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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: 591178 $, $Date: 2007-11-02 09:48:24 +0900 (금, 02 11월 2007) $
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         try {
156             synchronized (decoderOut) {
157                 decoder.decode(session, in, decoderOut);
158             }
159         } catch (Throwable t) {
160             ProtocolDecoderException pde;
161             if (t instanceof ProtocolDecoderException) {
162                 pde = (ProtocolDecoderException) t;
163             } else {
164                 pde = new ProtocolDecoderException(t);
165             }
166             pde.setHexdump(in.getHexDump());
167             throw pde;
168         } finally {
169             try {
170                 // Release the read buffer.
171                 in.release();
172             } finally {
173                 decoderOut.flush();
174             }
175         }
176     }
177 
178     @Override
179     public void messageSent(NextFilter nextFilter, IoSession session,
180             Object message) throws Exception {
181         if (message instanceof HiddenByteBuffer) {
182             return;
183         }
184 
185         if (!(message instanceof MessageByteBuffer)) {
186             nextFilter.messageSent(session, message);
187             return;
188         }
189 
190         nextFilter.messageSent(session, ((MessageByteBuffer) message).message);
191     }
192 
193     @Override
194     public void filterWrite(NextFilter nextFilter, IoSession session,
195             WriteRequest writeRequest) throws Exception {
196         Object message = writeRequest.getMessage();
197         if (message instanceof ByteBuffer) {
198             nextFilter.filterWrite(session, writeRequest);
199             return;
200         }
201 
202         ProtocolEncoder encoder = getEncoder(session);
203         ProtocolEncoderOutputImpl encoderOut = getEncoderOut(session,
204                 nextFilter, writeRequest);
205 
206         try {
207             encoder.encode(session, message, encoderOut);
208             encoderOut.flush();
209             nextFilter.filterWrite(session, new WriteRequest(
210                     new MessageByteBuffer(writeRequest.getMessage()),
211                     writeRequest.getFuture(), writeRequest.getDestination()));
212         } catch (Throwable t) {
213             ProtocolEncoderException pee;
214             if (t instanceof ProtocolEncoderException) {
215                 pee = (ProtocolEncoderException) t;
216             } else {
217                 pee = new ProtocolEncoderException(t);
218             }
219             throw pee;
220         }
221     }
222 
223     @Override
224     public void sessionClosed(NextFilter nextFilter, IoSession session)
225             throws Exception {
226         // Call finishDecode() first when a connection is closed.
227         ProtocolDecoder decoder = getDecoder(session);
228         ProtocolDecoderOutput decoderOut = getDecoderOut(session, nextFilter);
229         try {
230             decoder.finishDecode(session, decoderOut);
231         } catch (Throwable t) {
232             ProtocolDecoderException pde;
233             if (t instanceof ProtocolDecoderException) {
234                 pde = (ProtocolDecoderException) t;
235             } else {
236                 pde = new ProtocolDecoderException(t);
237             }
238             throw pde;
239         } finally {
240             // Dispose all.
241             disposeEncoder(session);
242             disposeDecoder(session);
243             disposeDecoderOut(session);
244             decoderOut.flush();
245         }
246 
247         nextFilter.sessionClosed(session);
248     }
249 
250     private ProtocolEncoder getEncoder(IoSession session) throws Exception {
251         ProtocolEncoder encoder = (ProtocolEncoder) session
252                 .getAttribute(ENCODER);
253         if (encoder == null) {
254             encoder = factory.getEncoder();
255             session.setAttribute(ENCODER, encoder);
256         }
257         return encoder;
258     }
259 
260     private ProtocolEncoderOutputImpl getEncoderOut(IoSession session,
261             NextFilter nextFilter, WriteRequest writeRequest) {
262         return new ProtocolEncoderOutputImpl(session, nextFilter, writeRequest);
263     }
264 
265     private ProtocolDecoder getDecoder(IoSession session) throws Exception {
266         ProtocolDecoder decoder = (ProtocolDecoder) session
267                 .getAttribute(DECODER);
268         if (decoder == null) {
269             decoder = factory.getDecoder();
270             session.setAttribute(DECODER, decoder);
271         }
272         return decoder;
273     }
274 
275     private ProtocolDecoderOutput getDecoderOut(IoSession session,
276             NextFilter nextFilter) {
277         ProtocolDecoderOutput out = (ProtocolDecoderOutput) session.getAttribute(DECODER_OUT);
278         if (out == null) {
279             out = new SimpleProtocolDecoderOutput(session, nextFilter);
280             session.setAttribute(DECODER_OUT, out);
281         }
282         return out;
283     }
284 
285     private void disposeEncoder(IoSession session) {
286         ProtocolEncoder encoder = (ProtocolEncoder) session
287                 .removeAttribute(ENCODER);
288         if (encoder == null) {
289             return;
290         }
291 
292         try {
293             encoder.dispose(session);
294         } catch (Throwable t) {
295             SessionLog.warn(session, "Failed to dispose: "
296                     + encoder.getClass().getName() + " (" + encoder + ')');
297         }
298     }
299 
300     private void disposeDecoder(IoSession session) {
301         ProtocolDecoder decoder = (ProtocolDecoder) session
302                 .removeAttribute(DECODER);
303         if (decoder == null) {
304             return;
305         }
306 
307         try {
308             decoder.dispose(session);
309         } catch (Throwable t) {
310             SessionLog.warn(session, "Falied to dispose: "
311                     + decoder.getClass().getName() + " (" + decoder + ')');
312         }
313     }
314     
315     private void disposeDecoderOut(IoSession session) {
316         session.removeAttribute(DECODER_OUT);
317     }
318     
319     private static class HiddenByteBuffer extends ByteBufferProxy {
320         private HiddenByteBuffer(ByteBuffer buf) {
321             super(buf);
322         }
323     }
324 
325     private static class MessageByteBuffer extends ByteBufferProxy {
326         private final Object message;
327 
328         private MessageByteBuffer(Object message) {
329             super(EMPTY_BUFFER);
330             this.message = message;
331         }
332 
333         @Override
334         public void acquire() {
335             // no-op since we are wraping a zero-byte buffer, this instance is to just curry the message
336         }
337 
338         @Override
339         public void release() {
340             // no-op since we are wraping a zero-byte buffer, this instance is to just curry the message
341         }
342     }
343 
344     private static class ProtocolEncoderOutputImpl extends
345             SimpleProtocolEncoderOutput {
346         private final IoSession session;
347 
348         private final NextFilter nextFilter;
349 
350         private final WriteRequest writeRequest;
351 
352         ProtocolEncoderOutputImpl(IoSession session, NextFilter nextFilter,
353                 WriteRequest writeRequest) {
354             this.session = session;
355             this.nextFilter = nextFilter;
356             this.writeRequest = writeRequest;
357         }
358 
359         @Override
360         protected WriteFuture doFlush(ByteBuffer buf) {
361             WriteFuture future = new DefaultWriteFuture(session);
362             nextFilter.filterWrite(session, new WriteRequest(
363                     new HiddenByteBuffer(buf), future, writeRequest
364                             .getDestination()));
365             return future;
366         }
367     }
368 }