[INLONG-11147][SDK] Transform support CASE Operator (#11184)

inlong-sdk/transform-sdk/src/main/java/org/apache/inlong/sdk/transform/process/parser/CaseParser.java

@@ -0,0 +1,92 @@
+/*
+ * 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.inlong.sdk.transform.process.parser;
+
+import org.apache.inlong.sdk.transform.decode.SourceData;
+import org.apache.inlong.sdk.transform.process.Context;
+import org.apache.inlong.sdk.transform.process.operator.ExpressionOperator;
+import org.apache.inlong.sdk.transform.process.operator.OperatorTools;
+
+import net.sf.jsqlparser.expression.CaseExpression;
+import net.sf.jsqlparser.expression.WhenClause;
+
+import java.util.ArrayList;
+import java.util.List;
+/**
+ * CASE value WHEN compare_value THEN result [WHEN compare_value THEN result ...] [ELSE result] END
+ * CASE WHEN condition THEN result [WHEN condition THEN result ...] [ELSE result] END
+ *
+ * The first CASE syntax returns the result for the first value=compare_value comparison that is true.
+ * The second syntax returns the result for the first condition that is true.
+ * If no comparison or condition is true, the result after ELSE is returned, or NULL if there is no ELSE part.
+ */
+@TransformParser(values = CaseExpression.class)
+public class CaseParser implements ValueParser {
+
+    private final ValueParser switchValue;
+    private final List<CaseWhen> caseWhens;
+    private final ValueParser elseResult;
+
+    public CaseParser(CaseExpression expr) {
+        this.switchValue = OperatorTools.buildParser(expr.getSwitchExpression());
+        this.caseWhens = new ArrayList<>();
+        this.elseResult = OperatorTools.buildParser(expr.getElseExpression());
+        for (WhenClause whenClause : expr.getWhenClauses()) {
+            Object condition = null;
+            if (switchValue == null) {
+                condition = OperatorTools.buildOperator(whenClause.getWhenExpression());
+            } else {
+                condition = OperatorTools.buildParser(whenClause.getWhenExpression());
+            }
+            ValueParser result = OperatorTools.buildParser(whenClause.getThenExpression());
+            this.caseWhens.add(new CaseWhen(condition, result));
+        }
+    }
+
+    @SuppressWarnings("rawtypes")
+    @Override
+    public Object parse(SourceData sourceData, int rowIndex, Context context) {
+        if (switchValue == null) {
+            for (CaseWhen caseWhen : caseWhens) {
+                if (((ExpressionOperator) caseWhen.condition).check(sourceData, rowIndex, context)) {
+                    return caseWhen.result.parse(sourceData, rowIndex, context);
+                }
+            }
+        } else {
+            for (CaseWhen caseWhen : caseWhens) {
+                Comparable left = (Comparable) switchValue.parse(sourceData, rowIndex, context);
+                Comparable right = (Comparable) ((ValueParser) caseWhen.condition).parse(sourceData, rowIndex, context);
+                if (OperatorTools.compareValue(left, right) == 0) {
+                    return caseWhen.result.parse(sourceData, rowIndex, context);
+                }
+            }
+        }
+        return elseResult == null ? null : elseResult.parse(sourceData, rowIndex, context);
+    }
+
+    private static class CaseWhen {
+
+        private final Object condition;
+        private final ValueParser result;
+
+        public CaseWhen(Object condition, ValueParser result) {
+            this.condition = condition;
+            this.result = result;
+        }
+    }
+}

inlong-sdk/transform-sdk/src/test/java/org/apache/inlong/sdk/transform/process/function/flowcontrol/TestCaseFunction.java

@@ -0,0 +1,165 @@
+/*
+ * 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.inlong.sdk.transform.process.function.flowcontrol;
+
+import org.apache.inlong.sdk.transform.decode.SourceDecoderFactory;
+import org.apache.inlong.sdk.transform.encode.SinkEncoderFactory;
+import org.apache.inlong.sdk.transform.pojo.TransformConfig;
+import org.apache.inlong.sdk.transform.process.TransformProcessor;
+import org.apache.inlong.sdk.transform.process.function.arithmetic.AbstractFunctionArithmeticTestBase;
+
+import org.junit.Assert;
+import org.junit.Test;
+
+import java.util.HashMap;
+import java.util.List;
+
+public class TestCaseFunction extends AbstractFunctionArithmeticTestBase {
+
+    @Test
+    public void testCaseFunction() throws Exception {
+        String transformSql = null, data = null;
+        TransformConfig config = null;
+        TransformProcessor<String, String> processor = null;
+        List<String> output = null;
+
+        // case1: CASE WHEN numeric1 > numeric2 THEN 'greater' ELSE 'lesser' END
+        transformSql = "select case " +
+                "when numeric1 > numeric2 then 'greater' " +
+                "else 'lesser' end " +
+                "from source";
+        config = new TransformConfig(transformSql);
+        processor = TransformProcessor
+                .create(config, SourceDecoderFactory.createCsvDecoder(csvSource),
+                        SinkEncoderFactory.createKvEncoder(kvSink));
+        data = "5|3|3|5";
+        output = processor.transform(data, new HashMap<>());
+        Assert.assertEquals(1, output.size());
+        Assert.assertEquals("result=greater", output.get(0));
+
+        // case2: CASE numeric1 WHEN 5 THEN 'five' ELSE 'other' END
+        transformSql = "select case numeric1 " +
+                "when 5 then 'five' " +
+                "else 'other' end " +
+                "from source";
+        config = new TransformConfig(transformSql);
+        processor = TransformProcessor
+                .create(config, SourceDecoderFactory.createCsvDecoder(csvSource),
+                        SinkEncoderFactory.createKvEncoder(kvSink));
+        data = "5|0|3|5";
+        output = processor.transform(data, new HashMap<>());
+        Assert.assertEquals(1, output.size());
+        Assert.assertEquals("result=five", output.get(0));
+
+        // case3: CASE numeric1 WHEN 3 THEN 'three' WHEN 5 THEN 'five' ELSE 'other' END
+        transformSql = "select case numeric1 " +
+                "when 3 then 'three' " +
+                "when 5 then 'five' " +
+                "else 'other' end " +
+                "from source";
+        config = new TransformConfig(transformSql);
+        processor = TransformProcessor
+                .create(config, SourceDecoderFactory.createCsvDecoder(csvSource),
+                        SinkEncoderFactory.createKvEncoder(kvSink));
+        data = "6|0|3|5";
+        output = processor.transform(data, new HashMap<>());
+        Assert.assertEquals(1, output.size());
+        Assert.assertEquals("result=other", output.get(0));
+
+        // case4: CASE WHEN numeric1 >= 90 THEN 'Excellent' WHEN numeric1 >= 80 THEN 'Good' WHEN numeric1 >= 60 THEN
+        // 'Pass' ELSE 'Fail' END
+        transformSql = "select case " +
+                "when numeric1 >= 90 then 'Excellent' " +
+                "when numeric1 >= 80 then 'Good' " +
+                "when numeric1 >= 60 then 'Pass' " +
+                "else 'Fail' end " +
+                "from source";
+        config = new TransformConfig(transformSql);
+        processor = TransformProcessor
+                .create(config, SourceDecoderFactory.createCsvDecoder(csvSource),
+                        SinkEncoderFactory.createKvEncoder(kvSink));
+        data = "85|0|3|5";
+        output = processor.transform(data, new HashMap<>());
+        Assert.assertEquals(1, output.size());
+        Assert.assertEquals("result=Good", output.get(0));
+
+        // case5: CASE WHEN numeric1 = 5 THEN 'five' WHEN numeric1 > 3 THEN 'greater' END
+        transformSql = "select case " +
+                "when numeric1 = 5 then 'five' " +
+                "when numeric1 > 3 then 'greater' " +
+                "end " +
+                "from source";
+        config = new TransformConfig(transformSql);
+        processor = TransformProcessor
+                .create(config, SourceDecoderFactory.createCsvDecoder(csvSource),
+                        SinkEncoderFactory.createKvEncoder(kvSink));
+        data = "5|0|3|5";
+        output = processor.transform(data, new HashMap<>());
+        Assert.assertEquals(1, output.size());
+        Assert.assertEquals("result=five", output.get(0));
+
+        // case6: CASE numeric1 + numeric2 WHEN 3 THEN 3 WHEN 5 THEN 'five' WHEN 5.4 THEN 5.4 ELSE 'other' END
+        transformSql = "select case numeric1 + numeric2 " +
+                "when 3 then 3 " +
+                "when 5 then 'five' " +
+                "when 5.4 then 5.4 " +
+                "else 'other' end " +
+                "from source";
+        config = new TransformConfig(transformSql);
+        processor = TransformProcessor
+                .create(config, SourceDecoderFactory.createCsvDecoder(csvSource),
+                        SinkEncoderFactory.createKvEncoder(kvSink));
+        data = "3.2|2.2|3|5";
+        output = processor.transform(data, new HashMap<>());
+        Assert.assertEquals(1, output.size());
+        Assert.assertEquals("result=5.4", output.get(0));
+
+        // case7: CASE numeric1 / numeric2 WHEN 3 THEN 'three' WHEN 5 THEN 'five' ELSE 'other' END
+        transformSql = "select case numeric1 / numeric2 " +
+                "when 3 then 'three' " +
+                "when 5 then 'five' " +
+                "else 'other' end " +
+                "from source";
+        config = new TransformConfig(transformSql);
+        processor = TransformProcessor
+                .create(config, SourceDecoderFactory.createCsvDecoder(csvSource),
+                        SinkEncoderFactory.createKvEncoder(kvSink));
+        data = "3|0|3|5";
+        output = processor.transform(data, new HashMap<>());
+        Assert.assertEquals(1, output.size());
+        Assert.assertEquals("result=", output.get(0));
+
+        // case8: Nested CASE Expression
+        transformSql = "select case " +
+                "when numeric1 >= 90 then 'Excellent' " +
+                "when numeric1 >= 80 then 'Good' " +
+                "when numeric1 >= 60 then case " +
+                "when numeric2 >= 70 then 'Pass with Merit' " +
+                "else 'Pass' end " +
+                "else 'Fail' end " +
+                "from source";
+        config = new TransformConfig(transformSql);
+        processor = TransformProcessor
+                .create(config, SourceDecoderFactory.createCsvDecoder(csvSource),
+                        SinkEncoderFactory.createKvEncoder(kvSink));
+        data = "65|75|3|5";
+        output = processor.transform(data, new HashMap<>());
+        Assert.assertEquals(1, output.size());
+        Assert.assertEquals("result=Pass with Merit", output.get(0));
+    }
+}