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Class GaugeMonitor

All Implemented Interfaces:
MBeanRegistration, GaugeMonitorMBean, MonitorMBean, NotificationBroadcaster, NotificationEmitter 
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).
Since:
1.5

Fields

Fields inherited from class javax.management.monitor.Monitor

alreadyNotified, alreadyNotifieds, capacityIncrement, dbgTag, elementCount, OBSERVED_ATTRIBUTE_ERROR_NOTIFIED, OBSERVED_ATTRIBUTE_TYPE_ERROR_NOTIFIED, OBSERVED_OBJECT_ERROR_NOTIFIED, RESET_FLAGS_ALREADY_NOTIFIED, RUNTIME_ERROR_NOTIFIED, server

Constructors

GaugeMonitor

public GaugeMonitor()

Default constructor.

Methods

start

public void start()

Starts the gauge monitor.

Specified by:
start in interface MonitorMBean
Specified by:
start in class Monitor

stop

public void stop()

Stops the gauge monitor.

Specified by:
stop in interface MonitorMBean
Specified by:
stop in class Monitor

getDerivedGauge

public Number getDerivedGauge(ObjectName object)

Gets the derived gauge of the specified object, if this object is contained in the set of observed MBeans, or null otherwise.

Specified by:
getDerivedGauge in interface GaugeMonitorMBean
Parameters:
object - the name of the MBean.
Returns:
The derived gauge of the specified object.

getDerivedGaugeTimeStamp

public long getDerivedGaugeTimeStamp(ObjectName object)

Gets the derived gauge timestamp of the specified object, if this object is contained in the set of observed MBeans, or 0 otherwise.

Specified by:
getDerivedGaugeTimeStamp in interface GaugeMonitorMBean
Parameters:
object - the name of the object whose derived gauge timestamp is to be returned.
Returns:
The derived gauge timestamp of the specified object.

getDerivedGauge

@Deprecated
public Number getDerivedGauge()

Deprecated. As of JMX 1.2, replaced by getDerivedGauge(ObjectName)

Returns the derived gauge of the first object in the set of observed MBeans.

Specified by:
getDerivedGauge in interface GaugeMonitorMBean
Returns:
The derived gauge.

getDerivedGaugeTimeStamp

@Deprecated
public long getDerivedGaugeTimeStamp()

Deprecated. As of JMX 1.2, replaced by getDerivedGaugeTimeStamp(ObjectName)

Gets the derived gauge timestamp of the first object in the set of observed MBeans.

Specified by:
getDerivedGaugeTimeStamp in interface GaugeMonitorMBean
Returns:
The derived gauge timestamp.

getHighThreshold

public Number getHighThreshold()

Gets the high threshold value common to all observed MBeans.

Specified by:
getHighThreshold in interface GaugeMonitorMBean
Returns:
The high threshold value.
See Also:
setThresholds(java.lang.Number, java.lang.Number)

getLowThreshold

public Number getLowThreshold()

Gets the low threshold value common to all observed MBeans.

Specified by:
getLowThreshold in interface GaugeMonitorMBean
Returns:
The low threshold value.
See Also:
setThresholds(java.lang.Number, java.lang.Number)

setThresholds

public void setThresholds(Number highValue,
                          Number lowValue)
                   throws IllegalArgumentException

Sets the high and the low threshold values common to all observed MBeans.

Specified by:
setThresholds in interface GaugeMonitorMBean
Parameters:
highValue - The high threshold value.
lowValue - The low threshold value.
Throws:
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.
See Also:
getHighThreshold(), getLowThreshold()

getNotifyHigh

public boolean getNotifyHigh()

Gets the high notification's on/off switch value common to all observed MBeans.

Specified by:
getNotifyHigh in interface GaugeMonitorMBean
Returns:
true if the gauge monitor notifies when exceeding the high threshold, false otherwise.
See Also:
setNotifyHigh(boolean)

setNotifyHigh

public void setNotifyHigh(boolean value)

Sets the high notification's on/off switch value common to all observed MBeans.

Specified by:
setNotifyHigh in interface GaugeMonitorMBean
Parameters:
value - The high notification's on/off switch value.
See Also:
getNotifyHigh()

getNotifyLow

public boolean getNotifyLow()

Gets the low notification's on/off switch value common to all observed MBeans.

Specified by:
getNotifyLow in interface GaugeMonitorMBean
Returns:
true if the gauge monitor notifies when exceeding the low threshold, false otherwise.
See Also:
setNotifyLow(boolean)

setNotifyLow

public void setNotifyLow(boolean value)

Sets the low notification's on/off switch value common to all observed MBeans.

Specified by:
setNotifyLow in interface GaugeMonitorMBean
Parameters:
value - The low notification's on/off switch value.
See Also:
getNotifyLow()

getDifferenceMode

public boolean getDifferenceMode()

Gets the difference mode flag value common to all observed MBeans.

Specified by:
getDifferenceMode in interface GaugeMonitorMBean
Returns:
true if the difference mode is used, false otherwise.
See Also:
setDifferenceMode(boolean)

setDifferenceMode

public void setDifferenceMode(boolean value)

Sets the difference mode flag value common to all observed MBeans.

Specified by:
setDifferenceMode in interface GaugeMonitorMBean
Parameters:
value - The difference mode flag value.
See Also:
getDifferenceMode()

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 gauge monitor.

Specified by:
getNotificationInfo in interface NotificationBroadcaster
Overrides:
getNotificationInfo in class NotificationBroadcasterSupport
Returns:
the array of possible notifications.

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Documentation extracted from Debian's OpenJDK Development Kit package.
Licensed under the GNU General Public License, version 2, with the Classpath Exception.
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