server/filter/TCPReader.java

//---PACKAGE DECLARATION---
package uk.ac.ukc.iscream.filter;

//---IMPORTS---
import uk.ac.ukc.iscream.core.*;
import uk.ac.ukc.iscream.filter.*;
import java.net.Socket;
import java.net.ServerSocket;
import java.io.OutputStream;
import java.io.IOException;
import java.net.InetAddress;
import java.net.UnknownHostException;
import uk.ac.ukc.iscream.util.*;

/**
 * A socket listener to listen for new hosts registering with the system.
 * When a host makes a connection, the connecton is past to an instance
 * of the HostInit class, which handles further communication.
 *
 * @author  $Author: ajm4 $
 * @version $Id: TCPReader.java,v 1.5 2000/12/13 13:36:46 ajm4 Exp $
 */
class TCPReader extends Thread {

//---FINAL ATTRIBUTES---

    /**
     * The current CVS revision of this class
     */
    public final String REVISION = "$Revision: 1.5 $";
    
//---STATIC METHODS---

//---CONSTRUCTORS---

        /**
     * Constructs a new listener
     *
     * @param logger a reference to the logger we are using
     * @param configManager a reference to the ConfigurationManager we are using
         * @param port The port that the server will listen on.
         */
    public TCPReader(int port, Queue queue) {
        _port = port;
        _queue = queue;
        _logger.write(toString(), Logger.SYSINIT, "started");
    }

    

//---PUBLIC METHODS---

        /**
         * The run() method is the main loop for this thread, and we
         * will remain in here until such a point as something goes
         * wrong with the listening. After initially setting up the
         * ServerSocket we go round a while loop receiving connections
         * and then passing them off to other processes to deal with.
         */
    public void run(){
        ServerSocket listenPort=null;
                // We use this boolean so we can break out of the while loop if we want
        boolean run = true;
        try{
                        // Setup the ServerSocket so that clients can connect
            listenPort = new ServerSocket(_port);
        }
        catch(IOException e){
        }
                // Log what machine/port we're listening on
                try{
                        _logger.write(toString(), Logger.SYSMSG, "TCPReader listening on "
                                                                                +InetAddress.getLocalHost().getHostName()
                                                                                +"/"+InetAddress.getLocalHost().getHostAddress()
                                                                                +" port "+listenPort.getLocalPort());
                }
                catch(UnknownHostException e){
                        _logger.write(toString(), Logger.SYSMSG, "TCPReader listening on UnknownHost "
                                                                                +"port "+listenPort.getLocalPort());
                }
                // Loop round constantly until we decide to stop
        while(run){
            Socket hostSocket=null;
            try{
                _logger.write(toString(), Logger.SYSMSG, "Waiting for Connection");
                                // This will block until a host connects - at which point we get a Socket
                hostSocket = listenPort.accept();
                _logger.write(toString(), Logger.SYSMSG, "Connection accepted from: " + hostSocket.toString());
            }
            catch(IOException e){
                                // Something went wrong with the ServerSocket, so we'll stop listening
                run=false;
            }
                        // If we've stopped on the line above we won't want to try this !
            if(run){
                                try {
                                    // Setup the HostInit so it can carry on communications with the host
                    TCPReaderInit init = new TCPReaderInit(hostSocket, _queue);
                                    // and start it
                    init.start();
                } catch (IOException e) {
                    _logger.write(toString(), Logger.ERROR, e.toString());
                }
            }
        }
                // Best log the fact that we're stopping
        _logger.write(toString(), Logger.FATAL, "Fatal error, shutdown pending");
    }

    /**
     * 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 on which the server should listen.
         */
    private int _port;
    
    private Queue _queue;
    
//---STATIC ATTRIBUTES---

}
Revision:	1.6
Committed:	Fri Jan 12 00:45:25 2001 UTC (23 years, 4 months ago) by tdb
Branch:	MAIN
Changes since 1.5:	+6 -6 lines
Log Message:	A structural change to the Filter. The old setup looked like this; UDPReader ------> FilterThread (thread) --> (parent) TCPReader ------> FilterThread (thread) --> (parent) FilterServant --> FilterThread (thread) --> (parent) Seeing this from a threaded point of view, each time a packet came in (through whatever means - UDP, TCP or CORBA), a FilterThread instance was created to deal with it. If the link to the parent was slow this resulting in a build-up of FilterThreads all waiting to talk to the parent - and there is only one actual parent object, with a synchronised thread, so they have to queue up anyway. As a result of this, the following change has been made. UDPReader -------\ TCPReader ----------> Queue (single) >-- FilterThread --> (parent) FilterServant ---/ In this setup, each of the three objects that generate packets only see the single instance of a Queue. They all add their data to this Queue, and then carry on with the task of listening. The FilterThread (having it's role changed slightly) now acts as a consumer of the Queue, in that it grabs data from the Queue and deals with passing it on to the parent. This setup should be more efficient in the long run, especially under a high load situation. The only problem could be the Queue growing to an unlimited size, but this is a Queue design issue.
#	User	Rev	Content
1	tdb	1.1	//---PACKAGE DECLARATION---
2	tdb	1.2	package uk.ac.ukc.iscream.filter;
3	tdb	1.1
4			//---IMPORTS---
5			import uk.ac.ukc.iscream.core.*;
6			import uk.ac.ukc.iscream.filter.*;
7			import java.net.Socket;
8			import java.net.ServerSocket;
9			import java.io.OutputStream;
10			import java.io.IOException;
11			import java.net.InetAddress;
12			import java.net.UnknownHostException;
13	ajm	1.4	import uk.ac.ukc.iscream.util.*;
14	tdb	1.1
15			/**
16			* A socket listener to listen for new hosts registering with the system.
17			* When a host makes a connection, the connecton is past to an instance
18			* of the HostInit class, which handles further communication.
19			*
20	ajm	1.5	* @author $Author: ajm4 $
21	tdb	1.6	* @version $Id: TCPReader.java,v 1.5 2000/12/13 13:36:46 ajm4 Exp $
22	tdb	1.1	*/
23			class TCPReader extends Thread {
24
25			//---FINAL ATTRIBUTES---
26
27			/**
28			* The current CVS revision of this class
29			*/
30	tdb	1.6	public final String REVISION = "$Revision: 1.5 $";
31	tdb	1.1
32			//---STATIC METHODS---
33
34			//---CONSTRUCTORS---
35
36			/**
37			* Constructs a new listener
38			*
39			* @param logger a reference to the logger we are using
40			* @param configManager a reference to the ConfigurationManager we are using
41			* @param port The port that the server will listen on.
42			*/
43	tdb	1.6	public TCPReader(int port, Queue queue) {
44	tdb	1.1	_port = port;
45	tdb	1.6	_queue = queue;
46	tdb	1.1	_logger.write(toString(), Logger.SYSINIT, "started");
47			}
48
49
50
51			//---PUBLIC METHODS---
52
53			/**
54			* The run() method is the main loop for this thread, and we
55			* will remain in here until such a point as something goes
56			* wrong with the listening. After initially setting up the
57			* ServerSocket we go round a while loop receiving connections
58			* and then passing them off to other processes to deal with.
59			*/
60			public void run(){
61			ServerSocket listenPort=null;
62			// We use this boolean so we can break out of the while loop if we want
63			boolean run = true;
64			try{
65			// Setup the ServerSocket so that clients can connect
66			listenPort = new ServerSocket(_port);
67			}
68			catch(IOException e){
69			}
70			// Log what machine/port we're listening on
71			try{
72			_logger.write(toString(), Logger.SYSMSG, "TCPReader listening on "
73			+InetAddress.getLocalHost().getHostName()
74			+"/"+InetAddress.getLocalHost().getHostAddress()
75			+" port "+listenPort.getLocalPort());
76			}
77			catch(UnknownHostException e){
78			_logger.write(toString(), Logger.SYSMSG, "TCPReader listening on UnknownHost "
79			+"port "+listenPort.getLocalPort());
80			}
81			// Loop round constantly until we decide to stop
82			while(run){
83			Socket hostSocket=null;
84			try{
85			_logger.write(toString(), Logger.SYSMSG, "Waiting for Connection");
86			// This will block until a host connects - at which point we get a Socket
87			hostSocket = listenPort.accept();
88			_logger.write(toString(), Logger.SYSMSG, "Connection accepted from: " + hostSocket.toString());
89			}
90			catch(IOException e){
91			// Something went wrong with the ServerSocket, so we'll stop listening
92			run=false;
93			}
94			// If we've stopped on the line above we won't want to try this !
95			if(run){
96			try {
97			// Setup the HostInit so it can carry on communications with the host
98	tdb	1.6	TCPReaderInit init = new TCPReaderInit(hostSocket, _queue);
99	tdb	1.1	// and start it
100			init.start();
101			} catch (IOException e) {
102			_logger.write(toString(), Logger.ERROR, e.toString());
103			}
104			}
105			}
106			// Best log the fact that we're stopping
107			_logger.write(toString(), Logger.FATAL, "Fatal error, shutdown pending");
108			}
109
110			/**
111			* Overrides the {@link java.lang.Object#toString() Object.toString()}
112			* method to provide clean logging (every class should have this).
113			*
114	ajm	1.5	* This uses the uk.ac.ukc.iscream.util.NameFormat class
115			* to format the toString()
116			*
117	tdb	1.1	* @return the name of this class and its CVS revision
118			*/
119			public String toString() {
120	ajm	1.5	return FormatName.getName(
121			_name,
122			getClass().getName(),
123			REVISION);
124	tdb	1.1	}
125
126			//---PRIVATE METHODS---
127
128			//---ACCESSOR/MUTATOR METHODS---
129
130			//---ATTRIBUTES---
131
132			/**
133	ajm	1.5	* This is the friendly identifier of the
134			* component this class is running in.
135			* eg, a Filter may be called "filter1",
136			* If this class does not have an owning
137			* component, a name from the configuration
138			* can be placed here. This name could also
139			* be changed to null for utility classes.
140			*/
141			private String _name = FilterMain.NAME;
142
143			/**
144			* This holds a reference to the
145			* system logger that is being used.
146	tdb	1.1	*/
147	ajm	1.5	private Logger _logger = ReferenceManager.getInstance().getLogger();
148	tdb	1.1
149			/**
150			* The port on which the server should listen.
151			*/
152			private int _port;
153
154	tdb	1.6	private Queue _queue;
155	tdb	1.1
156			//---STATIC ATTRIBUTES---
157
158			}