How to use

getDefaultInstanceForType

method

in

com.google.protobuf.Message$Builder

  return (TYPE) getBuilder(messageClass).getDefaultInstanceForType();
} catch (Exception e) {
  logger.warn("Error building protobuf object of type {} from json: {}",

/**
 * Utility function for creating a default PB Messgae from a Class object that
 * works with both protoc 2.3.0 and 2.4.x.
 * @param clazz The class of the protocol buffer to create
 * @return An instance of a protocol buffer
 */
public static <M extends Message> M getDefaultInstance(Class<M> clazz) {
 if (clazz.getConstructors().length > 0) {
  // Protobuf 2.3.0
  return ReflectionUtils.newInstance(clazz, null);
 } else {
  // Protobuf 2.4.x
  try {
   Message.Builder mb = (Message.Builder) clazz.getDeclaredMethod("newBuilder").invoke(null);
   return (M) mb.getDefaultInstanceForType();
  } catch (Exception e) {
   throw new CrunchRuntimeException(e);
  }  
 }
}

/**
 * Utility function for creating a default PB Messgae from a Class object that
 * works with both protoc 2.3.0 and 2.4.x.
 * @param clazz The class of the protocol buffer to create
 * @return An instance of a protocol buffer
 */
public static <M extends Message> M getDefaultInstance(Class<M> clazz) {
 if (clazz.getConstructors().length > 0) {
  // Protobuf 2.3.0
  return ReflectionUtils.newInstance(clazz, null);
 } else {
  // Protobuf 2.4.x
  try {
   Message.Builder mb = (Message.Builder) clazz.getDeclaredMethod("newBuilder").invoke(null);
   return (M) mb.getDefaultInstanceForType();
  } catch (Exception e) {
   throw new CrunchRuntimeException(e);
  }  
 }
}

 subMessageType = defaultInstance.getClass();
} else {
 subMessageType = builder.newBuilderForField(field).getDefaultInstanceForType().getClass();

private JsonDeserializer<Object> getMessageDeserializer(
    Message.Builder builder,
    FieldDescriptor field,
    Message defaultInstance,
    DeserializationContext context
) throws IOException {
 JsonDeserializer<Object> deserializer = deserializerCache.get(field);
 if (deserializer == null) {
  final Class<?> subType;
  if (defaultInstance == null) {
   Message.Builder subBuilder = builder.newBuilderForField(field);
   subType = subBuilder.getDefaultInstanceForType().getClass();
  } else {
   subType = defaultInstance.getClass();
  }
  JavaType type = context.constructType(subType);
  deserializer = context.findContextualValueDeserializer(type, null);
  deserializerCache.put(field, deserializer);
 }
 return deserializer;
}

/**
 * Decode the a protobuf from the given input stream 
 * @param builder - Builder of the protobuf to decode
 * @param dis - DataInputStream to read the protobuf
 * @return Message - decoded protobuf
 * @throws WrappedRpcServerException - deserialization failed
 */
@SuppressWarnings("unchecked")
private <T extends Message> T decodeProtobufFromStream(Builder builder,
  DataInputStream dis) throws WrappedRpcServerException {
 try {
  builder.mergeDelimitedFrom(dis);
  return (T)builder.build();
 } catch (Exception ioe) {
  Class<?> protoClass = builder.getDefaultInstanceForType().getClass();
  throw new WrappedRpcServerException(
    RpcErrorCodeProto.FATAL_DESERIALIZING_REQUEST,
    "Error decoding " + protoClass.getSimpleName() + ": "+ ioe);
 }
}

/**
 * Decode the a protobuf from the given input stream 
 * @param builder - Builder of the protobuf to decode
 * @param dis - DataInputStream to read the protobuf
 * @return Message - decoded protobuf
 * @throws WrappedRpcServerException - deserialization failed
 */
@SuppressWarnings("unchecked")
private <T extends Message> T decodeProtobufFromStream(Builder builder,
  DataInputStream dis) throws WrappedRpcServerException {
 try {
  builder.mergeDelimitedFrom(dis);
  return (T)builder.build();
 } catch (Exception ioe) {
  Class<?> protoClass = builder.getDefaultInstanceForType().getClass();
  throw new WrappedRpcServerException(
    RpcErrorCodeProto.FATAL_DESERIALIZING_REQUEST,
    "Error decoding " + protoClass.getSimpleName() + ": "+ ioe);
 }
}

/**
 * Clears the value of the field.
 *
 * @return the builder
 */
@Override
@SuppressWarnings("unchecked")
public void clear() {
 message =
   (MType) (message != null ? message.getDefaultInstanceForType() : builder
     .getDefaultInstanceForType());
 if (builder != null) {
  dispose(builder);
  builder = null;
 }
 onChanged();
}

@SuppressWarnings("unchecked")
@Override
public T defaultValue() {
 return (T) internalBuilder.getDefaultInstanceForType();
}

@SuppressWarnings("unchecked")
public M fromBytes(byte[] messageBuffer, int offset, int len)
  throws InvalidProtocolBufferException, UninitializedMessageException {
 if (defaultInstance == null) {
  defaultInstance = Protobufs.getMessageBuilder(typeRef.getRawClass())
                .getDefaultInstanceForType();
 }
 return (M) defaultInstance.newBuilderForType()
              .mergeFrom(messageBuffer, offset, len)
              .build();
}