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 filterd.  It harvests UDP traffic, and queues it.
 *
 * @author  $Author: tdb1 $
 * @version $Id: UDPReader.java,v 1.14 2001/01/28 05:34:38 tdb1 Exp $
 */
public class UDPReader extends Thread{

//---FINAL ATTRIBUTES---

    /**
     * The current CVS revision of this class
     */
    public final String REVISION = "$Revision: 1.14 $";
    
    /**
     * The maximum size of a packet
     */
    private final int packetSizeLimit = 8192;   
    
//---STATIC METHODS---

//---CONSTRUCTORS---

    /**
     * Constructs a new UDPReader.
     *
     * @param port The port on which we listen for UDP data
     * @param queue The queue which we are using
     */
    public UDPReader(int port, Queue queue){
        _port = port;
        _queue = queue;
        _logger.write(toString(), Logger.SYSINIT, "started");
    }

//---PUBLIC METHODS---
    
    /**
     * The main method in the class. Reads and queues XML sent
     * over UDP.
     */
    public void run() {
        
        // setup a Datagram socket
        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;
        
        // read UDP packets and queue them
        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);
                running = false;
            }
        }
        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:	1.15
Committed:	Thu Feb 1 00:18:42 2001 UTC (23 years, 3 months ago) by tdb
Branch:	MAIN
Changes since 1.14:	+10 -9 lines
Log Message:	General tidy up, specifically focussing on the verbosity of logging messages.
#	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	tdb	1.14	* the filterd. It harvests UDP traffic, and queues it.
16	tdb	1.6	*
17	tdb	1.13	* @author $Author: tdb1 $
18	tdb	1.15	* @version $Id: UDPReader.java,v 1.14 2001/01/28 05:34:38 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	1.15	public final String REVISION = "$Revision: 1.14 $";
28
29	ajm	1.11	/**
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	tdb	1.14	* Constructs a new UDPReader.
40			*
41			* @param port The port on which we listen for UDP data
42			* @param queue The queue which we are using
43	ajm	1.10	*/
44	tdb	1.12	public UDPReader(int port, Queue queue){
45	tdb	1.8	_port = port;
46	tdb	1.12	_queue = queue;
47	tdb	1.15	_logger.write(toString(), Logger.SYSINIT, "started");
48	pjm2	1.1	}
49
50	tdb	1.6	//---PUBLIC METHODS---
51	tdb	1.14
52			/**
53			* The main method in the class. Reads and queues XML sent
54			* over UDP.
55			*/
56	pjm2	1.1	public void run() {
57	tdb	1.14
58			// setup a Datagram socket
59	pjm2	1.1	DatagramSocket socket = null;
60			try {
61	tdb	1.8	socket = new DatagramSocket(_port);
62	pjm2	1.1	}
63			catch (BindException e){
64	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.");
65	pjm2	1.1	return;
66			}
67			catch (Exception e){
68	tdb	1.8	_logger.write(this.toString(), Logger.FATAL, "Could not start the UDPReader thread on port "+_port+".");
69	pjm2	1.1	return;
70			}
71
72	tdb	1.8	_logger.write(this.toString(), Logger.SYSMSG, "UDPReader thread ready and listening for UDP packets on port "+_port);
73	tdb	1.15
74	pjm2	1.1	byte[] buf;
75
76	tdb	1.14	// read UDP packets and queue them
77	pjm2	1.1	boolean running = true;
78			while (running){
79			try {
80	tdb	1.15
81			// receive request and put it in the Queue
82	pjm2	1.1	buf = new byte[packetSizeLimit];
83			DatagramPacket packet = new DatagramPacket(buf, buf.length);
84			socket.receive(packet);
85	tdb	1.12	String xml = new String(packet.getData());
86			_queue.add(xml);
87	pjm2	1.1	}
88			catch (IOException e) {
89	tdb	1.8	_logger.write(this.toString(), Logger.WARNING, "This UDPReader thread has been shut down as an exception occured: "+e);
90	tdb	1.14	running = false;
91	pjm2	1.1	}
92			}
93			socket.close();
94			}
95	tdb	1.15
96	tdb	1.6	/**
97			* Overrides the {@link java.lang.Object#toString() Object.toString()}
98			* method to provide clean logging (every class should have this).
99			*
100	ajm	1.11	* This uses the uk.ac.ukc.iscream.util.NameFormat class
101			* to format the toString()
102			*
103	tdb	1.6	* @return the name of this class and its CVS revision
104			*/
105			public String toString() {
106	ajm	1.11	return FormatName.getName(
107			_name,
108			getClass().getName(),
109			REVISION);
110	tdb	1.6	}
111
112			//---PRIVATE METHODS---
113
114			//---ACCESSOR/MUTATOR METHODS---
115
116			//---ATTRIBUTES---
117
118	ajm	1.11	/**
119			* This is the friendly identifier of the
120			* component this class is running in.
121			* eg, a Filter may be called "filter1",
122			* If this class does not have an owning
123			* component, a name from the configuration
124			* can be placed here. This name could also
125			* be changed to null for utility classes.
126			*/
127			private String _name = FilterMain.NAME;
128	tdb	1.15
129	ajm	1.11	/**
130			* This holds a reference to the
131			* system logger that is being used.
132			*/
133			private Logger _logger = ReferenceManager.getInstance().getLogger();
134
135			/**
136			* The port that this reader is using
137			*/
138	tdb	1.8	int _port;
139	ajm	1.11
140			/**
141	tdb	1.12	* The Queue object
142	ajm	1.11	*/
143	tdb	1.15	Queue _queue;
144	tdb	1.6
145			//---STATIC ATTRIBUTES---
146
147	pjm2	1.1	}