From e652170188fadfb5cece0365f6b60892d5279286 Mon Sep 17 00:00:00 2001
From: mushao999 <mushaoqiong@126.com>
Date: Fri, 29 Oct 2021 20:07:08 +0800
Subject: [PATCH] update code from David's suggestion

---
 .../action/admin/indices/segments/IndexSegments.java  | 11 +++--------
 .../indices/segments/IndicesSegmentResponse.java      | 11 +++++------
 2 files changed, 8 insertions(+), 14 deletions(-)

diff --git a/server/src/main/java/org/elasticsearch/action/admin/indices/segments/IndexSegments.java b/server/src/main/java/org/elasticsearch/action/admin/indices/segments/IndexSegments.java
index fe501e41f2d9a..3107727f5174d 100644
--- a/server/src/main/java/org/elasticsearch/action/admin/indices/segments/IndexSegments.java
+++ b/server/src/main/java/org/elasticsearch/action/admin/indices/segments/IndexSegments.java
@@ -23,17 +23,12 @@ public class IndexSegments implements Iterable<IndexShardSegments> {
     IndexSegments(String index, List<ShardSegments> shards) {
         this.index = index;
 
-        Map<Integer, List<ShardSegments>> tmpIndexShards = new HashMap<>();
+        final Map<Integer, List<ShardSegments>> segmentsByShardId = new HashMap<>();
         for (ShardSegments shard : shards) {
-            List<ShardSegments> lst = tmpIndexShards.get(shard.getShardRouting().id());
-            if (lst == null) {
-                lst = new ArrayList<>();
-                tmpIndexShards.put(shard.getShardRouting().id(), lst);
-            }
-            lst.add(shard);
+            segmentsByShardId.computeIfAbsent(shard.getShardRouting().id(), k -> new ArrayList<>()).add(shard);
         }
         indexShards = new HashMap<>();
-        for (Map.Entry<Integer, List<ShardSegments>> entry : tmpIndexShards.entrySet()) {
+        for (Map.Entry<Integer, List<ShardSegments>> entry : segmentsByShardId.entrySet()) {
             indexShards.put(
                 entry.getKey(),
                 new IndexShardSegments(
diff --git a/server/src/main/java/org/elasticsearch/action/admin/indices/segments/IndicesSegmentResponse.java b/server/src/main/java/org/elasticsearch/action/admin/indices/segments/IndicesSegmentResponse.java
index 340201be57b1a..32d264907c054 100644
--- a/server/src/main/java/org/elasticsearch/action/admin/indices/segments/IndicesSegmentResponse.java
+++ b/server/src/main/java/org/elasticsearch/action/admin/indices/segments/IndicesSegmentResponse.java
@@ -35,7 +35,7 @@ public class IndicesSegmentResponse extends BroadcastResponse {
 
     private final ShardSegments[] shards;
 
-    private Map<String, IndexSegments> indicesSegments;
+    private volatile Map<String, IndexSegments> indicesSegments;
 
     IndicesSegmentResponse(StreamInput in) throws IOException {
         super(in);
@@ -59,15 +59,14 @@ public Map<String, IndexSegments> getIndices() {
         }
         Map<String, IndexSegments> indicesSegments = new HashMap<>();
 
-        Map<String, List<ShardSegments>> tmpIndicesSegment = new HashMap<>();
+        final Map<String, List<ShardSegments>> segmentsByIndex = new HashMap<>();
         for (ShardSegments shard : shards) {
-            List<ShardSegments> indexSegments = tmpIndicesSegment.computeIfAbsent(
+            segmentsByIndex.computeIfAbsent(
                 shard.getShardRouting().getIndexName(),
                 k -> new ArrayList<>()
-            );
-            indexSegments.add(shard);
+            ).add(shard);
         }
-        for (Map.Entry<String, List<ShardSegments>> entry : tmpIndicesSegment.entrySet()) {
+        for (Map.Entry<String, List<ShardSegments>> entry : segmentsByIndex.entrySet()) {
             indicesSegments.put(entry.getKey(), new IndexSegments(entry.getKey(), entry.getValue()));
         }
         this.indicesSegments = indicesSegments;