javax.management.monitor
class GaugeMonitor

java.lang.Object javax.management.NotificationBroadcasterSupport javax.management.monitor.Monitor javax.management.monitor.GaugeMonitor

All Implemented Interfaces:

MBeanRegistration, NotificationEmitter, GaugeMonitorMBean, MonitorMBean

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 {@link MonitorNotification#THRESHOLD_HIGH_VALUE_EXCEEDED 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 {@link MonitorNotification#THRESHOLD_LOW_VALUE_EXCEEDED 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.

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]

GaugeMonitor

public GaugeMonitor()

Default constructor.

getDerivedGauge

public synchronized Number getDerivedGauge()

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

Returns:

The derived gauge.

getDerivedGauge

public synchronized 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.

Overrides:

getDerivedGauge in class Monitor

Parameters:

object - the name of the MBean.

Returns:

The derived gauge of the specified object.

getDerivedGaugeTimeStamp

public synchronized long getDerivedGaugeTimeStamp()

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

Returns:

The derived gauge timestamp.

getDerivedGaugeTimeStamp

public synchronized 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.

Overrides:

getDerivedGaugeTimeStamp in class Monitor

Parameters:

object - the name of the object whose derived gauge timestamp is to be returned.

Returns:

The derived gauge timestamp of the specified object.

getDifferenceMode

public synchronized boolean getDifferenceMode()

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

Returns:

true if the difference mode is used, false otherwise.

getHighThreshold

public synchronized Number getHighThreshold()

Gets the high threshold value common to all observed MBeans.

Returns:

The high threshold value.

getLowThreshold

public synchronized Number getLowThreshold()

Gets the low threshold value common to all observed MBeans.

Returns:

The low threshold 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 gauge monitor.

Overrides:

getNotificationInfo in class NotificationBroadcasterSupport

getNotifyHigh

public synchronized boolean getNotifyHigh()

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

Returns:

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

getNotifyLow

public synchronized boolean getNotifyLow()

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

Returns:

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

setDifferenceMode

public synchronized void setDifferenceMode(boolean value)

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

Parameters:

value - The difference mode flag value.

setNotifyHigh

public synchronized void setNotifyHigh(boolean value)

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

Parameters:

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

setNotifyLow

public synchronized void setNotifyLow(boolean value)

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

Parameters:

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

setThresholds

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

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

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.

start

public synchronized void start()

Starts the gauge monitor.

Overrides:

start in class Monitor

stop

public synchronized void stop()

Stops the gauge monitor.

Overrides:

stop in class Monitor