Refactoring

Signed-off-by: Sarthak Aggarwal <sarthagg@amazon.com>

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

@@ -21,15 +21,15 @@ public class MetricTypeFieldPair implements Comparable<MetricTypeFieldPair> {
     public static final String STAR = "*";
     public static final MetricTypeFieldPair COUNT_STAR = new MetricTypeFieldPair(MetricType.COUNT, STAR);
 
-    private final MetricType functionType;
+    private final MetricType metricType;
     private final String field;
 
     /**
      * Constructor for MetricTypeFieldPair
      */
-    public MetricTypeFieldPair(MetricType functionType, String field) {
-        this.functionType = functionType;
-        if (functionType == MetricType.COUNT) {
+    public MetricTypeFieldPair(MetricType metricType, String field) {
+        this.metricType = metricType;
+        if (metricType == MetricType.COUNT) {
             this.field = STAR;
         } else {
             this.field = field;
@@ -39,8 +39,8 @@ public MetricTypeFieldPair(MetricType functionType, String field) {
     /**
      * @return Metric Type
      */
-    public MetricType getFunctionType() {
-        return functionType;
+    public MetricType getMetricType() {
+        return metricType;
     }
 
     /**
@@ -51,42 +51,42 @@ public String getField() {
     }
 
     /**
-     * @return field name with function type and field
+     * @return field name with metric type and field
      */
     public String toFieldName() {
-        return toFieldName(functionType, field);
+        return toFieldName(metricType, field);
     }
 
     /**
-     * Builds field name with function type and field
+     * Builds field name with metric type and field
      */
-    public static String toFieldName(MetricType functionType, String field) {
-        return functionType.getTypeName() + DELIMITER + field;
+    public static String toFieldName(MetricType metricType, String field) {
+        return metricType.getTypeName() + DELIMITER + field;
     }
 
     /**
      * Builds MetricTypeFieldPair from field name
      */
     public static MetricTypeFieldPair fromFieldName(String fieldName) {
         String[] parts = fieldName.split(DELIMITER, 2);
-        return fromFunctionAndFieldName(parts[0], parts[1]);
+        return fromMetricAndFieldName(parts[0], parts[1]);
     }
 
     /**
-     * Builds MetricTypeFieldPair from function and field name
+     * Builds MetricTypeFieldPair from metric and field name
      */
-    private static MetricTypeFieldPair fromFunctionAndFieldName(String functionName, String fieldName) {
-        MetricType functionType = MetricType.fromTypeName(functionName);
-        if (functionType == MetricType.COUNT) {
+    private static MetricTypeFieldPair fromMetricAndFieldName(String metricName, String fieldName) {
+        MetricType metricType = MetricType.fromTypeName(metricName);
+        if (metricType == MetricType.COUNT) {
             return COUNT_STAR;
         } else {
-            return new MetricTypeFieldPair(functionType, fieldName);
+            return new MetricTypeFieldPair(metricType, fieldName);
         }
     }
 
     @Override
     public int hashCode() {
-        return 31 * functionType.hashCode() + field.hashCode();
+        return 31 * metricType.hashCode() + field.hashCode();
     }
 
     @Override
@@ -96,7 +96,7 @@ public boolean equals(Object obj) {
         }
         if (obj instanceof MetricTypeFieldPair) {
             MetricTypeFieldPair anotherPair = (MetricTypeFieldPair) obj;
-            return functionType == anotherPair.functionType && field.equals(anotherPair.field);
+            return metricType == anotherPair.metricType && field.equals(anotherPair.field);
         }
         return false;
     }
@@ -109,7 +109,7 @@ public String toString() {
     @Override
     public int compareTo(MetricTypeFieldPair other) {
         return Comparator.comparing((MetricTypeFieldPair o) -> o.field)
-            .thenComparing((MetricTypeFieldPair o) -> o.functionType)
+            .thenComparing((MetricTypeFieldPair o) -> o.metricType)
             .compare(this, other);
     }
 }

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

@@ -8,6 +8,7 @@
 package org.opensearch.index.compositeindex.startree.aggregators;
 
 import org.opensearch.index.compositeindex.MetricType;
+import org.opensearch.index.compositeindex.startree.data.DataType;
 
 /**
  * Sum value aggregator for star tree

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

@@ -8,6 +8,7 @@
 package org.opensearch.index.compositeindex.startree.aggregators;
 
 import org.opensearch.index.compositeindex.MetricType;
+import org.opensearch.index.compositeindex.startree.data.DataType;
 
 /**
  * A value aggregator that pre-aggregates on the input values for a specific type of aggregation.

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

@@ -8,6 +8,7 @@
 package org.opensearch.index.compositeindex.startree.aggregators;
 
 import org.opensearch.index.compositeindex.MetricType;
+import org.opensearch.index.compositeindex.startree.data.DataType;
 
 /**
  * Value aggregator factory for a given aggregation type

server/src/main/java/org/opensearch/index/compositeindex/startree/builder/CompositeFieldWriter.java → server/src/main/java/org/opensearch/index/compositeindex/startree/builder/SingleTreeBuilder.java

@@ -8,6 +8,8 @@
 
 package org.opensearch.index.compositeindex.startree.builder;
 
+import org.opensearch.index.compositeindex.startree.data.StarTreeDocValues;
+
 import java.io.Closeable;
 import java.io.IOException;
 import java.util.List;
@@ -16,7 +18,7 @@
  * A star-tree builder that builds a single star-tree.
  * @opensearch.experimental
  */
-public interface CompositeFieldWriter extends Closeable {
+public interface SingleTreeBuilder extends Closeable {
 
     /**
      * Builds the data structure for the given composite index config.

server/src/main/java/org/opensearch/index/compositeindex/startree/aggregators/DataType.java → server/src/main/java/org/opensearch/index/compositeindex/startree/data/DataType.java

@@ -5,7 +5,7 @@
  * this file be licensed under the Apache-2.0 license or a
  * compatible open source license.
  */
-package org.opensearch.index.compositeindex.startree.aggregators;
+package org.opensearch.index.compositeindex.startree.data;
 
 /**
  * Data type of doc values

server/src/main/java/org/opensearch/index/compositeindex/startree/builder/StarTreeDocValues.java → server/src/main/java/org/opensearch/index/compositeindex/startree/data/StarTreeDocValues.java

@@ -5,7 +5,7 @@
  * this file be licensed under the Apache-2.0 license or a
  * compatible open source license.
  */
-package org.opensearch.index.compositeindex.startree.builder;
+package org.opensearch.index.compositeindex.startree.data;
 
 import org.apache.lucene.index.SortedNumericDocValues;
 import org.opensearch.index.compositeindex.startree.node.StarTree;

server/src/main/java/org/opensearch/index/compositeindex/startree/data/StarTreeDocument.java

@@ -0,0 +1,29 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.index.compositeindex.startree.data;
+
+import java.util.Arrays;
+
+/**
+ * Star tree document
+ */
+public class StarTreeDocument {
+    public final long[] dimensions;
+    public final Object[] metrics;
+
+    public StarTreeDocument(long[] dimensions, Object[] metrics) {
+        this.dimensions = dimensions;
+        this.metrics = metrics;
+    }
+
+    @Override
+    public String toString() {
+        return Arrays.toString(dimensions) + " | " + Arrays.toString(metrics);
+    }
+}

server/src/main/java/org/opensearch/index/compositeindex/startree/node/StarTreeNode.java

@@ -12,6 +12,7 @@
 
 /**
  * Class representing each node in star tree
+ * The interface is implemented by build-mode based nodes
  * @opensearch.experimental
  */
 public interface StarTreeNode {

server/src/main/java/org/opensearch/index/compositeindex/startree/utils/StarTreeBuilderUtils.java

@@ -37,17 +37,17 @@ public class StarTreeBuilderUtils {
 
     private StarTreeBuilderUtils() {}
 
-    public static final int INVALID_ID = -1;
+    public static final int ALL = -1;
     public static final long MAGIC_MARKER = 0xBADDA55B00DAD00DL;
 
     /** Tree node representation */
     public static class TreeNode {
-        public int dimensionId = INVALID_ID;
-        public long dimensionValue = INVALID_ID;
-        public int startDocId = INVALID_ID;
-        public int endDocId = INVALID_ID;
-        public int aggregatedDocId = INVALID_ID;
-        public int childDimensionId = INVALID_ID;
+        public int dimensionId = ALL;
+        public long dimensionValue = ALL;
+        public int startDocId = ALL;
+        public int endDocId = ALL;
+        public int aggregatedDocId = ALL;
+        public int childDimensionId = ALL;
         public Map<Long, TreeNode> children;
     }
 
@@ -100,7 +100,7 @@ static void writeNodes(IndexOutput output, TreeNode rootNode) throws IOException
             TreeNode node = queue.remove();
 
             if (node.children == null) {
-                writeNode(output, node, INVALID_ID, INVALID_ID);
+                writeNode(output, node, ALL, ALL);
             } else {
                 // Sort all children nodes based on dimension value
                 List<TreeNode> sortedChildren = new ArrayList<>(node.children.values());