server/clientinterface/TCPDataHandler.java

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

//---IMPORTS---
import uk.ac.ukc.iscream.util.*;
import uk.ac.ukc.iscream.componentmanager.*;
import uk.ac.ukc.iscream.core.*;
import java.net.Socket;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.IOException;
import java.io.BufferedReader;
import java.io.PrintWriter;
import java.io.InputStreamReader;

/**
 * Acts as a Data Handler to a TCP based client, providing
 * it with a constant stream of XML data for the hosts the
 * client has requested.
 *
 * @author  $Author: tdb1 $
 * @version $Id: TCPDataHandler.java,v 1.9 2001/02/26 00:18:42 tdb1 Exp $
 */
class TCPDataHandler extends Thread {

//---FINAL ATTRIBUTES---

    /**
     * The current CVS revision of this class
     */
    public final String REVISION = "$Revision: 1.9 $";
    
//---STATIC METHODS---

//---CONSTRUCTORS---
    
    /**
     * Construct a new TCPDataHandler with a Socket provided
     * by the Control Handler.
     *
     * @param socket The socket to which the Client has connected
     * @throws IOException if something goes wrong, the Control Handler can deal with it
     */
    public TCPDataHandler(Socket socket) throws IOException {
        // set the Thread name
        setName("clientinterface.TCPDataHandler");
        
        _socket = socket;
        _queue = new Queue();
        // setup the reader and writer
        _socketIn = new BufferedReader(new InputStreamReader(_socket.getInputStream()));
        _socketOut = new PrintWriter(_socket.getOutputStream(), true);
        _logger.write(toString(), Logger.SYSINIT, "created");
    }
    
//---PUBLIC METHODS---
    /**
     * Main loop for the Data Handler, keeps sending data from
     * it's local Queue.
     */
    public void run() {
        run = true;
        _queueID = _queue.getQueue();
        // run until we get told to stop
        while(run) {
            // get some data, and send some data
            try {
                String xml = (String) _queue.get(_queueID);
                // if we're shutting down and we've been "bumped"
                // it's likely we'll get a null back, and we don't
                // want to send that on to the Client
                if(xml != null) {
                    _socketOut.println(xml);
                }
            }
            catch(InvalidQueueException e) {
                run = false;
                _logger.write(toString(), Logger.ERROR, "Queue failure: "+e);
            }
        }
        // if we get here we've been told to stop
        _logger.write(toString(), Logger.SYSMSG, "Shutting Down");
        // shut down the reader, writer and Socket
        try {
            _socketOut.close();
            _socketIn.close();
            _socket.close();
        }
        catch(IOException e) {
            _logger.write(toString(), Logger.ERROR, "Exception whilst shutting down: "+e);
        }
        // remove ourselves from the queue
        _queue.removeQueue(_queueID);
        _queue.stopMonitor();
    }
    
    /**
     * Method to shutdown this Data Handler. All this actually does
     * is set a flag which the main loop will see and commence shutting
     * down. This method will return before the main loop stops.
     */
    public void shutdown() {
        // set the main loop to stop
        run=false;
        // if the main loop is waiting for data it won't notice the
        // above flag to stop. This bumps it out of the blocked get.
        _queue.releaseQueue(_queueID);
    }
    
    /**
     * 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---
    
    /**
     * Accessor to our Queue. The Control Handler needs to
     * get this reference to register us.
     *
     * @return a reference to our Queue
     */
    public Queue getQueue() {
        return _queue;
    }

//---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 = ClientInterfaceMain.NAME;
    
    /**
     * This holds a reference to the
     * system logger that is being used.
     */
    private Logger _logger = ReferenceManager.getInstance().getLogger();
    
    /** 
     * A hook to the inbound data from the socket
     */
    private BufferedReader _socketIn;
    
    /**
     * A hook to the outbound stream for the socket
     */
    private PrintWriter _socketOut;
    
    /**
     * A reference to the Socket connected to the client
     */
    private Socket _socket;
    
    /**
     * A reference to our Queue
     */
    private Queue _queue;
    
    /**
     * The flag that dictates whether we should be running
     */
    private boolean run;
    
    /**
     * Our queue number within our Queue
     */
    private int _queueID;
    
//---STATIC ATTRIBUTES---

}
Revision:	1.10
Committed:	Tue Mar 13 02:19:44 2001 UTC (23 years, 2 months ago) by tdb
Branch:	MAIN
Changes since 1.9:	+5 -2 lines
Log Message:	Given all the classes that extend Thread a name using Thread.setName(). It is only representative as far as it will tell us which class the Thread is, but this will go some way to aiding debugging. If time permitted, more effort could be taken to name each thread according to what it was dealing with.
#	User	Rev	Content
1	tdb	1.1	//---PACKAGE DECLARATION---
2			package uk.ac.ukc.iscream.clientinterface;
3
4			//---IMPORTS---
5			import uk.ac.ukc.iscream.util.*;
6			import uk.ac.ukc.iscream.componentmanager.*;
7			import uk.ac.ukc.iscream.core.*;
8			import java.net.Socket;
9			import java.io.InputStream;
10			import java.io.OutputStream;
11			import java.io.IOException;
12			import java.io.BufferedReader;
13			import java.io.PrintWriter;
14			import java.io.InputStreamReader;
15
16			/**
17	tdb	1.6	* Acts as a Data Handler to a TCP based client, providing
18			* it with a constant stream of XML data for the hosts the
19			* client has requested.
20	tdb	1.1	*
21	tdb	1.2	* @author $Author: tdb1 $
22	tdb	1.10	* @version $Id: TCPDataHandler.java,v 1.9 2001/02/26 00:18:42 tdb1 Exp $
23	tdb	1.1	*/
24	tdb	1.2	class TCPDataHandler extends Thread {
25	tdb	1.1
26			//---FINAL ATTRIBUTES---
27
28			/**
29			* The current CVS revision of this class
30			*/
31	tdb	1.10	public final String REVISION = "$Revision: 1.9 $";
32	tdb	1.1
33			//---STATIC METHODS---
34
35			//---CONSTRUCTORS---
36	tdb	1.6
37			/**
38			* Construct a new TCPDataHandler with a Socket provided
39			* by the Control Handler.
40			*
41			* @param socket The socket to which the Client has connected
42			* @throws IOException if something goes wrong, the Control Handler can deal with it
43			*/
44	tdb	1.4	public TCPDataHandler(Socket socket) throws IOException {
45	tdb	1.10	// set the Thread name
46			setName("clientinterface.TCPDataHandler");
47
48	tdb	1.1	_socket = socket;
49	tdb	1.4	_queue = new Queue();
50	tdb	1.6	// setup the reader and writer
51	tdb	1.1	_socketIn = new BufferedReader(new InputStreamReader(_socket.getInputStream()));
52	tdb	1.8	_socketOut = new PrintWriter(_socket.getOutputStream(), true);
53	tdb	1.1	_logger.write(toString(), Logger.SYSINIT, "created");
54			}
55
56			//---PUBLIC METHODS---
57	tdb	1.6	/**
58			* Main loop for the Data Handler, keeps sending data from
59			* it's local Queue.
60			*/
61	tdb	1.2	public void run() {
62			run = true;
63	tdb	1.5	_queueID = _queue.getQueue();
64	tdb	1.6	// run until we get told to stop
65	tdb	1.2	while(run) {
66	tdb	1.6	// get some data, and send some data
67	tdb	1.2	try {
68	tdb	1.5	String xml = (String) _queue.get(_queueID);
69	tdb	1.7	// if we're shutting down and we've been "bumped"
70			// it's likely we'll get a null back, and we don't
71			// want to send that on to the Client
72			if(xml != null) {
73			_socketOut.println(xml);
74			}
75	tdb	1.2	}
76			catch(InvalidQueueException e) {
77			run = false;
78			_logger.write(toString(), Logger.ERROR, "Queue failure: "+e);
79			}
80			}
81	tdb	1.6	// if we get here we've been told to stop
82	tdb	1.1	_logger.write(toString(), Logger.SYSMSG, "Shutting Down");
83	tdb	1.6	// shut down the reader, writer and Socket
84	tdb	1.2	try {
85			_socketOut.close();
86			_socketIn.close();
87			_socket.close();
88			}
89			catch(IOException e) {
90			_logger.write(toString(), Logger.ERROR, "Exception whilst shutting down: "+e);
91			}
92	tdb	1.6	// remove ourselves from the queue
93	tdb	1.5	_queue.removeQueue(_queueID);
94	tdb	1.9	_queue.stopMonitor();
95	tdb	1.2	}
96	tdb	1.6
97			/**
98			* Method to shutdown this Data Handler. All this actually does
99			* is set a flag which the main loop will see and commence shutting
100			* down. This method will return before the main loop stops.
101			*/
102	tdb	1.2	public void shutdown() {
103	tdb	1.6	// set the main loop to stop
104	tdb	1.2	run=false;
105	tdb	1.6	// if the main loop is waiting for data it won't notice the
106			// above flag to stop. This bumps it out of the blocked get.
107	tdb	1.5	_queue.releaseQueue(_queueID);
108	tdb	1.1	}
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			* This uses the uk.ac.ukc.iscream.util.NameFormat class
115			* to format the toString()
116			*
117			* @return the name of this class and its CVS revision
118			*/
119			public String toString() {
120			return FormatName.getName(
121			_name,
122			getClass().getName(),
123			REVISION);
124			}
125
126			//---PRIVATE METHODS---
127
128			//---ACCESSOR/MUTATOR METHODS---
129	tdb	1.6
130			/**
131			* Accessor to our Queue. The Control Handler needs to
132			* get this reference to register us.
133			*
134			* @return a reference to our Queue
135			*/
136	tdb	1.4	public Queue getQueue() {
137			return _queue;
138			}
139
140	tdb	1.1	//---ATTRIBUTES---
141
142			/**
143			* This is the friendly identifier of the
144			* component this class is running in.
145			* eg, a Filter may be called "filter1",
146			* If this class does not have an owning
147			* component, a name from the configuration
148			* can be placed here. This name could also
149			* be changed to null for utility classes.
150			*/
151			private String _name = ClientInterfaceMain.NAME;
152
153			/**
154			* This holds a reference to the
155			* system logger that is being used.
156			*/
157			private Logger _logger = ReferenceManager.getInstance().getLogger();
158
159			/**
160			* A hook to the inbound data from the socket
161			*/
162			private BufferedReader _socketIn;
163
164			/**
165			* A hook to the outbound stream for the socket
166			*/
167			private PrintWriter _socketOut;
168
169	tdb	1.6	/**
170			* A reference to the Socket connected to the client
171			*/
172	tdb	1.1	private Socket _socket;
173	tdb	1.2
174	tdb	1.6	/**
175			* A reference to our Queue
176			*/
177	tdb	1.2	private Queue _queue;
178	tdb	1.6
179			/**
180			* The flag that dictates whether we should be running
181			*/
182	tdb	1.2	private boolean run;
183	tdb	1.6
184			/**
185			* Our queue number within our Queue
186			*/
187	tdb	1.5	private int _queueID;
188	tdb	1.1
189			//---STATIC ATTRIBUTES---
190
191			}