server/clientinterface/PacketSorter.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.util.*;

/**
 * Receives data from the incoming CORBA servant, places
 * it in a Queue, and then arranges distribution to the
 * DataHandlers.
 * Has extra functionality to send data to DataHandlers
 * on a per-host basis - ie. the Client can request which
 * hosts it would like to listen for.
 *
 * @author  $Author: tdb1 $
 * @version $Id: PacketSorter.java,v 1.10 2001/03/01 16:53:16 tdb1 Exp $
 */
class PacketSorter extends Thread {

//---FINAL ATTRIBUTES---

    /**
     * The current CVS revision of this class
     */
    public final String REVISION = "$Revision: 1.10 $";
    
//---STATIC METHODS---

//---CONSTRUCTORS---

    /**
     * Creates a new PacketSorter.
     *
     * @param queueMonitorInterval The interval at which to monitor the Queue
     */
    public PacketSorter(int queueMonitorInterval) {
        _queue = new Queue();
        // startup a monitor on this queue, every minute
        String queueName = _name + " PacketSorterQueue";
        _queue.startMonitor(queueMonitorInterval*1000, queueName);
        _hostMap = new HashMap();
        _allHostDataList = new LinkedList();
        _allHostsList = new LinkedList();
        _logger.write(toString(), Logger.SYSINIT, "created");
    }
    
//---PUBLIC METHODS---

    /**
     * Method to start the PacketSorter running. This method will
     * loop forever processing and sending data.
     */
    public void run() {
        int qID = _queue.getQueue();
        while(true) {
            // attempt to get some data from the Queue
            String xml = "";
            try {
                xml = (String) _queue.get(qID);
            }
            catch(InvalidQueueException e) {
                _logger.write(toString(), Logger.ERROR, "Queue failure: "+e);
            }
            
            XMLPacket packet = null;
            
            try {
                XMLPacketMaker xmlPacketMaker = new XMLPacketMaker(xml);
                packet = xmlPacketMaker.createXMLPacket();
            } catch(InvalidXMLException e) {
                _logger.write(toString(), Logger.ERROR, "Invalid XML: "+e);
                // skip the rest of this loop iteration
                continue;
            }
            
            String packetType = packet.getParam("packet.attributes.type");
            // check if we need to send it regardless
            if(packetType.equals("data") || packetType.equals("heartbeat")) {
                String host = packet.getParam("packet.attributes.machine_name");
                
                // look in the hostMap to see if anyone wants this data
                synchronized(this) {
                    if(_hostMap.containsKey(host)) {
                        LinkedList list = (LinkedList) _hostMap.get(host);
                        Iterator i = list.iterator();
                        // push the data to the listening Handler's queue
                        while(i.hasNext()) {
                            ((Queue) i.next()).add(xml);
                        }
                    }
                }
                
                // any handler in this list wants all packets, so send
                // it on to them regardless
                synchronized(this) {
                    Iterator i = _allHostDataList.iterator();
                    while(i.hasNext()) {
                        ((Queue) i.next()).add(xml);
                    }
                }
            }
            else {
                // always send this packet to all hosts, because it's
                // "extra" data, not host data
                synchronized(this) {
                    Iterator i = _allHostsList.iterator();
                    while(i.hasNext()) {
                        ((Queue) i.next()).add(xml);
                    }
                }
            }
        }
    }
    
    /**
     * Register a DataHandler in the system. This method
     * actually takes a reference to a Queue, which should be
     * a Queue that the DataHandler is making use of.
     * It also takes a hostList, this being a semi-colon
     * seperated list of hosts that the Client the DataHandler
     * is serving has requested. If this list is simply an empty
     * String, it is assumed the Client wants to listen to all
     * host information.
     *
     * @param dhQueue a Queue being used by the DataHandler that is registering
     * @param hostList a semi-colon seperated list of hosts
     */
    public synchronized void register(Queue dhQueue, String hostList) {
        // check to see if we want all hosts
        if(hostList.equals("")) {
            _allHostDataList.add(dhQueue);
            _logger.write(toString(), Logger.SYSMSG, "registered DataHandler for all hosts");
        }
        else {
            // go through the list of hosts
            StringTokenizer st = new StringTokenizer(hostList, ";");
            while(st.hasMoreTokens()) {
                String host = st.nextToken();
                // see if we already have a list in the map for this host
                if(_hostMap.containsKey(host)) {
                    // we do, so add to it
                    List list = (List) _hostMap.get(host);
                    list.add(dhQueue);
                }
                else {
                    // we don't, so create a list and put it in the map
                    LinkedList list = new LinkedList();
                    list.add(dhQueue);
                    _hostMap.put(host, list);
                }
            }
            _logger.write(toString(), Logger.SYSMSG, "registered DataHandler for hosts: "+hostList);
        }
        // always add host to our complete host list
        _allHostsList.add(dhQueue);
    }
    
    /**
     * Deregister a DataHandler. The DataHandler should give a reference
     * to the Queue it's using, and the *same* hostList it gave when it
     * register. It is imperative that the hostList is the same, otherwise
     * there will be all sorts of problems with lists getting out of sync.
     *
     * NB: Possible future addition would be recording of hostList's.
     *
     * @param dhQueue a Queue being used by the DataHandler that is deregistering
     * @param hostList a semi-colon seperated list of hosts
     */
    public synchronized void deregister(Queue dhQueue, String hostList) {
        // go through the list of hosts
        if(hostList.equals("")) {
            _allHostDataList.remove(dhQueue);
            _logger.write(toString(), Logger.SYSMSG, "deregistered DataHandler for all hosts");
        }
        else {
            StringTokenizer st = new StringTokenizer(hostList, ";");
            while(st.hasMoreTokens()) {
                String host = st.nextToken();
                // this should in reality always be true, but best check
                if(_hostMap.containsKey(host)) {
                    // get the list and remove the host in question
                    LinkedList list = (LinkedList) _hostMap.get(host);
                    list.remove(dhQueue);
                    // if the list is now empty, we might as well remove it
                    if(list.size()==0) {
                        _hostMap.remove(host);
                    }
                }
            }
            _logger.write(toString(), Logger.SYSMSG, "deregistered DataHandler for hosts: "+hostList);
        }
        // always remove host from our complete host list
        _allHostsList.remove(dhQueue);
    }
    
    /**
     * 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 return a reference to the Queue object. This
     * is needed so the ClientInterfaceServant can get add data
     * easily.
     *
     * @return a reference to our Queue object.
     */
    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 reference to the Queue we're using.
     */
    private Queue _queue;
    
    /**
     * A HashMap to store lists of Queue's (in the DataHandlers)
     * in a way that can be easily accessed when data comes in.
     */
    private HashMap _hostMap;
    
    /**
     * A list specifically for a Queue's associated with DataHandlers
     * that want all host information.
     */
    private LinkedList _allHostDataList;
    
    /**
     * A list of all hosts.
     */
    private LinkedList _allHostsList;
    
//---STATIC ATTRIBUTES---

}
Revision:	1.11
Committed:	Thu Mar 1 17:29:46 2001 UTC (23 years, 3 months ago) by tdb
Branch:	MAIN
Changes since 1.10:	+30 -24 lines
Log Message:	Just for the record, Collections.synchronizedList() doesn't work :) I've now manually synchronized the methods that access the lists and map, and put the sections of the run method that do the same in synchronized blocks. This should work, I hope. A lot of hoping seems to be going on here :)
#	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 java.util.*;
9
10	/**
11	* Receives data from the incoming CORBA servant, places
12	* it in a Queue, and then arranges distribution to the
13	* DataHandlers.
14	* Has extra functionality to send data to DataHandlers
15	* on a per-host basis - ie. the Client can request which
16	* hosts it would like to listen for.
17	*
18	* @author $Author: tdb1 $
19	* @version $Id: PacketSorter.java,v 1.10 2001/03/01 16:53:16 tdb1 Exp $
20	*/
21	class PacketSorter extends Thread {
22
23	//---FINAL ATTRIBUTES---
24
25	/**
26	* The current CVS revision of this class
27	*/
28	public final String REVISION = "$Revision: 1.10 $";
29
30	//---STATIC METHODS---
31
32	//---CONSTRUCTORS---
33
34	/**
35	* Creates a new PacketSorter.
36	*
37	* @param queueMonitorInterval The interval at which to monitor the Queue
38	*/
39	public PacketSorter(int queueMonitorInterval) {
40	_queue = new Queue();
41	// startup a monitor on this queue, every minute
42	String queueName = _name + " PacketSorterQueue";
43	_queue.startMonitor(queueMonitorInterval*1000, queueName);
44	_hostMap = new HashMap();
45	_allHostDataList = new LinkedList();
46	_allHostsList = new LinkedList();
47	_logger.write(toString(), Logger.SYSINIT, "created");
48	}
49
50	//---PUBLIC METHODS---
51
52	/**
53	* Method to start the PacketSorter running. This method will
54	* loop forever processing and sending data.
55	*/
56	public void run() {
57	int qID = _queue.getQueue();
58	while(true) {
59	// attempt to get some data from the Queue
60	String xml = "";
61	try {
62	xml = (String) _queue.get(qID);
63	}
64	catch(InvalidQueueException e) {
65	_logger.write(toString(), Logger.ERROR, "Queue failure: "+e);
66	}
67
68	XMLPacket packet = null;
69
70	try {
71	XMLPacketMaker xmlPacketMaker = new XMLPacketMaker(xml);
72	packet = xmlPacketMaker.createXMLPacket();
73	} catch(InvalidXMLException e) {
74	_logger.write(toString(), Logger.ERROR, "Invalid XML: "+e);
75	// skip the rest of this loop iteration
76	continue;
77	}
78
79	String packetType = packet.getParam("packet.attributes.type");
80	// check if we need to send it regardless
81	if(packetType.equals("data") \|\| packetType.equals("heartbeat")) {
82	String host = packet.getParam("packet.attributes.machine_name");
83
84	// look in the hostMap to see if anyone wants this data
85	synchronized(this) {
86	if(_hostMap.containsKey(host)) {
87	LinkedList list = (LinkedList) _hostMap.get(host);
88	Iterator i = list.iterator();
89	// push the data to the listening Handler's queue
90	while(i.hasNext()) {
91	((Queue) i.next()).add(xml);
92	}
93	}
94	}
95
96	// any handler in this list wants all packets, so send
97	// it on to them regardless
98	synchronized(this) {
99	Iterator i = _allHostDataList.iterator();
100	while(i.hasNext()) {
101	((Queue) i.next()).add(xml);
102	}
103	}
104	}
105	else {
106	// always send this packet to all hosts, because it's
107	// "extra" data, not host data
108	synchronized(this) {
109	Iterator i = _allHostsList.iterator();
110	while(i.hasNext()) {
111	((Queue) i.next()).add(xml);
112	}
113	}
114	}
115	}
116	}
117
118	/**
119	* Register a DataHandler in the system. This method
120	* actually takes a reference to a Queue, which should be
121	* a Queue that the DataHandler is making use of.
122	* It also takes a hostList, this being a semi-colon
123	* seperated list of hosts that the Client the DataHandler
124	* is serving has requested. If this list is simply an empty
125	* String, it is assumed the Client wants to listen to all
126	* host information.
127	*
128	* @param dhQueue a Queue being used by the DataHandler that is registering
129	* @param hostList a semi-colon seperated list of hosts
130	*/
131	public synchronized void register(Queue dhQueue, String hostList) {
132	// check to see if we want all hosts
133	if(hostList.equals("")) {
134	_allHostDataList.add(dhQueue);
135	_logger.write(toString(), Logger.SYSMSG, "registered DataHandler for all hosts");
136	}
137	else {
138	// go through the list of hosts
139	StringTokenizer st = new StringTokenizer(hostList, ";");
140	while(st.hasMoreTokens()) {
141	String host = st.nextToken();
142	// see if we already have a list in the map for this host
143	if(_hostMap.containsKey(host)) {
144	// we do, so add to it
145	List list = (List) _hostMap.get(host);
146	list.add(dhQueue);
147	}
148	else {
149	// we don't, so create a list and put it in the map
150	LinkedList list = new LinkedList();
151	list.add(dhQueue);
152	_hostMap.put(host, list);
153	}
154	}
155	_logger.write(toString(), Logger.SYSMSG, "registered DataHandler for hosts: "+hostList);
156	}
157	// always add host to our complete host list
158	_allHostsList.add(dhQueue);
159	}
160
161	/**
162	* Deregister a DataHandler. The DataHandler should give a reference
163	* to the Queue it's using, and the same hostList it gave when it
164	* register. It is imperative that the hostList is the same, otherwise
165	* there will be all sorts of problems with lists getting out of sync.
166	*
167	* NB: Possible future addition would be recording of hostList's.
168	*
169	* @param dhQueue a Queue being used by the DataHandler that is deregistering
170	* @param hostList a semi-colon seperated list of hosts
171	*/
172	public synchronized void deregister(Queue dhQueue, String hostList) {
173	// go through the list of hosts
174	if(hostList.equals("")) {
175	_allHostDataList.remove(dhQueue);
176	_logger.write(toString(), Logger.SYSMSG, "deregistered DataHandler for all hosts");
177	}
178	else {
179	StringTokenizer st = new StringTokenizer(hostList, ";");
180	while(st.hasMoreTokens()) {
181	String host = st.nextToken();
182	// this should in reality always be true, but best check
183	if(_hostMap.containsKey(host)) {
184	// get the list and remove the host in question
185	LinkedList list = (LinkedList) _hostMap.get(host);
186	list.remove(dhQueue);
187	// if the list is now empty, we might as well remove it
188	if(list.size()==0) {
189	_hostMap.remove(host);
190	}
191	}
192	}
193	_logger.write(toString(), Logger.SYSMSG, "deregistered DataHandler for hosts: "+hostList);
194	}
195	// always remove host from our complete host list
196	_allHostsList.remove(dhQueue);
197	}
198
199	/**
200	* Overrides the {@link java.lang.Object#toString() Object.toString()}
201	* method to provide clean logging (every class should have this).
202	*
203	* This uses the uk.ac.ukc.iscream.util.NameFormat class
204	* to format the toString()
205	*
206	* @return the name of this class and its CVS revision
207	*/
208	public String toString() {
209	return FormatName.getName(
210	_name,
211	getClass().getName(),
212	REVISION);
213	}
214
215	//---PRIVATE METHODS---
216
217	//---ACCESSOR/MUTATOR METHODS---
218
219	/**
220	* Accessor to return a reference to the Queue object. This
221	* is needed so the ClientInterfaceServant can get add data
222	* easily.
223	*
224	* @return a reference to our Queue object.
225	*/
226	public Queue getQueue() {
227	return _queue;
228	}
229
230	//---ATTRIBUTES---
231
232	/**
233	* This is the friendly identifier of the
234	* component this class is running in.
235	* eg, a Filter may be called "filter1",
236	* If this class does not have an owning
237	* component, a name from the configuration
238	* can be placed here. This name could also
239	* be changed to null for utility classes.
240	*/
241	private String _name = ClientInterfaceMain.NAME;
242
243	/**
244	* This holds a reference to the
245	* system logger that is being used.
246	*/
247	private Logger _logger = ReferenceManager.getInstance().getLogger();
248
249	/**
250	* A reference to the Queue we're using.
251	*/
252	private Queue _queue;
253
254	/**
255	* A HashMap to store lists of Queue's (in the DataHandlers)
256	* in a way that can be easily accessed when data comes in.
257	*/
258	private HashMap _hostMap;
259
260	/**
261	* A list specifically for a Queue's associated with DataHandlers
262	* that want all host information.
263	*/
264	private LinkedList _allHostDataList;
265
266	/**
267	* A list of all hosts.
268	*/
269	private LinkedList _allHostsList;
270
271	//---STATIC ATTRIBUTES---
272
273	}