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1   /*
2    *  Licensed to the Apache Software Foundation (ASF) under one
3    *  or more contributor license agreements.  See the NOTICE file
4    *  distributed with this work for additional information
5    *  regarding copyright ownership.  The ASF licenses this file
6    *  to you under the Apache License, Version 2.0 (the
7    *  "License"); you may not use this file except in compliance
8    *  with the License.  You may obtain a copy of the License at
9    *  
10   *    http://www.apache.org/licenses/LICENSE-2.0
11   *  
12   *  Unless required by applicable law or agreed to in writing,
13   *  software distributed under the License is distributed on an
14   *  "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
15   *  KIND, either express or implied.  See the License for the
16   *  specific language governing permissions and limitations
17   *  under the License. 
18   *  
19   */
20  package org.apache.mina.transport.socket.nio.support;
21  
22  import java.io.IOException;
23  import java.net.InetSocketAddress;
24  import java.net.SocketAddress;
25  import java.nio.channels.DatagramChannel;
26  import java.nio.channels.SelectionKey;
27  import java.nio.channels.Selector;
28  import java.util.Iterator;
29  import java.util.Set;
30  
31  import org.apache.mina.common.ByteBuffer;
32  import org.apache.mina.common.ConnectFuture;
33  import org.apache.mina.common.ExceptionMonitor;
34  import org.apache.mina.common.IoConnector;
35  import org.apache.mina.common.IoHandler;
36  import org.apache.mina.common.IoServiceConfig;
37  import org.apache.mina.common.IoSession;
38  import org.apache.mina.common.IoSessionRecycler;
39  import org.apache.mina.common.IoFilter.WriteRequest;
40  import org.apache.mina.common.support.AbstractIoFilterChain;
41  import org.apache.mina.common.support.BaseIoConnector;
42  import org.apache.mina.common.support.DefaultConnectFuture;
43  import org.apache.mina.transport.socket.nio.DatagramConnectorConfig;
44  import org.apache.mina.transport.socket.nio.DatagramServiceConfig;
45  import org.apache.mina.transport.socket.nio.DatagramSessionConfig;
46  import org.apache.mina.util.NamePreservingRunnable;
47  import org.apache.mina.util.Queue;
48  
49  import edu.emory.mathcs.backport.java.util.concurrent.Executor;
50  
51  /**
52   * {@link IoConnector} for datagram transport (UDP/IP).
53   * 
54   * @author The Apache Directory Project (mina-dev@directory.apache.org)
55   * @version $Rev: 563373 $, $Date: 2007-08-07 11:49:24 +0900 (화, 07  8월 2007) $
56   */
57  public class DatagramConnectorDelegate extends BaseIoConnector implements
58          DatagramService {
59      private static volatile int nextId = 0;
60  
61      private final IoConnector wrapper;
62  
63      private final Executor executor;
64  
65      private final int id = nextId++;
66  
67      private Selector selector;
68  
69      private DatagramConnectorConfig defaultConfig = new DatagramConnectorConfig();
70  
71      private final Queue registerQueue = new Queue();
72  
73      private final Queue cancelQueue = new Queue();
74  
75      private final Queue flushingSessions = new Queue();
76  
77      private final Queue trafficControllingSessions = new Queue();
78  
79      private Worker worker;
80  
81      /**
82       * Creates a new instance.
83       */
84      public DatagramConnectorDelegate(IoConnector wrapper, Executor executor) {
85          this.wrapper = wrapper;
86          this.executor = executor;
87      }
88  
89      public ConnectFuture connect(SocketAddress address, IoHandler handler,
90              IoServiceConfig config) {
91          return connect(address, null, handler, config);
92      }
93  
94      public ConnectFuture connect(SocketAddress address,
95              SocketAddress localAddress, IoHandler handler,
96              IoServiceConfig config) {
97          if (address == null)
98              throw new NullPointerException("address");
99          if (handler == null)
100             throw new NullPointerException("handler");
101 
102         if (!(address instanceof InetSocketAddress))
103             throw new IllegalArgumentException("Unexpected address type: "
104                     + address.getClass());
105 
106         if (localAddress != null
107                 && !(localAddress instanceof InetSocketAddress)) {
108             throw new IllegalArgumentException(
109                     "Unexpected local address type: " + localAddress.getClass());
110         }
111 
112         if (config == null) {
113             config = getDefaultConfig();
114         }
115 
116         DatagramChannel ch = null;
117         boolean initialized = false;
118         try {
119             ch = DatagramChannel.open();
120             DatagramSessionConfig cfg;
121             if (config.getSessionConfig() instanceof DatagramSessionConfig) {
122                 cfg = (DatagramSessionConfig) config.getSessionConfig();
123             } else {
124                 cfg = (DatagramSessionConfig) getDefaultConfig()
125                         .getSessionConfig();
126             }
127 
128             ch.socket().setReuseAddress(cfg.isReuseAddress());
129             ch.socket().setBroadcast(cfg.isBroadcast());
130             ch.socket().setReceiveBufferSize(cfg.getReceiveBufferSize());
131             ch.socket().setSendBufferSize(cfg.getSendBufferSize());
132 
133             if (ch.socket().getTrafficClass() != cfg.getTrafficClass()) {
134                 ch.socket().setTrafficClass(cfg.getTrafficClass());
135             }
136 
137             if (localAddress != null) {
138                 ch.socket().bind(localAddress);
139             }
140             ch.connect(address);
141             ch.configureBlocking(false);
142             initialized = true;
143         } catch (IOException e) {
144             return DefaultConnectFuture.newFailedFuture(e);
145         } finally {
146             if (!initialized && ch != null) {
147                 try {
148                     ch.disconnect();
149                     ch.close();
150                 } catch (IOException e) {
151                     ExceptionMonitor.getInstance().exceptionCaught(e);
152                 }
153             }
154         }
155 
156         RegistrationRequest request = new RegistrationRequest(ch, handler,
157                 config);
158         synchronized (this) {
159             try {
160                 startupWorker();
161             } catch (IOException e) {
162                 try {
163                     ch.disconnect();
164                     ch.close();
165                 } catch (IOException e2) {
166                     ExceptionMonitor.getInstance().exceptionCaught(e2);
167                 }
168 
169                 return DefaultConnectFuture.newFailedFuture(e);
170             }
171 
172             synchronized (registerQueue) {
173                 registerQueue.push(request);
174             }
175             selector.wakeup();
176         }
177 
178         return request;
179     }
180 
181     public IoServiceConfig getDefaultConfig() {
182         return defaultConfig;
183     }
184 
185     /**
186      * Sets the config this connector will use by default.
187      * 
188      * @param defaultConfig the default config.
189      * @throws NullPointerException if the specified value is <code>null</code>.
190      */
191     public void setDefaultConfig(DatagramConnectorConfig defaultConfig) {
192         if (defaultConfig == null) {
193             throw new NullPointerException("defaultConfig");
194         }
195         this.defaultConfig = defaultConfig;
196     }
197     
198     private synchronized Selector getSelector() {
199         return this.selector;
200     }
201 
202     private synchronized void startupWorker() throws IOException {
203         if (worker == null) {
204             selector = Selector.open();
205             worker = new Worker();
206             executor.execute(new NamePreservingRunnable(worker));
207         }
208     }
209 
210     public void closeSession(DatagramSessionImpl session) {
211         synchronized (this) {
212             try {
213                 startupWorker();
214             } catch (IOException e) {
215                 // IOException is thrown only when Worker thread is not
216                 // running and failed to open a selector.  We simply return
217                 // silently here because it we can simply conclude that
218                 // this session is not managed by this connector or
219                 // already closed.
220                 return;
221             }
222 
223             synchronized (cancelQueue) {
224                 cancelQueue.push(session);
225             }
226 
227             selector.wakeup();
228         }
229     }
230 
231     public void flushSession(DatagramSessionImpl session) {
232         scheduleFlush(session);
233         Selector selector = getSelector();
234         if (selector != null) {
235             selector.wakeup();
236         }
237     }
238 
239     private void scheduleFlush(DatagramSessionImpl session) {
240         synchronized (flushingSessions) {
241             flushingSessions.push(session);
242         }
243     }
244 
245     public void updateTrafficMask(DatagramSessionImpl session) {
246         scheduleTrafficControl(session);
247         Selector selector = getSelector();
248         if (selector != null) {
249             selector.wakeup();
250         }
251     }
252 
253     private void scheduleTrafficControl(DatagramSessionImpl session) {
254         synchronized (trafficControllingSessions) {
255             trafficControllingSessions.push(session);
256         }
257     }
258 
259     private void doUpdateTrafficMask() {
260         if (trafficControllingSessions.isEmpty())
261             return;
262 
263         for (;;) {
264             DatagramSessionImpl session;
265 
266             synchronized (trafficControllingSessions) {
267                 session = (DatagramSessionImpl) trafficControllingSessions
268                         .pop();
269             }
270 
271             if (session == null)
272                 break;
273 
274             SelectionKey key = session.getSelectionKey();
275             // Retry later if session is not yet fully initialized.
276             // (In case that Session.suspend??() or session.resume??() is 
277             // called before addSession() is processed)
278             if (key == null) {
279                 scheduleTrafficControl(session);
280                 break;
281             }
282             // skip if channel is already closed
283             if (!key.isValid()) {
284                 continue;
285             }
286 
287             // The normal is OP_READ and, if there are write requests in the
288             // session's write queue, set OP_WRITE to trigger flushing.
289             int ops = SelectionKey.OP_READ;
290             Queue writeRequestQueue = session.getWriteRequestQueue();
291             synchronized (writeRequestQueue) {
292                 if (!writeRequestQueue.isEmpty()) {
293                     ops |= SelectionKey.OP_WRITE;
294                 }
295             }
296 
297             // Now mask the preferred ops with the mask of the current session
298             int mask = session.getTrafficMask().getInterestOps();
299             key.interestOps(ops & mask);
300         }
301     }
302 
303     private class Worker implements Runnable {
304         public void run() {
305             Thread.currentThread().setName("DatagramConnector-" + id);
306 
307             Selector selector = getSelector();
308             for (;;) {
309                 try {
310                     int nKeys = selector.select();
311 
312                     registerNew();
313                     doUpdateTrafficMask();
314 
315                     if (nKeys > 0) {
316                         processReadySessions(selector.selectedKeys());
317                     }
318 
319                     flushSessions();
320                     cancelKeys();
321 
322                     if (selector.keys().isEmpty()) {
323                         synchronized (DatagramConnectorDelegate.this) {
324                             if (selector.keys().isEmpty()
325                                     && registerQueue.isEmpty()
326                                     && cancelQueue.isEmpty()) {
327                                 worker = null;
328                                 try {
329                                     selector.close();
330                                 } catch (IOException e) {
331                                     ExceptionMonitor.getInstance()
332                                             .exceptionCaught(e);
333                                 } finally {
334                                     DatagramConnectorDelegate.this.selector = null;
335                                 }
336                                 break;
337                             }
338                         }
339                     }
340                 } catch (IOException e) {
341                     ExceptionMonitor.getInstance().exceptionCaught(e);
342 
343                     try {
344                         Thread.sleep(1000);
345                     } catch (InterruptedException e1) {
346                     }
347                 }
348             }
349         }
350     }
351 
352     private void processReadySessions(Set keys) {
353         Iterator it = keys.iterator();
354         while (it.hasNext()) {
355             SelectionKey key = (SelectionKey) it.next();
356             it.remove();
357 
358             DatagramSessionImpl session = (DatagramSessionImpl) key
359                     .attachment();
360 
361             // Let the recycler know that the session is still active. 
362             getSessionRecycler(session).recycle(session.getLocalAddress(),
363                     session.getRemoteAddress());
364 
365             if (key.isReadable() && session.getTrafficMask().isReadable()) {
366                 readSession(session);
367             }
368 
369             if (key.isWritable() && session.getTrafficMask().isWritable()) {
370                 scheduleFlush(session);
371             }
372         }
373     }
374 
375     private IoSessionRecycler getSessionRecycler(IoSession session) {
376         IoServiceConfig config = session.getServiceConfig();
377         IoSessionRecycler sessionRecycler;
378         if (config instanceof DatagramServiceConfig) {
379             sessionRecycler = ((DatagramServiceConfig) config)
380                     .getSessionRecycler();
381         } else {
382             sessionRecycler = defaultConfig.getSessionRecycler();
383         }
384         return sessionRecycler;
385     }
386 
387     private void readSession(DatagramSessionImpl session) {
388 
389         ByteBuffer readBuf = ByteBuffer.allocate(session.getReadBufferSize());
390         try {
391             int readBytes = session.getChannel().read(readBuf.buf());
392             if (readBytes > 0) {
393                 readBuf.flip();
394                 ByteBuffer newBuf = ByteBuffer.allocate(readBuf.limit());
395                 newBuf.put(readBuf);
396                 newBuf.flip();
397 
398                 session.increaseReadBytes(readBytes);
399                 session.getFilterChain().fireMessageReceived(session, newBuf);
400             }
401         } catch (IOException e) {
402             session.getFilterChain().fireExceptionCaught(session, e);
403         } finally {
404             readBuf.release();
405         }
406     }
407 
408     private void flushSessions() {
409         if (flushingSessions.size() == 0)
410             return;
411 
412         for (;;) {
413             DatagramSessionImpl session;
414 
415             synchronized (flushingSessions) {
416                 session = (DatagramSessionImpl) flushingSessions.pop();
417             }
418 
419             if (session == null)
420                 break;
421 
422             try {
423                 flush(session);
424             } catch (IOException e) {
425                 session.getFilterChain().fireExceptionCaught(session, e);
426             }
427         }
428     }
429 
430     private void flush(DatagramSessionImpl session) throws IOException {
431         DatagramChannel ch = session.getChannel();
432 
433         Queue writeRequestQueue = session.getWriteRequestQueue();
434 
435         WriteRequest req;
436         for (;;) {
437             synchronized (writeRequestQueue) {
438                 req = (WriteRequest) writeRequestQueue.first();
439             }
440 
441             if (req == null)
442                 break;
443 
444             ByteBuffer buf = (ByteBuffer) req.getMessage();
445             if (buf.remaining() == 0) {
446                 // pop and fire event
447                 synchronized (writeRequestQueue) {
448                     writeRequestQueue.pop();
449                 }
450 
451                 session.increaseWrittenMessages();
452                 buf.reset();
453                 session.getFilterChain().fireMessageSent(session, req);
454                 continue;
455             }
456 
457             SelectionKey key = session.getSelectionKey();
458             if (key == null) {
459                 scheduleFlush(session);
460                 break;
461             }
462             if (!key.isValid()) {
463                 continue;
464             }
465 
466             int writtenBytes = ch.write(buf.buf());
467 
468             if (writtenBytes == 0) {
469                 // Kernel buffer is full
470                 key.interestOps(key.interestOps() | SelectionKey.OP_WRITE);
471             } else if (writtenBytes > 0) {
472                 key.interestOps(key.interestOps() & (~SelectionKey.OP_WRITE));
473 
474                 // pop and fire event
475                 synchronized (writeRequestQueue) {
476                     writeRequestQueue.pop();
477                 }
478 
479                 session.increaseWrittenBytes(writtenBytes);
480                 session.increaseWrittenMessages();
481                 buf.reset();
482                 session.getFilterChain().fireMessageSent(session, req);
483             }
484         }
485     }
486 
487     private void registerNew() {
488         if (registerQueue.isEmpty())
489             return;
490 
491         Selector selector = getSelector();
492         for (;;) {
493             RegistrationRequest req;
494             synchronized (registerQueue) {
495                 req = (RegistrationRequest) registerQueue.pop();
496             }
497 
498             if (req == null)
499                 break;
500 
501             DatagramSessionImpl session = new DatagramSessionImpl(wrapper,
502                     this, req.config, req.channel, req.handler, req.channel
503                             .socket().getRemoteSocketAddress(), req.channel
504                             .socket().getLocalSocketAddress());
505 
506             // AbstractIoFilterChain will notify the connect future.
507             session.setAttribute(AbstractIoFilterChain.CONNECT_FUTURE, req);
508 
509             boolean success = false;
510             try {
511                 SelectionKey key = req.channel.register(selector,
512                         SelectionKey.OP_READ, session);
513 
514                 session.setSelectionKey(key);
515                 buildFilterChain(req, session);
516                 getSessionRecycler(session).put(session);
517 
518                 // The CONNECT_FUTURE attribute is cleared and notified here.
519                 getListeners().fireSessionCreated(session);
520                 success = true;
521             } catch (Throwable t) {
522                 // The CONNECT_FUTURE attribute is cleared and notified here.
523                 session.getFilterChain().fireExceptionCaught(session, t);
524             } finally {
525                 if (!success) {
526                     try {
527                         req.channel.disconnect();
528                         req.channel.close();
529                     } catch (IOException e) {
530                         ExceptionMonitor.getInstance().exceptionCaught(e);
531                     }
532                 }
533             }
534         }
535     }
536 
537     private void buildFilterChain(RegistrationRequest req, IoSession session)
538             throws Exception {
539         getFilterChainBuilder().buildFilterChain(session.getFilterChain());
540         req.config.getFilterChainBuilder().buildFilterChain(
541                 session.getFilterChain());
542         req.config.getThreadModel().buildFilterChain(session.getFilterChain());
543     }
544 
545     private void cancelKeys() {
546         if (cancelQueue.isEmpty())
547             return;
548 
549         Selector selector = getSelector();
550         for (;;) {
551             DatagramSessionImpl session;
552             synchronized (cancelQueue) {
553                 session = (DatagramSessionImpl) cancelQueue.pop();
554             }
555 
556             if (session == null)
557                 break;
558             else {
559                 SelectionKey key = session.getSelectionKey();
560                 DatagramChannel ch = (DatagramChannel) key.channel();
561                 try {
562                     ch.disconnect();
563                     ch.close();
564                 } catch (IOException e) {
565                     ExceptionMonitor.getInstance().exceptionCaught(e);
566                 }
567 
568                 getListeners().fireSessionDestroyed(session);
569                 session.getCloseFuture().setClosed();
570                 key.cancel();
571                 selector.wakeup(); // wake up again to trigger thread death
572             }
573         }
574     }
575 
576     private static class RegistrationRequest extends DefaultConnectFuture {
577         private final DatagramChannel channel;
578 
579         private final IoHandler handler;
580 
581         private final IoServiceConfig config;
582 
583         private RegistrationRequest(DatagramChannel channel, IoHandler handler,
584                 IoServiceConfig config) {
585             this.channel = channel;
586             this.handler = handler;
587             this.config = config;
588         }
589     }
590 }