szaszm commented on a change in pull request #1042: URL: https://github.com/apache/nifi-minifi-cpp/pull/1042#discussion_r619226036
########## File path: libminifi/include/core/Annotation.h ########## @@ -0,0 +1,79 @@ +/** + + * Licensed to the Apache Software Foundation (ASF) under one or more + * contributor license agreements. See the NOTICE file distributed with + * this work for additional information regarding copyright ownership. + * The ASF licenses this file to You 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. + */ + +#pragma once + +#include <string> + +namespace org { +namespace apache { +namespace nifi { +namespace minifi { +namespace core { +namespace annotation { + +template <typename T> +struct Annotation { + const T value_; Review comment: This implicitly disables move, because it's a non-static const data member, inherited by the . It should be `static constexpr` IMO. It also pollutes the scope of derived classes with an overly generic name `value_`, because it's all used through inheritance. I don't like using inheritance for this purpose. I would prefer if classes could just declare their requirements by creating a type alias of a well known name, like `struct MyProcessor : Processor { using input_requirements = annotation::input::required; };`. In other words, using type traits to check this at compile-time, with no runtime cost, less invasive dependencies and less pollution. -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. For queries about this service, please contact Infrastructure at: us...@infra.apache.org
