Simplify OpenSearchIndexScanBuilder

opensearch/src/main/java/org/opensearch/sql/opensearch/storage/OpenSearchIndex.java

@@ -10,6 +10,7 @@
 import java.util.HashMap;
 import java.util.LinkedHashMap;
 import java.util.Map;
+import java.util.function.Function;
 import lombok.RequiredArgsConstructor;
 import org.opensearch.common.unit.TimeValue;
 import org.opensearch.sql.common.setting.Settings;
@@ -33,7 +34,6 @@
 import org.opensearch.sql.planner.logical.LogicalPlan;
 import org.opensearch.sql.planner.physical.PhysicalPlan;
 import org.opensearch.sql.storage.Table;
-import org.opensearch.sql.storage.TableScanOperator;
 import org.opensearch.sql.storage.read.TableScanBuilder;
 
 /** OpenSearch table (index) implementation. */
@@ -171,19 +171,14 @@ public PhysicalPlan implement(LogicalPlan plan) {
   public TableScanBuilder createScanBuilder() {
     final int querySizeLimit = settings.getSettingValue(Settings.Key.QUERY_SIZE_LIMIT);
 
+    final TimeValue cursorKeepAlive = settings.getSettingValue(Settings.Key.SQL_CURSOR_KEEP_ALIVE);
     var builder = new OpenSearchRequestBuilder(
         querySizeLimit,
         createExprValueFactory());
-
-    return new OpenSearchIndexScanBuilder(builder) {
-      @Override
-      protected TableScanOperator createScan(OpenSearchRequestBuilder requestBuilder) {
-        final TimeValue cursorKeepAlive =
-            settings.getSettingValue(Settings.Key.SQL_CURSOR_KEEP_ALIVE);
-        return new OpenSearchIndexScan(client, requestBuilder.getMaxResponseSize(),
-            requestBuilder.build(indexName, getMaxResultWindow(), cursorKeepAlive));
-      }
-    };
+    Function<OpenSearchRequestBuilder, OpenSearchIndexScan> createScanOperator =
+        requestBuilder -> new OpenSearchIndexScan(client, requestBuilder.getMaxResponseSize(),
+        requestBuilder.build(indexName, getMaxResultWindow(), cursorKeepAlive));
+    return new OpenSearchIndexScanBuilder(builder, createScanOperator);
   }
 
   private OpenSearchExprValueFactory createExprValueFactory() {

opensearch/src/main/java/org/opensearch/sql/opensearch/storage/scan/OpenSearchIndexScanBuilder.java

@@ -5,6 +5,7 @@
 
 package org.opensearch.sql.opensearch.storage.scan;
 
+import java.util.function.Function;
 import lombok.EqualsAndHashCode;
 import org.opensearch.sql.expression.ReferenceExpression;
 import org.opensearch.sql.opensearch.request.OpenSearchRequestBuilder;
@@ -24,8 +25,9 @@
  * by delegated builder internally. This is to avoid conditional check of different push down logic
  * for non-aggregate and aggregate query everywhere.
  */
-public abstract class OpenSearchIndexScanBuilder extends TableScanBuilder {
+public class OpenSearchIndexScanBuilder extends TableScanBuilder {
 
+  private final Function<OpenSearchRequestBuilder, OpenSearchIndexScan> scanFactory;
   /**
    * Delegated index scan builder for non-aggregate or aggregate query.
    */
@@ -38,25 +40,27 @@ public abstract class OpenSearchIndexScanBuilder extends TableScanBuilder {
   /**
    * Constructor used during query execution.
    */
-  protected OpenSearchIndexScanBuilder(OpenSearchRequestBuilder requestBuilder) {
+  public OpenSearchIndexScanBuilder(OpenSearchRequestBuilder requestBuilder,
+      Function<OpenSearchRequestBuilder, OpenSearchIndexScan> scanFactory) {
     this.delegate = new OpenSearchIndexScanQueryBuilder(requestBuilder);
+    this.scanFactory = scanFactory;
 
   }
 
   /**
    * Constructor used for unit tests.
    */
-  protected OpenSearchIndexScanBuilder(PushDownQueryBuilder translator) {
+  protected OpenSearchIndexScanBuilder(PushDownQueryBuilder translator,
+      Function<OpenSearchRequestBuilder, OpenSearchIndexScan> scanFactory) {
     this.delegate = translator;
+    this.scanFactory = scanFactory;
   }
 
   @Override
   public TableScanOperator build() {
-    return createScan(delegate.build());
+    return scanFactory.apply(delegate.build());
   }
 
-  protected abstract TableScanOperator createScan(OpenSearchRequestBuilder requestBuilder);
-
   @Override
   public boolean pushDownFilter(LogicalFilter filter) {
     return delegate.pushDownFilter(filter);

opensearch/src/test/java/org/opensearch/sql/opensearch/storage/scan/OpenSearchIndexScanOptimizationTest.java

@@ -7,7 +7,6 @@
 package org.opensearch.sql.opensearch.storage.scan;
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
-import static org.junit.jupiter.api.Assertions.assertThrows;
 import static org.mockito.Mockito.mock;
 import static org.mockito.Mockito.reset;
 import static org.mockito.Mockito.times;
@@ -86,7 +85,6 @@
 import org.opensearch.sql.planner.optimizer.PushDownPageSize;
 import org.opensearch.sql.planner.optimizer.rule.read.CreateTableScanBuilder;
 import org.opensearch.sql.storage.Table;
-import org.opensearch.sql.storage.TableScanOperator;
 
 @ExtendWith(MockitoExtension.class)
 class OpenSearchIndexScanOptimizationTest {
@@ -106,12 +104,7 @@ class OpenSearchIndexScanOptimizationTest {
 
   @BeforeEach
   void setUp() {
-    indexScanBuilder = new OpenSearchIndexScanBuilder(requestBuilder) {
-      @Override
-      protected TableScanOperator createScan(OpenSearchRequestBuilder build) {
-        return indexScan;
-      }
-    };
+    indexScanBuilder = new OpenSearchIndexScanBuilder(requestBuilder, requestBuilder -> indexScan);
     when(table.createScanBuilder()).thenReturn(indexScanBuilder);
   }
 
@@ -698,23 +691,15 @@ void project_literal_should_not_be_pushed_down() {
 
   private OpenSearchIndexScanBuilder indexScanBuilder(Runnable... verifyPushDownCalls) {
     this.verifyPushDownCalls = verifyPushDownCalls;
-    return new OpenSearchIndexScanBuilder(new OpenSearchIndexScanQueryBuilder(requestBuilder)) {
-      @Override
-      protected TableScanOperator createScan(OpenSearchRequestBuilder build) {
-        return indexScan;
-      }
-    };
+    return new OpenSearchIndexScanBuilder(new OpenSearchIndexScanQueryBuilder(requestBuilder),
+        requestBuilder -> indexScan);
   }
 
   private OpenSearchIndexScanBuilder indexScanAggBuilder(Runnable... verifyPushDownCalls) {
     this.verifyPushDownCalls = verifyPushDownCalls;
-    return new OpenSearchIndexScanBuilder(new OpenSearchIndexScanAggregationBuilder(
-        requestBuilder, mock(LogicalAggregation.class))) {
-      @Override
-      protected TableScanOperator createScan(OpenSearchRequestBuilder build) {
-        return indexScan;
-      }
-    };
+    var aggregationBuilder = new OpenSearchIndexScanAggregationBuilder(
+        requestBuilder, mock(LogicalAggregation.class));
+    return new OpenSearchIndexScanBuilder(aggregationBuilder, builder -> indexScan);
   }
 
   private void assertEqualsAfterOptimization(LogicalPlan expected, LogicalPlan actual) {