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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;
21  
22  import java.io.IOException;
23  import java.nio.channels.SelectionKey;
24  import java.nio.channels.Selector;
25  import java.nio.channels.SocketChannel;
26  import java.util.Queue;
27  import java.util.Set;
28  import java.util.concurrent.ConcurrentLinkedQueue;
29  import java.util.concurrent.Executor;
30  
31  import org.apache.mina.common.ByteBuffer;
32  import org.apache.mina.common.ExceptionMonitor;
33  import org.apache.mina.common.IdleStatus;
34  import org.apache.mina.common.IoFilter.WriteRequest;
35  import org.apache.mina.common.WriteTimeoutException;
36  import org.apache.mina.util.NamePreservingRunnable;
37  
38  /**
39   * Performs all I/O operations for sockets which is connected or bound. This class is used by MINA internally.
40   *
41   * @author The Apache Directory Project (mina-dev@directory.apache.org)
42   * @version $Rev: 556539 $, $Date: 2007-07-16 16:48:36 +0900 (월, 16  7월 2007) $,
43   */
44  class SocketIoProcessor {
45      private final Object lock = new Object();
46  
47      private final String threadName;
48  
49      private final Executor executor;
50  
51      private Selector selector;
52  
53      private final Queue<SocketSessionImpl> newSessions = new ConcurrentLinkedQueue<SocketSessionImpl>();
54  
55      private final Queue<SocketSessionImpl> removingSessions = new ConcurrentLinkedQueue<SocketSessionImpl>();
56  
57      private final Queue<SocketSessionImpl> flushingSessions = new ConcurrentLinkedQueue<SocketSessionImpl>();
58  
59      private final Queue<SocketSessionImpl> trafficControllingSessions = new ConcurrentLinkedQueue<SocketSessionImpl>();
60  
61      private Worker worker;
62  
63      private long lastIdleCheckTime = System.currentTimeMillis();
64  
65      SocketIoProcessor(String threadName, Executor executor) {
66          this.threadName = threadName;
67          this.executor = executor;
68      }
69  
70      void addNew(SocketSessionImpl session) throws IOException {
71          newSessions.add(session);
72          startupWorker();
73      }
74  
75      void remove(SocketSessionImpl session) throws IOException {
76          scheduleRemove(session);
77          startupWorker();
78      }
79  
80      private void startupWorker() throws IOException {
81          synchronized (lock) {
82              if (worker == null) {
83                  selector = Selector.open();
84                  worker = new Worker();
85                  executor.execute(new NamePreservingRunnable(worker));
86              }
87              selector.wakeup();
88          }
89      }
90  
91      void flush(SocketSessionImpl session) {
92          scheduleFlush(session);
93          Selector selector = this.selector;
94          if (selector != null) {
95              selector.wakeup();
96          }
97      }
98  
99      void updateTrafficMask(SocketSessionImpl session) {
100         scheduleTrafficControl(session);
101         Selector selector = this.selector;
102         if (selector != null) {
103             selector.wakeup();
104         }
105     }
106 
107     private void scheduleRemove(SocketSessionImpl session) {
108         removingSessions.add(session);
109     }
110 
111     private void scheduleFlush(SocketSessionImpl session) {
112         flushingSessions.add(session);
113     }
114 
115     private void scheduleTrafficControl(SocketSessionImpl session) {
116         trafficControllingSessions.add(session);
117     }
118 
119     private void doAddNew() {
120         for (;;) {
121             SocketSessionImpl session = newSessions.poll();
122 
123             if (session == null)
124                 break;
125 
126             SocketChannel ch = session.getChannel();
127             try {
128                 ch.configureBlocking(false);
129                 session.setSelectionKey(ch.register(selector,
130                         SelectionKey.OP_READ, session));
131 
132                 // AbstractIoFilterChain.CONNECT_FUTURE is cleared inside here
133                 // in AbstractIoFilterChain.fireSessionOpened().
134                 session.getServiceListeners().fireSessionCreated(session);
135             } catch (IOException e) {
136                 // Clear the AbstractIoFilterChain.CONNECT_FUTURE attribute
137                 // and call ConnectFuture.setException().
138                 session.getFilterChain().fireExceptionCaught(session, e);
139             }
140         }
141     }
142 
143     private void doRemove() {
144         for (;;) {
145             SocketSessionImpl session = removingSessions.poll();
146 
147             if (session == null)
148                 break;
149 
150             SocketChannel ch = session.getChannel();
151             SelectionKey key = session.getSelectionKey();
152             // Retry later if session is not yet fully initialized.
153             // (In case that Session.close() is called before addSession() is processed)
154             if (key == null) {
155                 scheduleRemove(session);
156                 break;
157             }
158             // skip if channel is already closed
159             if (!key.isValid()) {
160                 continue;
161             }
162 
163             try {
164                 key.cancel();
165                 ch.close();
166             } catch (IOException e) {
167                 session.getFilterChain().fireExceptionCaught(session, e);
168             } finally {
169                 releaseWriteBuffers(session);
170                 session.getServiceListeners().fireSessionDestroyed(session);
171             }
172         }
173     }
174 
175     private void process(Set<SelectionKey> selectedKeys) {
176         for (SelectionKey key : selectedKeys) {
177             SocketSessionImpl session = (SocketSessionImpl) key.attachment();
178 
179             if (key.isReadable() && session.getTrafficMask().isReadable()) {
180                 read(session);
181             }
182 
183             if (key.isWritable() && session.getTrafficMask().isWritable()) {
184                 scheduleFlush(session);
185             }
186         }
187 
188         selectedKeys.clear();
189     }
190 
191     private void read(SocketSessionImpl session) {
192         ByteBuffer buf = ByteBuffer.allocate(session.getReadBufferSize());
193         SocketChannel ch = session.getChannel();
194 
195         try {
196             int readBytes = 0;
197             int ret;
198 
199             try {
200                 while ((ret = ch.read(buf.buf())) > 0) {
201                     readBytes += ret;
202                 }
203             } finally {
204                 buf.flip();
205             }
206 
207             session.increaseReadBytes(readBytes);
208 
209             if (readBytes > 0) {
210                 session.getFilterChain().fireMessageReceived(session, buf);
211                 buf = null;
212                 
213                 if (readBytes * 2 < session.getReadBufferSize()) {
214                     if (session.getReadBufferSize() > 64) {
215                         session.setReadBufferSize(session.getReadBufferSize() >>> 1);
216                     }
217                 } else if (readBytes == session.getReadBufferSize()) {
218                     session.setReadBufferSize(session.getReadBufferSize() << 1);
219                 }
220             }
221             if (ret < 0) {
222                 scheduleRemove(session);
223             }
224         } catch (Throwable e) {
225             if (e instanceof IOException)
226                 scheduleRemove(session);
227             session.getFilterChain().fireExceptionCaught(session, e);
228         } finally {
229             if (buf != null)
230                 buf.release();
231         }
232     }
233 
234     private void notifyIdleness() {
235         // process idle sessions
236         long currentTime = System.currentTimeMillis();
237         if ((currentTime - lastIdleCheckTime) >= 1000) {
238             lastIdleCheckTime = currentTime;
239             Set<SelectionKey> keys = selector.keys();
240             if (keys != null) {
241                 for (SelectionKey key : keys) {
242                     SocketSessionImpl session = (SocketSessionImpl) key
243                             .attachment();
244                     notifyIdleness(session, currentTime);
245                 }
246             }
247         }
248     }
249 
250     private void notifyIdleness(SocketSessionImpl session, long currentTime) {
251         notifyIdleness0(session, currentTime, session
252                 .getIdleTimeInMillis(IdleStatus.BOTH_IDLE),
253                 IdleStatus.BOTH_IDLE, Math.max(session.getLastIoTime(), session
254                         .getLastIdleTime(IdleStatus.BOTH_IDLE)));
255         notifyIdleness0(session, currentTime, session
256                 .getIdleTimeInMillis(IdleStatus.READER_IDLE),
257                 IdleStatus.READER_IDLE, Math.max(session.getLastReadTime(),
258                         session.getLastIdleTime(IdleStatus.READER_IDLE)));
259         notifyIdleness0(session, currentTime, session
260                 .getIdleTimeInMillis(IdleStatus.WRITER_IDLE),
261                 IdleStatus.WRITER_IDLE, Math.max(session.getLastWriteTime(),
262                         session.getLastIdleTime(IdleStatus.WRITER_IDLE)));
263 
264         notifyWriteTimeout(session, currentTime, session
265                 .getWriteTimeoutInMillis(), session.getLastWriteTime());
266     }
267 
268     private void notifyIdleness0(SocketSessionImpl session, long currentTime,
269             long idleTime, IdleStatus status, long lastIoTime) {
270         if (idleTime > 0 && lastIoTime != 0
271                 && (currentTime - lastIoTime) >= idleTime) {
272             session.increaseIdleCount(status);
273             session.getFilterChain().fireSessionIdle(session, status);
274         }
275     }
276 
277     private void notifyWriteTimeout(SocketSessionImpl session,
278             long currentTime, long writeTimeout, long lastIoTime) {
279         SelectionKey key = session.getSelectionKey();
280         if (writeTimeout > 0 && (currentTime - lastIoTime) >= writeTimeout
281                 && key != null && key.isValid()
282                 && (key.interestOps() & SelectionKey.OP_WRITE) != 0) {
283             session.getFilterChain().fireExceptionCaught(session,
284                     new WriteTimeoutException());
285         }
286     }
287 
288     private void doFlush() {
289         for (;;) {
290             SocketSessionImpl session = flushingSessions.poll();
291 
292             if (session == null)
293                 break;
294 
295             if (!session.isConnected()) {
296                 releaseWriteBuffers(session);
297                 continue;
298             }
299 
300             SelectionKey key = session.getSelectionKey();
301             // Retry later if session is not yet fully initialized.
302             // (In case that Session.write() is called before addSession() is processed)
303             if (key == null) {
304                 scheduleFlush(session);
305                 break;
306             }
307 
308             // Skip if the channel is already closed.
309             if (!key.isValid()) {
310                 continue;
311             }
312 
313             try {
314                 doFlush(session);
315             } catch (IOException e) {
316                 scheduleRemove(session);
317                 session.getFilterChain().fireExceptionCaught(session, e);
318             }
319         }
320     }
321 
322     private void releaseWriteBuffers(SocketSessionImpl session) {
323         Queue<WriteRequest> writeRequestQueue = session.getWriteRequestQueue();
324         WriteRequest req;
325 
326         while ((req = writeRequestQueue.poll()) != null) {
327             try {
328                 ((ByteBuffer) req.getMessage()).release();
329             } catch (IllegalStateException e) {
330                 session.getFilterChain().fireExceptionCaught(session, e);
331             } finally {
332                 req.getFuture().setWritten(false);
333             }
334         }
335     }
336 
337     private void doFlush(SocketSessionImpl session) throws IOException {
338         // Clear OP_WRITE
339         SelectionKey key = session.getSelectionKey();
340         key.interestOps(key.interestOps() & (~SelectionKey.OP_WRITE));
341 
342         SocketChannel ch = session.getChannel();
343         Queue<WriteRequest> writeRequestQueue = session.getWriteRequestQueue();
344 
345         for (;;) {
346             WriteRequest req = writeRequestQueue.peek();
347 
348             if (req == null)
349                 break;
350 
351             ByteBuffer buf = (ByteBuffer) req.getMessage();
352             if (buf.remaining() == 0) {
353                 writeRequestQueue.poll();
354 
355                 session.increaseWrittenMessages();
356 
357                 buf.reset();
358                 session.getFilterChain().fireMessageSent(session, req);
359                 continue;
360             }
361 
362             if (key.isWritable()) {
363                 int writtenBytes = ch.write(buf.buf());
364                 if (writtenBytes > 0) {
365                     session.increaseWrittenBytes(writtenBytes);
366                 }
367             }
368 
369             if (buf.hasRemaining()) {
370                 // Kernel buffer is full
371                 key.interestOps(key.interestOps() | SelectionKey.OP_WRITE);
372                 break;
373             }
374         }
375     }
376 
377     private void doUpdateTrafficMask() {
378         if (trafficControllingSessions.isEmpty())
379             return;
380 
381         for (;;) {
382             SocketSessionImpl session = trafficControllingSessions.poll();
383 
384             if (session == null)
385                 break;
386 
387             SelectionKey key = session.getSelectionKey();
388             // Retry later if session is not yet fully initialized.
389             // (In case that Session.suspend??() or session.resume??() is
390             // called before addSession() is processed)
391             if (key == null) {
392                 scheduleTrafficControl(session);
393                 break;
394             }
395             // skip if channel is already closed
396             if (!key.isValid()) {
397                 continue;
398             }
399 
400             // The normal is OP_READ and, if there are write requests in the
401             // session's write queue, set OP_WRITE to trigger flushing.
402             int ops = SelectionKey.OP_READ;
403             Queue<WriteRequest> writeRequestQueue = session
404                     .getWriteRequestQueue();
405             synchronized (writeRequestQueue) {
406                 if (!writeRequestQueue.isEmpty()) {
407                     ops |= SelectionKey.OP_WRITE;
408                 }
409             }
410 
411             // Now mask the preferred ops with the mask of the current session
412             int mask = session.getTrafficMask().getInterestOps();
413             key.interestOps(ops & mask);
414         }
415     }
416 
417     private class Worker implements Runnable {
418         public void run() {
419             Thread.currentThread().setName(SocketIoProcessor.this.threadName);
420 
421             for (;;) {
422                 try {
423                     int nKeys = selector.select(1000);
424                     doAddNew();
425                     doUpdateTrafficMask();
426 
427                     if (nKeys > 0) {
428                         process(selector.selectedKeys());
429                     }
430 
431                     doFlush();
432                     doRemove();
433                     notifyIdleness();
434 
435                     if (selector.keys().isEmpty()) {
436                         synchronized (lock) {
437                             if (selector.keys().isEmpty()
438                                     && newSessions.isEmpty()) {
439                                 worker = null;
440 
441                                 try {
442                                     selector.close();
443                                 } catch (IOException e) {
444                                     ExceptionMonitor.getInstance()
445                                             .exceptionCaught(e);
446                                 } finally {
447                                     selector = null;
448                                 }
449 
450                                 break;
451                             }
452                         }
453                     }
454                 } catch (Throwable t) {
455                     ExceptionMonitor.getInstance().exceptionCaught(t);
456 
457                     try {
458                         Thread.sleep(1000);
459                     } catch (InterruptedException e1) {
460                         ExceptionMonitor.getInstance().exceptionCaught(e1);
461                     }
462                 }
463             }
464         }
465     }
466 
467 }