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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  }