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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.Method;
24  
25  import org.apache.mina.codec.IoBuffer;
26  import org.apache.mina.codec.ProtocolDecoderException;
27  import org.apache.mina.codec.delimited.IoBufferDecoder;
28  
29  import com.google.protobuf.ExtensionRegistryLite;
30  import com.google.protobuf.GeneratedMessage;
31  
32  /**
33   * @author <a href="http://mina.apache.org">Apache MINA Project</a>
34   */
35  public final class ProtobufMessageDecoder<IN extends GeneratedMessage> extends IoBufferDecoder<IN> {
36      private final Method parseMethod;
37  
38      private final ExtensionRegistryLite registry;
39  
40      public static <TYPE extends GeneratedMessage> ProtobufMessageDecoder<TYPE> newInstance(Class<TYPE> c)
41              throws NoSuchMethodException {
42          return newInstance(c, ExtensionRegistryLite.getEmptyRegistry());
43      }
44  
45      public static <TYPE extends GeneratedMessage> ProtobufMessageDecoder<TYPE> newInstance(Class<TYPE> c,
46              ExtensionRegistryLite registry) throws NoSuchMethodException {
47          return new ProtobufMessageDecoder<TYPE>(c, registry);
48      }
49  
50      private ProtobufMessageDecoder(Class<IN> clazz, ExtensionRegistryLite registry) throws NoSuchMethodException {
51          super();
52          parseMethod = clazz.getDeclaredMethod("parseFrom", InputStream.class, ExtensionRegistryLite.class);
53          this.registry = registry;
54      }
55  
56      @SuppressWarnings("unchecked")
57      @Override
58      public IN decode(IoBuffer input) {
59          try {
60              return (IN) parseMethod.invoke(null, input.asInputStream(), registry);
61          } catch (Exception e) {
62              throw new ProtocolDecoderException(e);
63          }
64      }
65  }