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.componentmanager.*;
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: tdb1 $
 * @version $Id: UDPReader.java,v 1.12 2001/01/12 00:45:25 tdb1 Exp $
 */
public class UDPReader extends Thread{

//---FINAL ATTRIBUTES---

    /**
     * The current CVS revision of this class
     */
    public final String REVISION = "$Revision: 1.12 $";

    /**
     * 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, Queue queue){
        _port = port;
        _queue = queue;
    }

//---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 put it in the Queue               
                buf = new byte[packetSizeLimit];
                DatagramPacket packet = new DatagramPacket(buf, buf.length);
                socket.receive(packet);
                String xml = new String(packet.getData());
                _queue.add(xml);
            }
            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 Queue object
     */
    Queue _queue;    

//---STATIC ATTRIBUTES---

}
Revision:	1.13
Committed:	Thu Jan 18 23:16:21 2001 UTC (23 years, 4 months ago) by tdb
Branch:	MAIN
Changes since 1.12:	+4 -3 lines
Log Message:	Changes to reflect move of Component, ComponentStartException, and the ReferenceManager from util to componentmanager.
#	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	tdb	1.13	import uk.ac.ukc.iscream.componentmanager.*;
10	tdb	1.2	import uk.ac.ukc.iscream.filter.*;
11	ajm	1.9	import uk.ac.ukc.iscream.util.*;
12	pjm2	1.1
13	tdb	1.6	/**
14			* This class contains the main method to be run by
15			* the filter children. It harvests UDP traffic.
16			*
17	tdb	1.13	* @author $Author: tdb1 $
18			* @version $Id: UDPReader.java,v 1.12 2001/01/12 00:45:25 tdb1 Exp $
19	tdb	1.6	*/
20	pjm2	1.1	public class UDPReader extends Thread{
21
22	tdb	1.6	//---FINAL ATTRIBUTES---
23
24			/**
25			* The current CVS revision of this class
26			*/
27	tdb	1.13	public final String REVISION = "$Revision: 1.12 $";
28	ajm	1.11
29			/**
30			* The maximum size of a packet
31			*/
32			private final int packetSizeLimit = 8192;
33	tdb	1.6
34			//---STATIC METHODS---
35
36			//---CONSTRUCTORS---
37
38	ajm	1.10	/**
39			* It is normal to use this constructor in preference
40			* to any other in this class.
41			*/
42	tdb	1.12	public UDPReader(int port, Queue queue){
43	tdb	1.8	_port = port;
44	tdb	1.12	_queue = queue;
45	pjm2	1.1	}
46
47	tdb	1.6	//---PUBLIC METHODS---
48
49	pjm2	1.1	public void run() {
50
51			DatagramSocket socket = null;
52			try {
53	tdb	1.8	socket = new DatagramSocket(_port);
54	pjm2	1.1	}
55			catch (BindException e){
56	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.");
57	pjm2	1.1	return;
58			}
59			catch (Exception e){
60	tdb	1.8	_logger.write(this.toString(), Logger.FATAL, "Could not start the UDPReader thread on port "+_port+".");
61	pjm2	1.1	return;
62			}
63
64	tdb	1.8	_logger.write(this.toString(), Logger.SYSMSG, "UDPReader thread ready and listening for UDP packets on port "+_port);
65	pjm2	1.1
66			byte[] buf;
67
68			boolean running = true;
69			while (running){
70			try {
71	pjm2	1.3
72	tdb	1.12	// receive request and put it in the Queue
73	pjm2	1.1	buf = new byte[packetSizeLimit];
74			DatagramPacket packet = new DatagramPacket(buf, buf.length);
75			socket.receive(packet);
76	tdb	1.12	String xml = new String(packet.getData());
77			_queue.add(xml);
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	tdb	1.12	* The Queue object
133	ajm	1.11	*/
134	tdb	1.12	Queue _queue;
135	tdb	1.6
136			//---STATIC ATTRIBUTES---
137
138	pjm2	1.1	}