| /** |
| * Copyright 2015 Pivotal Software, Inc. |
| * |
| * 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. |
| **/ |
| |
| #ifndef QUICKSTEP_EXPRESSIONS_AGGREGATION_AGGREGATE_FUNCTION_FACTORY_HPP_ |
| #define QUICKSTEP_EXPRESSIONS_AGGREGATION_AGGREGATE_FUNCTION_FACTORY_HPP_ |
| |
| #include <string> |
| |
| #include "expressions/aggregation/AggregationID.hpp" |
| #include "utility/Macros.hpp" |
| |
| namespace quickstep { |
| |
| class AggregateFunction; |
| namespace serialization { class AggregateFunction; } |
| |
| /** \addtogroup Expressions |
| * @{ |
| */ |
| |
| /** |
| * @brief All-static factory class that provides access to the various concrete |
| * implementations of AggregateFunction. |
| * |
| * AggregateFunctionFactory allows client code to use any AggregateFunction in |
| * Quickstep in a generic way without having to know about all the specific |
| * subclasses of AggregateFunction. In particular, it is used to deserialize |
| * AggregateFunctions used in AggregationOperationState from their protobuf |
| * representations (originally created by the optimizer) when deserializing a |
| * QueryContext. |
| **/ |
| class AggregateFunctionFactory { |
| public: |
| /** |
| * @brief Get a particular AggregateFunction by its ID. |
| * |
| * @param agg_id The ID of the desired AggregateFunction. |
| * @return A reference to the singleton instance of the AggregateFunction |
| * specified by agg_id. |
| **/ |
| static const AggregateFunction& Get(const AggregationID agg_id); |
| |
| /** |
| * @brief Get a particular AggregateFunction by its name in SQL syntax. |
| * |
| * @param name The name of the desired AggregateFunction in lower case. |
| * @return A pointer to the AggregateFunction specified by name, or NULL if |
| * name does not match any known AggregateFunction. |
| **/ |
| static const AggregateFunction* GetByName(const std::string &name); |
| |
| /** |
| * @brief Determine if a serialized protobuf representation of an |
| * AggregateFunction is fully-formed and valid. |
| * |
| * @param proto A serialized protobuf representation of an AggregateFunction |
| * to check for validity. |
| * @return Whether proto is fully-formed and valid. |
| **/ |
| static bool ProtoIsValid(const serialization::AggregateFunction &proto); |
| |
| /** |
| * @brief Get the AggregateFunction represented by a proto. |
| * |
| * @warning It is an error to call this method with an invalid proto. |
| * ProtoIsValid() should be called first to check. |
| * |
| * @param proto A serialized protobuf representation of an AggregateFunction. |
| * @return The AggregateFunction represented by proto. |
| **/ |
| static const AggregateFunction& ReconstructFromProto( |
| const serialization::AggregateFunction &proto); |
| |
| private: |
| // Class is all-static and can not be instantiated. |
| AggregateFunctionFactory(); |
| |
| DISALLOW_COPY_AND_ASSIGN(AggregateFunctionFactory); |
| }; |
| |
| /** @} */ |
| |
| } // namespace quickstep |
| |
| #endif // QUICKSTEP_EXPRESSIONS_AGGREGATION_AGGREGATE_FUNCTION_FACTORY_HPP_ |