[INLONG-10883][SDK] Transform SQL support InitCap function

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

@@ -0,0 +1,74 @@
+/*
+ * 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;
+
+/**
+ * InitCapFunction
+ * description: initcap(string)--returns a new form of STRING with the first character of each word converted to
+ * uppercase and the rest characters to lowercase
+ */
+@TransformFunction(names = {"initcap", "init_cap"})
+public class InitCapFunction implements ValueParser {
+
+    private ValueParser stringParser;
+
+    public InitCapFunction(Function expr) {
+        List<Expression> expressions = expr.getParameters().getExpressions();
+        stringParser = OperatorTools.buildParser(expressions.get(0));
+    }
+
+    @Override
+    public Object parse(SourceData sourceData, int rowIndex, Context context) {
+        Object strObject = stringParser.parse(sourceData, rowIndex, context);
+        if (strObject == null) {
+            return null;
+        }
+        String str = OperatorTools.parseString(strObject);
+        if (str == null) {
+            return null;
+        }
+
+        StringBuilder result = new StringBuilder();
+        boolean capitalizeNext = true;
+        for (char c : str.toCharArray()) {
+            if (Character.isLetterOrDigit(c)) {
+                if (capitalizeNext) {
+                    result.append(Character.toUpperCase(c));
+                    capitalizeNext = false;
+                } else {
+                    result.append(Character.toLowerCase(c));
+                }
+            } else {
+                capitalizeNext = true;
+                result.append(c);
+            }
+        }
+
+        return result.toString();
+    }
+}

inlong-sdk/transform-sdk/src/test/java/org/apache/inlong/sdk/transform/process/function/string/TestInitCapFunction.java

@@ -0,0 +1,61 @@
+/*
+ * 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.string;
+
+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.junit.Assert;
+import org.junit.Test;
+
+import java.util.HashMap;
+import java.util.List;
+
+public class TestInitCapFunction extends AbstractFunctionStringTestBase {
+
+    @Test
+    public void testInitCapFunction() throws Exception {
+        String transformSql = "select initcap(string1) from source";
+        TransformConfig config = new TransformConfig(transformSql);
+        TransformProcessor<String, String> processor = TransformProcessor
+                .create(config, SourceDecoderFactory.createCsvDecoder(csvSource),
+                        SinkEncoderFactory.createKvEncoder(kvSink));
+
+        // case1: initcap('hello world')
+        List<String> output1 = processor.transform("hello world", new HashMap<>());
+        Assert.assertEquals(1, output1.size());
+        Assert.assertEquals(output1.get(0), "result=Hello World");
+
+        // case2: initcap('apache inLong')
+        List<String> output2 = processor.transform("apache inLong", new HashMap<>());
+        Assert.assertEquals(1, output2.size());
+        Assert.assertEquals(output2.get(0), "result=Apache Inlong");
+
+        String transformSql2 = "select initcap(stringX) from source";
+        TransformConfig config2 = new TransformConfig(transformSql2);
+        TransformProcessor<String, String> processor2 = TransformProcessor
+                .create(config2, SourceDecoderFactory.createCsvDecoder(csvSource),
+                        SinkEncoderFactory.createKvEncoder(kvSink));
+        // case3: initcap(null)
+        List<String> output3 = processor2.transform("apache inLong", new HashMap<>());
+        Assert.assertEquals(1, output3.size());
+        Assert.assertEquals(output3.get(0), "result=");
+    }
+}