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 Control Handler to a CORBA based client.
 *
 * !!! FUNDAMENTAL DESIGN PROBLEM !!!
 * !!! Need a way to "shutdown" this class !!!
 *
 * @author  $Author$
 * @version $Id$
 */
class CorbaControlHandlerServant extends CorbaControlHandlerPOA {

//---FINAL ATTRIBUTES---

    /**
     * The current CVS revision of this class
     */
    public final String REVISION = "$Revision: 1.2 $";
    
//---STATIC METHODS---

//---CONSTRUCTORS---
    
    /**
     * Construct a new CorbaControlHandlerServant.
     *
     * @param packetSorter A reference to the PacketSorter in the component
     * @param client A reference to the "servant" part of the connecting client.
     */
    public CorbaControlHandlerServant(PacketSorter packetSorter, Client client) {
        _packetSorter = packetSorter;
        _hostList = "";
        _client = client;
        _dataHandler = null;
        _logger.write(toString(), Logger.SYSINIT, "created");
    }
    
//---PUBLIC METHODS---
    
    /**
     * Start sending data to the client.
     *
     * @return a boolean stating whether the attempt to start succeeded
     */
    public boolean startData() {
        if(_dataHandler == null) {
            // create a new DataHandler
            CorbaDataHandler dh = new CorbaDataHandler(_client);
            // register the Queue
            _packetSorter.register(dh.getQueue(), _hostList);
            // start the DataHandler running
            dh.start();
            // keep a reference
            _dataHandler = dh;
            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(_dataHandler != null) {
            // deregister the Queue
            _packetSorter.deregister(_dataHandler.getQueue(), _hostList);
            // stop the DataHandler
            _dataHandler.shutdown();
            // destroy the reference
            _dataHandler = null;
            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(_dataHandler == null) {
            _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 PacketSorter.
         */
    private PacketSorter _packetSorter;
    
    /**
     * The host list the Client has requested
     */
    private String _hostList;
    
    /**
     * The "servant" part of the client we're connected to.
     */
    private Client _client;
    
    /**
     * A reference to our DataHandler, if we have one
     */
    private CorbaDataHandler _dataHandler;
    
//---STATIC ATTRIBUTES---

}
Revision:	1.3
Committed:	Mon Feb 5 00:58:46 2001 UTC (23 years, 3 months ago) by tdb
Branch:	MAIN
Changes since 1.2:	+25 -94 lines
Log Message:	The original "all in one" class didn't work quite right, so it's been broken down into two classes; one for control, and one for sending data. The whole lot functions in a very similar way to the TCP setup, except that communication happens over CORBA.
#	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 uk.ac.ukc.iscream.client.*;
9
10
11			/**
12	tdb	1.3	* Acts as a Control Handler to a CORBA based client.
13	tdb	1.1	*
14			* !!! FUNDAMENTAL DESIGN PROBLEM !!!
15			* !!! Need a way to "shutdown" this class !!!
16			*
17	tdb	1.3	* @author $Author$
18			* @version $Id$
19	tdb	1.1	*/
20	tdb	1.3	class CorbaControlHandlerServant extends CorbaControlHandlerPOA {
21	tdb	1.1
22			//---FINAL ATTRIBUTES---
23
24			/**
25			* The current CVS revision of this class
26			*/
27	tdb	1.3	public final String REVISION = "$Revision: 1.2 $";
28	tdb	1.1
29			//---STATIC METHODS---
30
31			//---CONSTRUCTORS---
32
33			/**
34	tdb	1.3	* Construct a new CorbaControlHandlerServant.
35	tdb	1.1	*
36			* @param packetSorter A reference to the PacketSorter in the component
37			* @param client A reference to the "servant" part of the connecting client.
38			*/
39	tdb	1.3	public CorbaControlHandlerServant(PacketSorter packetSorter, Client client) {
40	tdb	1.1	_packetSorter = packetSorter;
41			_hostList = "";
42			_client = client;
43	tdb	1.3	_dataHandler = null;
44	tdb	1.1	_logger.write(toString(), Logger.SYSINIT, "created");
45			}
46
47			//---PUBLIC METHODS---
48
49			/**
50			* Start sending data to the client.
51			*
52			* @return a boolean stating whether the attempt to start succeeded
53			*/
54			public boolean startData() {
55	tdb	1.3	if(_dataHandler == null) {
56			// create a new DataHandler
57			CorbaDataHandler dh = new CorbaDataHandler(_client);
58	tdb	1.1	// register the Queue
59	tdb	1.3	_packetSorter.register(dh.getQueue(), _hostList);
60			// start the DataHandler running
61			dh.start();
62			// keep a reference
63			_dataHandler = dh;
64	tdb	1.1	return true;
65			}
66			else {
67			return false;
68			}
69			}
70
71			/**
72			* Stop sending data to the client.
73			*
74			* @return a boolean stating whether the attempt to stop succeeded
75			*/
76			public boolean stopData() {
77	tdb	1.3	if(_dataHandler != null) {
78	tdb	1.1	// deregister the Queue
79	tdb	1.3	_packetSorter.deregister(_dataHandler.getQueue(), _hostList);
80			// stop the DataHandler
81			_dataHandler.shutdown();
82			// destroy the reference
83			_dataHandler = null;
84	tdb	1.1	return true;
85			}
86			else {
87			return false;
88			}
89			}
90
91			/**
92			* Sets the host list for the Client to the requested semi-colon separated
93			* list of hostnames. This will only succeed if we are not sending data.
94			*
95			* @param hostList A semi-colon separated list of hostnames to use.
96			* @return Whether the request succeeded.
97			*/
98			public boolean setHostList(String hostList) {
99	tdb	1.3	if(_dataHandler == null) {
100	tdb	1.1	_hostList = hostList;
101			return true;
102			}
103			else {
104			return false;
105			}
106			}
107
108			/**
109			* Overrides the {@link java.lang.Object#toString() Object.toString()}
110			* method to provide clean logging (every class should have this).
111			*
112			* This uses the uk.ac.ukc.iscream.util.NameFormat class
113			* to format the toString()
114			*
115			* @return the name of this class and its CVS revision
116			*/
117			public String toString() {
118			return FormatName.getName(
119			_name,
120			getClass().getName(),
121			REVISION);
122			}
123
124			//---PRIVATE METHODS---
125
126			//---ACCESSOR/MUTATOR METHODS---
127
128			//---ATTRIBUTES---
129
130			/**
131			* This is the friendly identifier of the
132			* component this class is running in.
133			* eg, a Filter may be called "filter1",
134			* If this class does not have an owning
135			* component, a name from the configuration
136			* can be placed here. This name could also
137			* be changed to null for utility classes.
138			*/
139			private String _name = ClientInterfaceMain.NAME;
140
141			/**
142			* This holds a reference to the
143			* system logger that is being used.
144			*/
145			private Logger _logger = ReferenceManager.getInstance().getLogger();
146
147			/**
148			* A reference to the PacketSorter.
149			*/
150			private PacketSorter _packetSorter;
151
152			/**
153			* The host list the Client has requested
154			*/
155			private String _hostList;
156
157			/**
158			* The "servant" part of the client we're connected to.
159			*/
160			private Client _client;
161
162			/**
163	tdb	1.3	* A reference to our DataHandler, if we have one
164	tdb	1.1	*/
165	tdb	1.3	private CorbaDataHandler _dataHandler;
166	tdb	1.1
167			//---STATIC ATTRIBUTES---
168
169			}