[INLONG-10882][SDK] Transform SQL support ASCII function

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

@@ -0,0 +1,66 @@
+/*
+ * 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 net.sf.jsqlparser.expression.Expression;
+import net.sf.jsqlparser.expression.Function;
+
+import java.util.List;
+
+/**
+ * ASCIIFunction
+ * description: ASCII(string) -- Returns the numeric value of the first character of string. Returns NULL if string is NULL.
+ */
+@TransformFunction(names = {"ascii"})
+public class AsciiFunction implements ValueParser {
+
+    private final ValueParser stringParser;
+
+    /**
+     * Constructor
+     * @param expr
+     */
+    public AsciiFunction(Function expr) {
+        List<Expression> expressions = expr.getParameters().getExpressions();
+        stringParser = OperatorTools.buildParser(expressions.get(0));
+    }
+
+    /**
+     * parse
+     * @param sourceData
+     * @param rowIndex
+     * @return
+     */
+    @Override
+    public Object parse(SourceData sourceData, int rowIndex, Context context) {
+        Object stringObj = stringParser.parse(sourceData, rowIndex, context);
+        if (stringObj == null) {
+            return null;
+        }
+        String str = OperatorTools.parseString(stringObj);
+        if (str == null || str.isEmpty()) {
+            return null;
+        }
+        return (int) str.charAt(0);
+    }
+}

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

@@ -690,4 +690,34 @@ public void testTranslateFunction() throws Exception {
         Assert.assertEquals(output3.get(0), "result=Apache Inlong");
     }
 
+    @Test
+    public void testAsciiFunction() throws Exception {
+        String transformSql1 = "select ascii(string1) from source";
+        TransformConfig config1 = new TransformConfig(transformSql1);
+        TransformProcessor<String, String> processor1 = TransformProcessor
+                .create(config1, SourceDecoderFactory.createCsvDecoder(csvSource),
+                        SinkEncoderFactory.createKvEncoder(kvSink));
+
+        // case1: ascii('abc') -> 97
+        List<String> output1 = processor1.transform("abc|el|EL|2|1|3", new HashMap<>());
+        Assert.assertEquals(1, output1.size());
+        Assert.assertEquals(output1.get(0), "result=97");
+
+        // case1: ascii('A') -> 65
+        output1 = processor1.transform("A|el|EL|2|1|3", new HashMap<>());
+        Assert.assertEquals(1, output1.size());
+        Assert.assertEquals(output1.get(0), "result=65");
+
+        String transformSql2 = "select ascii(stringX) from source";
+        TransformConfig config2 = new TransformConfig(transformSql2);
+        TransformProcessor<String, String> processor2 = TransformProcessor
+                .create(config2, SourceDecoderFactory.createCsvDecoder(csvSource),
+                        SinkEncoderFactory.createKvEncoder(kvSink));
+
+        // case3: ascii(null) -> null
+        List<String> output2 = processor2.transform("A|el|EL|2|1|3", new HashMap<>());
+        Assert.assertEquals(1, output2.size());
+        Assert.assertEquals(output2.get(0), "result=null");
+    }
+
 }