code: /*
   * Copyright 2019 Mitsunori Komatsu (komamitsu)
   *
   * Licensed under the Apache License, Version 2.0 (the "License");
   * you may not use this file except in compliance with the License.
   * You may obtain a copy of the License at
   *
   *      http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  
  package org.komamitsu.fluency.recordformat.recordaccessor;
  
  import com.fasterxml.jackson.databind.ObjectMapper;
  import org.msgpack.core.MessagePack;
  import org.msgpack.core.MessagePacker;
  import org.msgpack.core.MessageUnpacker;
  import org.msgpack.value.StringValue;
  import org.msgpack.value.Value;
  import org.msgpack.value.ValueFactory;
  
  import java.io.ByteArrayOutputStream;
  import java.io.IOException;
  import java.nio.ByteBuffer;
  import java.util.Map;
  
  public class MessagePackRecordAccessor
          implements RecordAccessor
  {
      private static final StringValue KEY_TIME = ValueFactory.newString("time");
      private MapValueBytes mapValueBytes;
  
      private static class MapValueBytes {
          private final byte[] byteArray;
          private final Map<Value, Value> map;
  
          MapValueBytes(ByteBuffer byteBuffer)
          {
              byte[] mapValueBytes = new byte[byteBuffer.remaining()];
              byteBuffer.get(mapValueBytes);
              try (MessageUnpacker unpacker = MessagePack.newDefaultUnpacker(mapValueBytes)) {
                  this.map = unpacker.unpackValue().asMapValue().map();
                  this.byteArray = mapValueBytes;
              }
              catch (IOException e) {
                  throw new IllegalArgumentException("Invalid MessagePack ByteBuffer", e);
              }
          }
  
          byte[] byteArray()
          {
              return byteArray;
          }
  
          Map<Value, Value> map()
          {
              return map;
          }
      }
  
      public MessagePackRecordAccessor(ByteBuffer byteBuffer)
      {
          mapValueBytes = new MapValueBytes(byteBuffer);
      }
  
      @Override
      public String getAsString(String key)
      {
          Value value = mapValueBytes.map().get(ValueFactory.newString(key));
          if (value == null) {
              return null;
          }
          return value.toString();
      }
  
      @Override
      public void setTimestamp(long timestamp)
      {
          int mapSize = mapValueBytes.map().size();
          try (ByteArrayOutputStream output = new ByteArrayOutputStream(mapValueBytes.byteArray().length + 16)) {
              try (MessagePacker packer = MessagePack.newDefaultPacker(output)) {
                  if (mapValueBytes.map().containsKey(KEY_TIME)) {
                      packer.packMapHeader(mapSize);
                  }
                  else {
                      packer.packMapHeader(mapSize + 1);
                      KEY_TIME.writeTo(packer);
                      packer.packLong(timestamp);
                  }
  
                  for (Map.Entry<Value, Value> entry : mapValueBytes.map().entrySet()) {
                      packer.packValue(entry.getKey());
                      packer.packValue(entry.getValue());
                  }
              }
              mapValueBytes = new MapValueBytes(ByteBuffer.wrap(output.toByteArray()));
          }
          catch (IOException e) {
              throw new IllegalStateException("Failed to upsert `time` field", e);
          }
      }
  
      @Override
      public byte[] toMessagePack(ObjectMapper objectMapperForMessagePack)
      {
          return mapValueBytes.byteArray();
      }
  
      @Override
      public String toJson(ObjectMapper objectMapperForJson)
      {
          return ValueFactory.newMap(mapValueBytes.map()).toJson();
      }
  }
  