| /* |
| * 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. |
| */ |
| |
| package org.apache.samza.sql.interfaces; |
| |
| import org.apache.samza.operators.KV; |
| import org.apache.samza.sql.data.SamzaSqlRelMessage; |
| |
| |
| /** |
| * Samza SQL application uses {@link SamzaRelConverter} to convert the Samza messages to relational message before |
| * it can be processed by the calcite engine. |
| * The {@link SamzaRelConverter} is configurable at a system level, So it is possible to configure different |
| * {@link SamzaRelConverter} for different systems. |
| */ |
| public interface SamzaRelConverter { |
| /** |
| * Determine if the input samza message is a system message. |
| * This API will soon be removed when descriptor creation is done by SamzaRelConverter. |
| * @param message input samza message. |
| * @return true if the input message is system message. |
| */ |
| default boolean isSystemMessage(KV<Object, Object> message) { |
| return false; |
| } |
| |
| /** |
| * Converts the object to relational message corresponding to the tableName with relational schema. |
| * @param message samza message that needs to be converted. |
| * @return Relational message extracted from the object. |
| */ |
| SamzaSqlRelMessage convertToRelMessage(KV<Object, Object> message); |
| |
| /** |
| * Convert the relational message to the output message. |
| * @param relMessage relational message that needs to be converted. |
| * @return the key and value of the Samza message |
| */ |
| KV<Object, Object> convertToSamzaMessage(SamzaSqlRelMessage relMessage); |
| |
| } |