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Class CounterMonitor

java.lang.Object
javax.management.NotificationBroadcasterSupport
javax.management.monitor.Monitor
javax.management.monitor.CounterMonitor
All Implemented Interfaces:
MBeanRegistration, CounterMonitorMBean, 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).
Since:
1.5

Field Summary

Fields declared in 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

Constructor Summary

Constructor Description
CounterMonitor()
Default constructor.

Method Summary

Modifier and Type Method Description
Number getDerivedGauge()
Deprecated.
As of JMX 1.2, replaced by getDerivedGauge(ObjectName)
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.
long getDerivedGaugeTimeStamp()
Deprecated.
As of JMX 1.2, replaced by getDerivedGaugeTimeStamp(ObjectName)
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.
boolean getDifferenceMode()
Gets the difference mode flag value common to all observed MBeans.
Number getInitThreshold()
Gets the initial threshold value common to all observed objects.
Number getModulus()
Gets the modulus value common to all observed MBeans.
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 common to all observed MBeans.
Number getOffset()
Gets the offset value common to all observed MBeans.
Number getThreshold()
Deprecated.
As of JMX 1.2, replaced by getThreshold(ObjectName)
Number getThreshold(ObjectName object)
Gets the current threshold value of the specified object, if this object is contained in the set of observed MBeans, or null otherwise.
void setDifferenceMode(boolean value)
Sets the difference mode flag value common to all observed MBeans.
void setInitThreshold(Number value)
Sets the initial threshold value common to all observed objects.
void setModulus(Number value)
Sets the modulus value common to all observed MBeans.
void setNotify(boolean value)
Sets the notification's on/off switch value common to all observed MBeans.
void setOffset(Number value)
Sets the offset value common to all observed MBeans.
void setThreshold(Number value)
Deprecated.
As of JMX 1.2, replaced by setInitThreshold(java.lang.Number)
void start()
Starts the counter monitor.
void stop()
Stops the counter monitor.

Methods declared in class javax.management.monitor.Monitor

addObservedObject, containsObservedObject, getGranularityPeriod, getObservedAttribute, getObservedObject, getObservedObjects, isActive, postDeregister, postRegister, preDeregister, preRegister, removeObservedObject, setGranularityPeriod, setObservedAttribute, setObservedObject

Methods declared in class javax.management.NotificationBroadcasterSupport

addNotificationListener, handleNotification, removeNotificationListener, removeNotificationListener, sendNotification

Methods declared in class java.lang.Object

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

Methods declared in interface javax.management.monitor.MonitorMBean

addObservedObject, containsObservedObject, getGranularityPeriod, getObservedAttribute, getObservedObject, getObservedObjects, isActive, removeObservedObject, setGranularityPeriod, setObservedAttribute, setObservedObject

Constructor Details

CounterMonitor

public CounterMonitor()
Default constructor.

Method Details

start

public void start()
Starts the counter monitor.
Specified by:
start in interface MonitorMBean
Specified by:
start in class Monitor

stop

public void stop()
Stops the counter 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 CounterMonitorMBean
Parameters:
object - the name of the object whose derived gauge is to be returned.
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 CounterMonitorMBean
Parameters:
object - the name of the object whose derived gauge timestamp is to be returned.
Returns:
The derived gauge timestamp of the specified object.

getThreshold

public Number getThreshold(ObjectName object)
Gets the current threshold value of the specified object, if this object is contained in the set of observed MBeans, or null otherwise.
Specified by:
getThreshold in interface CounterMonitorMBean
Parameters:
object - the name of the object whose threshold is to be returned.
Returns:
The threshold value of the specified object.
See Also:

getInitThreshold

public Number getInitThreshold()
Gets the initial threshold value common to all observed objects.
Specified by:
getInitThreshold in interface CounterMonitorMBean
Returns:
The initial threshold.
See Also:

setInitThreshold

public void setInitThreshold(Number value) throws IllegalArgumentException
Sets the initial threshold value common to all observed objects.
The current threshold of every object in the set of observed MBeans is updated consequently.
Specified by:
setInitThreshold in interface CounterMonitorMBean
Parameters:
value - The initial threshold value.
Throws:
IllegalArgumentException - The specified threshold is null or the threshold value is less than zero.
See Also:

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 CounterMonitorMBean
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 CounterMonitorMBean
Returns:
The derived gauge timestamp.

getThreshold

@Deprecated public Number getThreshold()
Deprecated.
As of JMX 1.2, replaced by getThreshold(ObjectName)
Gets the threshold value of the first object in the set of observed MBeans.
Specified by:
getThreshold in interface CounterMonitorMBean
Returns:
The threshold value.
See Also:

setThreshold

@Deprecated public void setThreshold(Number value) throws IllegalArgumentException
Deprecated.
As of JMX 1.2, replaced by setInitThreshold(java.lang.Number)
Sets the initial threshold value.
Specified by:
setThreshold in interface CounterMonitorMBean
Parameters:
value - The initial threshold value.
Throws:
IllegalArgumentException - The specified threshold is null or the threshold value is less than zero.
See Also:

getOffset

public Number getOffset()
Gets the offset value common to all observed MBeans.
Specified by:
getOffset in interface CounterMonitorMBean
Returns:
The offset value.
See Also:

setOffset

public void setOffset(Number value) throws IllegalArgumentException
Sets the offset value common to all observed MBeans.
Specified by:
setOffset in interface CounterMonitorMBean
Parameters:
value - The offset value.
Throws:
IllegalArgumentException - The specified offset is null or the offset value is less than zero.
See Also:

getModulus

public Number getModulus()
Gets the modulus value common to all observed MBeans.
Specified by:
getModulus in interface CounterMonitorMBean
Returns:
The modulus value.
See Also:

setModulus

public void setModulus(Number value) throws IllegalArgumentException
Sets the modulus value common to all observed MBeans.
Specified by:
setModulus in interface CounterMonitorMBean
Parameters:
value - The modulus value.
Throws:
IllegalArgumentException - The specified modulus is null or the modulus value is less than zero.
See Also:

getNotify

public boolean getNotify()
Gets the notification's on/off switch value common to all observed MBeans.
Specified by:
getNotify in interface CounterMonitorMBean
Returns:
true if the counter monitor notifies when exceeding the threshold, false otherwise.
See Also:

setNotify

public void setNotify(boolean value)
Sets the notification's on/off switch value common to all observed MBeans.
Specified by:
setNotify in interface CounterMonitorMBean
Parameters:
value - The notification's on/off switch value.
See Also:

getDifferenceMode

public boolean getDifferenceMode()
Gets the difference mode flag value common to all observed MBeans.
Specified by:
getDifferenceMode in interface CounterMonitorMBean
Returns:
true if the difference mode is used, false otherwise.
See Also:

setDifferenceMode

public void setDifferenceMode(boolean value)
Sets the difference mode flag value common to all observed MBeans.
Specified by:
setDifferenceMode in interface CounterMonitorMBean
Parameters:
value - The difference mode flag value.
See Also:

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.
Specified by:
getNotificationInfo in interface NotificationBroadcaster
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.
Various third party code in OpenJDK is licensed under different licenses (see Debian package).
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https://docs.oracle.com/en/java/javase/21/docs/api/java.management/javax/management/monitor/CounterMonitor.html