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java.management /
share /
classes /
javax /
management /
monitor /
CounterMonitor.java
/*
* Copyright (c) 1999, 2017, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation. Oracle designates this
* particular file as subject to the "Classpath" exception as provided
* by Oracle in the LICENSE file that accompanied this code.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
* or visit www.oracle.com if you need additional information or have any
* questions.
*/
package javax.management.monitor;
import static com.sun.jmx.defaults.JmxProperties.MONITOR_LOGGER;
import java.lang.System.Logger.Level;
import javax.management.ObjectName;
import javax.management.MBeanNotificationInfo;
import static javax.management.monitor.Monitor.NumericalType.*;
import static javax.management.monitor.MonitorNotification.*;
/**
* Defines a monitor MBean designed to observe the values of a counter
* attribute.
*
* <P> 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 <CODE>true</CODE>.
*
* <P> 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.
*
* <P> 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.
*
* <P> 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:
*
* <UL>
* <LI>if (counter[t] - counter[t-GP]) is positive then
* V[t] = counter[t] - counter[t-GP]
* <LI>if (counter[t] - counter[t-GP]) is negative then
* V[t] = counter[t] - counter[t-GP] + MODULUS
* </UL>
*
* This implementation of the counter monitor requires the observed
* attribute to be of the type integer (<CODE>Byte</CODE>,
* <CODE>Integer</CODE>, <CODE>Short</CODE>, <CODE>Long</CODE>).
*
*
* @since 1.5
*/
public class CounterMonitor extends Monitor implements CounterMonitorMBean {
/*
* ------------------------------------------
* PACKAGE CLASSES
* ------------------------------------------
*/
static class CounterMonitorObservedObject extends ObservedObject {
public CounterMonitorObservedObject(ObjectName observedObject) {
super(observedObject);
}
public final synchronized Number getThreshold() {
return threshold;
}
public final synchronized void setThreshold(Number threshold) {
this.threshold = threshold;
}
public final synchronized Number getPreviousScanCounter() {
return previousScanCounter;
}
public final synchronized void setPreviousScanCounter(
Number previousScanCounter) {
this.previousScanCounter = previousScanCounter;
}
public final synchronized boolean getModulusExceeded() {
return modulusExceeded;
}
public final synchronized void setModulusExceeded(
boolean modulusExceeded) {
this.modulusExceeded = modulusExceeded;
}
public final synchronized Number getDerivedGaugeExceeded() {
return derivedGaugeExceeded;
}
public final synchronized void setDerivedGaugeExceeded(
Number derivedGaugeExceeded) {
this.derivedGaugeExceeded = derivedGaugeExceeded;
}
public final synchronized boolean getDerivedGaugeValid() {
return derivedGaugeValid;
}
public final synchronized void setDerivedGaugeValid(
boolean derivedGaugeValid) {
this.derivedGaugeValid = derivedGaugeValid;
}
public final synchronized boolean getEventAlreadyNotified() {
return eventAlreadyNotified;
}
public final synchronized void setEventAlreadyNotified(
boolean eventAlreadyNotified) {
this.eventAlreadyNotified = eventAlreadyNotified;
}
public final synchronized NumericalType getType() {
return type;
}
public final synchronized void setType(NumericalType type) {
this.type = type;
}
private Number threshold;
private Number previousScanCounter;
private boolean modulusExceeded;
private Number derivedGaugeExceeded;
private boolean derivedGaugeValid;
private boolean eventAlreadyNotified;
private NumericalType type;
}
/*
* ------------------------------------------
* PRIVATE VARIABLES
* ------------------------------------------
*/
/**
* Counter modulus.
* <BR>The default value is a null Integer object.
*/
private Number modulus = INTEGER_ZERO;
/**
* Counter offset.
* <BR>The default value is a null Integer object.
*/
private Number offset = INTEGER_ZERO;
/**
* Flag indicating if the counter monitor notifies when exceeding
* the threshold. The default value is set to
* <CODE>false</CODE>.
*/
private boolean notify = false;
/**
* Flag indicating if the counter difference mode is used. If the
* counter difference mode is used, the derived gauge is the
* difference between two consecutive observed values. Otherwise,
* the derived gauge is directly the value of the observed
* attribute. The default value is set to <CODE>false</CODE>.
*/
private boolean differenceMode = false;
/**
* Initial counter threshold. This value is used to initialize
* the threshold when a new object is added to the list and reset
* the threshold to its initial value each time the counter
* resets.
*/
private Number initThreshold = INTEGER_ZERO;
private static final String[] types = {
RUNTIME_ERROR,
OBSERVED_OBJECT_ERROR,
OBSERVED_ATTRIBUTE_ERROR,
OBSERVED_ATTRIBUTE_TYPE_ERROR,
THRESHOLD_ERROR,
THRESHOLD_VALUE_EXCEEDED
};
private static final MBeanNotificationInfo[] notifsInfo = {
new MBeanNotificationInfo(
types,
"javax.management.monitor.MonitorNotification",
"Notifications sent by the CounterMonitor MBean")
};
/*
* ------------------------------------------
* CONSTRUCTORS
* ------------------------------------------
*/
/**
* Default constructor.
*/
public CounterMonitor() {
}
/*
* ------------------------------------------
* PUBLIC METHODS
* ------------------------------------------
*/
/**
* Starts the counter monitor.
*/
public synchronized void start() {
if (isActive()) {
MONITOR_LOGGER.log(Level.TRACE, "the monitor is already active");
return;
}
// Reset values.
//
for (ObservedObject o : observedObjects) {
final CounterMonitorObservedObject cmo =
(CounterMonitorObservedObject) o;
cmo.setThreshold(initThreshold);
cmo.setModulusExceeded(false);
cmo.setEventAlreadyNotified(false);
cmo.setPreviousScanCounter(null);
}
doStart();
}
/**
* Stops the counter monitor.
*/
public synchronized void stop() {
doStop();
}
// GETTERS AND SETTERS
//--------------------
/**
* Gets the derived gauge of the specified object, if this object is
* contained in the set of observed MBeans, or <code>null</code> otherwise.
*
* @param object the name of the object whose derived gauge is to
* be returned.
*
* @return The derived gauge of the specified object.
*
*/
@Override
public synchronized Number getDerivedGauge(ObjectName object) {
return (Number) super.getDerivedGauge(object);
}
/**
* Gets the derived gauge timestamp of the specified object, if
* this object is contained in the set of observed MBeans, or
* <code>0</code> otherwise.
*
* @param object the name of the object whose derived gauge
* timestamp is to be returned.
*
* @return The derived gauge timestamp of the specified object.
*
*/
@Override
public synchronized long getDerivedGaugeTimeStamp(ObjectName object) {
return super.getDerivedGaugeTimeStamp(object);
}
/**
* Gets the current threshold value of the specified object, if
* this object is contained in the set of observed MBeans, or
* <code>null</code> otherwise.
*
* @param object the name of the object whose threshold is to be
* returned.
*
* @return The threshold value of the specified object.
*
*/
public synchronized Number getThreshold(ObjectName object) {
final CounterMonitorObservedObject o =
(CounterMonitorObservedObject) getObservedObject(object);
if (o == null)
return null;
// If the counter that is monitored rolls over when it reaches a
// maximum value, then the modulus value needs to be set to that
// maximum value. The threshold will then also roll over whenever
// it strictly exceeds the modulus value. When the threshold rolls
// over, it is reset to the value that was specified through the
// latest call to the monitor's setInitThreshold method, before
// any offsets were applied.
//
if (offset.longValue() > 0L &&
modulus.longValue() > 0L &&
o.getThreshold().longValue() > modulus.longValue()) {
return initThreshold;
} else {
return o.getThreshold();
}
}
/**
* Gets the initial threshold value common to all observed objects.
*
* @return The initial threshold.
*
* @see #setInitThreshold
*
*/
public synchronized Number getInitThreshold() {
return initThreshold;
}
/**
* Sets the initial threshold value common to all observed objects.
*
* <BR>The current threshold of every object in the set of
* observed MBeans is updated consequently.
*
* @param value The initial threshold value.
*
* @exception IllegalArgumentException The specified
* threshold is null or the threshold value is less than zero.
*
* @see #getInitThreshold
*
*/
public synchronized void setInitThreshold(Number value)
throws IllegalArgumentException {
if (value == null) {
throw new IllegalArgumentException("Null threshold");
}
if (value.longValue() < 0L) {
throw new IllegalArgumentException("Negative threshold");
}
if (initThreshold.equals(value))
return;
initThreshold = value;
// Reset values.
//
int index = 0;
for (ObservedObject o : observedObjects) {
resetAlreadyNotified(o, index++, THRESHOLD_ERROR_NOTIFIED);
final CounterMonitorObservedObject cmo =
(CounterMonitorObservedObject) o;
cmo.setThreshold(value);
cmo.setModulusExceeded(false);
cmo.setEventAlreadyNotified(false);
}
}
/**
* Returns the derived gauge of the first object in the set of
* observed MBeans.
*
* @return The derived gauge.
*
* @deprecated As of JMX 1.2, replaced by
* {@link #getDerivedGauge(ObjectName)}
*/
@Deprecated
public synchronized Number getDerivedGauge() {
if (observedObjects.isEmpty()) {
return null;
} else {
return (Number) observedObjects.get(0).getDerivedGauge();
}
}
/**
* Gets the derived gauge timestamp of the first object in the set
* of observed MBeans.
*
* @return The derived gauge timestamp.
*
* @deprecated As of JMX 1.2, replaced by
* {@link #getDerivedGaugeTimeStamp(ObjectName)}
*/
@Deprecated
public synchronized long getDerivedGaugeTimeStamp() {
if (observedObjects.isEmpty()) {
return 0;
} else {
return observedObjects.get(0).getDerivedGaugeTimeStamp();
}
}
/**
* Gets the threshold value of the first object in the set of
* observed MBeans.
*
* @return The threshold value.
*
* @see #setThreshold
*
* @deprecated As of JMX 1.2, replaced by {@link #getThreshold(ObjectName)}
*/
@Deprecated
public synchronized Number getThreshold() {
return getThreshold(getObservedObject());
}
/**
* Sets the initial threshold value.
*
* @param value The initial threshold value.
*
* @exception IllegalArgumentException The specified threshold is
* null or the threshold value is less than zero.
*
* @see #getThreshold()
*
* @deprecated As of JMX 1.2, replaced by {@link #setInitThreshold}
*/
@Deprecated
public synchronized void setThreshold(Number value)
throws IllegalArgumentException {
setInitThreshold(value);
}
/**
* Gets the offset value common to all observed MBeans.
*
* @return The offset value.
*
* @see #setOffset
*/
public synchronized Number getOffset() {
return offset;
}
/**
* Sets the offset value common to all observed MBeans.
*
* @param value The offset value.
*
* @exception IllegalArgumentException The specified
* offset is null or the offset value is less than zero.
*
* @see #getOffset
*/
public synchronized void setOffset(Number value)
throws IllegalArgumentException {
if (value == null) {
throw new IllegalArgumentException("Null offset");
}
if (value.longValue() < 0L) {
throw new IllegalArgumentException("Negative offset");
}
if (offset.equals(value))
return;
offset = value;
int index = 0;
for (ObservedObject o : observedObjects) {
resetAlreadyNotified(o, index++, THRESHOLD_ERROR_NOTIFIED);
}
}
/**
* Gets the modulus value common to all observed MBeans.
*
* @see #setModulus
*
* @return The modulus value.
*/
public synchronized Number getModulus() {
return modulus;
}
/**
* Sets the modulus value common to all observed MBeans.
*
* @param value The modulus value.
*
* @exception IllegalArgumentException The specified
* modulus is null or the modulus value is less than zero.
*
* @see #getModulus
*/
public synchronized void setModulus(Number value)
throws IllegalArgumentException {
if (value == null) {
throw new IllegalArgumentException("Null modulus");
}
if (value.longValue() < 0L) {
throw new IllegalArgumentException("Negative modulus");
}
if (modulus.equals(value))
return;
modulus = value;
// Reset values.
//
int index = 0;
for (ObservedObject o : observedObjects) {
resetAlreadyNotified(o, index++, THRESHOLD_ERROR_NOTIFIED);
final CounterMonitorObservedObject cmo =
(CounterMonitorObservedObject) o;
cmo.setModulusExceeded(false);
}
}
/**
* Gets the notification's on/off switch value common to all
* observed MBeans.
*
* @return <CODE>true</CODE> if the counter monitor notifies when
* exceeding the threshold, <CODE>false</CODE> otherwise.
*
* @see #setNotify
*/
public synchronized boolean getNotify() {
return notify;
}
/**
* Sets the notification's on/off switch value common to all
* observed MBeans.
*
* @param value The notification's on/off switch value.
*
* @see #getNotify
*/
public synchronized void setNotify(boolean value) {
if (notify == value)
return;
notify = value;
}
/**
* Gets the difference mode flag value common to all observed MBeans.
*
* @return <CODE>true</CODE> if the difference mode is used,
* <CODE>false</CODE> otherwise.
*
* @see #setDifferenceMode
*/
public synchronized boolean getDifferenceMode() {
return differenceMode;
}
/**
* Sets the difference mode flag value common to all observed MBeans.
*
* @param value The difference mode flag value.
*
* @see #getDifferenceMode
*/
public synchronized void setDifferenceMode(boolean value) {
if (differenceMode == value)
return;
differenceMode = value;
// Reset values.
//
for (ObservedObject o : observedObjects) {
final CounterMonitorObservedObject cmo =
(CounterMonitorObservedObject) o;
cmo.setThreshold(initThreshold);
cmo.setModulusExceeded(false);
cmo.setEventAlreadyNotified(false);
cmo.setPreviousScanCounter(null);
}
}
/**
* Returns a <CODE>NotificationInfo</CODE> object containing the
* name of the Java class of the notification and the notification
* types sent by the counter monitor.
*/
@Override
public MBeanNotificationInfo[] getNotificationInfo() {
return notifsInfo.clone();
}
/*
* ------------------------------------------
* PRIVATE METHODS
* ------------------------------------------
*/
/**
* Updates the derived gauge attribute of the observed object.
*
* @param scanCounter The value of the observed attribute.
* @param o The observed object.
* @return <CODE>true</CODE> if the derived gauge value is valid,
* <CODE>false</CODE> otherwise. The derived gauge value is
* invalid when the differenceMode flag is set to
* <CODE>true</CODE> and it is the first notification (so we
* haven't 2 consecutive values to update the derived gauge).
*/
private synchronized boolean updateDerivedGauge(
Object scanCounter, CounterMonitorObservedObject o) {
boolean is_derived_gauge_valid;
// The counter difference mode is used.
//
if (differenceMode) {
// The previous scan counter has been initialized.
//
if (o.getPreviousScanCounter() != null) {
setDerivedGaugeWithDifference((Number)scanCounter, null, o);
// If derived gauge is negative it means that the
// counter has wrapped around and the value of the
// threshold needs to be reset to its initial value.
//
if (((Number)o.getDerivedGauge()).longValue() < 0L) {
if (modulus.longValue() > 0L) {
setDerivedGaugeWithDifference((Number)scanCounter,
modulus, o);
}
o.setThreshold(initThreshold);
o.setEventAlreadyNotified(false);
}
is_derived_gauge_valid = true;
}
// The previous scan counter has not been initialized.
// We cannot update the derived gauge...
//
else {
is_derived_gauge_valid = false;
}
o.setPreviousScanCounter((Number)scanCounter);
}
// The counter difference mode is not used.
//
else {
o.setDerivedGauge((Number)scanCounter);
is_derived_gauge_valid = true;
}
return is_derived_gauge_valid;
}
/**
* Updates the notification attribute of the observed object
* and notifies the listeners only once if the notify flag
* is set to <CODE>true</CODE>.
* @param o The observed object.
*/
private synchronized MonitorNotification updateNotifications(
CounterMonitorObservedObject o) {
MonitorNotification n = null;
// Send notification if notify is true.
//
if (!o.getEventAlreadyNotified()) {
if (((Number)o.getDerivedGauge()).longValue() >=
o.getThreshold().longValue()) {
if (notify) {
n = new MonitorNotification(THRESHOLD_VALUE_EXCEEDED,
this,
0,
0,
"",
null,
null,
null,
o.getThreshold());
}
if (!differenceMode) {
o.setEventAlreadyNotified(true);
}
}
} else {
if (MONITOR_LOGGER.isLoggable(Level.TRACE)) {
final StringBuilder strb = new StringBuilder()
.append("The notification:")
.append("\n\tNotification observed object = ")
.append(o.getObservedObject())
.append("\n\tNotification observed attribute = ")
.append(getObservedAttribute())
.append("\n\tNotification threshold level = ")
.append(o.getThreshold())
.append("\n\tNotification derived gauge = ")
.append(o.getDerivedGauge())
.append("\nhas already been sent");
MONITOR_LOGGER.log(Level.TRACE, strb::toString);
}
}
return n;
}
/**
* Updates the threshold attribute of the observed object.
* @param o The observed object.
*/
private synchronized void updateThreshold(CounterMonitorObservedObject o) {
// Calculate the new threshold value if the threshold has been
// exceeded and if the offset value is greater than zero.
//
if (((Number)o.getDerivedGauge()).longValue() >=
o.getThreshold().longValue()) {
if (offset.longValue() > 0L) {
// Increment the threshold until its value is greater
// than the one for the current derived gauge.
//
long threshold_value = o.getThreshold().longValue();
while (((Number)o.getDerivedGauge()).longValue() >=
threshold_value) {
threshold_value += offset.longValue();
}
// Set threshold attribute.
//
switch (o.getType()) {
case INTEGER:
o.setThreshold(Integer.valueOf((int)threshold_value));
break;
case BYTE:
o.setThreshold(Byte.valueOf((byte)threshold_value));
break;
case SHORT:
o.setThreshold(Short.valueOf((short)threshold_value));
break;
case LONG:
o.setThreshold(Long.valueOf(threshold_value));
break;
default:
// Should never occur...
MONITOR_LOGGER.log(Level.TRACE,
"the threshold type is invalid");
break;
}
// If the counter can wrap around when it reaches
// its maximum and we are not dealing with counter
// differences then we need to reset the threshold
// to its initial value too.
//
if (!differenceMode) {
if (modulus.longValue() > 0L) {
if (o.getThreshold().longValue() >
modulus.longValue()) {
o.setModulusExceeded(true);
o.setDerivedGaugeExceeded(
(Number) o.getDerivedGauge());
}
}
}
// Threshold value has been modified so we can notify again.
//
o.setEventAlreadyNotified(false);
} else {
o.setModulusExceeded(true);
o.setDerivedGaugeExceeded((Number) o.getDerivedGauge());
}
}
}
/**
* Sets the derived gauge of the specified observed object when the
* differenceMode flag is set to <CODE>true</CODE>. Integer types
* only are allowed.
*
* @param scanCounter The value of the observed attribute.
* @param mod The counter modulus value.
* @param o The observed object.
*/
private synchronized void setDerivedGaugeWithDifference(
Number scanCounter, Number mod, CounterMonitorObservedObject o) {
/* We do the arithmetic using longs here even though the
result may end up in a smaller type. Since
l == (byte)l (mod 256) for any long l,
(byte) ((byte)l1 + (byte)l2) == (byte) (l1 + l2),
and likewise for subtraction. So it's the same as if
we had done the arithmetic in the smaller type.*/
long derived =
scanCounter.longValue() - o.getPreviousScanCounter().longValue();
if (mod != null)
derived += modulus.longValue();
switch (o.getType()) {
case INTEGER: o.setDerivedGauge(Integer.valueOf((int) derived)); break;
case BYTE: o.setDerivedGauge(Byte.valueOf((byte) derived)); break;
case SHORT: o.setDerivedGauge(Short.valueOf((short) derived)); break;
case LONG: o.setDerivedGauge(Long.valueOf(derived)); break;
default:
// Should never occur...
MONITOR_LOGGER.log(Level.TRACE,
"the threshold type is invalid");
break;
}
}
/*
* ------------------------------------------
* PACKAGE METHODS
* ------------------------------------------
*/
/**
* Factory method for ObservedObject creation.
*
* @since 1.6
*/
@Override
ObservedObject createObservedObject(ObjectName object) {
final CounterMonitorObservedObject cmo =
new CounterMonitorObservedObject(object);
cmo.setThreshold(initThreshold);
cmo.setModulusExceeded(false);
cmo.setEventAlreadyNotified(false);
cmo.setPreviousScanCounter(null);
return cmo;
}
/**
* This method globally sets the derived gauge type for the given
* "object" and "attribute" after checking that the type of the
* supplied observed attribute value is one of the value types
* supported by this monitor.
*/
@Override
synchronized boolean isComparableTypeValid(ObjectName object,
String attribute,
Comparable<?> value) {
final CounterMonitorObservedObject o =
(CounterMonitorObservedObject) getObservedObject(object);
if (o == null)
return false;
// Check that the observed attribute is of type "Integer".
//
if (value instanceof Integer) {
o.setType(INTEGER);
} else if (value instanceof Byte) {
o.setType(BYTE);
} else if (value instanceof Short) {
o.setType(SHORT);
} else if (value instanceof Long) {
o.setType(LONG);
} else {
return false;
}
return true;
}
@Override
synchronized Comparable<?> getDerivedGaugeFromComparable(
ObjectName object,
String attribute,
Comparable<?> value) {
final CounterMonitorObservedObject o =
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