server/rootfilter/CorbaDataHandler.java

/* 
 * i-scream central monitoring system
 * http://www.i-scream.org.uk
 * Copyright (C) 2000-2002 i-scream
 * 
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 * 
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 * 
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
 */

//---PACKAGE DECLARATION---
package uk.org.iscream.cms.server.rootfilter;

//---IMPORTS---
import uk.org.iscream.cms.util.*;
import uk.org.iscream.cms.server.componentmanager.*;
import uk.org.iscream.cms.server.core.*;
import uk.org.iscream.cms.server.clientinterface.*;


/**
 * Acts as a Data Handler to a CORBA based client.
 *
 * @author  $Author$
 * @version $Id$
 */
class CorbaDataHandler extends Thread {

//---FINAL ATTRIBUTES---

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

//---CONSTRUCTORS---
    
    /**
     * Construct a new CorbaDataHandler.
     *
     * @param client A reference to the "servant" part of the connecting client.
     * @param cchServer A reference to the class that is control us.
     */
    public CorbaDataHandler(Client client, CorbaControlHandlerServant cchServant, Queue queue) {
        // set the Thread name
        setName("clientinterface.CorbaDataHandler");
        
        _client = client;
        _cchServant = cchServant;
        _queue = queue;
        _logger.write(toString(), Logger.SYSINIT, "created");
    }
    
//---PUBLIC METHODS---
    
    /**
     * This method loops round until such a point as we shutdown. It keeps
     * grabbing data items from it's Queue, then sends them on to the connected
     * client over CORBA.
     */
    public void run() {
        // get a queue
        _queueID = _queue.getQueue();
        // we'll keep going until someone implements a "shutdown" :)
        run = true;
        // loop sending data
        while(run) {
            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) {
                    try {
                        _client.receiveXML(xml);
                    }
                    catch (org.omg.CORBA.COMM_FAILURE e) {
                        // lets stop sending, the client has quit
                        run = false;
                        _logger.write(toString(), Logger.ERROR, "Connection failure (COMM_FAILURE), client shutdown? : "+e);
                    }
                    catch (org.omg.CORBA.TRANSIENT e) {
                        // lets stop sending, the client has quit
                        run = false;
                        _logger.write(toString(), Logger.ERROR, "Connection failure (TRANSIENT), client shutdown? : "+e);
                    }
                }
            }
            catch(InvalidQueueException e) {
                // lets stop sending.
                run = false;
                _logger.write(toString(), Logger.ERROR, "Queue failure: "+e);
            }
        }
        // disconnect the servant above us, or at least try
        _cchServant.disconnect();
        // 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);
    }
    
    /**
     * 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.org.iscream.cms.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---

    /**
     * Overridden for debugging purposes
     * to see when an instance of this class
     * is destroyed
     */
    protected void finalize() throws Throwable {
        _logger.write(this.toString(), Logger.DEBUG, "finalized by GC");
    }

//---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 = RootFilter.NAME;
    
    /**
     * This holds a reference to the
     * system logger that is being used.
     */
    private Logger _logger = ReferenceManager.getInstance().getLogger();
    
    /**
     * 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;
    
    /**
     * A reference to our controlling class
     */
    private CorbaControlHandlerServant _cchServant;
    
//---STATIC ATTRIBUTES---

}
Revision:	1.1
Committed:	Mon May 5 22:05:14 2003 UTC (21 years ago) by tdb
Branch:	MAIN
Log Message:	Tidy up of the client interface code - more commonly known as the "right hand side of the server". Right since the start the filter side of the server has been nice and tree like - every Filter sent data to another Filter. At the top of the tree there was a "special" Filter known as the RootFilter, which to the other Filters just looked like a normal Filter. This was nice, and simple, and expandable. The Client Interface on the other hand was messy. The root filter had some hacky wrapper threads which pulled from a queue and pushed to the relevant client interfaces (one for real time stuff, and the other for databases). There was no simple room for expandability - it was all hardwired to do just what was needed at the time. This commit changes that. A Client Interface now connects to another Client Interface, with a special one being found in the RootFilter (yes, maybe that needs a name change now :-). So we can chain client interfaces, and move other bits and bobs around in the server - for example, alerting no longer needs to be connected to the Client Interface, it can connect straight to the RootFilter (or, wherever the config tells it ;). Hopefully this sanitizes the underlying layout of the server a bit. As a final note, I dropped the DBInterface. This used to insert data in to a MySQL database. We've long since stopped using that, and it's fallen behind and is way out of date. For now, it's gone in to the attic.
#	User	Rev	Content
1	tdb	1.1	/*
2			* i-scream central monitoring system
3			* http://www.i-scream.org.uk
4			* Copyright (C) 2000-2002 i-scream
5			*
6			* This program is free software; you can redistribute it and/or
7			* modify it under the terms of the GNU General Public License
8			* as published by the Free Software Foundation; either version 2
9			* of the License, or (at your option) any later version.
10			*
11			* This program is distributed in the hope that it will be useful,
12			* but WITHOUT ANY WARRANTY; without even the implied warranty of
13			* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14			* GNU General Public License for more details.
15			*
16			* You should have received a copy of the GNU General Public License
17			* along with this program; if not, write to the Free Software
18			* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
19			*/
20
21			//---PACKAGE DECLARATION---
22			package uk.org.iscream.cms.server.rootfilter;
23
24			//---IMPORTS---
25			import uk.org.iscream.cms.util.*;
26			import uk.org.iscream.cms.server.componentmanager.*;
27			import uk.org.iscream.cms.server.core.*;
28			import uk.org.iscream.cms.server.clientinterface.*;
29
30
31			/**
32			* Acts as a Data Handler to a CORBA based client.
33			*
34			* @author $Author$
35			* @version $Id$
36			*/
37			class CorbaDataHandler extends Thread {
38
39			//---FINAL ATTRIBUTES---
40
41			/**
42			* The current CVS revision of this class
43			*/
44			public final String REVISION = "$Revision: 1.1 $";
45
46			//---STATIC METHODS---
47
48			//---CONSTRUCTORS---
49
50			/**
51			* Construct a new CorbaDataHandler.
52			*
53			* @param client A reference to the "servant" part of the connecting client.
54			* @param cchServer A reference to the class that is control us.
55			*/
56			public CorbaDataHandler(Client client, CorbaControlHandlerServant cchServant, Queue queue) {
57			// set the Thread name
58			setName("clientinterface.CorbaDataHandler");
59
60			_client = client;
61			_cchServant = cchServant;
62			_queue = queue;
63			_logger.write(toString(), Logger.SYSINIT, "created");
64			}
65
66			//---PUBLIC METHODS---
67
68			/**
69			* This method loops round until such a point as we shutdown. It keeps
70			* grabbing data items from it's Queue, then sends them on to the connected
71			* client over CORBA.
72			*/
73			public void run() {
74			// get a queue
75			_queueID = _queue.getQueue();
76			// we'll keep going until someone implements a "shutdown" :)
77			run = true;
78			// loop sending data
79			while(run) {
80			try {
81			String xml = (String) _queue.get(_queueID);
82			// if it's not null (which could happen if we're "released")
83			// send it on to the client that we're connected to.
84			if(xml != null) {
85			try {
86			_client.receiveXML(xml);
87			}
88			catch (org.omg.CORBA.COMM_FAILURE e) {
89			// lets stop sending, the client has quit
90			run = false;
91			_logger.write(toString(), Logger.ERROR, "Connection failure (COMM_FAILURE), client shutdown? : "+e);
92			}
93			catch (org.omg.CORBA.TRANSIENT e) {
94			// lets stop sending, the client has quit
95			run = false;
96			_logger.write(toString(), Logger.ERROR, "Connection failure (TRANSIENT), client shutdown? : "+e);
97			}
98			}
99			}
100			catch(InvalidQueueException e) {
101			// lets stop sending.
102			run = false;
103			_logger.write(toString(), Logger.ERROR, "Queue failure: "+e);
104			}
105			}
106			// disconnect the servant above us, or at least try
107			_cchServant.disconnect();
108			// if we get here we've been told to stop
109			_logger.write(toString(), Logger.SYSMSG, "Shutting Down");
110			// remove ourselves from the queue
111			_queue.removeQueue(_queueID);
112			}
113
114			/**
115			* Method to shutdown this Data Handler. All this actually does
116			* is set a flag which the main loop will see and commence shutting
117			* down. This method will return before the main loop stops.
118			*/
119			public void shutdown() {
120			// set the main loop to stop
121			run=false;
122			// if the main loop is waiting for data it won't notice the
123			// above flag to stop. This bumps it out of the blocked get.
124			_queue.releaseQueue(_queueID);
125			}
126
127			/**
128			* Overrides the {@link java.lang.Object#toString() Object.toString()}
129			* method to provide clean logging (every class should have this).
130			*
131			* This uses the uk.org.iscream.cms.util.NameFormat class
132			* to format the toString()
133			*
134			* @return the name of this class and its CVS revision
135			*/
136			public String toString() {
137			return FormatName.getName(
138			_name,
139			getClass().getName(),
140			REVISION);
141			}
142
143			//---PRIVATE METHODS---
144
145			/**
146			* Overridden for debugging purposes
147			* to see when an instance of this class
148			* is destroyed
149			*/
150			protected void finalize() throws Throwable {
151			_logger.write(this.toString(), Logger.DEBUG, "finalized by GC");
152			}
153
154			//---ACCESSOR/MUTATOR METHODS---
155
156			//---ATTRIBUTES---
157
158			/**
159			* This is the friendly identifier of the
160			* component this class is running in.
161			* eg, a Filter may be called "filter1",
162			* If this class does not have an owning
163			* component, a name from the configuration
164			* can be placed here. This name could also
165			* be changed to null for utility classes.
166			*/
167			private String _name = RootFilter.NAME;
168
169			/**
170			* This holds a reference to the
171			* system logger that is being used.
172			*/
173			private Logger _logger = ReferenceManager.getInstance().getLogger();
174
175			/**
176			* The Queue we'll use for buffering data to the client.
177			*/
178			private Queue _queue;
179
180			/**
181			* The "servant" part of the client we're connected to.
182			*/
183			private Client _client;
184
185			/**
186			* Our queue number within our Queue
187			*/
188			private int _queueID;
189
190			/**
191			* The flag that dictates whether the main loop should completely exit
192			*/
193			private boolean run;
194
195			/**
196			* A reference to our controlling class
197			*/
198			private CorbaControlHandlerServant _cchServant;
199
200			//---STATIC ATTRIBUTES---
201
202			}