[INLONG-11064][SDK] Transform SQL supports NULLIF function (apache#11078

)

Co-authored-by: ZKpLo <[email protected]>

inlong-sdk/transform-sdk/src/main/java/org/apache/inlong/sdk/transform/process/function/NullIfFunction.java

@@ -0,0 +1,63 @@
+/*
+ * 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;
+
+import org.apache.inlong.sdk.transform.decode.SourceData;
+import org.apache.inlong.sdk.transform.process.Context;
+import org.apache.inlong.sdk.transform.process.operator.OperatorTools;
+import org.apache.inlong.sdk.transform.process.parser.ValueParser;
+
+import lombok.extern.slf4j.Slf4j;
+import net.sf.jsqlparser.expression.Expression;
+import net.sf.jsqlparser.expression.Function;
+
+import java.util.List;
+
+/**
+ * NullIfFunction
+ * description: NULLIF(expr1,expr2)
+ * - return NULL if expr1 = expr2 is true
+ * - returns expr1 otherwise
+ */
+@Slf4j
+@TransformFunction(names = {"nullif", "null_if"})
+public class NullIfFunction implements ValueParser {
+
+    private final ValueParser firstExprParser;
+    private final ValueParser secondExprParser;
+
+    public NullIfFunction(Function expr) {
+        List<Expression> expressions = expr.getParameters().getExpressions();
+        firstExprParser = OperatorTools.buildParser(expressions.get(0));
+        secondExprParser = OperatorTools.buildParser(expressions.get(1));
+    }
+
+    @Override
+    public Object parse(SourceData sourceData, int rowIndex, Context context) {
+        Object firstExprObj = firstExprParser.parse(sourceData, rowIndex, context);
+        if (firstExprObj == null) {
+            return null;
+        }
+        Object secondExprObj = secondExprParser.parse(sourceData, rowIndex, context);
+        if (secondExprObj == null) {
+            return firstExprObj;
+        }
+        int cmp = OperatorTools.compareValue((Comparable) firstExprObj, (Comparable) secondExprObj);
+        return cmp == 0 ? null : firstExprObj;
+    }
+}

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

@@ -0,0 +1,69 @@
+/*
+ * 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 TestNullIfFunction extends AbstractFunctionArithmeticTestBase {
+
+    @Test
+    public void testNullIfFunction() throws Exception {
+        String transformSql = null, data = null;
+        TransformConfig config = null;
+        TransformProcessor<String, String> processor = null;
+        List<String> output = null;
+
+        // case1: nullif(5, 3)
+        transformSql = "select nullif(numeric1,numeric2) 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=5", output.get(0));
+
+        // case2: nullif(5, 5)
+        data = "5|5|3|5";
+        output = processor.transform(data, new HashMap<>());
+        Assert.assertEquals(1, output.size());
+        Assert.assertEquals("result=null", output.get(0));
+
+        // case3: nullif(null,3)
+        transformSql = "select nullif(xxd,numeric2) 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=null", output.get(0));
+    }
+}