yuxiqian commented on code in PR #4482:
URL: https://github.com/apache/flink-cdc/pull/4482#discussion_r3654317371
##########
flink-cdc-runtime/src/main/java/org/apache/flink/cdc/runtime/parser/JaninoCompiler.java:
##########
@@ -804,6 +916,418 @@ private static String
generateInvokeExpression(UserDefinedFunctionDescriptor udf
}
}
+ private static class GeneratedExpressionGenerator {
+ private final Context context;
+ private int termId;
+
+ private GeneratedExpressionGenerator(Context context) {
+ this.context = context;
+ }
+
+ private GeneratedExpression translate(SqlNode sqlNode, Class<?>
resultClass) {
+ if (sqlNode instanceof SqlBasicCall) {
+ return translateSqlBasicCall((SqlBasicCall) sqlNode,
resultClass);
+ }
+ if (sqlNode instanceof SqlCase) {
+ return translateSqlCase((SqlCase) sqlNode, resultClass);
+ }
+ Java.Rvalue rvalue = translateSqlNodeToJaninoRvalue(context,
sqlNode);
+ if (rvalue == null) {
+ throw new ParseException("Unrecognized expression: " +
sqlNode);
+ }
+ return GeneratedExpression.fromExpression(rvalue.toString(),
resultClass);
Review Comment:
`rvalue.toString()` is for debugging purposes only and may not generate Java
code with correct parentheses.
For example, SQL statement `(a - b) / (c + 1)` will be converted to `a - b /
c + 1`.
##########
flink-cdc-runtime/src/main/java/org/apache/flink/cdc/runtime/parser/GeneratedExpression.java:
##########
@@ -0,0 +1,106 @@
+/*
+ * 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.cdc.runtime.parser;
+
+import java.io.Serializable;
+import java.util.Objects;
+
+/** Statement-level Java code generated from a transform expression. */
+public class GeneratedExpression implements Serializable {
+ private static final long serialVersionUID = 1L;
+
+ private final String code;
+ private final String resultTerm;
+ private final Class<?> resultClass;
+
+ private GeneratedExpression(String code, String resultTerm, Class<?>
resultClass) {
+ this.code = Objects.requireNonNull(code);
+ this.resultTerm = Objects.requireNonNull(resultTerm);
+ this.resultClass = Objects.requireNonNull(resultClass);
+ }
+
+ public String getCode() {
+ return code;
+ }
+
+ public String getResultTerm() {
+ return resultTerm;
+ }
+
+ public Class<?> getResultClass() {
+ return resultClass;
+ }
+
+ public String asScript() {
+ StringBuilder script = new StringBuilder();
+ appendCode(script, code);
+ script.append("return ").append(resultTerm).append(";");
+ return script.toString();
+ }
+
+ public static GeneratedExpression of(String code, String resultTerm,
Class<?> resultClass) {
+ return new GeneratedExpression(code, resultTerm, resultClass);
+ }
+
+ public static GeneratedExpression fromExpression(String resultTerm,
Class<?> resultClass) {
+ return of("", resultTerm, resultClass);
+ }
+
+ private static void appendCode(StringBuilder builder, String code) {
+ if (code.isEmpty()) {
+ return;
+ }
+ builder.append(code);
+ if (code.charAt(code.length() - 1) != '\n') {
+ builder.append('\n');
+ }
+ }
Review Comment:
Ditto, avoid string ops
##########
flink-cdc-runtime/src/main/java/org/apache/flink/cdc/runtime/parser/JaninoCompiler.java:
##########
@@ -496,6 +511,103 @@ private static Java.Rvalue generateEqualsOperation(
Location.NOWHERE, null,
StringUtils.convertToCamelCase("VALUE_EQUALS"), atoms);
}
+ private static Class<?> deduceGeneratedExpressionClass(Context context,
SqlNode sqlNode) {
+ if (sqlNode instanceof SqlIdentifier) {
+ return deduceIdentifierClass(context, (SqlIdentifier) sqlNode);
+ }
+ if (sqlNode instanceof SqlLiteral) {
+ return deduceLiteralClass((SqlLiteral) sqlNode);
+ }
+ if (sqlNode instanceof SqlBasicCall &&
isBooleanResultCall((SqlBasicCall) sqlNode)) {
+ return Boolean.class;
+ }
+ try {
+ return JavaClassConverter.toJavaClass(
+ TransformParser.deduceSubExpressionType(
+ context.columns,
+ sqlNode,
+ context.udfDescriptors,
+ context.supportedMetadataColumns));
+ } catch (RuntimeException e) {
+ return Object.class;
+ }
+ }
+
+ private static Class<?> deduceIdentifierClass(Context context,
SqlIdentifier sqlIdentifier) {
+ String columnName = sqlIdentifier.names.get(sqlIdentifier.names.size()
- 1);
+ for (Column column : context.columns) {
+ if (column.getName().equals(columnName)) {
+ return JavaClassConverter.toJavaClass(column.getType());
+ }
+ }
+ for (SupportedMetadataColumn metadataColumn :
context.supportedMetadataColumns) {
+ if (metadataColumn.getName().equals(columnName)) {
+ return metadataColumn.getJavaClass();
+ }
+ }
+ Optional<Class<?>> metadataColumnClass =
+ MetadataColumns.METADATA_COLUMNS.stream()
+ .filter(column -> column.f0.equals(columnName))
+ .findFirst()
+ .map(column -> (Class<?>) column.f2);
+ return metadataColumnClass.orElse(Object.class);
+ }
+
+ private static Class<?> deduceLiteralClass(SqlLiteral sqlLiteral) {
+ if (sqlLiteral.getValue() == null) {
+ return Object.class;
+ }
+ if (sqlLiteral instanceof SqlCharStringLiteral) {
+ return String.class;
+ }
+ if (sqlLiteral instanceof SqlNumericLiteral) {
+ SqlNumericLiteral numericLiteral = (SqlNumericLiteral) sqlLiteral;
+ if (numericLiteral.isInteger()) {
+ long longValue = numericLiteral.longValue(true);
+ if (longValue > Integer.MAX_VALUE || longValue <
Integer.MIN_VALUE) {
+ return Long.class;
+ }
+ return Integer.class;
+ }
+ return Double.class;
+ }
+ if (sqlLiteral.getTypeName() == SqlTypeName.BOOLEAN) {
+ return Boolean.class;
+ }
+ return Object.class;
+ }
+
+ private static boolean isBooleanResultCall(SqlBasicCall sqlBasicCall) {
Review Comment:
One may write a UDF returning `BOOLEAN`?
##########
flink-cdc-runtime/src/main/java/org/apache/flink/cdc/runtime/parser/GeneratedExpression.java:
##########
@@ -0,0 +1,106 @@
+/*
+ * 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.cdc.runtime.parser;
+
+import java.io.Serializable;
+import java.util.Objects;
+
+/** Statement-level Java code generated from a transform expression. */
+public class GeneratedExpression implements Serializable {
+ private static final long serialVersionUID = 1L;
+
+ private final String code;
+ private final String resultTerm;
+ private final Class<?> resultClass;
+
+ private GeneratedExpression(String code, String resultTerm, Class<?>
resultClass) {
+ this.code = Objects.requireNonNull(code);
+ this.resultTerm = Objects.requireNonNull(resultTerm);
+ this.resultClass = Objects.requireNonNull(resultClass);
+ }
+
+ public String getCode() {
+ return code;
+ }
+
+ public String getResultTerm() {
+ return resultTerm;
+ }
+
+ public Class<?> getResultClass() {
+ return resultClass;
+ }
+
+ public String asScript() {
+ StringBuilder script = new StringBuilder();
+ appendCode(script, code);
+ script.append("return ").append(resultTerm).append(";");
+ return script.toString();
+ }
Review Comment:
Better avoid string manipulations on dumped Java codes. Is
`Java.ReturnStatement` useful here?
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