@Override
    public void init(MapStructProcessingEnvironment processingEnvironment) {
        super.init(processingEnvironment);

        TypeElement typeElement = elementUtils.getTypeElement(PROTOBUF_MESSAGE_OR_BUILDER);
        if (typeElement != null) {
            protobufMesageOrBuilderType = typeElement.asType();
        }
    }
refer <a href="https://github.com/entur/mapstruct-spi-protobuf">mapstruct-spi-protobuf</a>
@author Arne Seime
commons-mapstruct-spi/src/main/java/com/navercorp/pinpoint/mapstruct/spi/ProtobufAccessorNamingStrategy.java