Resolve comments

Signed-off-by: xuxiong1 <[email protected]>

Author: xuxiong1

CHANGELOG.md

@@ -9,6 +9,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 - Add temporal routing processors for time-based document routing ([#18920](https://github.com/opensearch-project/OpenSearch/issues/18920))
 - The dynamic mapping parameter supports false_allow_templates ([#19065](https://github.com/opensearch-project/OpenSearch/pull/19065))
 - Add a toBuilder method in EngineConfig to support easy modification of configs([#19054](https://github.com/opensearch-project/OpenSearch/pull/19054))
+- Add StoreFactory plugin interface for custom Store implementations([#19091](https://github.com/opensearch-project/OpenSearch/pull/19091))
 
 ### Changed
 - Add CompletionStage variants to methods in the Client Interface and default to ActionListener impl ([#18998](https://github.com/opensearch-project/OpenSearch/pull/18998))

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

@@ -311,7 +311,7 @@ public IndexModule(
         this.allowExpensiveQueries = allowExpensiveQueries;
         this.expressionResolver = expressionResolver;
         this.recoveryStateFactories = recoveryStateFactories;
-        this.storeFactories = storeFactories == null ? Collections.emptyMap() : Collections.unmodifiableMap(storeFactories);
+        this.storeFactories = storeFactories;
         this.fileCache = fileCache;
         this.compositeIndexSettings = compositeIndexSettings;
     }
@@ -880,14 +880,14 @@ private static IndexStorePlugin.StoreFactory resolveStoreFactory(
         final Map<String, IndexStorePlugin.StoreFactory> storeFactories
     ) {
         final String key = indexSettings.getValue(INDEX_STORE_FACTORY_SETTING);
-        if (key != null && key.isEmpty() == false) {
-            final IndexStorePlugin.StoreFactory factory = storeFactories.get(key);
-            if (factory == null) {
-                throw new IllegalArgumentException("Unknown store factory [" + key + "]");
-            }
-            return factory;
+        if (key == null || key.isEmpty()) {
+            return Store::new;
         }
-        return Store::new;
+        final IndexStorePlugin.StoreFactory factory = storeFactories.get(key);
+        if (factory == null) {
+            throw new IllegalArgumentException("Unknown store factory [" + key + "]");
+        }
+        return factory;
     }
 
     /**

server/src/main/java/org/opensearch/index/store/Store.java

@@ -1082,7 +1082,7 @@ public long getNumDocs() {
          *
          * @opensearch.api
          */
-        @PublicApi(since = "3.1.0")
+        @PublicApi(since = "3.2.0")
         public static class LoadedMetadata {
             public final Map<String, StoreFileMetadata> fileMetadata;
             public final Map<String, String> userData;
@@ -1735,7 +1735,7 @@ public void markStoreCorrupted(IOException exception) throws IOException {
      *
      * @opensearch.api
      */
-    @PublicApi(since = "3.1.0")
+    @PublicApi(since = "3.2.0")
     public interface OnClose extends Consumer<ShardLock> {
         OnClose EMPTY = new OnClose() {
             /**