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 1.10 2000/12/13 13:36:46 ajm4 Exp $
 */
public class UDPReader extends Thread{

//---FINAL ATTRIBUTES---

    /**
     * The current CVS revision of this class
     */
    public final String REVISION = "$Revision: 1.10 $";

    /**
     * The maximum size of a packet
     */
    private final int packetSizeLimit = 8192;   
    
//---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).
     *
     * This uses the uk.ac.ukc.iscream.util.NameFormat 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 = FilterMain.NAME;

    /**
     * This holds a reference to the
     * system logger that is being used.
     */
    private Logger _logger = ReferenceManager.getInstance().getLogger();
    
    /**
     * The port that this reader is using
     */
    int _port;
    
    /**
     * The parent of this filter
     */
    Filter _parent;    

//---STATIC ATTRIBUTES---

}
Revision:	1.11
Committed:	Wed Dec 13 21:11:26 2000 UTC (23 years, 5 months ago) by ajm
Branch:	MAIN
Changes since 1.10:	+38 -6 lines
Log Message:	updated for new toString etc.
#	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	ajm	1.11	* @version $Id: UDPReader.java,v 1.10 2000/12/13 13:36:46 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	1.11	public final String REVISION = "$Revision: 1.10 $";
27
28			/**
29			* The maximum size of a packet
30			*/
31			private final int packetSizeLimit = 8192;
32	tdb	1.6
33			//---STATIC METHODS---
34
35			//---CONSTRUCTORS---
36
37	ajm	1.10	/**
38			* It is normal to use this constructor in preference
39			* to any other in this class.
40			*/
41	tdb	1.8	public UDPReader(int port, Filter parent){
42			_port = port;
43			_parent = parent;
44	pjm2	1.1	}
45
46	tdb	1.6	//---PUBLIC METHODS---
47
48	pjm2	1.1	public void run() {
49
50			DatagramSocket socket = null;
51			try {
52	tdb	1.8	socket = new DatagramSocket(_port);
53	pjm2	1.1	}
54			catch (BindException e){
55	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.");
56	pjm2	1.1	return;
57			}
58			catch (Exception e){
59	tdb	1.8	_logger.write(this.toString(), Logger.FATAL, "Could not start the UDPReader thread on port "+_port+".");
60	pjm2	1.1	return;
61			}
62
63	tdb	1.8	_logger.write(this.toString(), Logger.SYSMSG, "UDPReader thread ready and listening for UDP packets on port "+_port);
64	pjm2	1.1
65			byte[] buf;
66
67			boolean running = true;
68			while (running){
69			try {
70	pjm2	1.3
71			// receive request and pass on to the FilterThread.
72	pjm2	1.1	buf = new byte[packetSizeLimit];
73			DatagramPacket packet = new DatagramPacket(buf, buf.length);
74			socket.receive(packet);
75	tdb	1.8	FilterThread t = new FilterThread(packet, _parent);
76	pjm2	1.3	t.start();
77
78	pjm2	1.1	}
79			catch (IOException e) {
80	tdb	1.8	_logger.write(this.toString(), Logger.WARNING, "This UDPReader thread has been shut down as an exception occured: "+e);
81	pjm2	1.1	return;
82			}
83			}
84			socket.close();
85			}
86	tdb	1.6
87			/**
88			* Overrides the {@link java.lang.Object#toString() Object.toString()}
89			* method to provide clean logging (every class should have this).
90			*
91	ajm	1.11	* This uses the uk.ac.ukc.iscream.util.NameFormat class
92			* to format the toString()
93			*
94	tdb	1.6	* @return the name of this class and its CVS revision
95			*/
96			public String toString() {
97	ajm	1.11	return FormatName.getName(
98			_name,
99			getClass().getName(),
100			REVISION);
101	tdb	1.6	}
102
103			//---PRIVATE METHODS---
104
105			//---ACCESSOR/MUTATOR METHODS---
106
107			//---ATTRIBUTES---
108
109	ajm	1.11	/**
110			* This is the friendly identifier of the
111			* component this class is running in.
112			* eg, a Filter may be called "filter1",
113			* If this class does not have an owning
114			* component, a name from the configuration
115			* can be placed here. This name could also
116			* be changed to null for utility classes.
117			*/
118			private String _name = FilterMain.NAME;
119
120			/**
121			* This holds a reference to the
122			* system logger that is being used.
123			*/
124			private Logger _logger = ReferenceManager.getInstance().getLogger();
125
126			/**
127			* The port that this reader is using
128			*/
129	tdb	1.8	int _port;
130	ajm	1.11
131			/**
132			* The parent of this filter
133			*/
134	tdb	1.8	Filter _parent;
135	tdb	1.6
136			//---STATIC ATTRIBUTES---
137
138	pjm2	1.1	}