Implement WithFieldName interface in ValuesSourceAggregationBuilder & FieldSortBuilder (opensearch-project#15916)

Signed-off-by: David Zane <davizane@amazon.com>

Author: dzane17

CHANGELOG.md

@@ -8,6 +8,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 - MultiTermQueries in keyword fields now default to `indexed` approach and gated behind cluster setting ([#15637](https://github.com/opensearch-project/OpenSearch/pull/15637))
 - [Workload Management] QueryGroup resource cancellation framework changes ([#15651](https://github.com/opensearch-project/OpenSearch/pull/15651))
 - Fallback to Remote cluster-state on Term-Version check mismatch - ([#15424](https://github.com/opensearch-project/OpenSearch/pull/15424))
+- Implement WithFieldName interface in ValuesSourceAggregationBuilder & FieldSortBuilder ([#15916](https://github.com/opensearch-project/OpenSearch/pull/15916))
 
 ### Dependencies
 - Bump `com.azure:azure-identity` from 1.13.0 to 1.13.2 ([#15578](https://github.com/opensearch-project/OpenSearch/pull/15578))

server/src/main/java/org/opensearch/search/aggregations/support/ValuesSourceAggregationBuilder.java

@@ -40,6 +40,7 @@
 import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.query.QueryShardContext;
+import org.opensearch.index.query.WithFieldName;
 import org.opensearch.script.Script;
 import org.opensearch.search.aggregations.AbstractAggregationBuilder;
 import org.opensearch.search.aggregations.AggregationInitializationException;
@@ -57,7 +58,9 @@
  *
  * @opensearch.internal
  */
-public abstract class ValuesSourceAggregationBuilder<AB extends ValuesSourceAggregationBuilder<AB>> extends AbstractAggregationBuilder<AB> {
+public abstract class ValuesSourceAggregationBuilder<AB extends ValuesSourceAggregationBuilder<AB>> extends AbstractAggregationBuilder<AB>
+    implements
+        WithFieldName {
 
     public static <T> void declareFields(
         AbstractObjectParser<? extends ValuesSourceAggregationBuilder<?>, T> objectParser,
@@ -292,6 +295,11 @@ public String field() {
         return field;
     }
 
+    @Override
+    public String fieldName() {
+        return field();
+    }
+
     /**
      * Sets the script to use for this aggregation.
      */

server/src/main/java/org/opensearch/search/sort/FieldSortBuilder.java

@@ -65,6 +65,7 @@
 import org.opensearch.index.query.QueryRewriteContext;
 import org.opensearch.index.query.QueryShardContext;
 import org.opensearch.index.query.QueryShardException;
+import org.opensearch.index.query.WithFieldName;
 import org.opensearch.search.DocValueFormat;
 import org.opensearch.search.MultiValueMode;
 import org.opensearch.search.SearchSortValuesAndFormats;
@@ -86,7 +87,7 @@
  *
  * @opensearch.internal
  */
-public class FieldSortBuilder extends SortBuilder<FieldSortBuilder> {
+public class FieldSortBuilder extends SortBuilder<FieldSortBuilder> implements WithFieldName {
     private static final DeprecationLogger deprecationLogger = DeprecationLogger.getLogger(FieldSortBuilder.class);
 
     public static final String NAME = "field_sort";
@@ -184,6 +185,11 @@ public String getFieldName() {
         return this.fieldName;
     }
 
+    @Override
+    public String fieldName() {
+        return getFieldName();
+    }
+
     /**
      * Sets the value when a field is missing in a doc. Can also be set to {@code _last} or
      * {@code _first} to sort missing last or first respectively.

server/src/test/java/org/opensearch/search/aggregations/bucket/range/RangeAggregationBuilderTests.java

@@ -128,6 +128,7 @@ public void testNumericKeys() throws IOException {
         );
         assertThat(builder.getName(), equalTo("test"));
         assertThat(builder.field(), equalTo("f"));
+        assertThat(builder.fieldName(), equalTo("f"));
         assertThat(builder.ranges, equalTo(List.of(new RangeAggregator.Range("1", null, 0d))));
     }
 }

server/src/test/java/org/opensearch/search/sort/FieldSortBuilderTests.java

@@ -196,6 +196,7 @@ protected void sortFieldAssertions(FieldSortBuilder builder, SortField sortField
         assertEquals(builder.order() == SortOrder.ASC ? false : true, sortField.getReverse());
         if (expectedType == SortField.Type.CUSTOM) {
             assertEquals(builder.getFieldName(), sortField.getField());
+            assertEquals(builder.fieldName(), sortField.getField());
         }
         assertEquals(DocValueFormat.RAW, format);
     }