server/filter/UDPReader.java

//---PACKAGE DECLARATION---
package uk.org.iscream.filter;

//---IMPORTS---
import java.io.*;
import java.net.*;
import java.util.*;
import uk.org.iscream.core.*;
import uk.org.iscream.componentmanager.*;
import uk.org.iscream.filter.*;
import uk.org.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 1.16 2001/03/13 02:19:46 tdb1 Exp $
 */
public class UDPReader extends Thread{

//---FINAL ATTRIBUTES---

    /**
     * The current CVS revision of this class
     */
    public final String REVISION = "$Revision: 1.16 $";
    
    /**
     * 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){
        // set the Thread name
        setName("filter.UDPReader");
        
        _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.org.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:	1.17
Committed:	Wed Mar 14 23:25:29 2001 UTC (23 years, 2 months ago) by tdb
Branch:	MAIN
CVS Tags:	PROJECT_COMPLETION
Changes since 1.16:	+8 -8 lines
Log Message:	The whole server package structure has been changed. Old Package: uk.ac.ukc.iscream.* New Package: uk.org.iscream.*
#	Content
1	//---PACKAGE DECLARATION---
2	package uk.org.iscream.filter;
3
4	//---IMPORTS---
5	import java.io.*;
6	import java.net.*;
7	import java.util.*;
8	import uk.org.iscream.core.*;
9	import uk.org.iscream.componentmanager.*;
10	import uk.org.iscream.filter.*;
11	import uk.org.iscream.util.*;
12
13	/**
14	* This class contains the main method to be run by
15	* the filterd. It harvests UDP traffic, and queues it.
16	*
17	* @author $Author: tdb1 $
18	* @version $Id: UDPReader.java,v 1.16 2001/03/13 02:19:46 tdb1 Exp $
19	*/
20	public class UDPReader extends Thread{
21
22	//---FINAL ATTRIBUTES---
23
24	/**
25	* The current CVS revision of this class
26	*/
27	public final String REVISION = "$Revision: 1.16 $";
28
29	/**
30	* The maximum size of a packet
31	*/
32	private final int packetSizeLimit = 8192;
33
34	//---STATIC METHODS---
35
36	//---CONSTRUCTORS---
37
38	/**
39	* 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	*/
44	public UDPReader(int port, Queue queue){
45	// set the Thread name
46	setName("filter.UDPReader");
47
48	_port = port;
49	_queue = queue;
50	_logger.write(toString(), Logger.SYSINIT, "started");
51	}
52
53	//---PUBLIC METHODS---
54
55	/**
56	* The main method in the class. Reads and queues XML sent
57	* over UDP.
58	*/
59	public void run() {
60
61	// setup a Datagram socket
62	DatagramSocket socket = null;
63	try {
64	socket = new DatagramSocket(_port);
65	}
66	catch (BindException e){
67	_logger.write(this.toString(), Logger.FATAL, "Could not start the UDPReader thread on port "+_port+" as this port was already in use.");
68	return;
69	}
70	catch (Exception e){
71	_logger.write(this.toString(), Logger.FATAL, "Could not start the UDPReader thread on port "+_port+".");
72	return;
73	}
74
75	_logger.write(this.toString(), Logger.SYSMSG, "UDPReader thread ready and listening for UDP packets on port "+_port);
76
77	byte[] buf;
78
79	// read UDP packets and queue them
80	boolean running = true;
81	while (running){
82	try {
83
84	// receive request and put it in the Queue
85	buf = new byte[packetSizeLimit];
86	DatagramPacket packet = new DatagramPacket(buf, buf.length);
87	socket.receive(packet);
88	String xml = new String(packet.getData());
89	_queue.add(xml);
90	}
91	catch (IOException e) {
92	_logger.write(this.toString(), Logger.WARNING, "This UDPReader thread has been shut down as an exception occured: "+e);
93	running = false;
94	}
95	}
96	socket.close();
97	}
98
99	/**
100	* Overrides the {@link java.lang.Object#toString() Object.toString()}
101	* method to provide clean logging (every class should have this).
102	*
103	* This uses the uk.org.iscream.util.NameFormat class
104	* to format the toString()
105	*
106	* @return the name of this class and its CVS revision
107	*/
108	public String toString() {
109	return FormatName.getName(
110	_name,
111	getClass().getName(),
112	REVISION);
113	}
114
115	//---PRIVATE METHODS---
116
117	//---ACCESSOR/MUTATOR METHODS---
118
119	//---ATTRIBUTES---
120
121	/**
122	* This is the friendly identifier of the
123	* component this class is running in.
124	* eg, a Filter may be called "filter1",
125	* If this class does not have an owning
126	* component, a name from the configuration
127	* can be placed here. This name could also
128	* be changed to null for utility classes.
129	*/
130	private String _name = FilterMain.NAME;
131
132	/**
133	* This holds a reference to the
134	* system logger that is being used.
135	*/
136	private Logger _logger = ReferenceManager.getInstance().getLogger();
137
138	/**
139	* The port that this reader is using
140	*/
141	int _port;
142
143	/**
144	* The Queue object
145	*/
146	Queue _queue;
147
148	//---STATIC ATTRIBUTES---
149
150	}