twalthr commented on a change in pull request #18182: URL: https://github.com/apache/flink/pull/18182#discussion_r783924035
########## File path: flink-table/flink-table-planner/src/main/java/org/apache/flink/table/planner/functions/casting/StructuredToStringCastRule.java ########## @@ -0,0 +1,233 @@ +/* + * 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; + +import org.apache.flink.table.data.ArrayData; +import org.apache.flink.table.planner.codegen.CodeGenUtils; +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.StructuredType; +import org.apache.flink.table.types.logical.VarCharType; +import org.apache.flink.table.types.logical.utils.LogicalTypeChecks; + +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.calls.BuiltInMethods.BINARY_STRING_DATA_FROM_STRING; +import static org.apache.flink.table.planner.functions.casting.CastRuleUtils.constructorCall; +import static org.apache.flink.table.planner.functions.casting.CastRuleUtils.methodCall; +import static org.apache.flink.table.planner.functions.casting.CastRuleUtils.nullLiteral; +import static org.apache.flink.table.planner.functions.casting.CastRuleUtils.strLiteral; + +/** + * {@link LogicalTypeRoot#STRUCTURED_TYPE} to {@link LogicalTypeFamily#CHARACTER_STRING} cast rule. + */ +class StructuredToStringCastRule extends AbstractNullAwareCodeGeneratorCastRule<ArrayData, String> { + + static final StructuredToStringCastRule INSTANCE = new StructuredToStringCastRule(); + + private StructuredToStringCastRule() { + super(CastRulePredicate.builder().predicate(StructuredToStringCastRule::matches).build()); + } + + private static boolean matches(LogicalType input, LogicalType target) { + return target.is(LogicalTypeFamily.CHARACTER_STRING) + && input.is(LogicalTypeRoot.STRUCTURED_TYPE) + && LogicalTypeChecks.getFieldTypes(input).stream() + .allMatch(fieldType -> CastRuleProvider.exists(fieldType, target)); + } + + /* Example generated code for MyStructuredType in CastRulesTest: + + builder$287.setLength(0); + builder$287.append("{"); + long f0Value$289 = -1L; + boolean f0IsNull$290 = _myInput.isNullAt(0); + if (!f0IsNull$290) { + f0Value$289 = _myInput.getLong(0); + isNull$2 = f0IsNull$290; + if (!isNull$2) { + result$3 = org.apache.flink.table.data.binary.BinaryStringData.fromString("" + f0Value$289); + isNull$2 = result$3 == null; + } else { + result$3 = org.apache.flink.table.data.binary.BinaryStringData.EMPTY_UTF8; + } + builder$287.append("a=" + result$3); + } else { + builder$287.append("a=" + "NULL"); + } + builder$287.append(", "); + long f1Value$291 = -1L; + boolean f1IsNull$292 = _myInput.isNullAt(1); + if (!f1IsNull$292) { + f1Value$291 = _myInput.getLong(1); + isNull$4 = f1IsNull$292; + if (!isNull$4) { + result$5 = org.apache.flink.table.data.binary.BinaryStringData.fromString("" + f1Value$291); + isNull$4 = result$5 == null; + } else { + result$5 = org.apache.flink.table.data.binary.BinaryStringData.EMPTY_UTF8; + } + builder$287.append("b=" + result$5); + } else { + builder$287.append("b=" + "NULL"); + } + builder$287.append(", "); + org.apache.flink.table.data.binary.BinaryStringData f2Value$293 = org.apache.flink.table.data.binary.BinaryStringData.EMPTY_UTF8; + boolean f2IsNull$294 = _myInput.isNullAt(2); + if (!f2IsNull$294) { + f2Value$293 = ((org.apache.flink.table.data.binary.BinaryStringData) _myInput.getString(2)); + builder$287.append("c=" + f2Value$293); + } else { + builder$287.append("c=" + "NULL"); + } + builder$287.append(", "); + org.apache.flink.table.data.ArrayData f3Value$295 = null; + boolean f3IsNull$296 = _myInput.isNullAt(3); + if (!f3IsNull$296) { + f3Value$295 = _myInput.getArray(3); + isNull$6 = f3IsNull$296; + if (!isNull$6) { + builder$297.setLength(0); + builder$297.append("["); + for (int i$299 = 0; i$299 < f3Value$295.size(); i$299++) { + if (i$299 != 0) { + builder$297.append(", "); + } + org.apache.flink.table.data.binary.BinaryStringData element$300 = org.apache.flink.table.data.binary.BinaryStringData.EMPTY_UTF8; + boolean elementIsNull$301 = f3Value$295.isNullAt(i$299); + if (!elementIsNull$301) { + element$300 = ((org.apache.flink.table.data.binary.BinaryStringData) f3Value$295.getString(i$299)); + builder$297.append(element$300); + } else { + builder$297.append("NULL"); + } + } + builder$297.append("]"); + java.lang.String resultString$298; + resultString$298 = builder$297.toString(); + result$7 = org.apache.flink.table.data.binary.BinaryStringData.fromString(resultString$298); + isNull$6 = result$7 == null; + } else { + result$7 = org.apache.flink.table.data.binary.BinaryStringData.EMPTY_UTF8; + } + builder$287.append("d=" + result$7); + } else { + builder$287.append("d=" + "NULL"); + } + builder$287.append("}"); + java.lang.String resultString$288; + resultString$288 = builder$287.toString(); + result$1 = org.apache.flink.table.data.binary.BinaryStringData.fromString(resultString$288); + + */ + @Override + protected String generateCodeBlockInternal( + CodeGeneratorCastRule.Context context, + String inputTerm, + String returnVariable, + LogicalType inputLogicalType, + LogicalType targetLogicalType) { + StructuredType inputStructuredType = (StructuredType) inputLogicalType; + + final String builderTerm = newName("builder"); + context.declareClassField( + className(StringBuilder.class), builderTerm, constructorCall(StringBuilder.class)); + + final String resultStringTerm = newName("resultString"); + final int length = LogicalTypeChecks.getLength(targetLogicalType); + final CastRuleUtils.CodeWriter writer = + new CastRuleUtils.CodeWriter() + .stmt(methodCall(builderTerm, "setLength", 0)) + .stmt(methodCall(builderTerm, "append", strLiteral("{"))); Review comment: sorry, for the last minute suggestion. but how about we use `(...)` instead of `{...}` to distinguish structured types from maps. then they are also closer to rows which also use `(...)` -- This is an automated message from the Apache Git Service. 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