cms/util/QueueMonitor.java

//---PACKAGE DECLARATION---
package uk.ac.ukc.iscream.util;

//---IMPORTS---
import uk.ac.ukc.iscream.util.*;
import uk.ac.ukc.iscream.componentmanager.*;

/**
 * This class monitors a given Queue at regular intervals,
 * reporting back to a Queue with XML - this could be the
 * same Queue being monitored.
 *
 * @author  $Author$
 * @version $Id$
 */
class QueueMonitor extends Thread {

//---FINAL ATTRIBUTES---

    /**
     * The current CVS revision of this class
     */
    public static final String REVISION = "$Revision: 1.1 $";
    
//---STATIC METHODS---

//---CONSTRUCTORS---
    
    /**
     * Construct a new QueueMonitor.
     *
     * @param sourceQueue The Queue to monitor
     * @param destQueue The Queue to monitor to
     * @param interval The interval, in milliseconds, at which to sample
     * @param name A name to identify the source Queue with
     */
    public QueueMonitor (Queue sourceQueue, Queue destQueue, long interval, String name) {
        _sourceQueue = sourceQueue;
        _destQueue = destQueue;
        _interval = interval;
        _srcName = name;
    }

//---PUBLIC METHODS---
    
    /**
     * Loops continuosly polling our source Queue at
     * the given interval, and then logging the results
     * in the destination Queue.
     */
    public void run() {
        _run = true;
        // so we can stop this thread...
        while(_run) {
            // first sleep for our interval
            try { Thread.sleep(_interval); } catch(Exception e) {}
            // check the Queue
            String status = _sourceQueue.xmlStatus();
            // create some XML
            String date = new Long(System.currentTimeMillis()/((long) 1000)).toString();
            String xml = "<packet type=\"queueStat\" date=\""+date+"\" name=\""+_srcName+"\">" + status + "</packet>";
            // write XML to destination Queue
            _destQueue.add(xml);
        }
    }
    
    /**
     * Shuts down this QueueMonitor
     */
    public void shutdown() {
        // this will stop the main loop
        _run = false;
    }
    
    /**
     * Overrides the {@link java.lang.Object#toString() Object.toString()}
     * method to provide clean logging (every class should have this).
     *
     * This uses the uk.ac.ukc.iscream.util.FormatName class
     * to format the toString()
     *
     * @return the name of this class and its CVS revision
     */
    public String toString() {
        return FormatName.getName(
            _name,
            getClass().getName(),
            REVISION);
    }

//---PRIVATE METHODS---

//---ACCESSOR/MUTATOR METHODS---

//---ATTRIBUTES---

    /**
     * This is the friendly identifier of the
     * component this class is running in.
     * eg, a Filter may be called "filter1",
     * If this class does not have an owning
     * component,  a name from the configuration
     * can be placed here.  This name could also
     * be changed to null for utility classes.
     */
    private String _name = null;
    
    /**
     * The Queue we're monitoring.
     */
    private Queue _sourceQueue;
    
    /**
     * The Queue we'll output results to.
     */
    private Queue _destQueue;
    
    /**
     * The interval at which we'll check the
     * sourceQueue status.
     */
    private long _interval;
    
    /**
     * The name to identify the source Queue
     */
    private String _srcName;
    
    /**
     * Allows us to stop the main loop cleanly.
     */
    private boolean _run;
    
//---STATIC ATTRIBUTES---

}
Revision:	1.1
Committed:	Mon Feb 12 02:20:23 2001 UTC (23 years, 2 months ago) by tdb
Branch:	MAIN
Log Message:	Initial checkin of the class to monitor a Queue.
#	User	Rev	Content
1	tdb	1.1	//---PACKAGE DECLARATION---
2			package uk.ac.ukc.iscream.util;
3
4			//---IMPORTS---
5			import uk.ac.ukc.iscream.util.*;
6			import uk.ac.ukc.iscream.componentmanager.*;
7
8			/**
9			* This class monitors a given Queue at regular intervals,
10			* reporting back to a Queue with XML - this could be the
11			* same Queue being monitored.
12			*
13			* @author $Author$
14			* @version $Id$
15			*/
16			class QueueMonitor extends Thread {
17
18			//---FINAL ATTRIBUTES---
19
20			/**
21			* The current CVS revision of this class
22			*/
23			public static final String REVISION = "$Revision: 1.1 $";
24
25			//---STATIC METHODS---
26
27			//---CONSTRUCTORS---
28
29			/**
30			* Construct a new QueueMonitor.
31			*
32			* @param sourceQueue The Queue to monitor
33			* @param destQueue The Queue to monitor to
34			* @param interval The interval, in milliseconds, at which to sample
35			* @param name A name to identify the source Queue with
36			*/
37			public QueueMonitor (Queue sourceQueue, Queue destQueue, long interval, String name) {
38			_sourceQueue = sourceQueue;
39			_destQueue = destQueue;
40			_interval = interval;
41			_srcName = name;
42			}
43
44			//---PUBLIC METHODS---
45
46			/**
47			* Loops continuosly polling our source Queue at
48			* the given interval, and then logging the results
49			* in the destination Queue.
50			*/
51			public void run() {
52			_run = true;
53			// so we can stop this thread...
54			while(_run) {
55			// first sleep for our interval
56			try { Thread.sleep(_interval); } catch(Exception e) {}
57			// check the Queue
58			String status = _sourceQueue.xmlStatus();
59			// create some XML
60			String date = new Long(System.currentTimeMillis()/((long) 1000)).toString();
61			String xml = "<packet type=\"queueStat\" date=\""+date+"\" name=\""+_srcName+"\">" + status + "</packet>";
62			// write XML to destination Queue
63			_destQueue.add(xml);
64			}
65			}
66
67			/**
68			* Shuts down this QueueMonitor
69			*/
70			public void shutdown() {
71			// this will stop the main loop
72			_run = false;
73			}
74
75			/**
76			* Overrides the {@link java.lang.Object#toString() Object.toString()}
77			* method to provide clean logging (every class should have this).
78			*
79			* This uses the uk.ac.ukc.iscream.util.FormatName class
80			* to format the toString()
81			*
82			* @return the name of this class and its CVS revision
83			*/
84			public String toString() {
85			return FormatName.getName(
86			_name,
87			getClass().getName(),
88			REVISION);
89			}
90
91			//---PRIVATE METHODS---
92
93			//---ACCESSOR/MUTATOR METHODS---
94
95			//---ATTRIBUTES---
96
97			/**
98			* This is the friendly identifier of the
99			* component this class is running in.
100			* eg, a Filter may be called "filter1",
101			* If this class does not have an owning
102			* component, a name from the configuration
103			* can be placed here. This name could also
104			* be changed to null for utility classes.
105			*/
106			private String _name = null;
107
108			/**
109			* The Queue we're monitoring.
110			*/
111			private Queue _sourceQueue;
112
113			/**
114			* The Queue we'll output results to.
115			*/
116			private Queue _destQueue;
117
118			/**
119			* The interval at which we'll check the
120			* sourceQueue status.
121			*/
122			private long _interval;
123
124			/**
125			* The name to identify the source Queue
126			*/
127			private String _srcName;
128
129			/**
130			* Allows us to stop the main loop cleanly.
131			*/
132			private boolean _run;
133
134			//---STATIC ATTRIBUTES---
135
136			}