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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.codec.delimited.serialization;
21  
22  import java.io.InputStream;
23  import java.lang.reflect.InvocationTargetException;
24  import java.lang.reflect.Method;
25  
26  import org.apache.mina.codec.IoBuffer;
27  import org.apache.mina.codec.delimited.IoBufferDecoder;
28  
29  import com.google.protobuf.ExtensionRegistryLite;
30  import com.google.protobuf.GeneratedMessage;
31  
32  /**
33   * An alternative decoder for protobuf which allows the use various target
34   * classes with the same decoder.
35   * 
36   * This decoder converts incoming {@link IoBuffer} into
37   * {@link ProtobufSerializedMessage}.
38   * 
39   * @author <a href="http://mina.apache.org">Apache MINA Project</a>
40   */
41  public class ProtobufDynamicMessageDecoder extends
42          IoBufferDecoder<ProtobufDynamicMessageDecoder.ProtobufSerializedMessage> {
43  
44      public static ProtobufDynamicMessageDecoder newInstance() {
45          return new ProtobufDynamicMessageDecoder();
46      }
47  
48      @Override
49      public ProtobufSerializedMessage decode(IoBuffer input) {
50          return new ProtobufSerializedMessage(input);
51      }
52  
53      public static final class ProtobufSerializedMessage {
54          private final IoBuffer input;
55  
56          public ProtobufSerializedMessage(IoBuffer input) {
57              this.input = input;
58          }
59  
60          @SuppressWarnings("unchecked")
61          public <L extends GeneratedMessage> L get(Class<L> clazz, ExtensionRegistryLite registry)
62                  throws NoSuchMethodException, IllegalAccessException, InvocationTargetException {
63              Method parseMethod = clazz.getDeclaredMethod("parseFrom", InputStream.class, ExtensionRegistryLite.class);
64              return (L) parseMethod.invoke(null, input.asInputStream(), registry);
65          }
66  
67          public <L extends GeneratedMessage> L get(Class<L> clazz) throws NoSuchMethodException, IllegalAccessException,
68                  InvocationTargetException {
69              return get(clazz, ExtensionRegistryLite.getEmptyRegistry());
70          }
71      }
72  }