slinkydeveloper commented on a change in pull request #17658: URL: https://github.com/apache/flink/pull/17658#discussion_r742258394
########## File path: flink-table/flink-table-planner/src/main/java/org/apache/flink/table/planner/functions/casting/rules/RowToStringCastRule.java ########## @@ -0,0 +1,185 @@ +/* + * 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.planner.functions.casting.rules; + +import org.apache.flink.table.data.ArrayData; +import org.apache.flink.table.planner.functions.casting.CastCodeBlock; +import org.apache.flink.table.planner.functions.casting.CastRulePredicate; +import org.apache.flink.table.planner.functions.casting.CastRuleProvider; +import org.apache.flink.table.planner.functions.casting.CodeGeneratorCastRule; +import org.apache.flink.table.types.logical.LogicalType; +import org.apache.flink.table.types.logical.LogicalTypeFamily; +import org.apache.flink.table.types.logical.LogicalTypeRoot; +import org.apache.flink.table.types.logical.RowType; + +import java.util.List; +import java.util.stream.Collectors; + +import static org.apache.flink.table.planner.codegen.CodeGenUtils.className; +import static org.apache.flink.table.planner.codegen.CodeGenUtils.newName; +import static org.apache.flink.table.planner.codegen.CodeGenUtils.rowFieldReadAccess; +import static org.apache.flink.table.planner.codegen.calls.BuiltInMethods.BINARY_STRING_DATA_FROM_STRING; +import static org.apache.flink.table.planner.functions.casting.rules.CastRuleUtils.constructorCall; +import static org.apache.flink.table.planner.functions.casting.rules.CastRuleUtils.functionCall; +import static org.apache.flink.table.planner.functions.casting.rules.CastRuleUtils.methodCall; +import static org.apache.flink.table.planner.functions.casting.rules.CastRuleUtils.strLiteral; + +/** {@link LogicalTypeRoot#ROW} to {@link LogicalTypeFamily#CHARACTER_STRING} cast rule. */ +public class RowToStringCastRule extends AbstractNullAwareCodeGeneratorCastRule<ArrayData, String> { + + public static final RowToStringCastRule INSTANCE = new RowToStringCastRule(); + + private RowToStringCastRule() { + super( + CastRulePredicate.builder() + .predicate( + (input, target) -> + input.is(LogicalTypeRoot.ROW) + && target.is(LogicalTypeFamily.CHARACTER_STRING) + && ((RowType) input) + .getFields().stream() + .allMatch( + field -> + CastRuleProvider + .exists( + field + .getType(), + target))) + .build()); + } + + /* Example generated code for ROW<`f0` INT, `f1` STRING>: + + isNull$0 = _myInputIsNull; + if (!isNull$0) { Review comment: There isn't any loop, because the row has a type defined arity where in each index you already know what "extractor" you need to get the field. The code generator loops through each field and generates a cast for each field. -- 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: [email protected] For queries about this service, please contact Infrastructure at: [email protected]
