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 1.8 2001/02/07 13:47:33 tdb1 Exp $
 */
class TCPDataHandler extends Thread {

//---FINAL ATTRIBUTES---

    /**
     * The current CVS revision of this class
     */
    public final String REVISION = "$Revision: 1.8 $";
    
//---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 {
        _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:	1.9
Committed:	Mon Feb 26 00:18:42 2001 UTC (23 years, 3 months ago) by tdb
Branch:	MAIN
Changes since 1.8:	+3 -2 lines
Log Message:	We need to shutdown the Monitor's when closing down, otherwise the Queue's never get destroyed... and just sit there idle'ing away :)
#	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	1.9	* @version $Id: TCPDataHandler.java,v 1.8 2001/02/07 13:47:33 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	1.9	public final String REVISION = "$Revision: 1.8 $";
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	1.1	_socket = socket;
46	tdb	1.4	_queue = new Queue();
47	tdb	1.6	// setup the reader and writer
48	tdb	1.1	_socketIn = new BufferedReader(new InputStreamReader(_socket.getInputStream()));
49	tdb	1.8	_socketOut = new PrintWriter(_socket.getOutputStream(), true);
50	tdb	1.1	_logger.write(toString(), Logger.SYSINIT, "created");
51			}
52
53			//---PUBLIC METHODS---
54	tdb	1.6	/**
55			* Main loop for the Data Handler, keeps sending data from
56			* it's local Queue.
57			*/
58	tdb	1.2	public void run() {
59			run = true;
60	tdb	1.5	_queueID = _queue.getQueue();
61	tdb	1.6	// run until we get told to stop
62	tdb	1.2	while(run) {
63	tdb	1.6	// get some data, and send some data
64	tdb	1.2	try {
65	tdb	1.5	String xml = (String) _queue.get(_queueID);
66	tdb	1.7	// if we're shutting down and we've been "bumped"
67			// it's likely we'll get a null back, and we don't
68			// want to send that on to the Client
69			if(xml != null) {
70			_socketOut.println(xml);
71			}
72	tdb	1.2	}
73			catch(InvalidQueueException e) {
74			run = false;
75			_logger.write(toString(), Logger.ERROR, "Queue failure: "+e);
76			}
77			}
78	tdb	1.6	// if we get here we've been told to stop
79	tdb	1.1	_logger.write(toString(), Logger.SYSMSG, "Shutting Down");
80	tdb	1.6	// shut down the reader, writer and Socket
81	tdb	1.2	try {
82			_socketOut.close();
83			_socketIn.close();
84			_socket.close();
85			}
86			catch(IOException e) {
87			_logger.write(toString(), Logger.ERROR, "Exception whilst shutting down: "+e);
88			}
89	tdb	1.6	// remove ourselves from the queue
90	tdb	1.5	_queue.removeQueue(_queueID);
91	tdb	1.9	_queue.stopMonitor();
92	tdb	1.2	}
93	tdb	1.6
94			/**
95			* Method to shutdown this Data Handler. All this actually does
96			* is set a flag which the main loop will see and commence shutting
97			* down. This method will return before the main loop stops.
98			*/
99	tdb	1.2	public void shutdown() {
100	tdb	1.6	// set the main loop to stop
101	tdb	1.2	run=false;
102	tdb	1.6	// if the main loop is waiting for data it won't notice the
103			// above flag to stop. This bumps it out of the blocked get.
104	tdb	1.5	_queue.releaseQueue(_queueID);
105	tdb	1.1	}
106
107			/**
108			* Overrides the {@link java.lang.Object#toString() Object.toString()}
109			* method to provide clean logging (every class should have this).
110			*
111			* This uses the uk.ac.ukc.iscream.util.NameFormat class
112			* to format the toString()
113			*
114			* @return the name of this class and its CVS revision
115			*/
116			public String toString() {
117			return FormatName.getName(
118			_name,
119			getClass().getName(),
120			REVISION);
121			}
122
123			//---PRIVATE METHODS---
124
125			//---ACCESSOR/MUTATOR METHODS---
126	tdb	1.6
127			/**
128			* Accessor to our Queue. The Control Handler needs to
129			* get this reference to register us.
130			*
131			* @return a reference to our Queue
132			*/
133	tdb	1.4	public Queue getQueue() {
134			return _queue;
135			}
136
137	tdb	1.1	//---ATTRIBUTES---
138
139			/**
140			* This is the friendly identifier of the
141			* component this class is running in.
142			* eg, a Filter may be called "filter1",
143			* If this class does not have an owning
144			* component, a name from the configuration
145			* can be placed here. This name could also
146			* be changed to null for utility classes.
147			*/
148			private String _name = ClientInterfaceMain.NAME;
149
150			/**
151			* This holds a reference to the
152			* system logger that is being used.
153			*/
154			private Logger _logger = ReferenceManager.getInstance().getLogger();
155
156			/**
157			* A hook to the inbound data from the socket
158			*/
159			private BufferedReader _socketIn;
160
161			/**
162			* A hook to the outbound stream for the socket
163			*/
164			private PrintWriter _socketOut;
165
166	tdb	1.6	/**
167			* A reference to the Socket connected to the client
168			*/
169	tdb	1.1	private Socket _socket;
170	tdb	1.2
171	tdb	1.6	/**
172			* A reference to our Queue
173			*/
174	tdb	1.2	private Queue _queue;
175	tdb	1.6
176			/**
177			* The flag that dictates whether we should be running
178			*/
179	tdb	1.2	private boolean run;
180	tdb	1.6
181			/**
182			* Our queue number within our Queue
183			*/
184	tdb	1.5	private int _queueID;
185	tdb	1.1
186			//---STATIC ATTRIBUTES---
187
188			}