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.*;

/**
 * This class contains the main method to be run by
 * the filter children.  It harvests UDP traffic.
 *
 * @author  $Author$
 * @version $Id$
 */
public class UDPReader extends Thread{

//---FINAL ATTRIBUTES---

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

//---CONSTRUCTORS---

    // It is normal to use this constructor in preference
    // to any other in this class.
    public UDPReader(int port, Filter parent, Logger logger){
        this.logger = logger;
        this.port = port;
        this.parent = parent;
    }
    
    public UDPReader(Filter parent, Logger logger){
        this(4589, parent, logger);
    }

//---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, logger);
                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;
    int port;
    Filter parent;    

    final int packetSizeLimit = 8192;

//---STATIC ATTRIBUTES---

}
Revision:	1.6
Committed:	Wed Nov 29 19:26:00 2000 UTC (23 years, 6 months ago) by tdb
Branch:	MAIN
Changes since 1.5:	+44 -6 lines
Log Message:	Made changes to fit into the new package structure. Also made all classes, namely the UDPReader and FilterThread, conform to the Template class specification.
#	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	pjm2	1.1
11	tdb	1.6	/**
12			* This class contains the main method to be run by
13			* the filter children. It harvests UDP traffic.
14			*
15			* @author $Author$
16			* @version $Id$
17			*/
18	pjm2	1.1	public class UDPReader extends Thread{
19
20	tdb	1.6	//---FINAL ATTRIBUTES---
21
22			/**
23			* The current CVS revision of this class
24			*/
25			public final String REVISION = "$Revision: 1.1 $";
26
27			//---STATIC METHODS---
28
29			//---CONSTRUCTORS---
30
31	pjm2	1.1	// It is normal to use this constructor in preference
32			// to any other in this class.
33	tdb	1.2	public UDPReader(int port, Filter parent, Logger logger){
34	pjm2	1.1	this.logger = logger;
35			this.port = port;
36	tdb	1.2	this.parent = parent;
37	pjm2	1.1	}
38
39	tdb	1.2	public UDPReader(Filter parent, Logger logger){
40			this(4589, parent, logger);
41	pjm2	1.1	}
42
43	tdb	1.6	//---PUBLIC METHODS---
44
45	pjm2	1.1	public void run() {
46
47			DatagramSocket socket = null;
48			try {
49			socket = new DatagramSocket(port);
50			}
51			catch (BindException e){
52	pjm2	1.4	logger.write(this.toString(), Logger.FATAL, "Could not start the UDPReader thread on port "+port+" as this port was already in use.");
53	pjm2	1.1	return;
54			}
55			catch (Exception e){
56	pjm2	1.4	logger.write(this.toString(), Logger.FATAL, "Could not start the UDPReader thread on port "+port+".");
57	pjm2	1.1	return;
58			}
59
60			logger.write(this.toString(), Logger.SYSMSG, "UDPReader thread ready and listening for UDP packets on port "+port);
61
62			byte[] buf;
63
64			boolean running = true;
65			while (running){
66			try {
67	pjm2	1.3
68			// receive request and pass on to the FilterThread.
69	pjm2	1.1	buf = new byte[packetSizeLimit];
70			DatagramPacket packet = new DatagramPacket(buf, buf.length);
71			socket.receive(packet);
72	pjm2	1.5	FilterThread t = new FilterThread(packet, parent, logger);
73	pjm2	1.3	t.start();
74
75	pjm2	1.1	}
76			catch (IOException e) {
77	pjm2	1.4	logger.write(this.toString(), Logger.WARNING, "This UDPReader thread has been shut down as an exception occured: "+e);
78	pjm2	1.1	return;
79			}
80			}
81			socket.close();
82			}
83	tdb	1.6
84			/**
85			* Overrides the {@link java.lang.Object#toString() Object.toString()}
86			* method to provide clean logging (every class should have this).
87			*
88			* @return the name of this class and its CVS revision
89			*/
90			public String toString() {
91			return this.getClass().getName() + "(" + REVISION.substring(11, REVISION.length() - 2) + ")";
92			}
93
94			//---PRIVATE METHODS---
95
96			//---ACCESSOR/MUTATOR METHODS---
97
98			//---ATTRIBUTES---
99
100	pjm2	1.1	Logger logger;
101			int port;
102	tdb	1.2	Filter parent;
103
104	pjm2	1.1	final int packetSizeLimit = 8192;
105	tdb	1.6
106			//---STATIC ATTRIBUTES---
107
108	pjm2	1.1	}