twalthr commented on a change in pull request #17658: URL: https://github.com/apache/flink/pull/17658#discussion_r743701893
########## 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) { + builder$1.delete(0, builder$1.length()); + builder$1.append("("); + int f0Value$2 = -1; + boolean f0IsNull$3 = _myInput.isNullAt(0); + if (!f0IsNull$3) { + f0Value$2 = _myInput.getInt(0); + result$2 = org.apache.flink.table.data.binary.BinaryStringData.fromString("" + f0Value$2); + builder$1.append(result$2); + } else { + builder$1.append("NULL"); + } + builder$1.append(","); + org.apache.flink.table.data.binary.BinaryStringData f1Value$4 = org.apache.flink.table.data.binary.BinaryStringData.EMPTY_UTF8; + boolean f1IsNull$5 = _myInput.isNullAt(1); + if (!f1IsNull$5) { + f1Value$4 = ((org.apache.flink.table.data.binary.BinaryStringData) _myInput.getString(1)); + builder$1.append(f1Value$4); + } else { + builder$1.append("NULL"); + } + builder$1.append(")"); + result$1 = org.apache.flink.table.data.binary.BinaryStringData.fromString(builder$1.toString()); + } else { + result$1 = org.apache.flink.table.data.binary.BinaryStringData.EMPTY_UTF8; + } + + */ + @Override + protected String generateCodeBlockInternal( + CodeGeneratorCastRule.Context context, + String inputTerm, + String returnVariable, + LogicalType inputLogicalType, + LogicalType targetLogicalType) { + final List<LogicalType> fields = + ((RowType) inputLogicalType) + .getFields().stream() + .map(RowType.RowField::getType) + .collect(Collectors.toList()); + + final String builderTerm = newName("builder"); + context.declareClassField( + className(StringBuilder.class), builderTerm, constructorCall(StringBuilder.class)); + + final CastRuleUtils.CodeWriter writer = + new CastRuleUtils.CodeWriter() + .stmt( + methodCall( + builderTerm, + "delete", + 0, + methodCall(builderTerm, "length"))) + .stmt(methodCall(builderTerm, "append", strLiteral("("))); + + for (int i = 0; i < fields.size(); i++) { + final int fieldIndex = i; + final LogicalType fieldType = fields.get(fieldIndex); + + final String fieldTerm = newName("f" + fieldIndex + "Value"); + final String fieldIsNullTerm = newName("f" + fieldIndex + "IsNull"); + + final CastCodeBlock codeBlock = + CastRuleProvider.generateCodeBlock( + context, + fieldTerm, + fieldIsNullTerm, + // Null check is done at the row access level + fieldType.copy(false), + targetLogicalType); + + // Write the comma + if (fieldIndex != 0) { + writer.stmt(methodCall(builderTerm, "append", strLiteral(","))); Review comment: A row is not a collection type. But let me create a bunch of issues to not forget about it. -- 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]
