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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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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.MonitorNotification.*;


Defines a monitor MBean designed to observe the values of a string
attribute.


A string monitor sends notifications as follows:

    

  •  if the attribute value matches the string to compare value, a 
     match notification is sent. The notify match flag must be set to true.
     
    Subsequent matchings of the string to compare values do not
     cause further notifications unless
     the attribute value differs from the string to compare value.

  •  if the attribute value differs from the string to compare value, a 
     differ notification is sent. The notify differ flag must be set to true.
     
    Subsequent differences from the string to compare value do
     not cause further notifications unless
     the attribute value matches the string to compare value.



Since:1.5
/**
 * Defines a monitor MBean designed to observe the values of a string
 * attribute.
 * <P>
 * A string monitor sends notifications as follows:
 * <UL>
 * <LI> if the attribute value matches the string to compare value,
 *      a {@link MonitorNotification#STRING_TO_COMPARE_VALUE_MATCHED
 *      match notification} is sent.
 *      The notify match flag must be set to <CODE>true</CODE>.
 *      <BR>Subsequent matchings of the string to compare values do not
 *      cause further notifications unless
 *      the attribute value differs from the string to compare value.
 * <LI> if the attribute value differs from the string to compare value,
 *      a {@link MonitorNotification#STRING_TO_COMPARE_VALUE_DIFFERED
 *      differ notification} is sent.
 *      The notify differ flag must be set to <CODE>true</CODE>.
 *      <BR>Subsequent differences from the string to compare value do
 *      not cause further notifications unless
 *      the attribute value matches the string to compare value.
 * </UL>
 *
 *
 * @since 1.5
 */
public class StringMonitor extends Monitor implements StringMonitorMBean {

    /*
     * ------------------------------------------
     *  PACKAGE CLASSES
     * ------------------------------------------
     */

    static class StringMonitorObservedObject extends ObservedObject {

        public StringMonitorObservedObject(ObjectName observedObject) {
            super(observedObject);
        }

        public final synchronized int getStatus() {
            return status;
        }
        public final synchronized void setStatus(int status) {
            this.status = status;
        }

        private int status;
    }

    /*
     * ------------------------------------------
     *  PRIVATE VARIABLES
     * ------------------------------------------
     */

    
String to compare with the observed attribute.

The default value is an empty character sequence.

/**
     * String to compare with the observed attribute.
     * <BR>The default value is an empty character sequence.
     */
    private String stringToCompare = "";

    
Flag indicating if the string monitor notifies when matching
the string to compare.

The default value is set to false.

/**
     * Flag indicating if the string monitor notifies when matching
     * the string to compare.
     * <BR>The default value is set to <CODE>false</CODE>.
     */
    private boolean notifyMatch = false;

    
Flag indicating if the string monitor notifies when differing
from the string to compare.

The default value is set to false.

/**
     * Flag indicating if the string monitor notifies when differing
     * from the string to compare.
     * <BR>The default value is set to <CODE>false</CODE>.
     */
    private boolean notifyDiffer = false;

    private static final String[] types = {
        RUNTIME_ERROR,
        OBSERVED_OBJECT_ERROR,
        OBSERVED_ATTRIBUTE_ERROR,
        OBSERVED_ATTRIBUTE_TYPE_ERROR,
        STRING_TO_COMPARE_VALUE_MATCHED,
        STRING_TO_COMPARE_VALUE_DIFFERED
    };

    private static final MBeanNotificationInfo[] notifsInfo = {
        new MBeanNotificationInfo(
            types,
            "javax.management.monitor.MonitorNotification",
            "Notifications sent by the StringMonitor MBean")
    };

    // Flags needed to implement the matching/differing mechanism.
    //
    private static final int MATCHING                   = 0;
    private static final int DIFFERING                  = 1;
    private static final int MATCHING_OR_DIFFERING      = 2;

    /*
     * ------------------------------------------
     *  CONSTRUCTORS
     * ------------------------------------------
     */

    
Default constructor.

/**
     * Default constructor.
     */
    public StringMonitor() {
    }

    /*
     * ------------------------------------------
     *  PUBLIC METHODS
     * ------------------------------------------
     */

    
Starts the string monitor.

/**
     * Starts the string 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 StringMonitorObservedObject smo =
                (StringMonitorObservedObject) o;
            smo.setStatus(MATCHING_OR_DIFFERING);
        }
        doStart();
    }

    
Stops the string monitor.

/**
     * Stops the string 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 null otherwise.

Params:
  • object – the name of the MBean whose derived gauge is required.
Returns:The derived gauge of the specified object.
/**
     * 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 MBean whose derived gauge is required.
     *
     * @return The derived gauge of the specified object.
     *
     */
    @Override
    public synchronized String getDerivedGauge(ObjectName object) {
        return (String) super.getDerivedGauge(object);
    }

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

Params:
  • object – the name of the object whose derived gauge
timestamp is to be returned.
Returns:The derived gauge timestamp of the specified 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);
    }

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

Returns:The derived gauge.
Deprecated:As of JMX 1.2, replaced by getDerivedGauge(ObjectName)
/**
     * 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 String getDerivedGauge() {
        if (observedObjects.isEmpty()) {
            return null;
        } else {
            return (String) observedObjects.get(0).getDerivedGauge();
        }
    }

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

Returns:The derived gauge timestamp.
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.
     *
     * @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 string to compare with the observed attribute common
to all observed MBeans.

See Also:
Returns:The string value.
/**
     * Gets the string to compare with the observed attribute common
     * to all observed MBeans.
     *
     * @return The string value.
     *
     * @see #setStringToCompare
     */
    public synchronized String getStringToCompare() {
        return stringToCompare;
    }

    
Sets the string to compare with the observed attribute common
to all observed MBeans.

Params:
  • value – The string value.
Throws:
See Also:
/**
     * Sets the string to compare with the observed attribute common
     * to all observed MBeans.
     *
     * @param value The string value.
     *
     * @exception IllegalArgumentException The specified
     * string to compare is null.
     *
     * @see #getStringToCompare
     */
    public synchronized void setStringToCompare(String value)
        throws IllegalArgumentException {

        if (value == null) {
            throw new IllegalArgumentException("Null string to compare");
        }

        if (stringToCompare.equals(value))
            return;
        stringToCompare = value;

        // Reset values.
        //
        for (ObservedObject o : observedObjects) {
            final StringMonitorObservedObject smo =
                (StringMonitorObservedObject) o;
            smo.setStatus(MATCHING_OR_DIFFERING);
        }
    }

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

See Also:
Returns:true if the string monitor notifies when
matching the string to compare, false otherwise.
/**
     * Gets the matching notification's on/off switch value common to
     * all observed MBeans.
     *
     * @return <CODE>true</CODE> if the string monitor notifies when
     * matching the string to compare, <CODE>false</CODE> otherwise.
     *
     * @see #setNotifyMatch
     */
    public synchronized boolean getNotifyMatch() {
        return notifyMatch;
    }

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

Params:
  • value – The matching notification's on/off switch value.
See Also:
/**
     * Sets the matching notification's on/off switch value common to
     * all observed MBeans.
     *
     * @param value The matching notification's on/off switch value.
     *
     * @see #getNotifyMatch
     */
    public synchronized void setNotifyMatch(boolean value) {
        if (notifyMatch == value)
            return;
        notifyMatch = value;
    }

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

See Also:
Returns:true if the string monitor notifies when
differing from the string to compare, false otherwise.
/**
     * Gets the differing notification's on/off switch value common to
     * all observed MBeans.
     *
     * @return <CODE>true</CODE> if the string monitor notifies when
     * differing from the string to compare, <CODE>false</CODE> otherwise.
     *
     * @see #setNotifyDiffer
     */
    public synchronized boolean getNotifyDiffer() {
        return notifyDiffer;
    }

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

Params:
  • value – The differing notification's on/off switch value.
See Also:
/**
     * Sets the differing notification's on/off switch value common to
     * all observed MBeans.
     *
     * @param value The differing notification's on/off switch value.
     *
     * @see #getNotifyDiffer
     */
    public synchronized void setNotifyDiffer(boolean value) {
        if (notifyDiffer == value)
            return;
        notifyDiffer = value;
    }

    
Returns a NotificationInfo object containing the name of
the Java class of the notification and the notification types sent by
the string monitor.

/**
     * Returns a <CODE>NotificationInfo</CODE> object containing the name of
     * the Java class of the notification and the notification types sent by
     * the string monitor.
     */
    @Override
    public MBeanNotificationInfo[] getNotificationInfo() {
        return notifsInfo.clone();
    }

    /*
     * ------------------------------------------
     *  PACKAGE METHODS
     * ------------------------------------------
     */

    
Factory method for ObservedObject creation.

Since:1.6
/**
     * Factory method for ObservedObject creation.
     *
     * @since 1.6
     */
    @Override
    ObservedObject createObservedObject(ObjectName object) {
        final StringMonitorObservedObject smo =
            new StringMonitorObservedObject(object);
        smo.setStatus(MATCHING_OR_DIFFERING);
        return smo;
    }

    
Check that the type of the supplied observed attribute
value is one of the value types supported by this monitor.

/**
     * Check 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) {
        // Check that the observed attribute is of type "String".
        //
        if (value instanceof String) {
            return true;
        }
        return false;
    }

    @Override
    synchronized void onErrorNotification(MonitorNotification notification) {
        final StringMonitorObservedObject o = (StringMonitorObservedObject)
            getObservedObject(notification.getObservedObject());
        if (o == null)
            return;

        // Reset values.
        //
        o.setStatus(MATCHING_OR_DIFFERING);
    }

    @Override
    synchronized MonitorNotification buildAlarmNotification(
                                               ObjectName object,
                                               String attribute,
                                               Comparable<?> value) {
        String type = null;
        String msg = null;
        Object trigger = null;

        final StringMonitorObservedObject o =
            (StringMonitorObservedObject) getObservedObject(object);
        if (o == null)
            return null;

        // Send matching notification if notifyMatch is true.
        // Send differing notification if notifyDiffer is true.
        //
        if (o.getStatus() == MATCHING_OR_DIFFERING) {
            if (o.getDerivedGauge().equals(stringToCompare)) {
                if (notifyMatch) {
                    type = STRING_TO_COMPARE_VALUE_MATCHED;
                    msg = "";
                    trigger = stringToCompare;
                }
                o.setStatus(DIFFERING);
            } else {
                if (notifyDiffer) {
                    type = STRING_TO_COMPARE_VALUE_DIFFERED;
                    msg = "";
                    trigger = stringToCompare;
                }
                o.setStatus(MATCHING);
            }
        } else {
            if (o.getStatus() == MATCHING) {
                if (o.getDerivedGauge().equals(stringToCompare)) {
                    if (notifyMatch) {
                        type = STRING_TO_COMPARE_VALUE_MATCHED;
                        msg = "";
                        trigger = stringToCompare;
                    }
                    o.setStatus(DIFFERING);
                }
            } else if (o.getStatus() == DIFFERING) {
                if (!o.getDerivedGauge().equals(stringToCompare)) {
                    if (notifyDiffer) {
                        type = STRING_TO_COMPARE_VALUE_DIFFERED;
                        msg = "";
                        trigger = stringToCompare;
                    }
                    o.setStatus(MATCHING);
                }
            }
        }

        return new MonitorNotification(type,
                                       this,
                                       0,
                                       0,
                                       msg,
                                       null,
                                       null,
                                       null,
                                       trigger);
    }
}