parallel/services/MulticastDiscoveryService.java

package appl.parallel.services;

import java.io.IOException;
import java.net.DatagramPacket;
import java.net.InetAddress;
import java.net.MulticastSocket;
import java.net.UnknownHostException;
import java.rmi.Naming;
import java.rmi.RemoteException;
import java.util.Iterator;
import java.util.Vector;

import org.apache.log4j.BasicConfigurator;
import org.apache.log4j.LogManager;
import org.apache.log4j.Logger;

import appl.ext.XuluConfig;
import appl.parallel.ComputingResource;
import appl.parallel.ComputingResourceContainer;
import appl.parallel.server.XuluServer;
import appl.parallel.test.PingTestObject;
import appl.parallel.util.Helper;

/**
 * Responsible for discovery of RemoteResources on the network, especially but
 * not only {@link XuluServer XuluServers}. It listens for the following
 * messages: <br>
 * <br>
 * "Hello Xulu from XuluServer" - sent by RemoteResources like
 * {@link XuluServer} when starting <br>
 * "Goodbye Xulu" - sent by RemoteResources like {@link XuluServer} when
 * stopping <br>
 * <br>
 * and sends: <br>
 * "Hello Servers" - when started If multicasting does not work try to disable
 * your firewall or better configure it to allow multicast packages. Notice
 * also, that multicasting may not work in virtual machines like MS Virtual PC
 * 2004. <Warning><b>THIS CLASS IS STILL FOR DEMONSTRATION ONLY</b></Warning>
 * 
 * @author Dominik Appl
 * @see XuluServer
 */
public class MulticastDiscoveryService implements DiscoveryService {

        // the data to send
        final String sendHello = "Hello Servers";

        // data to receive
        final String helloFromXuluServers = "Hello Xulu from XuluServer";

        final String recGoodBye = "Goodbye Xulu";

        // the Thread which waits on Server hello/goodbyes
        volatile ReceiveThread receiveThread;

        // volatile RenewalThread renewalThread;

        // the thread that checks if servers are alive
        // volatile CheckThread checkThread;

        // the data is read from XuluConfig
        InetAddress group;

        int port;

        int lease;

        MulticastSocket socket;

        boolean isRunning = false;

        private final Logger LOG = LogManager.getLogger(this.getClass().getName());

        /**
         * Constructs a new service reading port and lease time from
         * {@link appl.ext.XuluConfig}
         */
        public MulticastDiscoveryService() {
                XuluConfig config = XuluConfig.getXuluConfig();
                port = Integer.valueOf(config
                                .getProperty("DiscoveryServices.multicast.port"));
                // lease = Integer.valueOf(config
                // .getProperty("MulticastDiscoveryService.lease"));
                try {
                        group = InetAddress.getByName(config
                                        .getProperty("DiscoveryServices.multicast.group"));
                } catch (UnknownHostException e) {
                        // TODO Auto-generated catch block
                        e.printStackTrace();
                }
        }

        /**
         * Constructs a new service
         * 
         * @param port
         *            port where the multicasting happens
         * @param lease
         *            timeintervall (in ms) after whi
         */
        public MulticastDiscoveryService(int port, int lease) {
                this();
                this.port = port;
                this.lease = lease;
        }

        /*
         * (non-Javadoc)
         * 
         * @see appl.parallel.services.Service#startService()
         */
        public void startService() {
                try {
                        LOG.info("Discoveryservice started");
                        // All Servers must listen on the port specified, in order fo
                        // the socket to receive
                        if (socket == null)
                                socket = new MulticastSocket(port);
                        // open a multicast group and join it

                        socket.joinGroup(group);

                        socket.setSoTimeout(5000);

                        // create and send Hello world
                        DatagramPacket datagram = new DatagramPacket(sendHello.getBytes(),
                                        sendHello.length(), group, port);
                        System.out.println(group);
                        LOG.info("Send hello to all listening servers with broadcast IP "
                                        + group);

                        socket.send(datagram);

                        if (receiveThread == null) {
                                receiveThread = new ReceiveThread(socket, helloFromXuluServers,
                                                recGoodBye);
                        }
                        if (!(receiveThread.isAlive()))
                                receiveThread.start();

                } catch (UnknownHostException e) {
                        e.printStackTrace();
                } catch (IOException e) {
                        e.printStackTrace();
                }

        }

        /*
         * (non-Javadoc)
         * 
         * @see appl.parallel.services.DiscoveryService#getResources()
         */
        public Vector<ComputingResourceContainer> getResources() {
                return receiveThread.getResources();
        }

        /*
         * (non-Javadoc)
         * 
         * @see appl.parallel.services.Service#stopService()
         */
        public void stopService() {
                receiveThread.stopThread();
                // renewalThread.stopThread();
                try {
                        Thread.currentThread().sleep(100);
                } catch (InterruptedException e) {
                        // TODO Auto-generated catch block
                        e.printStackTrace();
                }
                socket.close();

        }

        /*
         * (non-Javadoc)
         * 
         * @see appl.parallel.services.Service#isRunning()
         */
        public boolean isRunning() {
                return isRunning;
        }

        /** waits for incoming calls */

        class ReceiveThread extends Thread {

                // Resources discovered so far
                Vector<ComputingResource> discoveredResources;

                private volatile Thread receiveThread;

                boolean exit = false;

                MulticastSocket socket;

                private final String recHello2;

                private final String recGoodBye2;

                private boolean discoveryInProgress = false;

                /**
                 * @returns a Vector of discovered Ressources before return, all values
                 *          are pinged and only returned if alive
                 */
                public Vector<ComputingResourceContainer> getResources() {
                        return Helper.getResourceContainersForVector(discoveredResources);
                }

                /**
                 * @param socket2
                 *            Socket which is used for listening
                 * @param helloFromXuluServers
                 *            String that equals the hello message of the server
                 * @param recGoodBye
                 *            String that equals the Goordbye message of the server
                 */
                public ReceiveThread(MulticastSocket socket, String recHello,
                                String recGoodBye) {
                        recHello2 = recHello;
                        recGoodBye2 = recGoodBye;
                        this.socket = socket;
                        discoveredResources = new Vector<ComputingResource>();
                }

                /**
                 * Safe method to stop the Thread. Use this method instead of
                 * {@link Thread}
                 */
                public void stopThread() {
                        if (receiveThread != null) {
                                exit = true;
                                // the only way to stop the Thread is to send a package so that
                                // the receive operation no longer blocks
                                DatagramPacket datagram = new DatagramPacket(
                                                "Stopping receive Thread".getBytes(),
                                                "Stopping receive Thread".length(), group, port);
                                try {
                                        socket.send(datagram);
                                        // wait on stop
                                        Thread.currentThread().sleep(100);
                                } catch (IOException e) {
                                        e.printStackTrace();
                                } catch (InterruptedException e) {
                                        // TODO Auto-generated catch block
                                        e.printStackTrace();
                                } finally {
                                        exit = false;
                                }
                                exit = false;

                        }

                }

                public void run() {
                        receiveThread = Thread.currentThread();
                        while (!exit) {
                                try {
                                        // receive buffer

                                        byte[] buffer = new byte[256];
                                        DatagramPacket datagram = new DatagramPacket(buffer,
                                                        buffer.length);
                                        socket.receive(datagram);
                                        // get the message in the right
                                        byte[] result = new byte[datagram.getLength()];
                                        System.arraycopy(datagram.getData(), 0, result, 0, datagram
                                                        .getLength());
                                        // check if message is from XuluServer
                                        if (new String(result).equals(helloFromXuluServers)) {
                                                LOG.debug("received hello from server "
                                                                + datagram.getAddress());

                                                String newname = "rmi:/" + datagram.getAddress()
                                                                + "/XuluServer";

                                                ComputingResource server = (ComputingResource) Naming
                                                                .lookup(newname);
                                                addRessource(server, datagram.getAddress().toString());

                                        } else if (LOG.isDebugEnabled())
                                                LOG.debug("received message |" + new String(result)
                                                                + "| from " + datagram.getAddress());

                                } catch (java.net.SocketTimeoutException e) {
                                        // catch timeout exception
                                }

                                catch (IOException e) {
                                        // TODO Auto-generated catch block
                                        e.printStackTrace();
                                } catch (Exception e) {
                                        if (!(e instanceof InterruptedException))
                                                e.printStackTrace();
                                }
                        }
                        System.out.println("exit Thread " + this.toString());
                }

                /**
                 * adds ressource to vector but first looks if its not already added
                 * 
                 * @param server
                 */
                private void addRessource(ComputingResource server, String IP) {
                        // check for double entries
                        for (ComputingResource s : discoveredResources) {
                                if (s.equals(server)) {
                                        LOG.debug("Not adding " + server.toString()
                                                        + " to discovered Ressources again!");
                                        return;
                                }
                        }
                        LOG.info("Adding Xulu Server: " + IP + "to discovered Ressources");
                        // try {
                        // Thread.currentThread().sleep(2000);
                        // } catch (InterruptedException e) {
                        // // TODO Auto-generated catch block
                        // e.printStackTrace();
                        // }
                        discoveredResources.add(server);
                }

                /**
                 * Gets the {@link Resource
                 */
                public void pingResources() {
                        PingTestObject po = new PingTestObject(32);
                        // cannot make a for each loop because of
                        // java.util.ConcurrentModificationException
                        int i = discoveredResources.size() - 1;
                        while (i >= 0) {
                                boolean error = true;
                                ComputingResource r = discoveredResources.get(i);
                                if (!(r == null)) {

                                        try {
                                                r.ping();
                                                error = false;
                                                LOG.debug("Ping to " + r + " was successfull!");
                                        } catch (Exception e) {
                                                e.printStackTrace();
                                        }
                                        // if not successfull remove object
                                        if (error) {
                                                LOG.debug("Ping to " + r
                                                                + " was NOT successfull! Removing ressource");

                                                discoveredResources.remove(r);
                                        }
                                }
                                i--;
                        }
                }

        }

        /**
         * simple Thread that caused rediscovery of Ressources at a given time
         * intervall **
         */

        class RenewalThread extends Thread {

                private volatile Thread thisThread;

                boolean exit = false;

                private final long timeintervall;

                private volatile ReceiveThread discoveryToRenew;

                /**
                 * invokes rediscovery on the given thread at the given time intervall
                 */
                public RenewalThread(ReceiveThread discoveryToRenew, long timeintervall) {
                        this.discoveryToRenew = discoveryToRenew;
                        this.timeintervall = timeintervall;

                }

                /**
                 * Safe method to stop this Thread. Use this method instead of
                 * {@link Thread}
                 */
                public void stopThread() {
                        if (thisThread != null)
                                exit = true;
                }

                public void run() {
                        thisThread = Thread.currentThread();
                        while (!exit) {
                                discoveryToRenew.pingResources();
                                try {
                                        Thread.currentThread().sleep(timeintervall);
                                } catch (InterruptedException e) {
                                        // TODO Auto-generated catch block
                                        e.printStackTrace();
                                }
                        }
                        System.out.println("exit renewal Thread");
                }

        }

        /**
         * just for testing..edit as you like
         */
        public static void main(String[] args) {
                BasicConfigurator.configure();
                MulticastDiscoveryService bro = new MulticastDiscoveryService();
                bro.startService();
                try {
                        Thread.currentThread().sleep(5000);
                } catch (InterruptedException e) {
                        e.printStackTrace();
                }
                // bro.stopService();
                while (true)
                        try {
                                Vector<ComputingResourceContainer> v = bro.getResources();
                                for (ComputingResourceContainer container : v) {
                                        System.out.print("Active Object: ");
                                        System.out.println(container.getInformation().getProperty(
                                                        "name")
                                                        + " with IP "
                                                        + container.getInformation().getProperty("IP"));
                                }
                                Thread.currentThread().sleep(5000);
                        } catch (InterruptedException e) {

                        }
        }

}
1	package appl.parallel.services;
2
3	import java.io.IOException;
4	import java.net.DatagramPacket;
5	import java.net.InetAddress;
6	import java.net.MulticastSocket;
7	import java.net.UnknownHostException;
8	import java.rmi.Naming;
9	import java.rmi.RemoteException;
10	import java.util.Iterator;
11	import java.util.Vector;
12
13	import org.apache.log4j.BasicConfigurator;
14	import org.apache.log4j.LogManager;
15	import org.apache.log4j.Logger;
16
17	import appl.ext.XuluConfig;
18	import appl.parallel.ComputingResource;
19	import appl.parallel.ComputingResourceContainer;
20	import appl.parallel.server.XuluServer;
21	import appl.parallel.test.PingTestObject;
22	import appl.parallel.util.Helper;
23
24	/**
25	* Responsible for discovery of RemoteResources on the network, especially but
26	* not only {@link XuluServer XuluServers}. It listens for the following
27	* messages: <br>
28	* <br>
29	* "Hello Xulu from XuluServer" - sent by RemoteResources like
30	* {@link XuluServer} when starting <br>
31	* "Goodbye Xulu" - sent by RemoteResources like {@link XuluServer} when
32	* stopping <br>
33	* <br>
34	* and sends: <br>
35	* "Hello Servers" - when started If multicasting does not work try to disable
36	* your firewall or better configure it to allow multicast packages. Notice
37	* also, that multicasting may not work in virtual machines like MS Virtual PC
38	* 2004. <Warning><b>THIS CLASS IS STILL FOR DEMONSTRATION ONLY</b></Warning>
39	*
40	* @author Dominik Appl
41	* @see XuluServer
42	*/
43	public class MulticastDiscoveryService implements DiscoveryService {
44
45	// the data to send
46	final String sendHello = "Hello Servers";
47
48	// data to receive
49	final String helloFromXuluServers = "Hello Xulu from XuluServer";
50
51	final String recGoodBye = "Goodbye Xulu";
52
53	// the Thread which waits on Server hello/goodbyes
54	volatile ReceiveThread receiveThread;
55
56	// volatile RenewalThread renewalThread;
57
58	// the thread that checks if servers are alive
59	// volatile CheckThread checkThread;
60
61	// the data is read from XuluConfig
62	InetAddress group;
63
64	int port;
65
66	int lease;
67
68	MulticastSocket socket;
69
70	boolean isRunning = false;
71
72	private final Logger LOG = LogManager.getLogger(this.getClass().getName());
73
74	/**
75	* Constructs a new service reading port and lease time from
76	* {@link appl.ext.XuluConfig}
77	*/
78	public MulticastDiscoveryService() {
79	XuluConfig config = XuluConfig.getXuluConfig();
80	port = Integer.valueOf(config
81	.getProperty("DiscoveryServices.multicast.port"));
82	// lease = Integer.valueOf(config
83	// .getProperty("MulticastDiscoveryService.lease"));
84	try {
85	group = InetAddress.getByName(config
86	.getProperty("DiscoveryServices.multicast.group"));
87	} catch (UnknownHostException e) {
88	// TODO Auto-generated catch block
89	e.printStackTrace();
90	}
91	}
92
93	/**
94	* Constructs a new service
95	*
96	* @param port
97	* port where the multicasting happens
98	* @param lease
99	* timeintervall (in ms) after whi
100	*/
101	public MulticastDiscoveryService(int port, int lease) {
102	this();
103	this.port = port;
104	this.lease = lease;
105	}
106
107	/*
108	* (non-Javadoc)
109	*
110	* @see appl.parallel.services.Service#startService()
111	*/
112	public void startService() {
113	try {
114	LOG.info("Discoveryservice started");
115	// All Servers must listen on the port specified, in order fo
116	// the socket to receive
117	if (socket == null)
118	socket = new MulticastSocket(port);
119	// open a multicast group and join it
120
121	socket.joinGroup(group);
122
123	socket.setSoTimeout(5000);
124
125	// create and send Hello world
126	DatagramPacket datagram = new DatagramPacket(sendHello.getBytes(),
127	sendHello.length(), group, port);
128	System.out.println(group);
129	LOG.info("Send hello to all listening servers with broadcast IP "
130	+ group);
131
132	socket.send(datagram);
133
134	if (receiveThread == null) {
135	receiveThread = new ReceiveThread(socket, helloFromXuluServers,
136	recGoodBye);
137	}
138	if (!(receiveThread.isAlive()))
139	receiveThread.start();
140
141	} catch (UnknownHostException e) {
142	e.printStackTrace();
143	} catch (IOException e) {
144	e.printStackTrace();
145	}
146
147	}
148
149	/*
150	* (non-Javadoc)
151	*
152	* @see appl.parallel.services.DiscoveryService#getResources()
153	*/
154	public Vector<ComputingResourceContainer> getResources() {
155	return receiveThread.getResources();
156	}
157
158	/*
159	* (non-Javadoc)
160	*
161	* @see appl.parallel.services.Service#stopService()
162	*/
163	public void stopService() {
164	receiveThread.stopThread();
165	// renewalThread.stopThread();
166	try {
167	Thread.currentThread().sleep(100);
168	} catch (InterruptedException e) {
169	// TODO Auto-generated catch block
170	e.printStackTrace();
171	}
172	socket.close();
173
174	}
175
176	/*
177	* (non-Javadoc)
178	*
179	* @see appl.parallel.services.Service#isRunning()
180	*/
181	public boolean isRunning() {
182	return isRunning;
183	}
184
185	/** waits for incoming calls */
186
187	class ReceiveThread extends Thread {
188
189	// Resources discovered so far
190	Vector<ComputingResource> discoveredResources;
191
192	private volatile Thread receiveThread;
193
194	boolean exit = false;
195
196	MulticastSocket socket;
197
198	private final String recHello2;
199
200	private final String recGoodBye2;
201
202	private boolean discoveryInProgress = false;
203
204	/**
205	* @returns a Vector of discovered Ressources before return, all values
206	* are pinged and only returned if alive
207	*/
208	public Vector<ComputingResourceContainer> getResources() {
209	return Helper.getResourceContainersForVector(discoveredResources);
210	}
211
212	/**
213	* @param socket2
214	* Socket which is used for listening
215	* @param helloFromXuluServers
216	* String that equals the hello message of the server
217	* @param recGoodBye
218	* String that equals the Goordbye message of the server
219	*/
220	public ReceiveThread(MulticastSocket socket, String recHello,
221	String recGoodBye) {
222	recHello2 = recHello;
223	recGoodBye2 = recGoodBye;
224	this.socket = socket;
225	discoveredResources = new Vector<ComputingResource>();
226	}
227
228	/**
229	* Safe method to stop the Thread. Use this method instead of
230	* {@link Thread}
231	*/
232	public void stopThread() {
233	if (receiveThread != null) {
234	exit = true;
235	// the only way to stop the Thread is to send a package so that
236	// the receive operation no longer blocks
237	DatagramPacket datagram = new DatagramPacket(
238	"Stopping receive Thread".getBytes(),
239	"Stopping receive Thread".length(), group, port);
240	try {
241	socket.send(datagram);
242	// wait on stop
243	Thread.currentThread().sleep(100);
244	} catch (IOException e) {
245	e.printStackTrace();
246	} catch (InterruptedException e) {
247	// TODO Auto-generated catch block
248	e.printStackTrace();
249	} finally {
250	exit = false;
251	}
252	exit = false;
253
254	}
255
256	}
257
258	public void run() {
259	receiveThread = Thread.currentThread();
260	while (!exit) {
261	try {
262	// receive buffer
263
264	byte[] buffer = new byte[256];
265	DatagramPacket datagram = new DatagramPacket(buffer,
266	buffer.length);
267	socket.receive(datagram);
268	// get the message in the right
269	byte[] result = new byte[datagram.getLength()];
270	System.arraycopy(datagram.getData(), 0, result, 0, datagram
271	.getLength());
272	// check if message is from XuluServer
273	if (new String(result).equals(helloFromXuluServers)) {
274	LOG.debug("received hello from server "
275	+ datagram.getAddress());
276
277	String newname = "rmi:/" + datagram.getAddress()
278	+ "/XuluServer";
279
280	ComputingResource server = (ComputingResource) Naming
281	.lookup(newname);
282	addRessource(server, datagram.getAddress().toString());
283
284	} else if (LOG.isDebugEnabled())
285	LOG.debug("received message \|" + new String(result)
286	+ "\| from " + datagram.getAddress());
287
288	} catch (java.net.SocketTimeoutException e) {
289	// catch timeout exception
290	}
291
292	catch (IOException e) {
293	// TODO Auto-generated catch block
294	e.printStackTrace();
295	} catch (Exception e) {
296	if (!(e instanceof InterruptedException))
297	e.printStackTrace();
298	}
299	}
300	System.out.println("exit Thread " + this.toString());
301	}
302
303	/**
304	* adds ressource to vector but first looks if its not already added
305	*
306	* @param server
307	*/
308	private void addRessource(ComputingResource server, String IP) {
309	// check for double entries
310	for (ComputingResource s : discoveredResources) {
311	if (s.equals(server)) {
312	LOG.debug("Not adding " + server.toString()
313	+ " to discovered Ressources again!");
314	return;
315	}
316	}
317	LOG.info("Adding Xulu Server: " + IP + "to discovered Ressources");
318	// try {
319	// Thread.currentThread().sleep(2000);
320	// } catch (InterruptedException e) {
321	// // TODO Auto-generated catch block
322	// e.printStackTrace();
323	// }
324	discoveredResources.add(server);
325	}
326
327	/**
328	* Gets the {@link Resource
329	*/
330	public void pingResources() {
331	PingTestObject po = new PingTestObject(32);
332	// cannot make a for each loop because of
333	// java.util.ConcurrentModificationException
334	int i = discoveredResources.size() - 1;
335	while (i >= 0) {
336	boolean error = true;
337	ComputingResource r = discoveredResources.get(i);
338	if (!(r == null)) {
339
340	try {
341	r.ping();
342	error = false;
343	LOG.debug("Ping to " + r + " was successfull!");
344	} catch (Exception e) {
345	e.printStackTrace();
346	}
347	// if not successfull remove object
348	if (error) {
349	LOG.debug("Ping to " + r
350	+ " was NOT successfull! Removing ressource");
351
352	discoveredResources.remove(r);
353	}
354	}
355	i--;
356	}
357	}
358
359	}
360
361	/**
362	* simple Thread that caused rediscovery of Ressources at a given time
363	* intervall **
364	*/
365
366	class RenewalThread extends Thread {
367
368	private volatile Thread thisThread;
369
370	boolean exit = false;
371
372	private final long timeintervall;
373
374	private volatile ReceiveThread discoveryToRenew;
375
376	/**
377	* invokes rediscovery on the given thread at the given time intervall
378	*/
379	public RenewalThread(ReceiveThread discoveryToRenew, long timeintervall) {
380	this.discoveryToRenew = discoveryToRenew;
381	this.timeintervall = timeintervall;
382
383	}
384
385	/**
386	* Safe method to stop this Thread. Use this method instead of
387	* {@link Thread}
388	*/
389	public void stopThread() {
390	if (thisThread != null)
391	exit = true;
392	}
393
394	public void run() {
395	thisThread = Thread.currentThread();
396	while (!exit) {
397	discoveryToRenew.pingResources();
398	try {
399	Thread.currentThread().sleep(timeintervall);
400	} catch (InterruptedException e) {
401	// TODO Auto-generated catch block
402	e.printStackTrace();
403	}
404	}
405	System.out.println("exit renewal Thread");
406	}
407
408	}
409
410	/**
411	* just for testing..edit as you like
412	*/
413	public static void main(String[] args) {
414	BasicConfigurator.configure();
415	MulticastDiscoveryService bro = new MulticastDiscoveryService();
416	bro.startService();
417	try {
418	Thread.currentThread().sleep(5000);
419	} catch (InterruptedException e) {
420	e.printStackTrace();
421	}
422	// bro.stopService();
423	while (true)
424	try {
425	Vector<ComputingResourceContainer> v = bro.getResources();
426	for (ComputingResourceContainer container : v) {
427	System.out.print("Active Object: ");
428	System.out.println(container.getInformation().getProperty(
429	"name")
430	+ " with IP "
431	+ container.getInformation().getProperty("IP"));
432	}
433	Thread.currentThread().sleep(5000);
434	} catch (InterruptedException e) {
435
436	}
437	}
438
439	}