szaszm commented on a change in pull request #732: MINIFICPP-1013 URL: https://github.com/apache/nifi-minifi-cpp/pull/732#discussion_r377630872
########## File path: extensions/sql/processors/SQLProcessor.h ########## @@ -0,0 +1,105 @@ +/** + * @file SQLProcessor.h + * SQLProcessor class declaration + * + * 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 "core/Core.h" +#include "FlowFileRecord.h" +#include "concurrentqueue.h" +#include "core/Processor.h" +#include "core/ProcessSession.h" + +namespace org { +namespace apache { +namespace nifi { +namespace minifi { +namespace processors { + +template <typename T> +class SQLProcessor: public core::Processor { + protected: + SQLProcessor(const std::string& name, utils::Identifier uuid) + : core::Processor(name, uuid), logger_(logging::LoggerFactory<T>::getLogger()) { + } + + void onSchedule(const std::shared_ptr<core::ProcessContext>& context, const std::shared_ptr<core::ProcessSessionFactory>& sessionFactory) override { + std::string controllerService; + context->getProperty(dbControllerService().getName(), controllerService); + + dbService_ = std::dynamic_pointer_cast<sql::controllers::DatabaseService>(context->getControllerService(controllerService)); + if (!dbService_) + throw minifi::Exception(PROCESSOR_EXCEPTION, "'DB Controller Service' must be defined"); + + static_cast<T*>(this)->processOnSchedule(context, sessionFactory); + } + + void onTrigger(const std::shared_ptr<core::ProcessContext>& context, const std::shared_ptr<core::ProcessSession>& session) override { + std::unique_lock<std::mutex> lock(onTriggerMutex_, std::try_to_lock); + if (!lock.owns_lock()) { + logger_->log_warn("'onTrigger' is called before previous 'onTrigger' call is finished."); + context->yield(); + return; + } + + try { + if (!connection_) { + connection_ = dbService_->getConnection(); + } + static_cast<T*>(this)->processOnTrigger(context, session); Review comment: I don't think we need CRTP to avoid the overhead of a virtual function call, given that we abuse shared_ptr all over our codebase and nobody bats an eye. I suggest making `processOnTrigger` and `processOnSchedule` pure virtual in `SQLProcessor`, `final` in the implementations and not use CRTP. This will also prevent accidental instantiation of `SQLProcessor`, and it seems to me that it was not meant to be used directly, so that's positive in this case. ---------------------------------------------------------------- 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 With regards, Apache Git Services
