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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: 566957 $, $Date: 2007-08-17 16:36:58 +0900 (Fri, 17 Aug 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     public void onPostRemove(IoFilterChain parent, String name,
136             NextFilter nextFilter) throws Exception {
137         disposeEncoder(parent.getSession());
138         disposeDecoder(parent.getSession());
139         disposeDecoderOut(parent.getSession());
140     }
141 
142     @Override
143     public void messageReceived(NextFilter nextFilter, IoSession session,
144             Object message) throws Exception {
145         if (!(message instanceof ByteBuffer)) {
146             nextFilter.messageReceived(session, message);
147             return;
148         }
149 
150         ByteBuffer in = (ByteBuffer) message;
151         ProtocolDecoder decoder = getDecoder(session);
152         ProtocolDecoderOutput decoderOut = getDecoderOut(session, nextFilter);
153 
154         try {
155             synchronized (decoderOut) {
156                 decoder.decode(session, in, decoderOut);
157             }
158         } catch (Throwable t) {
159             ProtocolDecoderException pde;
160             if (t instanceof ProtocolDecoderException) {
161                 pde = (ProtocolDecoderException) t;
162             } else {
163                 pde = new ProtocolDecoderException(t);
164             }
165             pde.setHexdump(in.getHexDump());
166             throw pde;
167         } finally {
168             // Dispose the decoder if this session is connectionless.
169             if (session.getTransportType().isConnectionless()) {
170                 disposeDecoder(session);
171             }
172 
173             // Release the read buffer.
174             in.release();
175 
176             decoderOut.flush();
177         }
178     }
179 
180     @Override
181     public void messageSent(NextFilter nextFilter, IoSession session,
182             Object message) throws Exception {
183         if (message instanceof HiddenByteBuffer) {
184             return;
185         }
186 
187         if (!(message instanceof MessageByteBuffer)) {
188             nextFilter.messageSent(session, message);
189             return;
190         }
191 
192         nextFilter.messageSent(session, ((MessageByteBuffer) message).message);
193     }
194 
195     @Override
196     public void filterWrite(NextFilter nextFilter, IoSession session,
197             WriteRequest writeRequest) throws Exception {
198         Object message = writeRequest.getMessage();
199         if (message instanceof ByteBuffer) {
200             nextFilter.filterWrite(session, writeRequest);
201             return;
202         }
203 
204         ProtocolEncoder encoder = getEncoder(session);
205         ProtocolEncoderOutputImpl encoderOut = getEncoderOut(session,
206                 nextFilter, writeRequest);
207 
208         try {
209             encoder.encode(session, message, encoderOut);
210             encoderOut.flush();
211             nextFilter.filterWrite(session, new WriteRequest(
212                     new MessageByteBuffer(writeRequest.getMessage()),
213                     writeRequest.getFuture(), writeRequest.getDestination()));
214         } catch (Throwable t) {
215             ProtocolEncoderException pee;
216             if (t instanceof ProtocolEncoderException) {
217                 pee = (ProtocolEncoderException) t;
218             } else {
219                 pee = new ProtocolEncoderException(t);
220             }
221             throw pee;
222         }
223     }
224 
225     @Override
226     public void sessionClosed(NextFilter nextFilter, IoSession session)
227             throws Exception {
228         // Call finishDecode() first when a connection is closed.
229         ProtocolDecoder decoder = getDecoder(session);
230         ProtocolDecoderOutput decoderOut = getDecoderOut(session, nextFilter);
231         try {
232             decoder.finishDecode(session, decoderOut);
233         } catch (Throwable t) {
234             ProtocolDecoderException pde;
235             if (t instanceof ProtocolDecoderException) {
236                 pde = (ProtocolDecoderException) t;
237             } else {
238                 pde = new ProtocolDecoderException(t);
239             }
240             throw pde;
241         } finally {
242             // Dispose all.
243             disposeEncoder(session);
244             disposeDecoder(session);
245             disposeDecoderOut(session);
246             decoderOut.flush();
247         }
248 
249         nextFilter.sessionClosed(session);
250     }
251 
252     private ProtocolEncoder getEncoder(IoSession session) throws Exception {
253         ProtocolEncoder encoder = (ProtocolEncoder) session
254                 .getAttribute(ENCODER);
255         if (encoder == null) {
256             encoder = factory.getEncoder();
257             session.setAttribute(ENCODER, encoder);
258         }
259         return encoder;
260     }
261 
262     private ProtocolEncoderOutputImpl getEncoderOut(IoSession session,
263             NextFilter nextFilter, WriteRequest writeRequest) {
264         return new ProtocolEncoderOutputImpl(session, nextFilter, writeRequest);
265     }
266 
267     private ProtocolDecoder getDecoder(IoSession session) throws Exception {
268         ProtocolDecoder decoder = (ProtocolDecoder) session
269                 .getAttribute(DECODER);
270         if (decoder == null) {
271             decoder = factory.getDecoder();
272             session.setAttribute(DECODER, decoder);
273         }
274         return decoder;
275     }
276 
277     private ProtocolDecoderOutput getDecoderOut(IoSession session,
278             NextFilter nextFilter) {
279         ProtocolDecoderOutput out = (ProtocolDecoderOutput) session.getAttribute(DECODER_OUT);
280         if (out == null) {
281             out = new SimpleProtocolDecoderOutput(session, nextFilter);
282             session.setAttribute(DECODER_OUT, out);
283         }
284         return out;
285     }
286 
287     private void disposeEncoder(IoSession session) {
288         ProtocolEncoder encoder = (ProtocolEncoder) session
289                 .removeAttribute(ENCODER);
290         if (encoder == null) {
291             return;
292         }
293 
294         try {
295             encoder.dispose(session);
296         } catch (Throwable t) {
297             SessionLog.warn(session, "Failed to dispose: "
298                     + encoder.getClass().getName() + " (" + encoder + ')');
299         }
300     }
301 
302     private void disposeDecoder(IoSession session) {
303         ProtocolDecoder decoder = (ProtocolDecoder) session
304                 .removeAttribute(DECODER);
305         if (decoder == null) {
306             return;
307         }
308 
309         try {
310             decoder.dispose(session);
311         } catch (Throwable t) {
312             SessionLog.warn(session, "Falied to dispose: "
313                     + decoder.getClass().getName() + " (" + decoder + ')');
314         }
315     }
316     
317     private void disposeDecoderOut(IoSession session) {
318         session.removeAttribute(DECODER_OUT);
319     }
320     
321     private static class HiddenByteBuffer extends ByteBufferProxy {
322         private HiddenByteBuffer(ByteBuffer buf) {
323             super(buf);
324         }
325     }
326 
327     private static class MessageByteBuffer extends ByteBufferProxy {
328         private final Object message;
329 
330         private MessageByteBuffer(Object message) {
331             super(EMPTY_BUFFER);
332             this.message = message;
333         }
334 
335         @Override
336         public void acquire() {
337             // no-op since we are wraping a zero-byte buffer, this instance is to just curry the message
338         }
339 
340         @Override
341         public void release() {
342             // no-op since we are wraping a zero-byte buffer, this instance is to just curry the message
343         }
344     }
345 
346     private static class ProtocolEncoderOutputImpl extends
347             SimpleProtocolEncoderOutput {
348         private final IoSession session;
349 
350         private final NextFilter nextFilter;
351 
352         private final WriteRequest writeRequest;
353 
354         ProtocolEncoderOutputImpl(IoSession session, NextFilter nextFilter,
355                 WriteRequest writeRequest) {
356             this.session = session;
357             this.nextFilter = nextFilter;
358             this.writeRequest = writeRequest;
359         }
360 
361         @Override
362         protected WriteFuture doFlush(ByteBuffer buf) {
363             WriteFuture future = new DefaultWriteFuture(session);
364             nextFilter.filterWrite(session, new WriteRequest(
365                     new HiddenByteBuffer(buf), future, writeRequest
366                             .getDestination()));
367             return future;
368         }
369     }
370 }