server/filter/UDPReader.java

/* 
 * i-scream central monitoring system
 * http://www.i-scream.org.uk
 * Copyright (C) 2000-2002 i-scream
 * 
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 * 
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 * 
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
 */

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

//---IMPORTS---
import java.io.*;
import java.net.*;
import java.util.*;
import uk.org.iscream.cms.server.core.*;
import uk.org.iscream.cms.server.componentmanager.*;
import uk.org.iscream.cms.server.filter.*;
import uk.org.iscream.cms.util.*;

/**
 * This class contains the main method to be run by
 * the filterd.  It harvests UDP traffic, and queues it.
 *
 * @author  $Author: tdb $
 * @version $Id: UDPReader.java,v 1.24 2002/05/21 16:47:17 tdb Exp $
 */
public class UDPReader extends Thread{

//---FINAL ATTRIBUTES---

    /**
     * The current CVS revision of this class
     */
    public final String REVISION = "$Revision: 1.24 $";
    
    /**
     * 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 an empty ACL defaulting to ALLOW
        ACL acl = new ACL(ACL.ALLOW);
        
        // setup a Datagram socket
        DatagramSocket socket = null;
        try {
            socket = new ACLDatagramSocket(acl, _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;
        
        ConfigurationProxy cp = ConfigurationProxy.getInstance();
        String stringACL = "";
        String newStringACL = "";
        
        // read UDP packets and queue them
        boolean running = true;
        while (running){
            // get hold of the ACL in the configuration
            try {
                newStringACL = cp.getProperty("Filter." + FilterMain.NAME, "Filter.UDPACL");
            }
            catch(PropertyNotFoundException e) {
                // if we can't find it, we'll just use a null ACL
                newStringACL = "";
                _logger.write(toString(), Logger.WARNING, "No ACL found for UDPReader, using empty ACL instead: " + e);
            }
            // check to see if the ACL has changed
            if(!newStringACL.equals(stringACL)) {
                _logger.write(toString(), Logger.SYSMSG, "Reloading Access Control List");
                // clear the ACL
                acl.clear();
                // set the default to something sane
                acl.setDefaultMode(ACL.ALLOW);
                // add the new ACL (this may change the default)
                acl.add(newStringACL);
                stringACL = newStringACL;
            }
            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.cms.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:	1.25
Committed:	Wed Feb 5 16:43:47 2003 UTC (21 years, 3 months ago) by tdb
Branch:	MAIN
Changes since 1.24:	+4 -4 lines
Log Message:	Changed the server to use the external util package. Quite a minor change, but does affect a lot of files.
#	User	Rev	Content
1	tdb	1.23	/*
2			* i-scream central monitoring system
3	tdb	1.24	* http://www.i-scream.org.uk
4	tdb	1.23	* Copyright (C) 2000-2002 i-scream
5			*
6			* This program is free software; you can redistribute it and/or
7			* modify it under the terms of the GNU General Public License
8			* as published by the Free Software Foundation; either version 2
9			* of the License, or (at your option) any later version.
10			*
11			* This program is distributed in the hope that it will be useful,
12			* but WITHOUT ANY WARRANTY; without even the implied warranty of
13			* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14			* GNU General Public License for more details.
15			*
16			* You should have received a copy of the GNU General Public License
17			* along with this program; if not, write to the Free Software
18			* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
19			*/
20
21	tdb	1.6	//---PACKAGE DECLARATION---
22	tdb	1.18	package uk.org.iscream.cms.server.filter;
23	tdb	1.6
24			//---IMPORTS---
25	pjm2	1.1	import java.io.*;
26			import java.net.*;
27			import java.util.*;
28	tdb	1.18	import uk.org.iscream.cms.server.core.*;
29			import uk.org.iscream.cms.server.componentmanager.*;
30			import uk.org.iscream.cms.server.filter.*;
31	tdb	1.25	import uk.org.iscream.cms.util.*;
32	pjm2	1.1
33	tdb	1.6	/**
34			* This class contains the main method to be run by
35	tdb	1.14	* the filterd. It harvests UDP traffic, and queues it.
36	tdb	1.6	*
37	tdb	1.19	* @author $Author: tdb $
38	tdb	1.25	* @version $Id: UDPReader.java,v 1.24 2002/05/21 16:47:17 tdb Exp $
39	tdb	1.6	*/
40	pjm2	1.1	public class UDPReader extends Thread{
41
42	tdb	1.6	//---FINAL ATTRIBUTES---
43
44			/**
45			* The current CVS revision of this class
46			*/
47	tdb	1.25	public final String REVISION = "$Revision: 1.24 $";
48	tdb	1.15
49	ajm	1.11	/**
50			* The maximum size of a packet
51			*/
52			private final int packetSizeLimit = 8192;
53	tdb	1.6
54			//---STATIC METHODS---
55
56			//---CONSTRUCTORS---
57
58	ajm	1.10	/**
59	tdb	1.14	* Constructs a new UDPReader.
60			*
61			* @param port The port on which we listen for UDP data
62			* @param queue The queue which we are using
63	ajm	1.10	*/
64	tdb	1.12	public UDPReader(int port, Queue queue){
65	tdb	1.16	// set the Thread name
66			setName("filter.UDPReader");
67
68	tdb	1.8	_port = port;
69	tdb	1.12	_queue = queue;
70	tdb	1.15	_logger.write(toString(), Logger.SYSINIT, "started");
71	pjm2	1.1	}
72
73	tdb	1.6	//---PUBLIC METHODS---
74	tdb	1.14
75			/**
76			* The main method in the class. Reads and queues XML sent
77			* over UDP.
78			*/
79	pjm2	1.1	public void run() {
80	tdb	1.22	// setup an empty ACL defaulting to ALLOW
81			ACL acl = new ACL(ACL.ALLOW);
82	tdb	1.14
83			// setup a Datagram socket
84	pjm2	1.1	DatagramSocket socket = null;
85			try {
86	tdb	1.22	socket = new ACLDatagramSocket(acl, _port);
87	pjm2	1.1	}
88			catch (BindException e){
89	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.");
90	pjm2	1.1	return;
91			}
92			catch (Exception e){
93	tdb	1.8	_logger.write(this.toString(), Logger.FATAL, "Could not start the UDPReader thread on port "+_port+".");
94	pjm2	1.1	return;
95			}
96
97	tdb	1.8	_logger.write(this.toString(), Logger.SYSMSG, "UDPReader thread ready and listening for UDP packets on port "+_port);
98	tdb	1.15
99	pjm2	1.1	byte[] buf;
100
101	tdb	1.22	ConfigurationProxy cp = ConfigurationProxy.getInstance();
102			String stringACL = "";
103			String newStringACL = "";
104
105	tdb	1.14	// read UDP packets and queue them
106	pjm2	1.1	boolean running = true;
107			while (running){
108	tdb	1.22	// get hold of the ACL in the configuration
109			try {
110			newStringACL = cp.getProperty("Filter." + FilterMain.NAME, "Filter.UDPACL");
111			}
112			catch(PropertyNotFoundException e) {
113			// if we can't find it, we'll just use a null ACL
114			newStringACL = "";
115			_logger.write(toString(), Logger.WARNING, "No ACL found for UDPReader, using empty ACL instead: " + e);
116			}
117			// check to see if the ACL has changed
118			if(!newStringACL.equals(stringACL)) {
119			_logger.write(toString(), Logger.SYSMSG, "Reloading Access Control List");
120			// clear the ACL
121			acl.clear();
122			// set the default to something sane
123			acl.setDefaultMode(ACL.ALLOW);
124			// add the new ACL (this may change the default)
125			acl.add(newStringACL);
126			stringACL = newStringACL;
127			}
128	pjm2	1.1	try {
129	tdb	1.15
130			// receive request and put it in the Queue
131	pjm2	1.1	buf = new byte[packetSizeLimit];
132			DatagramPacket packet = new DatagramPacket(buf, buf.length);
133			socket.receive(packet);
134	tdb	1.12	String xml = new String(packet.getData());
135			_queue.add(xml);
136	pjm2	1.1	}
137			catch (IOException e) {
138	tdb	1.8	_logger.write(this.toString(), Logger.WARNING, "This UDPReader thread has been shut down as an exception occured: "+e);
139	tdb	1.14	running = false;
140	pjm2	1.1	}
141			}
142			socket.close();
143			}
144	tdb	1.15
145	tdb	1.6	/**
146			* Overrides the {@link java.lang.Object#toString() Object.toString()}
147			* method to provide clean logging (every class should have this).
148			*
149	tdb	1.25	* This uses the uk.org.iscream.cms.util.NameFormat class
150	ajm	1.11	* to format the toString()
151			*
152	tdb	1.6	* @return the name of this class and its CVS revision
153			*/
154			public String toString() {
155	ajm	1.11	return FormatName.getName(
156			_name,
157			getClass().getName(),
158			REVISION);
159	tdb	1.6	}
160
161			//---PRIVATE METHODS---
162
163			//---ACCESSOR/MUTATOR METHODS---
164
165			//---ATTRIBUTES---
166
167	ajm	1.11	/**
168			* This is the friendly identifier of the
169			* component this class is running in.
170			* eg, a Filter may be called "filter1",
171			* If this class does not have an owning
172			* component, a name from the configuration
173			* can be placed here. This name could also
174			* be changed to null for utility classes.
175			*/
176			private String _name = FilterMain.NAME;
177	tdb	1.15
178	ajm	1.11	/**
179			* This holds a reference to the
180			* system logger that is being used.
181			*/
182			private Logger _logger = ReferenceManager.getInstance().getLogger();
183
184			/**
185			* The port that this reader is using
186			*/
187	tdb	1.8	int _port;
188	ajm	1.11
189			/**
190	tdb	1.12	* The Queue object
191	ajm	1.11	*/
192	tdb	1.15	Queue _queue;
193	tdb	1.6
194			//---STATIC ATTRIBUTES---
195
196	pjm2	1.1	}