[Scalar Function][Array] Add ArrayJoinString Scalar function (apache#…

…14537) * [Scalar Function][Array] Add ArrayJoinString function * Update func name and allow null replacement * Remove unnecessary changes * Fix tests
vvivekiyer · Nov 26, 2024 · 1975268 · 1975268
1 parent b34e805
commit 1975268
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diff --git a/pinot-common/src/main/java/org/apache/pinot/common/function/scalar/ArrayFunctions.java b/pinot-common/src/main/java/org/apache/pinot/common/function/scalar/ArrayFunctions.java
@@ -347,4 +347,22 @@ public static double[] generateDoubleArray(double start, double end, double inc)
     }
     return arr;
   }
+
+  @ScalarFunction
+  public static String arrayToString(String[] values, String delimiter) {
+    return String.join(delimiter, values);
+  }
+
+  @ScalarFunction
+  public static String arrayToString(String[] values, String delimiter, String nullString) {
+    if (values == null || values.length == 0) {
+      return NullValuePlaceHolder.STRING;
+    }
+
+    return String.join(
+        delimiter,
+        Arrays.stream(values)
+            .map(s -> s == null || s.equals(NullValuePlaceHolder.STRING) ? nullString : s)
+            .toArray(String[]::new));
+  }
 }
diff --git a/pinot-core/src/test/java/org/apache/pinot/core/data/function/ArrayFunctionsTest.java b/pinot-core/src/test/java/org/apache/pinot/core/data/function/ArrayFunctionsTest.java
@@ -55,6 +55,7 @@ public Object[][] arrayFunctionsDataProvider() {
     row.putValue("intArray", new int[]{3, 2, 10, 6, 1, 12});
     row.putValue("integerArray", new Integer[]{3, 2, 10, 6, 1, 12});
     row.putValue("stringArray", new String[]{"3", "2", "10", "6", "1", "12"});
+    row.putValue("stringArrayWithNulls", new String[]{"3", "2", "10", "6", "1", "12", "", null});
 
     inputs.add(new Object[]{
         "array_reverse_int(intArray)", Collections.singletonList("intArray"), row, new int[]{12, 1, 6, 10, 2, 3}
@@ -180,6 +181,14 @@ public Object[][] arrayFunctionsDataProvider() {
         "array_concat_string(stringArray, stringArray)", Lists.newArrayList("stringArray", "stringArray"), row,
         new String[]{"3", "2", "10", "6", "1", "12", "3", "2", "10", "6", "1", "12"}
     });
+    inputs.add(new Object[]{
+        "array_to_string(stringArray, '::')", Collections.singletonList("stringArray"), row,
+        "3::2::10::6::1::12"
+    });
+    inputs.add(new Object[]{
+        "array_to_string(stringArrayWithNulls, '::', '*')", Collections.singletonList("stringArrayWithNulls"), row,
+        "3::2::10::6::1::12::*::*"
+    });
     return inputs.toArray(new Object[0][]);
   }
 }