[INLONG-11235][SDK] Transform SQL supports SUBSTRING_INDEX function

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

@@ -0,0 +1,116 @@
+/*
+ * 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.ArrayList;
+import java.util.List;
+
+/**
+ * SubstringIndexFunction  -> SUBSTRING_INDEX(str,delim,count)
+ * description: Returns the substring from string str before count occurrences of the delimiter delim
+ * return NULL if any parameter is NULL;
+ * return everything to the left of the final delimiter (counting from the left) if count is positive;
+ * return everything to the right of the final delimiter (counting from the right) if count is negative.
+ */
+@TransformFunction(names = {"substring_index"})
+public class SubstringIndexFunction implements ValueParser {
+
+    private ValueParser stringParser;
+    private ValueParser delimParser;
+    private ValueParser countParser;
+
+    public SubstringIndexFunction(Function expr) {
+        List<Expression> expressions = expr.getParameters().getExpressions();
+        stringParser = OperatorTools.buildParser(expressions.get(0));
+        delimParser = OperatorTools.buildParser(expressions.get(1));
+        countParser = OperatorTools.buildParser(expressions.get(2));
+    }
+
+    @Override
+    public Object parse(SourceData sourceData, int rowIndex, Context context) {
+        Object stringObj = stringParser.parse(sourceData, rowIndex, context);
+        Object delimObj = delimParser.parse(sourceData, rowIndex, context);
+        Object countObj = countParser.parse(sourceData, rowIndex, context);
+        if (stringObj == null || delimObj == null || countObj == null) {
+            return null;
+        }
+        String str = OperatorTools.parseString(stringObj);
+        String delim = OperatorTools.parseString(delimObj);
+        int count = OperatorTools.parseBigDecimal(countObj).intValue();
+        if (str.isEmpty() || delim.isEmpty() || count == 0) {
+            return "";
+        }
+        boolean isRight = count < 0;
+        count = Math.abs(count);
+        ArrayList<Integer> startIndexList = findStart(delim, str);
+        int size = startIndexList.size();
+        if (size < count) {
+            return str;
+        }
+        if (isRight) {
+            int start = startIndexList.get(size - count);
+            return str.substring(start + delim.length());
+        } else {
+            int start = startIndexList.get(count - 1);
+            return str.substring(0, start);
+        }
+    }
+
+    /**
+     * Use kmp to find all the starting subscripts of the pattern from str
+     *
+     * @param patten Pattern string
+     * @param str    target string
+     * @return starting index list
+     */
+    public ArrayList<Integer> findStart(String patten, String str) {
+        ArrayList<Integer> next = new ArrayList<>();
+        ArrayList<Integer> startIndexList = new ArrayList<>();
+        next.add(0);
+        for (int i = 1, j = 0; i < patten.length(); i++) {
+            while (j > 0 && patten.charAt(i) != patten.charAt(j)) {
+                j = next.get(j - 1);
+            }
+            if (patten.charAt(i) == patten.charAt(j)) {
+                j++;
+            }
+            next.add(j);
+        }
+        for (int i = 0, j = 0; i < str.length(); i++) {
+            while (j > 0 && str.charAt(i) != patten.charAt(j)) {
+                j = next.get(j - 1);
+            }
+            if (str.charAt(i) == patten.charAt(j)) {
+                j++;
+            }
+            if (j == patten.length()) {
+                startIndexList.add(i - patten.length() + 1);
+                j = 0;
+            }
+        }
+        return startIndexList;
+    }
+}

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

@@ -0,0 +1,82 @@
+/*
+ * 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 TestSubstringIndexFunction extends AbstractFunctionStringTestBase {
+
+    @Test
+    public void testSubstringIndexFunction() throws Exception {
+        String transformSql = null, data = null;
+        TransformConfig config = null;
+        TransformProcessor<String, String> processor = null;
+        List<String> output = null;
+
+        transformSql = "select substring_index(string1,string2,numeric1) from source";
+        config = new TransformConfig(transformSql);
+        processor = TransformProcessor
+                .create(config, SourceDecoderFactory.createCsvDecoder(csvSource),
+                        SinkEncoderFactory.createKvEncoder(kvSink));
+
+        // case1: SUBSTRING_INDEX('AA.','.',0)
+        data = "AA.|.||0|";
+        output = processor.transform(data, new HashMap<>());
+        Assert.assertEquals(1, output.size());
+        Assert.assertEquals("result=", output.get(0));
+
+        // case2: SUBSTRING_INDEX('AA. ',' ',1);
+        data = "AA. | ||1|";
+        output = processor.transform(data, new HashMap<>());
+        Assert.assertEquals(1, output.size());
+        Assert.assertEquals("result=AA.", output.get(0));
+
+        // case3: SUBSTRING_INDEX('apache.inlong','long',100);
+        data = "apache.inlong|long||100|";
+        output = processor.transform(data, new HashMap<>());
+        Assert.assertEquals(1, output.size());
+        Assert.assertEquals("result=apache.inlong", output.get(0));
+
+        // case4: SUBSTRING_INDEX('inlong.apache.org','.',-2);
+        data = "inlong.apache.org|.||-2|";
+        output = processor.transform(data, new HashMap<>());
+        Assert.assertEquals(1, output.size());
+        Assert.assertEquals("result=apache.org", output.get(0));
+
+        // case5: SUBSTRING_INDEX('inlong..apache....org','..',-2);
+        data = "inlong..apache....org|..||-2|";
+        output = processor.transform(data, new HashMap<>());
+        Assert.assertEquals(1, output.size());
+        Assert.assertEquals("result=..org", output.get(0));
+
+        // case6: SUBSTRING_INDEX('inlong..apache....org','..',-100);
+        data = "inlong..apache....org|..||-100|";
+        output = processor.transform(data, new HashMap<>());
+        Assert.assertEquals(1, output.size());
+        Assert.assertEquals("result=inlong..apache....org", output.get(0));
+    }
+}