The VMMetrics example is a JMS application that monitors the Java VM used by the Sun Java(tm) System Message Queue broker : Java Message Service JMS « J2EE « Java






The VMMetrics example is a JMS application that monitors the Java VM used by the Sun Java(tm) System Message Queue broker

 

/*
 * @(#)VMMetrics.java  1.3 04/01/05
 *
 * Copyright (c) 2000-2003 Sun Microsystems, Inc. All Rights Reserved.
 *
 * Sun grants you ("Licensee") a non-exclusive, royalty free, license to use,
 * modify and redistribute this software in source and binary code form,
 * provided that i) this copyright notice and license appear on all copies of
 * the software; and ii) Licensee does not utilize the software in a manner
 * which is disparaging to Sun.
 *
 * This software is provided "AS IS," without a warranty of any kind. ALL
 * EXPRESS OR IMPLIED CONDITIONS, REPRESENTATIONS AND WARRANTIES, INCLUDING ANY
 * IMPLIED WARRANTY OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE OR
 * NON-INFRINGEMENT, ARE HEREBY EXCLUDED. SUN AND ITS LICENSORS SHALL NOT BE
 * LIABLE FOR ANY DAMAGES SUFFERED BY LICENSEE AS A RESULT OF USING, MODIFYING
 * OR DISTRIBUTING THE SOFTWARE OR ITS DERIVATIVES. IN NO EVENT WILL SUN OR ITS
 * LICENSORS BE LIABLE FOR ANY LOST REVENUE, PROFIT OR DATA, OR FOR DIRECT,
 * INDIRECT, SPECIAL, CONSEQUENTIAL, INCIDENTAL OR PUNITIVE DAMAGES, HOWEVER
 * CAUSED AND REGARDLESS OF THE THEORY OF LIABILITY, ARISING OUT OF THE USE OF
 * OR INABILITY TO USE SOFTWARE, EVEN IF SUN HAS BEEN ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGES.
 *
 * This software is not designed or intended for use in on-line control of
 * aircraft, air traffic, aircraft navigation or aircraft communications; or in
 * the design, construction, operation or maintenance of any nuclear
 * facility. Licensee represents and warrants that it will not use or
 * redistribute the Software for such purposes.
 */

import java.util.Enumeration;
import java.util.Properties;
import javax.jms.*;

/**
 * The VMMetrics example is a JMS application that monitors the
 * Java VM used by the Sun Java(tm) System Message Queue broker. It does so by 
 * subscribing to a topic named 'mq.metrics.jvm'. The messages that arrive 
 * contain Java VM information such as:
 *  - amount of free memory
 *  - amount of maximum memory
 *  - total amount of memory
 *
 * By default VMMetrics will connect to the broker running on localhost:7676.
 * You can use -DimqAddressList attribute to change the host, port and 
 * transport:
 *
 *  java -DimqAddressList=mq://<host>:<port>/jms VMMetrics
 */
public class VMMetrics implements MessageListener  {
    ConnectionFactory        metricConnectionFactory;
    Connection               metricConnection;
    Session                  metricSession;
    MessageConsumer          metricConsumer;
    Topic                    metricTopic;
    MetricsPrinter           mp;
    int                      rowsPrinted = 0;
  
    public static void main(String args[])  {
  VMMetrics bm = new VMMetrics();
        bm.initPrinter();
        bm.initJMS();
        bm.subscribeToMetric();
    }

    /*
     * Initializes the class that does the printing, MetricsPrinter.
     * See the MetricsPrinter class for details.
     */
    private void initPrinter() {
  String oneRow[] = new String[ 3 ];
  int i = 0;

  mp = new MetricsPrinter(3, 2, "-");

  i = 0;
  oneRow[i++] = "Free Memory";
  oneRow[i++] = "Max Memory";
  oneRow[i++] = "Total Memory";
  mp.addTitle(oneRow);
    }

    /** 
     * Create the Connection and Session etc.
     */
    public void initJMS() {
        try {
            metricConnectionFactory = new com.sun.messaging.ConnectionFactory();
            metricConnection = metricConnectionFactory.createConnection();
            metricConnection.start();

            //  creating Session
            //  Transaction Mode: None
            //  Acknowledge Mode: Automatic
            metricSession = metricConnection.createSession(false,
        Session.AUTO_ACKNOWLEDGE);
        } catch(Exception e) {
            System.err.println("Cannot create metric connection or session: "
      + e.getMessage());
            e.printStackTrace();
      System.exit(1);
        }
    }
  
    public void subscribeToMetric() {
        try {
            metricTopic = metricSession.createTopic("mq.metrics.jvm");

            metricConsumer = metricSession.createConsumer(metricTopic);
            metricConsumer.setMessageListener(this);
        } catch(JMSException e) {
            System.err.println("Cannot subscribe to metric topic: "
      + e.getMessage());
            e.printStackTrace();
      System.exit(1);
        }
    }

    /*
     * When a metric message arrives
     *  - verify it's type
     *  - extract it's fields
     *  - print one row of output
     */
    public void onMessage(Message m)  {
  try  {
      MapMessage mapMsg = (MapMessage)m;
      String type = mapMsg.getStringProperty("type");

      if (type.equals("mq.metrics.jvm"))  {
          String oneRow[] = new String[ 3 ];
    int i = 0;

          /*
           * Extract broke metrics
           */
    oneRow[i++] = Long.toString(mapMsg.getLong("freeMemory"));
    oneRow[i++] = Long.toString(mapMsg.getLong("maxMemory"));
    oneRow[i++] = Long.toString(mapMsg.getLong("totalMemory"));

    mp.add(oneRow);

    if ((rowsPrinted % 20) == 0)  {
        mp.print();
    } else  {
        mp.print(false);
    }

    rowsPrinted++;

    mp.clear();
      } else  {
          System.err.println("Msg received: not vm metric type");
      }
  } catch (Exception e)  {
      System.err.println("onMessage: Exception caught: " + e);
  }
    }
}

        








JMQ-monitoring.zip( 18 k)

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