Cleanup some Dead Code in o.e.index.store (#52045)

One obviously unused method and an incorrect Javadoc that
referenced an otherwise unused class.

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

@@ -53,7 +53,6 @@ import org.elasticsearch.index.shard.IndexEventListener;
 import org.elasticsearch.index.shard.IndexingOperationListener;
 import org.elasticsearch.index.shard.SearchOperationListener;
 import org.elasticsearch.index.similarity.SimilarityService;
-import org.elasticsearch.index.store.DirectoryService;
 import org.elasticsearch.index.store.FsDirectoryFactory;
 import org.elasticsearch.indices.IndicesQueryCache;
 import org.elasticsearch.indices.breaker.CircuitBreakerService;
@@ -85,7 +84,8 @@ import java.util.function.Function;
  *     {@link #addSimilarity(String, TriFunction)} while existing Providers can be referenced through Settings under the
  *     {@link IndexModule#SIMILARITY_SETTINGS_PREFIX} prefix along with the "type" value.  For example, to reference the
  *     {@link BM25Similarity}, the configuration {@code "index.similarity.my_similarity.type : "BM25"} can be used.</li>
- *      <li>{@link DirectoryService} - Custom {@link DirectoryService} instances can be registered via {@link IndexStorePlugin}</li>
+ *      <li>{@link IndexStorePlugin.DirectoryFactory} - Custom {@link IndexStorePlugin.DirectoryFactory} instances can be registered
+ *      via {@link IndexStorePlugin}</li>
  *      <li>{@link IndexEventListener} - Custom {@link IndexEventListener} instances can be registered via
  *      {@link #addIndexEventListener(IndexEventListener)}</li>
  *      <li>Settings update listener - Custom settings update listener can be registered via

server/src/main/java/org/elasticsearch/index/store/DirectoryService.java

@@ -1,36 +0,0 @@
-/*
- * Licensed to Elasticsearch under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *    http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-
-package org.elasticsearch.index.store;
-
-import org.apache.lucene.store.Directory;
-import org.elasticsearch.index.IndexSettings;
-import org.elasticsearch.index.shard.AbstractIndexShardComponent;
-import org.elasticsearch.index.shard.ShardId;
-
-import java.io.IOException;
-
-public abstract class DirectoryService extends AbstractIndexShardComponent {
-
-    protected DirectoryService(ShardId shardId, IndexSettings indexSettings) {
-        super(shardId, indexSettings);
-    }
-
-    public abstract Directory newDirectory() throws IOException;
-}

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

@@ -208,18 +208,6 @@ public class Store extends AbstractIndexShardComponent implements Closeable, Ref
 
     }
 
-    /**
-     * Loads the maximum sequence number and local checkpoint from the given Lucene commit point or the latest if not provided.
-     *
-     * @param commit the commit point to load seqno stats, or the last commit in the store if the parameter is null
-     * @return {@link SequenceNumbers.CommitInfo} containing information about the last commit
-     * @throws IOException if an I/O exception occurred reading the latest Lucene commit point from disk
-     */
-    public static SequenceNumbers.CommitInfo loadSeqNoInfo(final IndexCommit commit) throws IOException {
-        final Map<String, String> userData = commit.getUserData();
-        return SequenceNumbers.loadSeqNoInfoFromLuceneCommit(userData.entrySet());
-    }
-
     final void ensureOpen() {
         if (this.refCounter.refCount() <= 0) {
             throw new AlreadyClosedException("store is already closed");