Loop replace with Collection.removeIf() (#36351)

Author: igor-suhorukov

server/src/main/java/org/elasticsearch/common/settings/SettingsFilter.java

@@ -28,7 +28,6 @@
 import java.util.Collection;
 import java.util.Collections;
 import java.util.HashSet;
-import java.util.Iterator;
 import java.util.List;
 import java.util.Set;
 
@@ -104,13 +103,7 @@ private static Settings filterSettings(Iterable<String> patterns, Settings setti
         }
         if (!simpleMatchPatternList.isEmpty()) {
             String[] simpleMatchPatterns = simpleMatchPatternList.toArray(new String[simpleMatchPatternList.size()]);
-            Iterator<String> iterator = builder.keys().iterator();
-            while (iterator.hasNext()) {
-                String key = iterator.next();
-                if (Regex.simpleMatch(simpleMatchPatterns, key)) {
-                    iterator.remove();
-                }
-            }
+            builder.keys().removeIf(key -> Regex.simpleMatch(simpleMatchPatterns, key));
         }
         return builder.build();
     }

server/src/main/java/org/elasticsearch/discovery/zen/ElectMasterService.java

@@ -33,7 +33,6 @@
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Collection;
-import java.util.Iterator;
 import java.util.List;
 import java.util.Objects;
 import java.util.stream.Collectors;
@@ -206,12 +205,7 @@ private List<DiscoveryNode> sortedMasterNodes(Iterable<DiscoveryNode> nodes) {
             return null;
         }
         // clean non master nodes
-        for (Iterator<DiscoveryNode> it = possibleNodes.iterator(); it.hasNext(); ) {
-            DiscoveryNode node = it.next();
-            if (!node.isMasterNode()) {
-                it.remove();
-            }
-        }
+        possibleNodes.removeIf(node -> !node.isMasterNode());
         CollectionUtil.introSort(possibleNodes, ElectMasterService::compareNodes);
         return possibleNodes;
     }

server/src/main/java/org/elasticsearch/gateway/AsyncShardFetch.java

@@ -245,12 +245,7 @@ private void fillShardCacheWithDataNodes(Map<String, NodeEntry<T>> shardCache, D
             }
         }
         // remove nodes that are not longer part of the data nodes set
-        for (Iterator<String> it = shardCache.keySet().iterator(); it.hasNext(); ) {
-            String nodeId = it.next();
-            if (nodes.nodeExists(nodeId) == false) {
-                it.remove();
-            }
-        }
+        shardCache.keySet().removeIf(nodeId -> !nodes.nodeExists(nodeId));
     }
 
     /**

server/src/main/java/org/elasticsearch/indices/store/IndicesStore.java

@@ -65,7 +65,6 @@
 import java.util.ArrayList;
 import java.util.EnumSet;
 import java.util.HashSet;
-import java.util.Iterator;
 import java.util.List;
 import java.util.Set;
 import java.util.concurrent.TimeUnit;
@@ -135,12 +134,7 @@ public void clusterChanged(ClusterChangedEvent event) {
         // remove entries from cache that don't exist in the routing table anymore (either closed or deleted indices)
         // - removing shard data of deleted indices is handled by IndicesClusterStateService
         // - closed indices don't need to be removed from the cache but we do it anyway for code simplicity
-        for (Iterator<ShardId> it = folderNotFoundCache.iterator(); it.hasNext(); ) {
-            ShardId shardId = it.next();
-            if (routingTable.hasIndex(shardId.getIndex()) == false) {
-                it.remove();
-            }
-        }
+        folderNotFoundCache.removeIf(shardId -> !routingTable.hasIndex(shardId.getIndex()));
         // remove entries from cache which are allocated to this node
         final String localNodeId = event.state().nodes().getLocalNodeId();
         RoutingNode localRoutingNode = event.state().getRoutingNodes().node(localNodeId);

server/src/test/java/org/elasticsearch/index/translog/TranslogTests.java

@@ -2188,14 +2188,8 @@ protected void afterAdd() throws IOException {
             Collections.sort(writtenOperations, (a, b) -> a.location.compareTo(b.location));
             assertFalse(translog.isOpen());
             final Checkpoint checkpoint = Checkpoint.read(config.getTranslogPath().resolve(Translog.CHECKPOINT_FILE_NAME));
-            Iterator<LocationOperation> iterator = writtenOperations.iterator();
-            while (iterator.hasNext()) {
-                LocationOperation next = iterator.next();
-                if (checkpoint.offset < (next.location.translogLocation + next.location.size)) {
-                    // drop all that haven't been synced
-                    iterator.remove();
-                }
-            }
+            // drop all that haven't been synced
+            writtenOperations.removeIf(next -> checkpoint.offset < (next.location.translogLocation + next.location.size));
             try (Translog tlog =
                      new Translog(config, translogUUID, createTranslogDeletionPolicy(),
                          () -> SequenceNumbers.NO_OPS_PERFORMED, primaryTerm::get);