javax.management.monitor
class CounterMonitor

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

All Implemented Interfaces:

MBeanRegistration, NotificationEmitter, CounterMonitorMBean, MonitorMBean

Most common way to construct:

CounterMonitor counterMonitor = new CounterMonitor();

Based on 7 examples

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 {@link MonitorNotification#THRESHOLD_VALUE_EXCEEDED 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

CounterMonitor

public CounterMonitor()

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 object whose derived gauge is to be returned.

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.

getInitThreshold

public synchronized Number getInitThreshold()

Gets the initial threshold value common to all observed objects.

Returns:

The initial threshold.

getModulus

public synchronized Number getModulus()

Gets the modulus value common to all observed MBeans.

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 synchronized boolean getNotify()

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

Returns:

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

getOffset

public synchronized Number getOffset()

Gets the offset value common to all observed MBeans.

Returns:

The offset value.

getThreshold

public synchronized Number getThreshold()

Gets the threshold value of the first object in the set of observed MBeans.

Returns:

The threshold value.

getThreshold

public synchronized 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.

Parameters:

object - the name of the object whose threshold is to be returned.

Returns:

The threshold value of the specified object.

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.

setInitThreshold

public synchronized 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.

Parameters:

value - The initial threshold value.

Throws:

IllegalArgumentException - The specified threshold is null or the threshold value is less than zero.

setModulus

public synchronized void setModulus(Number value)
                             throws IllegalArgumentException

Sets the modulus value common to all observed MBeans.

Parameters:

value - The modulus value.

Throws:

IllegalArgumentException - The specified modulus is null or the modulus value is less than zero.

setNotify

public synchronized void setNotify(boolean value)

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

Parameters:

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

setOffset

public synchronized void setOffset(Number value)
                            throws IllegalArgumentException

Sets the offset value common to all observed MBeans.

Parameters:

value - The offset value.

Throws:

IllegalArgumentException - The specified offset is null or the offset value is less than zero.

setThreshold

public synchronized void setThreshold(Number value)
                               throws IllegalArgumentException

Sets the initial threshold value.

Parameters:

value - The initial threshold value.

Throws:

IllegalArgumentException - The specified threshold is null or the threshold value is less than zero.

start

public synchronized void start()

Starts the counter monitor.

Overrides:

start in class Monitor

stop

public synchronized void stop()

Stops the counter monitor.

Overrides:

stop in class Monitor