server/filter/UDPReader.java

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

//---IMPORTS---
import java.io.*;
import java.net.*;
import java.util.*;
import uk.ac.ukc.iscream.core.*;
import uk.ac.ukc.iscream.filter.*;
import uk.ac.ukc.iscream.util.*;

/**
 * This class contains the main method to be run by
 * the filter children.  It harvests UDP traffic.
 *
 * @author  $Author: ajm4 $
 * @version $Id: UDPReader.java,v 1.9 2000/11/30 02:38:09 ajm4 Exp $
 */
public class UDPReader extends Thread{

//---FINAL ATTRIBUTES---

    /**
     * The current CVS revision of this class
     */
    public final String REVISION = "$Revision: 1.9 $";
    
//---STATIC METHODS---

//---CONSTRUCTORS---

    /**
     * It is normal to use this constructor in preference
     * to any other in this class.
     */
    public UDPReader(int port, Filter parent){
        _port = port;
        _parent = parent;
    }

//---PUBLIC METHODS---

    public void run() {

        DatagramSocket socket = null;
        try {
            socket = new DatagramSocket(_port);
        }
        catch (BindException e){
            _logger.write(this.toString(), Logger.FATAL, "Could not start the UDPReader thread on port "+_port+" as this port was already in use.");
            return;
        }
        catch (Exception e){
            _logger.write(this.toString(), Logger.FATAL, "Could not start the UDPReader thread on port "+_port+".");
            return;
        }
        
        _logger.write(this.toString(), Logger.SYSMSG, "UDPReader thread ready and listening for UDP packets on port "+_port);

        byte[] buf;
        
        boolean running = true;
        while (running){
            try {

                    // receive request and pass on to the FilterThread.                
                buf = new byte[packetSizeLimit];
                DatagramPacket packet = new DatagramPacket(buf, buf.length);
                socket.receive(packet);
                FilterThread t = new FilterThread(packet, _parent);
                t.start();

            }
            catch (IOException e) {
                _logger.write(this.toString(), Logger.WARNING, "This UDPReader thread has been shut down as an exception occured: "+e);
                return;
            }
        }
        socket.close();
    }

    /**
     * Overrides the {@link java.lang.Object#toString() Object.toString()}
     * method to provide clean logging (every class should have this).
     *
     * @return the name of this class and its CVS revision
     */
    public String toString() {
        return this.getClass().getName() + "(" + REVISION.substring(11, REVISION.length() - 2) + ")";
    }

//---PRIVATE METHODS---

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

//---ATTRIBUTES---

    Logger _logger = ReferenceManager.getInstance().getLogger();
    int _port;
    Filter _parent;    

    final int packetSizeLimit = 8192;

//---STATIC ATTRIBUTES---

}
Revision:	1.10
Committed:	Wed Dec 13 13:36:46 2000 UTC (23 years, 5 months ago) by ajm
Branch:	MAIN
Changes since 1.9:	+7 -5 lines
Log Message:	componenterized the filter and tidied all child classes, no all conform to toString standard
#	User	Rev	Content
1	tdb	1.6	//---PACKAGE DECLARATION---
2			package uk.ac.ukc.iscream.filter;
3
4			//---IMPORTS---
5	pjm2	1.1	import java.io.*;
6			import java.net.*;
7			import java.util.*;
8	tdb	1.2	import uk.ac.ukc.iscream.core.*;
9			import uk.ac.ukc.iscream.filter.*;
10	ajm	1.9	import uk.ac.ukc.iscream.util.*;
11	pjm2	1.1
12	tdb	1.6	/**
13			* This class contains the main method to be run by
14			* the filter children. It harvests UDP traffic.
15			*
16	ajm	1.10	* @author $Author: ajm4 $
17			* @version $Id: UDPReader.java,v 1.9 2000/11/30 02:38:09 ajm4 Exp $
18	tdb	1.6	*/
19	pjm2	1.1	public class UDPReader extends Thread{
20
21	tdb	1.6	//---FINAL ATTRIBUTES---
22
23			/**
24			* The current CVS revision of this class
25			*/
26	ajm	1.10	public final String REVISION = "$Revision: 1.9 $";
27	tdb	1.6
28			//---STATIC METHODS---
29
30			//---CONSTRUCTORS---
31
32	ajm	1.10	/**
33			* It is normal to use this constructor in preference
34			* to any other in this class.
35			*/
36	tdb	1.8	public UDPReader(int port, Filter parent){
37			_port = port;
38			_parent = parent;
39	pjm2	1.1	}
40
41	tdb	1.6	//---PUBLIC METHODS---
42
43	pjm2	1.1	public void run() {
44
45			DatagramSocket socket = null;
46			try {
47	tdb	1.8	socket = new DatagramSocket(_port);
48	pjm2	1.1	}
49			catch (BindException e){
50	tdb	1.8	_logger.write(this.toString(), Logger.FATAL, "Could not start the UDPReader thread on port "+_port+" as this port was already in use.");
51	pjm2	1.1	return;
52			}
53			catch (Exception e){
54	tdb	1.8	_logger.write(this.toString(), Logger.FATAL, "Could not start the UDPReader thread on port "+_port+".");
55	pjm2	1.1	return;
56			}
57
58	tdb	1.8	_logger.write(this.toString(), Logger.SYSMSG, "UDPReader thread ready and listening for UDP packets on port "+_port);
59	pjm2	1.1
60			byte[] buf;
61
62			boolean running = true;
63			while (running){
64			try {
65	pjm2	1.3
66			// receive request and pass on to the FilterThread.
67	pjm2	1.1	buf = new byte[packetSizeLimit];
68			DatagramPacket packet = new DatagramPacket(buf, buf.length);
69			socket.receive(packet);
70	tdb	1.8	FilterThread t = new FilterThread(packet, _parent);
71	pjm2	1.3	t.start();
72
73	pjm2	1.1	}
74			catch (IOException e) {
75	tdb	1.8	_logger.write(this.toString(), Logger.WARNING, "This UDPReader thread has been shut down as an exception occured: "+e);
76	pjm2	1.1	return;
77			}
78			}
79			socket.close();
80			}
81	tdb	1.6
82			/**
83			* Overrides the {@link java.lang.Object#toString() Object.toString()}
84			* method to provide clean logging (every class should have this).
85			*
86			* @return the name of this class and its CVS revision
87			*/
88			public String toString() {
89			return this.getClass().getName() + "(" + REVISION.substring(11, REVISION.length() - 2) + ")";
90			}
91
92			//---PRIVATE METHODS---
93
94			//---ACCESSOR/MUTATOR METHODS---
95
96			//---ATTRIBUTES---
97
98	tdb	1.8	Logger _logger = ReferenceManager.getInstance().getLogger();
99			int _port;
100			Filter _parent;
101	tdb	1.2
102	pjm2	1.1	final int packetSizeLimit = 8192;
103	tdb	1.6
104			//---STATIC ATTRIBUTES---
105
106	pjm2	1.1	}