[Rename] ElasticsearchReaderManager class in server module (#180)

This commit refactors ElasticsearchReaderManager class in the server module to
OpenSearchReaderManager. References and usages throughout the rest of the
codebase are fully refactored.

Signed-off-by: Nicholas Knize <nknize@amazon.com>

server/src/main/java/org/elasticsearch/index/engine/InternalEngine.java

@@ -135,7 +135,7 @@ public class InternalEngine extends Engine {
     private final IndexWriter indexWriter;
 
     private final ExternalReaderManager externalReaderManager;
-    private final ElasticsearchReaderManager internalReaderManager;
+    private final OpenSearchReaderManager internalReaderManager;
 
     private final Lock flushLock = new ReentrantLock();
     private final ReentrantLock optimizeLock = new ReentrantLock();
@@ -220,7 +220,7 @@ public InternalEngine(EngineConfig engineConfig) {
         IndexWriter writer = null;
         Translog translog = null;
         ExternalReaderManager externalReaderManager = null;
-        ElasticsearchReaderManager internalReaderManager = null;
+        OpenSearchReaderManager internalReaderManager = null;
         EngineMergeScheduler scheduler = null;
         boolean success = false;
         try {
@@ -348,10 +348,10 @@ public CompletionStats completionStats(String... fieldNamePatterns) {
     @SuppressForbidden(reason = "reference counting is required here")
     private static final class ExternalReaderManager extends ReferenceManager<OpenSearchDirectoryReader> {
         private final BiConsumer<OpenSearchDirectoryReader, OpenSearchDirectoryReader> refreshListener;
-        private final ElasticsearchReaderManager internalReaderManager;
+        private final OpenSearchReaderManager internalReaderManager;
         private boolean isWarmedUp; //guarded by refreshLock
 
-        ExternalReaderManager(ElasticsearchReaderManager internalReaderManager,
+        ExternalReaderManager(OpenSearchReaderManager internalReaderManager,
                               BiConsumer<OpenSearchDirectoryReader, OpenSearchDirectoryReader> refreshListener) throws IOException {
             this.refreshListener = refreshListener;
             this.internalReaderManager = internalReaderManager;
@@ -635,12 +635,12 @@ private String loadHistoryUUID(Map<String, String> commitData) {
 
     private ExternalReaderManager createReaderManager(RefreshWarmerListener externalRefreshListener) throws EngineException {
         boolean success = false;
-        ElasticsearchReaderManager internalReaderManager = null;
+        OpenSearchReaderManager internalReaderManager = null;
         try {
             try {
                 final OpenSearchDirectoryReader directoryReader =
                     OpenSearchDirectoryReader.wrap(DirectoryReader.open(indexWriter), shardId);
-                internalReaderManager = new ElasticsearchReaderManager(directoryReader,
+                internalReaderManager = new OpenSearchReaderManager(directoryReader,
                     new RamAccountingRefreshListener(engineConfig.getCircuitBreakerService()));
                 lastCommittedSegmentInfos = store.readLastCommittedSegmentsInfo();
                 ExternalReaderManager externalReaderManager = new ExternalReaderManager(internalReaderManager, externalRefreshListener);

server/src/main/java/org/elasticsearch/index/engine/ElasticsearchReaderManager.java → server/src/main/java/org/elasticsearch/index/engine/OpenSearchReaderManager.java

@@ -38,19 +38,19 @@
  *
  */
 @SuppressForbidden(reason = "reference counting is required here")
-class ElasticsearchReaderManager extends ReferenceManager<OpenSearchDirectoryReader> {
+class OpenSearchReaderManager extends ReferenceManager<OpenSearchDirectoryReader> {
     private final BiConsumer<OpenSearchDirectoryReader, OpenSearchDirectoryReader> refreshListener;
 
     /**
-     * Creates and returns a new ElasticsearchReaderManager from the given
+     * Creates and returns a new OpenSearchReaderManager from the given
      * already-opened {@link OpenSearchDirectoryReader}, stealing
      * the incoming reference.
      *
      * @param reader            the directoryReader to use for future reopens
      * @param refreshListener   A consumer that is called every time a new reader is opened
      */
-    ElasticsearchReaderManager(OpenSearchDirectoryReader reader,
-                               BiConsumer<OpenSearchDirectoryReader, OpenSearchDirectoryReader> refreshListener) {
+    OpenSearchReaderManager(OpenSearchDirectoryReader reader,
+                            BiConsumer<OpenSearchDirectoryReader, OpenSearchDirectoryReader> refreshListener) {
         this.current = reader;
         this.refreshListener = refreshListener;
         refreshListener.accept(current, null);

server/src/main/java/org/elasticsearch/index/engine/ReadOnlyEngine.java

@@ -67,7 +67,7 @@ public class ReadOnlyEngine extends Engine {
      */
     private final SegmentInfos lastCommittedSegmentInfos;
     private final SeqNoStats seqNoStats;
-    private final ElasticsearchReaderManager readerManager;
+    private final OpenSearchReaderManager readerManager;
     private final IndexCommit indexCommit;
     private final Lock indexWriterLock;
     private final RamAccountingRefreshListener refreshListener;
@@ -114,7 +114,7 @@ public ReadOnlyEngine(EngineConfig config, SeqNoStats seqNoStats, TranslogStats
                 this.seqNoStats = seqNoStats;
                 this.indexCommit = Lucene.getIndexCommit(lastCommittedSegmentInfos, directory);
                 reader = wrapReader(open(indexCommit), readerWrapperFunction);
-                readerManager = new ElasticsearchReaderManager(reader, refreshListener);
+                readerManager = new OpenSearchReaderManager(reader, refreshListener);
                 assert translogStats != null || obtainLock : "mutiple translogs instances should not be opened at the same time";
                 this.translogStats = translogStats != null ? translogStats : translogStats(config, lastCommittedSegmentInfos);
                 this.indexWriterLock = indexWriterLock;