nits

Signed-off-by: Sarthak Aggarwal <[email protected]>

server/src/main/java/org/opensearch/index/compositeindex/datacube/startree/aggregators/SumValueAggregator.java

@@ -16,9 +16,8 @@
  * <p>This implementation follows the Kahan summation algorithm to improve the accuracy
  * of the sum by tracking and compensating for the accumulated error in each iteration.
  *
- * @see <a href="http://en.wikipedia.org/wiki/Kahan_summation_algorithm">Kahan Summation Algorithm</a>
- *
  * @opensearch.experimental
+ * @see <a href="http://en.wikipedia.org/wiki/Kahan_summation_algorithm">Kahan Summation Algorithm</a>
  */
 class SumValueAggregator implements ValueAggregator<Double> {
 
@@ -67,11 +66,7 @@ public Double mergeAggregatedValues(Double value, Double aggregatedValue) {
         assert aggregatedValue == null || kahanSummation.value() == aggregatedValue;
         // add takes care of the sum and compensation internally
         if (value != null) {
-            if (value != null) {
-                kahanSummation.add(value);
-            } else {
-                kahanSummation.add(getIdentityMetricValue());
-            }
+            kahanSummation.add(value);
         } else {
             kahanSummation.add(getIdentityMetricValue());
         }

server/src/main/java/org/opensearch/index/compositeindex/datacube/startree/builder/BaseStarTreeBuilder.java

@@ -279,10 +279,11 @@ void appendDocumentsToStarTree(Iterator<StarTreeDocument> starTreeDocumentIterat
     private void serializeStarTree(int numSegmentStarTreeDocument, int numStarTreeDocs) throws IOException {
         // serialize the star tree data
         long dataFilePointer = dataOut.getFilePointer();
-        long totalStarTreeDataLength = StarTreeWriter.writeStarTree(dataOut, rootNode, numStarTreeNodes, starTreeField.getName());
+        StarTreeWriter starTreeWriter = new StarTreeWriter();
+        long totalStarTreeDataLength = starTreeWriter.writeStarTree(dataOut, rootNode, numStarTreeNodes, starTreeField.getName());
 
         // serialize the star tree meta
-        StarTreeWriter.writeStarTreeMetadata(
+        starTreeWriter.writeStarTreeMetadata(
             metaOut,
             starTreeField,
             metricAggregatorInfos,

server/src/main/java/org/opensearch/index/compositeindex/datacube/startree/builder/OnHeapStarTreeBuilder.java

@@ -125,7 +125,7 @@ Iterator<StarTreeDocument> mergeStarTrees(List<StarTreeValues> starTreeValuesSub
      * Returns an array of all the starTreeDocuments from all the segments
      * We only take the non-star documents from all the segments.
      *
-     * @param starTreeValuesSubs StarTreeValues from multiple segmentsx
+     * @param starTreeValuesSubs StarTreeValues from multiple segments
      * @return array of star tree documents
      */
     StarTreeDocument[] getSegmentsStarTreeDocuments(List<StarTreeValues> starTreeValuesSubs) throws IOException {

server/src/main/java/org/opensearch/index/compositeindex/datacube/startree/fileformats/StarTreeWriter.java

@@ -42,7 +42,7 @@ public StarTreeWriter() {}
      * @return total size of the three
      * @throws IOException when star-tree data serialization fails
      */
-    public static long writeStarTree(IndexOutput dataOut, InMemoryTreeNode rootNode, int numNodes, String name) throws IOException {
+    public long writeStarTree(IndexOutput dataOut, InMemoryTreeNode rootNode, int numNodes, String name) throws IOException {
         return StarTreeDataWriter.writeStarTree(dataOut, rootNode, numNodes, name);
     }
 
@@ -58,7 +58,7 @@ public static long writeStarTree(IndexOutput dataOut, InMemoryTreeNode rootNode,
      * @param dataFileLength          data file length
      * @throws IOException when star-tree data serialization fails
      */
-    public static void writeStarTreeMetadata(
+    public void writeStarTreeMetadata(
         IndexOutput metaOut,
         StarTreeField starTreeField,
         List<MetricAggregatorInfo> metricAggregatorInfos,