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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.filter.codec;
21  
22  import org.apache.mina.common.ByteBuffer;
23  import org.apache.mina.common.ByteBufferProxy;
24  import org.apache.mina.common.IoFilter;
25  import org.apache.mina.common.IoFilterAdapter;
26  import org.apache.mina.common.IoFilterChain;
27  import org.apache.mina.common.IoSession;
28  import org.apache.mina.common.WriteFuture;
29  import org.apache.mina.common.support.DefaultWriteFuture;
30  import org.apache.mina.filter.codec.support.SimpleProtocolDecoderOutput;
31  import org.apache.mina.filter.codec.support.SimpleProtocolEncoderOutput;
32  import org.apache.mina.util.SessionLog;
33  
34  /**
35   * An {@link IoFilter} which translates binary or protocol specific data into
36   * message object and vice versa using {@link ProtocolCodecFactory},
37   * {@link ProtocolEncoder}, or {@link ProtocolDecoder}.
38   *
39   * @author The Apache Directory Project (mina-dev@directory.apache.org)
40   * @version $Rev: 612026 $, $Date: 2008-01-15 15:16:14 +0900 (Tue, 15 Jan 2008) $
41   */
42  public class ProtocolCodecFilter extends IoFilterAdapter {
43      public static final String ENCODER = ProtocolCodecFilter.class.getName()
44              + ".encoder";
45  
46      public static final String DECODER = ProtocolCodecFilter.class.getName()
47              + ".decoder";
48  
49      private static final String DECODER_OUT = ProtocolCodecFilter.class.getName()
50              + ".decoderOut";
51  
52      private static final Class<?>[] EMPTY_PARAMS = new Class[0];
53  
54      private static final ByteBuffer EMPTY_BUFFER = ByteBuffer.wrap(new byte[0]);
55  
56      private final ProtocolCodecFactory factory;
57  
58      public ProtocolCodecFilter(ProtocolCodecFactory factory) {
59          if (factory == null) {
60              throw new NullPointerException("factory");
61          }
62          this.factory = factory;
63      }
64  
65      public ProtocolCodecFilter(final ProtocolEncoder encoder,
66              final ProtocolDecoder decoder) {
67          if (encoder == null) {
68              throw new NullPointerException("encoder");
69          }
70          if (decoder == null) {
71              throw new NullPointerException("decoder");
72          }
73  
74          this.factory = new ProtocolCodecFactory() {
75              public ProtocolEncoder getEncoder() {
76                  return encoder;
77              }
78  
79              public ProtocolDecoder getDecoder() {
80                  return decoder;
81              }
82          };
83      }
84  
85      public ProtocolCodecFilter(
86              final Class<? extends ProtocolEncoder> encoderClass,
87              final Class<? extends ProtocolDecoder> decoderClass) {
88          if (encoderClass == null) {
89              throw new NullPointerException("encoderClass");
90          }
91          if (decoderClass == null) {
92              throw new NullPointerException("decoderClass");
93          }
94          if (!ProtocolEncoder.class.isAssignableFrom(encoderClass)) {
95              throw new IllegalArgumentException("encoderClass: "
96                      + encoderClass.getName());
97          }
98          if (!ProtocolDecoder.class.isAssignableFrom(decoderClass)) {
99              throw new IllegalArgumentException("decoderClass: "
100                     + decoderClass.getName());
101         }
102         try {
103             encoderClass.getConstructor(EMPTY_PARAMS);
104         } catch (NoSuchMethodException e) {
105             throw new IllegalArgumentException(
106                     "encoderClass doesn't have a public default constructor.");
107         }
108         try {
109             decoderClass.getConstructor(EMPTY_PARAMS);
110         } catch (NoSuchMethodException e) {
111             throw new IllegalArgumentException(
112                     "decoderClass doesn't have a public default constructor.");
113         }
114 
115         this.factory = new ProtocolCodecFactory() {
116             public ProtocolEncoder getEncoder() throws Exception {
117                 return encoderClass.newInstance();
118             }
119 
120             public ProtocolDecoder getDecoder() throws Exception {
121                 return decoderClass.newInstance();
122             }
123         };
124     }
125 
126     @Override
127     public void onPreAdd(IoFilterChain parent, String name,
128             NextFilter nextFilter) throws Exception {
129         if (parent.contains(ProtocolCodecFilter.class)) {
130             throw new IllegalStateException(
131                     "A filter chain cannot contain more than one ProtocolCodecFilter.");
132         }
133     }
134 
135     @Override
136     public void onPostRemove(IoFilterChain parent, String name,
137             NextFilter nextFilter) throws Exception {
138         disposeEncoder(parent.getSession());
139         disposeDecoder(parent.getSession());
140         disposeDecoderOut(parent.getSession());
141     }
142 
143     @Override
144     public void messageReceived(NextFilter nextFilter, IoSession session,
145             Object message) throws Exception {
146         if (!(message instanceof ByteBuffer)) {
147             nextFilter.messageReceived(session, message);
148             return;
149         }
150 
151         ByteBuffer in = (ByteBuffer) message;
152         ProtocolDecoder decoder = getDecoder(session);
153         ProtocolDecoderOutput decoderOut = getDecoderOut(session, nextFilter);
154 
155         int oldPos = in.position();
156         try {
157             synchronized (decoderOut) {
158                 decoder.decode(session, in, decoderOut);
159             }
160         } catch (Throwable t) {
161             ProtocolDecoderException pde;
162             if (t instanceof ProtocolDecoderException) {
163                 pde = (ProtocolDecoderException) t;
164             } else {
165                 pde = new ProtocolDecoderException(t);
166             }
167 
168             if (pde.getHexdump() == null) {
169                 int curPos = in.position();
170                 in.position(oldPos);
171                 pde.setHexdump(in.getHexDump());
172                 in.position(curPos);
173             }
174             throw pde;
175         } finally {
176             try {
177                 // Release the read buffer.
178                 in.release();
179             } finally {
180                 decoderOut.flush();
181             }
182         }
183     }
184 
185     @Override
186     public void messageSent(NextFilter nextFilter, IoSession session,
187             Object message) throws Exception {
188         if (message instanceof HiddenByteBuffer) {
189             return;
190         }
191 
192         if (!(message instanceof MessageByteBuffer)) {
193             nextFilter.messageSent(session, message);
194             return;
195         }
196 
197         nextFilter.messageSent(session, ((MessageByteBuffer) message).message);
198     }
199 
200     @Override
201     public void filterWrite(NextFilter nextFilter, IoSession session,
202             WriteRequest writeRequest) throws Exception {
203         Object message = writeRequest.getMessage();
204         if (message instanceof ByteBuffer) {
205             nextFilter.filterWrite(session, writeRequest);
206             return;
207         }
208 
209         ProtocolEncoder encoder = getEncoder(session);
210         ProtocolEncoderOutputImpl encoderOut = getEncoderOut(session,
211                 nextFilter, writeRequest);
212 
213         try {
214             encoder.encode(session, message, encoderOut);
215             encoderOut.flush();
216             nextFilter.filterWrite(session, new WriteRequest(
217                     new MessageByteBuffer(writeRequest.getMessage()),
218                     writeRequest.getFuture(), writeRequest.getDestination()));
219         } catch (Throwable t) {
220             ProtocolEncoderException pee;
221             if (t instanceof ProtocolEncoderException) {
222                 pee = (ProtocolEncoderException) t;
223             } else {
224                 pee = new ProtocolEncoderException(t);
225             }
226             throw pee;
227         }
228     }
229 
230     @Override
231     public void sessionClosed(NextFilter nextFilter, IoSession session)
232             throws Exception {
233         // Call finishDecode() first when a connection is closed.
234         ProtocolDecoder decoder = getDecoder(session);
235         ProtocolDecoderOutput decoderOut = getDecoderOut(session, nextFilter);
236         try {
237             decoder.finishDecode(session, decoderOut);
238         } catch (Throwable t) {
239             ProtocolDecoderException pde;
240             if (t instanceof ProtocolDecoderException) {
241                 pde = (ProtocolDecoderException) t;
242             } else {
243                 pde = new ProtocolDecoderException(t);
244             }
245             throw pde;
246         } finally {
247             // Dispose all.
248             disposeEncoder(session);
249             disposeDecoder(session);
250             disposeDecoderOut(session);
251             decoderOut.flush();
252         }
253 
254         nextFilter.sessionClosed(session);
255     }
256 
257     private ProtocolEncoder getEncoder(IoSession session) throws Exception {
258         ProtocolEncoder encoder = (ProtocolEncoder) session
259                 .getAttribute(ENCODER);
260         if (encoder == null) {
261             encoder = factory.getEncoder();
262             session.setAttribute(ENCODER, encoder);
263         }
264         return encoder;
265     }
266 
267     private ProtocolEncoderOutputImpl getEncoderOut(IoSession session,
268             NextFilter nextFilter, WriteRequest writeRequest) {
269         return new ProtocolEncoderOutputImpl(session, nextFilter, writeRequest);
270     }
271 
272     private ProtocolDecoder getDecoder(IoSession session) throws Exception {
273         ProtocolDecoder decoder = (ProtocolDecoder) session
274                 .getAttribute(DECODER);
275         if (decoder == null) {
276             decoder = factory.getDecoder();
277             session.setAttribute(DECODER, decoder);
278         }
279         return decoder;
280     }
281 
282     private ProtocolDecoderOutput getDecoderOut(IoSession session,
283             NextFilter nextFilter) {
284         ProtocolDecoderOutput out = (ProtocolDecoderOutput) session.getAttribute(DECODER_OUT);
285         if (out == null) {
286             out = new SimpleProtocolDecoderOutput(session, nextFilter);
287             session.setAttribute(DECODER_OUT, out);
288         }
289         return out;
290     }
291 
292     private void disposeEncoder(IoSession session) {
293         ProtocolEncoder encoder = (ProtocolEncoder) session
294                 .removeAttribute(ENCODER);
295         if (encoder == null) {
296             return;
297         }
298 
299         try {
300             encoder.dispose(session);
301         } catch (Throwable t) {
302             SessionLog.warn(session, "Failed to dispose: "
303                     + encoder.getClass().getName() + " (" + encoder + ')');
304         }
305     }
306 
307     private void disposeDecoder(IoSession session) {
308         ProtocolDecoder decoder = (ProtocolDecoder) session
309                 .removeAttribute(DECODER);
310         if (decoder == null) {
311             return;
312         }
313 
314         try {
315             decoder.dispose(session);
316         } catch (Throwable t) {
317             SessionLog.warn(session, "Falied to dispose: "
318                     + decoder.getClass().getName() + " (" + decoder + ')');
319         }
320     }
321     
322     private void disposeDecoderOut(IoSession session) {
323         session.removeAttribute(DECODER_OUT);
324     }
325     
326     private static class HiddenByteBuffer extends ByteBufferProxy {
327         private HiddenByteBuffer(ByteBuffer buf) {
328             super(buf);
329         }
330     }
331 
332     private static class MessageByteBuffer extends ByteBufferProxy {
333         private final Object message;
334 
335         private MessageByteBuffer(Object message) {
336             super(EMPTY_BUFFER);
337             this.message = message;
338         }
339 
340         @Override
341         public void acquire() {
342             // no-op since we are wraping a zero-byte buffer, this instance is to just curry the message
343         }
344 
345         @Override
346         public void release() {
347             // no-op since we are wraping a zero-byte buffer, this instance is to just curry the message
348         }
349     }
350 
351     private static class ProtocolEncoderOutputImpl extends
352             SimpleProtocolEncoderOutput {
353         private final IoSession session;
354 
355         private final NextFilter nextFilter;
356 
357         private final WriteRequest writeRequest;
358 
359         ProtocolEncoderOutputImpl(IoSession session, NextFilter nextFilter,
360                 WriteRequest writeRequest) {
361             this.session = session;
362             this.nextFilter = nextFilter;
363             this.writeRequest = writeRequest;
364         }
365 
366         @Override
367         protected WriteFuture doFlush(ByteBuffer buf) {
368             WriteFuture future = new DefaultWriteFuture(session);
369             nextFilter.filterWrite(session, new WriteRequest(
370                     new HiddenByteBuffer(buf), future, writeRequest
371                             .getDestination()));
372             return future;
373         }
374     }
375 }