[INLONG-10873][SDK] Transform support factorial function

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

@@ -0,0 +1,117 @@
+/*
+ * 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.Function;
+
+import java.math.BigDecimal;
+
+/**
+ * FactorialFunction
+ * description: factorial(numeric)--returns the factorial of a non-negative
+ * integer
+ */
+@Slf4j
+public class FactorialFunction implements ValueParser {
+
+    private final ValueParser numberParser;
+
+    /**
+     * Constructor
+     *
+     * @param expr
+     */
+    public FactorialFunction(Function expr) {
+        if (expr == null || expr.getParameters() == null || expr.getParameters().getExpressions() == null
+                || expr.getParameters().getExpressions().isEmpty()
+                || expr.getParameters().getExpressions().get(0) == null) {
+            log.error("Invalid expression for factorial function.");
+            numberParser = null;
+        } else {
+            numberParser = OperatorTools.buildParser(expr.getParameters().getExpressions().get(0));
+        }
+    }
+
+    /**
+     * parse
+     *
+     * @param sourceData
+     * @param rowIndex
+     * @return
+     */
+    @Override
+    public Object parse(SourceData sourceData, int rowIndex, Context context) {
+        if (numberParser == null) {
+            log.error("Number parser is not initialized.");
+            return null;
+        }
+
+        Object numberObj;
+        try {
+            numberObj = numberParser.parse(sourceData, rowIndex, context);
+        } catch (Exception e) {
+            log.error("Error parsing number object", e);
+            return null;
+        }
+
+        if (numberObj == null) {
+            log.warn("Parsed number object is null.");
+            return null;
+        }
+
+        BigDecimal numberValue;
+        try {
+            numberValue = OperatorTools.parseBigDecimal(numberObj);
+        } catch (Exception e) {
+            log.error("Error converting parsed object to BigDecimal", e);
+            return null;
+        }
+
+        // Ensure the number is a non-negative integer
+        if (numberValue.scale() > 0 || numberValue.compareTo(BigDecimal.ZERO) < 0) {
+            log.warn("Factorial is only defined for non-negative integers. Invalid input: {}", numberValue);
+            return null;
+        }
+
+        return factorial(numberValue.intValue());
+    }
+
+    /**
+     * Helper method to calculate factorial
+     *
+     * @param n
+     * @return
+     */
+    private BigDecimal factorial(int n) {
+        if (n < 0) {
+            log.error("Factorial is not defined for negative numbers.");
+            return null;
+        }
+        BigDecimal result = BigDecimal.ONE;
+        for (int i = 2; i <= n; i++) {
+            result = result.multiply(BigDecimal.valueOf(i));
+        }
+        return result;
+    }
+}

inlong-sdk/transform-sdk/src/main/java/org/apache/inlong/sdk/transform/process/operator/OperatorTools.java

@@ -25,6 +25,7 @@
 import org.apache.inlong.sdk.transform.process.function.DateExtractFunction.DateExtractFunctionType;
 import org.apache.inlong.sdk.transform.process.function.DateFormatFunction;
 import org.apache.inlong.sdk.transform.process.function.ExpFunction;
+import org.apache.inlong.sdk.transform.process.function.FactorialFunction;
 import org.apache.inlong.sdk.transform.process.function.FloorFunction;
 import org.apache.inlong.sdk.transform.process.function.FromUnixTimeFunction;
 import org.apache.inlong.sdk.transform.process.function.LnFunction;
@@ -131,6 +132,7 @@ public class OperatorTools {
                 func -> new TimestampExtractFunction(TimestampExtractFunction.TimestampExtractFunctionType.SECOND,
                         func));
         functionMap.put("round", RoundFunction::new);
+        functionMap.put("factorial", FactorialFunction::new);
         functionMap.put("from_unixtime", FromUnixTimeFunction::new);
         functionMap.put("unix_timestamp", UnixTimestampFunction::new);
         functionMap.put("to_timestamp", ToTimestampFunction::new);
@@ -203,6 +205,7 @@ public static ValueParser buildParser(Expression expr) {
 
     /**
      * parseBigDecimal
+     * 
      * @param value
      * @return
      */
@@ -236,6 +239,7 @@ public static Timestamp parseTimestamp(Object value) {
 
     /**
      * compareValue
+     * 
      * @param left
      * @param right
      * @return

inlong-sdk/transform-sdk/src/test/java/org/apache/inlong/sdk/transform/process/TestTransformArithmeticFunctionsProcessor.java

@@ -174,6 +174,46 @@ public void testLog10Function() throws Exception {
         Assert.assertEquals(output2.get(0), "result=3.0");
     }
 
+    @Test
+    public void testFactorialFunction() throws Exception {
+
+        List<FieldInfo> fields = new ArrayList<>();
+        FieldInfo numeric1 = new FieldInfo();
+        numeric1.setName("numeric1");
+        fields.add(numeric1);
+
+        CsvSourceInfo csvSource = new CsvSourceInfo("UTF-8", '|', '\\', fields);
+        KvSinkInfo kvSink = new KvSinkInfo("UTF-8", fields);
+
+        String transformSql = "select factorial(numeric1) as numeric1 from source";
+
+        TransformConfig config = new TransformConfig(transformSql);
+
+        TransformProcessor<String, String> processor = TransformProcessor
+                .create(config, SourceDecoderFactory.createCsvDecoder(csvSource),
+                        SinkEncoderFactory.createKvEncoder(kvSink));
+
+        // case1: Valid input - 5!
+        List<String> output1 = processor.transform("5|4|6|8");
+        Assert.assertEquals(1, output1.size());
+        Assert.assertEquals("numeric1=120", output1.get(0));
+
+        // case2: Valid input - 0!
+        List<String> output2 = processor.transform("0|4|6|8");
+        Assert.assertEquals(1, output2.size());
+        Assert.assertEquals("numeric1=1", output2.get(0));
+
+        // case3: Non-integer input (5.5) should return null
+        List<String> output3 = processor.transform("5.5|4|6|8");
+        Assert.assertEquals(1, output3.size());
+        Assert.assertNull(output3.get(0));
+
+        // case4: Negative input (-5) should return null
+        List<String> output4 = processor.transform("-5|4|6|8");
+        Assert.assertEquals(1, output4.size());
+        Assert.assertNull(output4.get(0));
+    }
+
     @Test
     public void testLog2Function() throws Exception {
         String transformSql = "select log2(numeric1) from source";