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 1.3 2001/01/23 18:23:03 tdb1 Exp $
 */
class PacketSorter extends Thread {

//---FINAL ATTRIBUTES---

    /**
     * The current CVS revision of this class
     */
    public final String REVISION = "$Revision: 1.3 $";
    
//---STATIC METHODS---

//---CONSTRUCTORS---

    /**
     * Creates a new PacketSorter.
     */
    public PacketSorter() {
        _queue = new Queue();
        _hostMap = new HashMap();
        _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);
            }
            
            // find out which host this packet is actually for
            XMLPacketMaker xmlPacketMaker = new XMLPacketMaker(xml);
            XMLPacket packet = xmlPacketMaker.createXMLPacket();
            String host = packet.getParam("packet.attributes.machine_name");
            
            // look in the hostMap to see if anyone wants this data
            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
            Iterator j = _allHostsList.iterator();
            while(j.hasNext()) {
                ((Queue) j.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 void register(Queue dhQueue, String hostList) {
        // check to see if we want all hosts
        if(hostList.equals("")) {
            _allHostsList.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
                    LinkedList list = (LinkedList) _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);
        }
    }
    
    /**
     * 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 void deregister(Queue dhQueue, String hostList) {
        // go through the list of hosts
        if(hostList.equals("")) {
            _allHostsList.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);
        }
    }
    
    /**
     * 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 _allHostsList;
    
//---STATIC ATTRIBUTES---

}
Revision:	1.4
Committed:	Sat Jan 27 23:30:40 2001 UTC (23 years, 4 months ago) by tdb
Branch:	MAIN
Changes since 1.3:	+69 -11 lines
Log Message:	All of these classes have been javadoc'd and commented.
#	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	1.4	* @version $Id: PacketSorter.java,v 1.3 2001/01/23 18:23:03 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	1.4	public final String REVISION = "$Revision: 1.3 $";
29	tdb	1.1
30			//---STATIC METHODS---
31
32			//---CONSTRUCTORS---
33
34			/**
35			* Creates a new PacketSorter.
36			*/
37			public PacketSorter() {
38			_queue = new Queue();
39			_hostMap = new HashMap();
40	tdb	1.2	_allHostsList = new LinkedList();
41	tdb	1.1	_logger.write(toString(), Logger.SYSINIT, "created");
42			}
43
44			//---PUBLIC METHODS---
45
46	tdb	1.4	/**
47			* Method to start the PacketSorter running. This method will
48			* loop forever processing and sending data.
49			*/
50	tdb	1.1	public void run() {
51			int qID = _queue.getQueue();
52			while(true) {
53	tdb	1.4	// attempt to get some data from the Queue
54	tdb	1.1	String xml = "";
55			try {
56			xml = (String) _queue.get(qID);
57			}
58			catch(InvalidQueueException e) {
59			_logger.write(toString(), Logger.ERROR, "Queue failure: "+e);
60			}
61
62	tdb	1.4	// find out which host this packet is actually for
63	tdb	1.3	XMLPacketMaker xmlPacketMaker = new XMLPacketMaker(xml);
64			XMLPacket packet = xmlPacketMaker.createXMLPacket();
65	tdb	1.1	String host = packet.getParam("packet.attributes.machine_name");
66
67	tdb	1.4	// look in the hostMap to see if anyone wants this data
68	tdb	1.3	if(_hostMap.containsKey(host)) {
69			LinkedList list = (LinkedList) _hostMap.get(host);
70			Iterator i = list.iterator();
71	tdb	1.4	// push the data to the listening Handler's queue
72	tdb	1.3	while(i.hasNext()) {
73			((Queue) i.next()).add(xml);
74			}
75	tdb	1.1	}
76	tdb	1.2
77	tdb	1.4	// any handler in this list wants all packets, so send
78			// it on to them regardless
79	tdb	1.2	Iterator j = _allHostsList.iterator();
80			while(j.hasNext()) {
81			((Queue) j.next()).add(xml);
82			}
83	tdb	1.1	}
84			}
85
86	tdb	1.4	/**
87			* Register a DataHandler in the system. This method
88			* actually takes a reference to a Queue, which should be
89			* a Queue that the DataHandler is making use of.
90			* It also takes a hostList, this being a semi-colon
91			* seperated list of hosts that the Client the DataHandler
92			* is serving has requested. If this list is simply an empty
93			* String, it is assumed the Client wants to listen to all
94			* host information.
95			*
96			* @param dhQueue a Queue being used by the DataHandler that is registering
97			* @param hostList a semi-colon seperated list of hosts
98			*/
99	tdb	1.1	public void register(Queue dhQueue, String hostList) {
100	tdb	1.4	// check to see if we want all hosts
101	tdb	1.2	if(hostList.equals("")) {
102			_allHostsList.add(dhQueue);
103			_logger.write(toString(), Logger.SYSMSG, "registered DataHandler for all hosts");
104			}
105			else {
106	tdb	1.4	// go through the list of hosts
107	tdb	1.2	StringTokenizer st = new StringTokenizer(hostList, ";");
108			while(st.hasMoreTokens()) {
109			String host = st.nextToken();
110	tdb	1.4	// see if we already have a list in the map for this host
111	tdb	1.2	if(_hostMap.containsKey(host)) {
112	tdb	1.4	// we do, so add to it
113	tdb	1.2	LinkedList list = (LinkedList) _hostMap.get(host);
114			list.add(dhQueue);
115			}
116			else {
117	tdb	1.4	// we don't, so create a list and put it in the map
118	tdb	1.2	LinkedList list = new LinkedList();
119			list.add(dhQueue);
120			_hostMap.put(host, list);
121			}
122	tdb	1.1	}
123	tdb	1.2	_logger.write(toString(), Logger.SYSMSG, "registered DataHandler for hosts: "+hostList);
124	tdb	1.1	}
125			}
126
127	tdb	1.4	/**
128			* Deregister a DataHandler. The DataHandler should give a reference
129			* to the Queue it's using, and the same hostList it gave when it
130			* register. It is imperative that the hostList is the same, otherwise
131			* there will be all sorts of problems with lists getting out of sync.
132			*
133			* NB: Possible future addition would be recording of hostList's.
134			*
135			* @param dhQueue a Queue being used by the DataHandler that is deregistering
136			* @param hostList a semi-colon seperated list of hosts
137			*/
138	tdb	1.1	public void deregister(Queue dhQueue, String hostList) {
139	tdb	1.4	// go through the list of hosts
140	tdb	1.2	if(hostList.equals("")) {
141			_allHostsList.remove(dhQueue);
142			_logger.write(toString(), Logger.SYSMSG, "deregistered DataHandler for all hosts");
143			}
144			else {
145			StringTokenizer st = new StringTokenizer(hostList, ";");
146			while(st.hasMoreTokens()) {
147			String host = st.nextToken();
148	tdb	1.4	// this should in reality always be true, but best check
149	tdb	1.2	if(_hostMap.containsKey(host)) {
150	tdb	1.4	// get the list and remove the host in question
151	tdb	1.2	LinkedList list = (LinkedList) _hostMap.get(host);
152			list.remove(dhQueue);
153	tdb	1.4	// if the list is now empty, we might as well remove it
154	tdb	1.2	if(list.size()==0) {
155			_hostMap.remove(host);
156			}
157	tdb	1.1	}
158			}
159	tdb	1.2	_logger.write(toString(), Logger.SYSMSG, "deregistered DataHandler for hosts: "+hostList);
160	tdb	1.1	}
161			}
162
163			/**
164			* Overrides the {@link java.lang.Object#toString() Object.toString()}
165			* method to provide clean logging (every class should have this).
166			*
167			* This uses the uk.ac.ukc.iscream.util.NameFormat class
168			* to format the toString()
169			*
170			* @return the name of this class and its CVS revision
171			*/
172			public String toString() {
173			return FormatName.getName(
174			_name,
175			getClass().getName(),
176			REVISION);
177			}
178
179			//---PRIVATE METHODS---
180
181			//---ACCESSOR/MUTATOR METHODS---
182	tdb	1.4
183			/**
184			* Accessor to return a reference to the Queue object. This
185			* is needed so the ClientInterfaceServant can get add data
186			* easily.
187			*
188			* @return a reference to our Queue object.
189			*/
190	tdb	1.1	public Queue getQueue() {
191			return _queue;
192			}
193
194			//---ATTRIBUTES---
195
196			/**
197			* This is the friendly identifier of the
198			* component this class is running in.
199			* eg, a Filter may be called "filter1",
200			* If this class does not have an owning
201			* component, a name from the configuration
202			* can be placed here. This name could also
203			* be changed to null for utility classes.
204			*/
205			private String _name = ClientInterfaceMain.NAME;
206
207			/**
208			* This holds a reference to the
209			* system logger that is being used.
210			*/
211			private Logger _logger = ReferenceManager.getInstance().getLogger();
212
213	tdb	1.4	/**
214			* A reference to the Queue we're using.
215			*/
216	tdb	1.1	private Queue _queue;
217
218	tdb	1.4	/**
219			* A HashMap to store lists of Queue's (in the DataHandlers)
220			* in a way that can be easily accessed when data comes in.
221			*/
222	tdb	1.1	private HashMap _hostMap;
223	tdb	1.4
224			/**
225			* A list specifically for a Queue's associated with DataHandlers
226			* that want all host information.
227			*/
228	tdb	1.2	private LinkedList _allHostsList;
229	tdb	1.1
230			//---STATIC ATTRIBUTES---
231
232			}