View Javadoc

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(final Class encoderClass,
86              final Class decoderClass) {
87          if (encoderClass == null) {
88              throw new NullPointerException("encoderClass");
89          }
90          if (decoderClass == null) {
91              throw new NullPointerException("decoderClass");
92          }
93          if (!ProtocolEncoder.class.isAssignableFrom(encoderClass)) {
94              throw new IllegalArgumentException("encoderClass: "
95                      + encoderClass.getName());
96          }
97          if (!ProtocolDecoder.class.isAssignableFrom(decoderClass)) {
98              throw new IllegalArgumentException("decoderClass: "
99                      + decoderClass.getName());
100         }
101         try {
102             encoderClass.getConstructor(EMPTY_PARAMS);
103         } catch (NoSuchMethodException e) {
104             throw new IllegalArgumentException(
105                     "encoderClass doesn't have a public default constructor.");
106         }
107         try {
108             decoderClass.getConstructor(EMPTY_PARAMS);
109         } catch (NoSuchMethodException e) {
110             throw new IllegalArgumentException(
111                     "decoderClass doesn't have a public default constructor.");
112         }
113 
114         this.factory = new ProtocolCodecFactory() {
115             public ProtocolEncoder getEncoder() throws Exception {
116                 return (ProtocolEncoder) encoderClass.newInstance();
117             }
118 
119             public ProtocolDecoder getDecoder() throws Exception {
120                 return (ProtocolDecoder) decoderClass.newInstance();
121             }
122         };
123     }
124 
125     public void onPreAdd(IoFilterChain parent, String name,
126             NextFilter nextFilter) throws Exception {
127         if (parent.contains(ProtocolCodecFilter.class)) {
128             throw new IllegalStateException(
129                     "A filter chain cannot contain more than one ProtocolCodecFilter.");
130         }
131     }
132 
133     public void onPostRemove(IoFilterChain parent, String name,
134             NextFilter nextFilter) throws Exception {
135         disposeEncoder(parent.getSession());
136         disposeDecoder(parent.getSession());
137         disposeDecoderOut(parent.getSession());
138     }
139 
140     public void messageReceived(NextFilter nextFilter, IoSession session,
141             Object message) throws Exception {
142         if (!(message instanceof ByteBuffer)) {
143             nextFilter.messageReceived(session, message);
144             return;
145         }
146 
147         ByteBuffer in = (ByteBuffer) message;
148         ProtocolDecoder decoder = getDecoder(session);
149         ProtocolDecoderOutput decoderOut = getDecoderOut(session, nextFilter);
150 
151         try {
152             synchronized (decoderOut) {
153                 decoder.decode(session, in, decoderOut);
154             }
155         } catch (Throwable t) {
156             ProtocolDecoderException pde;
157             if (t instanceof ProtocolDecoderException) {
158                 pde = (ProtocolDecoderException) t;
159             } else {
160                 pde = new ProtocolDecoderException(t);
161             }
162             pde.setHexdump(in.getHexDump());
163             throw pde;
164         } finally {
165             try {
166                 // Release the read buffer.
167                 in.release();
168             } finally {
169                 decoderOut.flush();
170             }
171         }
172     }
173 
174     public void messageSent(NextFilter nextFilter, IoSession session,
175             Object message) throws Exception {
176         if (message instanceof HiddenByteBuffer) {
177             return;
178         }
179 
180         if (!(message instanceof MessageByteBuffer)) {
181             nextFilter.messageSent(session, message);
182             return;
183         }
184 
185         nextFilter.messageSent(session, ((MessageByteBuffer) message).message);
186     }
187 
188     public void filterWrite(NextFilter nextFilter, IoSession session,
189             WriteRequest writeRequest) throws Exception {
190         Object message = writeRequest.getMessage();
191         if (message instanceof ByteBuffer) {
192             nextFilter.filterWrite(session, writeRequest);
193             return;
194         }
195 
196         ProtocolEncoder encoder = getEncoder(session);
197         ProtocolEncoderOutputImpl encoderOut = getEncoderOut(session,
198                 nextFilter, writeRequest);
199 
200         try {
201             encoder.encode(session, message, encoderOut);
202             encoderOut.flush();
203             nextFilter.filterWrite(session, new WriteRequest(
204                     new MessageByteBuffer(writeRequest.getMessage()),
205                     writeRequest.getFuture(), writeRequest.getDestination()));
206         } catch (Throwable t) {
207             ProtocolEncoderException pee;
208             if (t instanceof ProtocolEncoderException) {
209                 pee = (ProtocolEncoderException) t;
210             } else {
211                 pee = new ProtocolEncoderException(t);
212             }
213             throw pee;
214         }
215     }
216 
217     public void sessionClosed(NextFilter nextFilter, IoSession session)
218             throws Exception {
219         // Call finishDecode() first when a connection is closed.
220         ProtocolDecoder decoder = getDecoder(session);
221         ProtocolDecoderOutput decoderOut = getDecoderOut(session, nextFilter);
222         try {
223             decoder.finishDecode(session, decoderOut);
224         } catch (Throwable t) {
225             ProtocolDecoderException pde;
226             if (t instanceof ProtocolDecoderException) {
227                 pde = (ProtocolDecoderException) t;
228             } else {
229                 pde = new ProtocolDecoderException(t);
230             }
231             throw pde;
232         } finally {
233             // Dispose all.
234             disposeEncoder(session);
235             disposeDecoder(session);
236             disposeDecoderOut(session);
237             decoderOut.flush();
238         }
239 
240         nextFilter.sessionClosed(session);
241     }
242 
243     private ProtocolEncoder getEncoder(IoSession session) throws Exception {
244         ProtocolEncoder encoder = (ProtocolEncoder) session
245                 .getAttribute(ENCODER);
246         if (encoder == null) {
247             encoder = factory.getEncoder();
248             session.setAttribute(ENCODER, encoder);
249         }
250         return encoder;
251     }
252 
253     private ProtocolEncoderOutputImpl getEncoderOut(IoSession session,
254             NextFilter nextFilter, WriteRequest writeRequest) {
255         return new ProtocolEncoderOutputImpl(session, nextFilter, writeRequest);
256     }
257 
258     private ProtocolDecoder getDecoder(IoSession session) throws Exception {
259         ProtocolDecoder decoder = (ProtocolDecoder) session
260                 .getAttribute(DECODER);
261         if (decoder == null) {
262             decoder = factory.getDecoder();
263             session.setAttribute(DECODER, decoder);
264         }
265         return decoder;
266     }
267 
268     private ProtocolDecoderOutput getDecoderOut(IoSession session,
269             NextFilter nextFilter) {
270         ProtocolDecoderOutput out = (ProtocolDecoderOutput) session.getAttribute(DECODER_OUT);
271         if (out == null) {
272             out = new SimpleProtocolDecoderOutput(session, nextFilter);
273             session.setAttribute(DECODER_OUT, out);
274         }
275 
276         return out;
277     }
278 
279     private void disposeEncoder(IoSession session) {
280         ProtocolEncoder encoder = (ProtocolEncoder) session
281                 .removeAttribute(ENCODER);
282         if (encoder == null) {
283             return;
284         }
285 
286         try {
287             encoder.dispose(session);
288         } catch (Throwable t) {
289             SessionLog.warn(session, "Failed to dispose: "
290                     + encoder.getClass().getName() + " (" + encoder + ')');
291         }
292     }
293 
294     private void disposeDecoder(IoSession session) {
295         ProtocolDecoder decoder = (ProtocolDecoder) session
296                 .removeAttribute(DECODER);
297         if (decoder == null) {
298             return;
299         }
300 
301         try {
302             decoder.dispose(session);
303         } catch (Throwable t) {
304             SessionLog.warn(session, "Falied to dispose: "
305                     + decoder.getClass().getName() + " (" + decoder + ')');
306         }
307     }
308     
309     private void disposeDecoderOut(IoSession session) {
310         session.removeAttribute(DECODER_OUT);
311     }
312     
313     private static class HiddenByteBuffer extends ByteBufferProxy {
314         private HiddenByteBuffer(ByteBuffer buf) {
315             super(buf);
316         }
317     }
318 
319     private static class MessageByteBuffer extends ByteBufferProxy {
320         private final Object message;
321 
322         private MessageByteBuffer(Object message) {
323             super(EMPTY_BUFFER);
324             this.message = message;
325         }
326 
327         public void acquire() {
328             // no-op since we are wraping a zero-byte buffer, this instance is to just curry the message
329         }
330 
331         public void release() {
332             // no-op since we are wraping a zero-byte buffer, this instance is to just curry the message
333         }
334     }
335 
336     private static class ProtocolEncoderOutputImpl extends
337             SimpleProtocolEncoderOutput {
338         private final IoSession session;
339 
340         private final NextFilter nextFilter;
341 
342         private final WriteRequest writeRequest;
343 
344         public ProtocolEncoderOutputImpl(IoSession session,
345                 NextFilter nextFilter, WriteRequest writeRequest) {
346             this.session = session;
347             this.nextFilter = nextFilter;
348             this.writeRequest = writeRequest;
349         }
350 
351         protected WriteFuture doFlush(ByteBuffer buf) {
352             WriteFuture future = new DefaultWriteFuture(session);
353             nextFilter.filterWrite(session, new WriteRequest(
354                     new HiddenByteBuffer(buf), future, writeRequest
355                             .getDestination()));
356             return future;
357         }
358     }
359 }