Move getMetadataFields to IndexService

CHANGELOG.md

@@ -33,6 +33,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 - Updated the `indices.query.bool.max_clause_count` setting from being static to dynamically updateable ([#13568](https://github.com/opensearch-project/OpenSearch/pull/13568))
 - Make the class CommunityIdProcessor final ([#14448](https://github.com/opensearch-project/OpenSearch/pull/14448))
 - Allow @InternalApi annotation on classes not meant to be constructed outside of the OpenSearch core ([#14575](https://github.com/opensearch-project/OpenSearch/pull/14575))
+- Move getMetadataFields to IndexService ([#14586](https://github.com/opensearch-project/OpenSearch/pull/14586))
 
 ### Deprecated
 

server/src/main/java/org/opensearch/index/IndexService.java

@@ -156,6 +156,7 @@ public class IndexService extends AbstractIndexComponent implements IndicesClust
     private final CheckedFunction<DirectoryReader, DirectoryReader, IOException> readerWrapper;
     private final IndexCache indexCache;
     private final MapperService mapperService;
+    private final MapperRegistry mapperRegistry;
     private final NamedXContentRegistry xContentRegistry;
     private final NamedWriteableRegistry namedWriteableRegistry;
     private final SimilarityService similarityService;
@@ -239,6 +240,7 @@ public IndexService(
         this.circuitBreakerService = circuitBreakerService;
         this.expressionResolver = expressionResolver;
         this.valuesSourceRegistry = valuesSourceRegistry;
+        this.mapperRegistry = mapperRegistry;
         if (needsMapperService(indexSettings, indexCreationContext)) {
             assert indexAnalyzers != null;
             this.mapperService = new MapperService(
@@ -1233,6 +1235,13 @@ private TimeValue getRefreshInterval() {
         return clusterDefaultRefreshIntervalSupplier.get();
     }
 
+    /**
+     * Returns a set containing the registered metadata fields
+     */
+    public Set<String> getMetadataFields() {
+        return Collections.unmodifiableSet(mapperRegistry.getMetadataMapperParsers().keySet());
+    }
+
     /**
      * Base asynchronous task
      *

server/src/main/java/org/opensearch/index/mapper/MapperService.java

@@ -714,13 +714,6 @@ public boolean isMetadataField(String field) {
         return mapperRegistry.isMetadataField(field);
     }
 
-    /**
-     * Returns a set containing the registered metadata fields
-     */
-    public Set<String> getMetadataFields() {
-        return Collections.unmodifiableSet(mapperRegistry.getMetadataMapperParsers().keySet());
-    }
-
     /**
      * An analyzer wrapper that can lookup fields within the index mappings
      */

server/src/test/java/org/opensearch/index/mapper/MapperServiceTests.java

@@ -92,8 +92,8 @@ public void testTypeValidation() {
     }
 
     public void testGetMetadataFieldsReturnsExpectedSet() throws Throwable {
-        final MapperService mapperService = createIndex("test1").mapperService();
-        assertEquals(mapperService.getMetadataFields(), IndicesModule.getBuiltInMetadataFields());
+        final IndexService indexService = createIndex("test1");
+        assertEquals(indexService.getMetadataFields(), IndicesModule.getBuiltInMetadataFields());
     }
 
     public void testPreflightUpdateDoesNotChangeMapping() throws Throwable {