raminqaf commented on code in PR #26704: URL: https://github.com/apache/flink/pull/26704#discussion_r2159031058
########## flink-table/flink-table-common/src/main/java/org/apache/flink/table/types/inference/strategies/ObjectOfTypeStrategy.java: ########## @@ -0,0 +1,133 @@ +/* + * 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.flink.table.types.inference.strategies; + +import org.apache.flink.table.api.DataTypes; +import org.apache.flink.table.api.DataTypes.Field; +import org.apache.flink.table.types.DataType; +import org.apache.flink.table.types.inference.CallContext; +import org.apache.flink.table.types.inference.TypeStrategy; +import org.apache.flink.table.types.logical.LogicalType; +import org.apache.flink.table.types.logical.LogicalTypeFamily; +import org.apache.flink.table.types.utils.TypeConversions; + +import java.util.List; +import java.util.Optional; +import java.util.stream.IntStream; + +/** + * Type strategy for the {@code OBJECT_OF} function that infers the output type as a structured + * type. + * + * <p>This strategy creates a {@link DataTypes#STRUCTURED} type based on the provided class name and + * key-value pairs. The function signature is: {@code OBJECT_OF(className, key1, value1, key2, + * value2, ...)} + * + * <p>The strategy performs the following operations: + * + * <ul> + * <li>Extracts the class name from the first argument (must be a string literal) + * <li>Processes key-value pairs starting from the second argument + * <li>Extracts field names from odd-positioned arguments (indices 1, 3, 5, ...) + * <li>Normalizes field types from even-positioned arguments (indices 2, 4, 6, ...) + * <li>Creates a structured type with the given class name and normalized fields + * </ul> + * + * <p>Field type normalization includes: + * + * <ul> + * <li>Converting CHARACTER_STRING types (CHAR, VARCHAR) to nullable VARCHAR (STRING) + * <li>Making all field types nullable for flexibility in structured types + * </ul> + * + * <p>The strategy returns {@code Optional.empty()} if the class name argument is not available as a + * literal value (e.g., during type inference testing scenarios). + * + * <p><b>Note: Users are responsible for providing a valid fully qualified class name that exists in + * the classpath. The class name should follow Java naming conventions. If an invalid or + * non-existent class name is provided, the function will fall back to using Row.class as the type + * representation.</b> + * + * <p><b>Examples:</b> + * + * <ul> + * <li>{@code OBJECT_OF('com.example.User', 'name', 'Alice', 'age', 30)} → {@code + * STRUCTURED<com.example.User>(name STRING, age INT)} + * <li>{@code OBJECT_OF('com.example.Point', 'x', 1.5, 'y', 2.0)} → {@code + * STRUCTURED<com.example.Point>(x DOUBLE, y DOUBLE)} + * </ul> Review Comment: Good point... We can also validate if the field name has a space, a dot `.`, or a hyphen `-`. `OBJECT_OF('com.example.User', 'field 1', 'Alice', 'field.2', 30, 'field-3', 60)`. If we want to do the validation very specifically, we should also check against reserved JVM keywords (`if`, `void`, etc.). @twalthr what is your opinion on this? -- 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. To unsubscribe, e-mail: issues-unsubscr...@flink.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org
