreshold

public java.lang.Number getHighThreshold()

Gets the high threshold value.

Specified by:

getHighThreshold in interface GaugeMonitorMBean

 

Returns:

The high threshold value

getLowThreshold

public java.lang.Number getLowThreshold()

Gets the low threshold value.

Specified by:

getLowThreshold in interface GaugeMonitorMBean

 

Returns:

The low threshold value.

setDifferenceMode

public void setDifferenceMode(boolean value)

Sets the difference mode flag value.

Specified by:

setDifferenceMode in interface GaugeMonitorMBean

 

Parameters:

value - The difference mode flag value.

setNotifyHigh

public void setNotifyHigh(boolean value)

Sets the high notification's on/off switch value.

Specified by:

setNotifyHigh in interface GaugeMonitorMBean

 

Parameters:

value - The high notification's on/off switch value.

setNotifyLow

public void setNotifyLow(boolean value)

Sets the low notification's on/off switch value.

Specified by:

setNotifyLow in interface GaugeMonitorMBean

 

Parameters:

value - The low notification's on/off switch value.

setThresholds

public void setThresholds(java.lang.Number highValue,
                          java.lang.Number lowValue)
                   throws java.lang.IllegalArgumentException

Sets the high and the low threshold values.

Specified by:

setThresholds in interface GaugeMonitorMBean

 

Parameters:

highValue - The high threshold value.

lowValue - The low threshold value.

 

Throws:

java.lang.IllegalArgumentException - The specified high/low threshold is null or the low threshold is greater than the high threshold or the high threshold and the low threshold are not of the same type.

start

public void start()

Starts the gauge monitor.

Overrides:

start in class Monitor

stop

public void stop()

Stops the gauge monitor.

Overrides:

stop in class Monitor