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, 2 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 :)
#	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.util.*;
9
10			/**
11			* Receives data from the incoming CORBA servant, places
12			* it in a Queue, and then arranges distribution to the
13	tdb	1.4	* 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	tdb	1.1	*
18	tdb	1.2	* @author $Author: tdb1 $
19	tdb	1.11	* @version $Id: PacketSorter.java,v 1.10 2001/03/01 16:53:16 tdb1 Exp $
20	tdb	1.1	*/
21			class PacketSorter extends Thread {
22
23			//---FINAL ATTRIBUTES---
24
25			/**
26			* The current CVS revision of this class
27			*/
28	tdb	1.11	public final String REVISION = "$Revision: 1.10 $";
29	tdb	1.1
30			//---STATIC METHODS---
31
32			//---CONSTRUCTORS---
33
34			/**
35			* Creates a new PacketSorter.
36	tdb	1.6	*
37			* @param queueMonitorInterval The interval at which to monitor the Queue
38	tdb	1.1	*/
39	tdb	1.6	public PacketSorter(int queueMonitorInterval) {
40	tdb	1.1	_queue = new Queue();
41	tdb	1.5	// startup a monitor on this queue, every minute
42	tdb	1.6	String queueName = _name + " PacketSorterQueue";
43			_queue.startMonitor(queueMonitorInterval*1000, queueName);
44	tdb	1.11	_hostMap = new HashMap();
45			_allHostDataList = new LinkedList();
46			_allHostsList = new LinkedList();
47	tdb	1.1	_logger.write(toString(), Logger.SYSINIT, "created");
48			}
49
50			//---PUBLIC METHODS---
51
52	tdb	1.4	/**
53			* Method to start the PacketSorter running. This method will
54			* loop forever processing and sending data.
55			*/
56	tdb	1.1	public void run() {
57			int qID = _queue.getQueue();
58			while(true) {
59	tdb	1.4	// attempt to get some data from the Queue
60	tdb	1.1	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	tdb	1.10	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	tdb	1.1
79	tdb	1.8	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	tdb	1.11	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	tdb	1.8	}
94			}
95
96			// any handler in this list wants all packets, so send
97			// it on to them regardless
98	tdb	1.11	synchronized(this) {
99			Iterator i = _allHostDataList.iterator();
100			while(i.hasNext()) {
101			((Queue) i.next()).add(xml);
102			}
103			}
104	tdb	1.1	}
105	tdb	1.8	else {
106	tdb	1.10	// always send this packet to all hosts, because it's
107			// "extra" data, not host data
108	tdb	1.11	synchronized(this) {
109			Iterator i = _allHostsList.iterator();
110			while(i.hasNext()) {
111			((Queue) i.next()).add(xml);
112			}
113			}
114	tdb	1.2	}
115	tdb	1.1	}
116			}
117
118	tdb	1.4	/**
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	tdb	1.10	public synchronized void register(Queue dhQueue, String hostList) {
132	tdb	1.4	// check to see if we want all hosts
133	tdb	1.2	if(hostList.equals("")) {
134	tdb	1.10	_allHostDataList.add(dhQueue);
135	tdb	1.2	_logger.write(toString(), Logger.SYSMSG, "registered DataHandler for all hosts");
136			}
137			else {
138	tdb	1.4	// go through the list of hosts
139	tdb	1.2	StringTokenizer st = new StringTokenizer(hostList, ";");
140			while(st.hasMoreTokens()) {
141			String host = st.nextToken();
142	tdb	1.4	// see if we already have a list in the map for this host
143	tdb	1.2	if(_hostMap.containsKey(host)) {
144	tdb	1.4	// we do, so add to it
145	tdb	1.9	List list = (List) _hostMap.get(host);
146	tdb	1.2	list.add(dhQueue);
147			}
148			else {
149	tdb	1.4	// we don't, so create a list and put it in the map
150	tdb	1.11	LinkedList list = new LinkedList();
151	tdb	1.2	list.add(dhQueue);
152			_hostMap.put(host, list);
153			}
154	tdb	1.1	}
155	tdb	1.2	_logger.write(toString(), Logger.SYSMSG, "registered DataHandler for hosts: "+hostList);
156	tdb	1.1	}
157	tdb	1.10	// always add host to our complete host list
158			_allHostsList.add(dhQueue);
159	tdb	1.1	}
160
161	tdb	1.4	/**
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	tdb	1.10	public synchronized void deregister(Queue dhQueue, String hostList) {
173	tdb	1.4	// go through the list of hosts
174	tdb	1.2	if(hostList.equals("")) {
175	tdb	1.10	_allHostDataList.remove(dhQueue);
176	tdb	1.2	_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	tdb	1.4	// this should in reality always be true, but best check
183	tdb	1.2	if(_hostMap.containsKey(host)) {
184	tdb	1.4	// get the list and remove the host in question
185	tdb	1.11	LinkedList list = (LinkedList) _hostMap.get(host);
186	tdb	1.2	list.remove(dhQueue);
187	tdb	1.4	// if the list is now empty, we might as well remove it
188	tdb	1.2	if(list.size()==0) {
189			_hostMap.remove(host);
190			}
191	tdb	1.1	}
192			}
193	tdb	1.2	_logger.write(toString(), Logger.SYSMSG, "deregistered DataHandler for hosts: "+hostList);
194	tdb	1.1	}
195	tdb	1.10	// always remove host from our complete host list
196			_allHostsList.remove(dhQueue);
197	tdb	1.1	}
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	tdb	1.4
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	tdb	1.1	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	tdb	1.4	/**
250			* A reference to the Queue we're using.
251			*/
252	tdb	1.1	private Queue _queue;
253
254	tdb	1.4	/**
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	tdb	1.11	private HashMap _hostMap;
259	tdb	1.4
260			/**
261			* A list specifically for a Queue's associated with DataHandlers
262			* that want all host information.
263	tdb	1.10	*/
264	tdb	1.11	private LinkedList _allHostDataList;
265	tdb	1.10
266			/**
267			* A list of all hosts.
268	tdb	1.4	*/
269	tdb	1.11	private LinkedList _allHostsList;
270	tdb	1.1
271			//---STATIC ATTRIBUTES---
272
273			}