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Posted to issues@flink.apache.org by GitBox <gi...@apache.org> on 2022/01/07 13:29:55 UTC
[GitHub] [flink] slinkydeveloper commented on a change in pull request #18182: [FLINK-25341][table-planner] Add StructuredToStringCastRule to support user POJO toString implementation
slinkydeveloper commented on a change in pull request #18182:
URL: https://github.com/apache/flink/pull/18182#discussion_r780263379
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File path: flink-table/flink-table-planner/src/main/java/org/apache/flink/table/planner/functions/casting/StructuredToStringCastRule.java
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@@ -0,0 +1,249 @@
+/*
+ * 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)
+ && (((StructuredType) input).getImplementationClass().isPresent()
+ || 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("{")));
+
+ for (int i = 0; i < inputStructuredType.getAttributes().size(); i++) {
+ final int fieldIndex = i;
+ final StructuredType.StructuredAttribute attribute =
+ inputStructuredType.getAttributes().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
+ attribute.getType().copy(false),
+ VarCharType.STRING_TYPE);
+
+ // Write the comma
+ if (fieldIndex != 0) {
+ final String comma = getDelimiter(context);
+ writer.stmt(methodCall(builderTerm, "append", comma));
+ }
+
+ writer
+ // Extract value from row
+ .declPrimitiveStmt(attribute.getType(), fieldTerm)
+ .declStmt(
+ boolean.class,
+ fieldIsNullTerm,
+ methodCall(inputTerm, "isNullAt", fieldIndex))
+ .ifStmt(
+ "!" + fieldIsNullTerm,
+ thenBodyWriter ->
+ thenBodyWriter
+ // If element not null, extract it and
+ // execute the cast
+ .assignStmt(
+ fieldTerm,
+ CodeGenUtils.rowFieldReadAccess(
+ fieldIndex,
+ inputTerm,
+ attribute.getType()))
+ .append(codeBlock)
+ .stmt(
+ methodCall(
+ builderTerm,
+ "append",
+ strLiteral(attribute.getName() + "=")
+ + " + "
+ + codeBlock.getReturnTerm())),
+ elseBodyWriter ->
+ // If element is null, just write NULL
+ elseBodyWriter.stmt(
+ methodCall(
+ builderTerm,
+ "append",
+ strLiteral(attribute.getName() + "=")
+ + " + "
+ + nullLiteral(
+ context.legacyBehaviour()))));
+ }
+
+ writer.stmt(methodCall(builderTerm, "append", strLiteral("}")));
+
+ return CharVarCharTrimPadCastRule.padAndTrimStringIfNeeded(
+ writer,
+ targetLogicalType,
+ context.legacyBehaviour(),
+ length,
+ resultStringTerm,
+ builderTerm)
+ // Assign the result value
+ .assignStmt(
+ returnVariable,
+ CastRuleUtils.staticCall(
+ BINARY_STRING_DATA_FROM_STRING(), resultStringTerm))
+ .toString();
+ }
+
+ private static String getDelimiter(CodeGeneratorCastRule.Context context) {
+ final String comma;
+ if (context.legacyBehaviour()) {
Review comment:
TBH I don't think there is any legacy behaviour for this casting at all, as users weren't able to execute `CAST(structuredVal AS STRING)` anyway.
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