server/clientinterface/CorbaControlHandlerServant.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 uk.ac.ukc.iscream.client.*;


/**
 * Acts as a Handler to a CORBA based client.
 *
 * !!! FUNDAMENTAL DESIGN PROBLEM !!!
 * !!! Need a way to "shutdown" this class !!!
 *
 * @author  $Author: tdb1 $
 * @version $Id: CorbaHandlerServant.java,v 1.1 2001/02/03 00:42:54 tdb1 Exp $
 */
class CorbaHandlerServant extends Thread implements CorbaHandlerOperations {

//---FINAL ATTRIBUTES---

    /**
     * The current CVS revision of this class
     */
    public final String REVISION = "$Revision: 1.1 $";
    
//---STATIC METHODS---

//---CONSTRUCTORS---
    
    /**
     * Construct a new CorbaHandlerServant.
     *
     * @param packetSorter A reference to the PacketSorter in the component
     * @param name The name of the client
     * @param client A reference to the "servant" part of the connecting client.
     */
    public CorbaHandlerServant(PacketSorter packetSorter, String name, Client client) {
        _packetSorter = packetSorter;
        _clientName = name;
        _hostList = "";
        _queue = new Queue();
        _client = client;
        _logger.write(toString(), Logger.SYSINIT, "created");
    }
    
//---PUBLIC METHODS---
    
    /**
     * This method loops round until we "shutdown" (not implemented yet). Inside
     * the main loop we will first wait until the startData() method is called,
     * then we'll send data constantly until stopData() is called.
     */
    public void run() {
        // !!! OUGHT TO CHECK QUEUE START OF USE !!!
        // get a queue
        _queueID = _queue.getQueue();
        // we'll keep going until someone implements a "shutdown" :)
        run = true;
        while(run) {
            // initially lock until someone tells us to start
            synchronized(this) {
                try { wait(); } catch(Exception e) {}
            }
            // loop sending data
            while(_sendingData) {
                try {
                    String xml = (String) _queue.get(_queueID);
                    // if it's not null (which could happen if we're "released")
                    // send it on to the client that we're connected to.
                    if(xml != null) {
                        _client.receiveXML(xml);
                    }
                }
                catch(InvalidQueueException e) {
                    // lets stop sending - maybe stop altogether ?
                    stopData();
                    _logger.write(toString(), Logger.ERROR, "Queue failure: "+e);
                }
            }
            // now, we've obviously been stopped, so we'll head back round this
            // while loop until someone starts us again.
        }
        // if we get here we've been told to stop
        _logger.write(toString(), Logger.SYSMSG, "Shutting Down");
        // remove ourselves from the queue
        _queue.removeQueue(_queueID);
    }
    
    /**
     * Start sending data to the client.
     *
     * @return a boolean stating whether the attempt to start succeeded
     */
    public boolean startData() {
        if(!_sendingData) {
            // register the Queue
            _packetSorter.register(_queue, _hostList);
            // mark the running flag
            _sendingData = true;
            // bump the loop
            synchronized(this) {
                try { notifyAll(); } catch(Exception e) {}
            }
            return true;
        }
        else {
            return false;
        }
    }
    
    /**
     * Stop sending data to the client.
     *
     * @return a boolean stating whether the attempt to stop succeeded
     */
    public boolean stopData() {
        if(_sendingData) {
            // deregister the Queue
            _packetSorter.deregister(_queue, _hostList);
            // stop ourselves running
            _sendingData = 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);
            return true;
        }
        else {
            return false;
        }
    }
    
    /**
     * Sets the host list for the Client to the requested semi-colon separated
     * list of hostnames. This will only succeed if we are not sending data.
     *
     * @param hostList A semi-colon separated list of hostnames to use.
     * @return Whether the request succeeded.
     */
    public boolean setHostList(String hostList) {
        if(!_sendingData) {
            _hostList = hostList;
            return true;
        }
        else {
            return false;
        }
    }
    
    /**
     * 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 = ClientInterfaceMain.NAME;
    
    /**
     * This holds a reference to the
     * system logger that is being used.
     */
    private Logger _logger = ReferenceManager.getInstance().getLogger();
    
    /**
     * A reference to the Configuration Manager the system is using
     */
    private ConfigurationManager _configManager = ReferenceManager.getInstance().getCM();
    
    /**
         * A reference to the PacketSorter.
         */
    private PacketSorter _packetSorter;
    
    /**
     * The host list the Client has requested
     */
    private String _hostList;
    
    /**
     * The name of the connected client.
     */
    private String _clientName;
    
    /**
     * Whether we are active and sending data.
     */
    private boolean _sendingData;
    
    /**
     * The Queue we'll use for buffering data to the client.
     */
    private Queue _queue;
    
    /**
     * The "servant" part of the client we're connected to.
     */
    private Client _client;
    
    /**
     * Our queue number within our Queue
     */
    private int _queueID;
    
    /**
     * The flag that dictates whether the main loop should *completely* exit
     */
    private boolean run;
    
//---STATIC ATTRIBUTES---

}
Revision:	1.2
Committed:	Sat Feb 3 04:44:09 2001 UTC (23 years, 3 months ago) by tdb
Branch:	MAIN
Changes since 1.1:	+3 -2 lines
Log Message:	A few subtle changes... I keep forgetting to start Threads :)
#	Content
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 uk.ac.ukc.iscream.client.*;
9
10
11	/**
12	* Acts as a Handler to a CORBA based client.
13	*
14	* !!! FUNDAMENTAL DESIGN PROBLEM !!!
15	* !!! Need a way to "shutdown" this class !!!
16	*
17	* @author $Author: tdb1 $
18	* @version $Id: CorbaHandlerServant.java,v 1.1 2001/02/03 00:42:54 tdb1 Exp $
19	*/
20	class CorbaHandlerServant extends Thread implements CorbaHandlerOperations {
21
22	//---FINAL ATTRIBUTES---
23
24	/**
25	* The current CVS revision of this class
26	*/
27	public final String REVISION = "$Revision: 1.1 $";
28
29	//---STATIC METHODS---
30
31	//---CONSTRUCTORS---
32
33	/**
34	* Construct a new CorbaHandlerServant.
35	*
36	* @param packetSorter A reference to the PacketSorter in the component
37	* @param name The name of the client
38	* @param client A reference to the "servant" part of the connecting client.
39	*/
40	public CorbaHandlerServant(PacketSorter packetSorter, String name, Client client) {
41	_packetSorter = packetSorter;
42	_clientName = name;
43	_hostList = "";
44	_queue = new Queue();
45	_client = client;
46	_logger.write(toString(), Logger.SYSINIT, "created");
47	}
48
49	//---PUBLIC METHODS---
50
51	/**
52	* This method loops round until we "shutdown" (not implemented yet). Inside
53	* the main loop we will first wait until the startData() method is called,
54	* then we'll send data constantly until stopData() is called.
55	*/
56	public void run() {
57	// !!! OUGHT TO CHECK QUEUE START OF USE !!!
58	// get a queue
59	_queueID = _queue.getQueue();
60	// we'll keep going until someone implements a "shutdown" :)
61	run = true;
62	while(run) {
63	// initially lock until someone tells us to start
64	synchronized(this) {
65	try { wait(); } catch(Exception e) {}
66	}
67	// loop sending data
68	while(_sendingData) {
69	try {
70	String xml = (String) _queue.get(_queueID);
71	// if it's not null (which could happen if we're "released")
72	// send it on to the client that we're connected to.
73	if(xml != null) {
74	_client.receiveXML(xml);
75	}
76	}
77	catch(InvalidQueueException e) {
78	// lets stop sending - maybe stop altogether ?
79	stopData();
80	_logger.write(toString(), Logger.ERROR, "Queue failure: "+e);
81	}
82	}
83	// now, we've obviously been stopped, so we'll head back round this
84	// while loop until someone starts us again.
85	}
86	// if we get here we've been told to stop
87	_logger.write(toString(), Logger.SYSMSG, "Shutting Down");
88	// remove ourselves from the queue
89	_queue.removeQueue(_queueID);
90	}
91
92	/**
93	* Start sending data to the client.
94	*
95	* @return a boolean stating whether the attempt to start succeeded
96	*/
97	public boolean startData() {
98	if(!_sendingData) {
99	// register the Queue
100	_packetSorter.register(_queue, _hostList);
101	// mark the running flag
102	_sendingData = true;
103	// bump the loop
104	synchronized(this) {
105	try { notifyAll(); } catch(Exception e) {}
106	}
107	return true;
108	}
109	else {
110	return false;
111	}
112	}
113
114	/**
115	* Stop sending data to the client.
116	*
117	* @return a boolean stating whether the attempt to stop succeeded
118	*/
119	public boolean stopData() {
120	if(_sendingData) {
121	// deregister the Queue
122	_packetSorter.deregister(_queue, _hostList);
123	// stop ourselves running
124	_sendingData = false;
125	// if the main loop is waiting for data it won't notice the
126	// above flag to stop. This bumps it out of the blocked get().
127	_queue.releaseQueue(_queueID);
128	return true;
129	}
130	else {
131	return false;
132	}
133	}
134
135	/**
136	* Sets the host list for the Client to the requested semi-colon separated
137	* list of hostnames. This will only succeed if we are not sending data.
138	*
139	* @param hostList A semi-colon separated list of hostnames to use.
140	* @return Whether the request succeeded.
141	*/
142	public boolean setHostList(String hostList) {
143	if(!_sendingData) {
144	_hostList = hostList;
145	return true;
146	}
147	else {
148	return false;
149	}
150	}
151
152	/**
153	* Overrides the {@link java.lang.Object#toString() Object.toString()}
154	* method to provide clean logging (every class should have this).
155	*
156	* This uses the uk.ac.ukc.iscream.util.NameFormat class
157	* to format the toString()
158	*
159	* @return the name of this class and its CVS revision
160	*/
161	public String toString() {
162	return FormatName.getName(
163	_name,
164	getClass().getName(),
165	REVISION);
166	}
167
168	//---PRIVATE METHODS---
169
170	//---ACCESSOR/MUTATOR METHODS---
171
172	//---ATTRIBUTES---
173
174	/**
175	* This is the friendly identifier of the
176	* component this class is running in.
177	* eg, a Filter may be called "filter1",
178	* If this class does not have an owning
179	* component, a name from the configuration
180	* can be placed here. This name could also
181	* be changed to null for utility classes.
182	*/
183	private String _name = ClientInterfaceMain.NAME;
184
185	/**
186	* This holds a reference to the
187	* system logger that is being used.
188	*/
189	private Logger _logger = ReferenceManager.getInstance().getLogger();
190
191	/**
192	* A reference to the Configuration Manager the system is using
193	*/
194	private ConfigurationManager _configManager = ReferenceManager.getInstance().getCM();
195
196	/**
197	* A reference to the PacketSorter.
198	*/
199	private PacketSorter _packetSorter;
200
201	/**
202	* The host list the Client has requested
203	*/
204	private String _hostList;
205
206	/**
207	* The name of the connected client.
208	*/
209	private String _clientName;
210
211	/**
212	* Whether we are active and sending data.
213	*/
214	private boolean _sendingData;
215
216	/**
217	* The Queue we'll use for buffering data to the client.
218	*/
219	private Queue _queue;
220
221	/**
222	* The "servant" part of the client we're connected to.
223	*/
224	private Client _client;
225
226	/**
227	* Our queue number within our Queue
228	*/
229	private int _queueID;
230
231	/**
232	* The flag that dictates whether the main loop should completely exit
233	*/
234	private boolean run;
235
236	//---STATIC ATTRIBUTES---
237
238	}