Immutable collections

alexey-ivanov-es · Dec 9, 2024 · 0292929 · 0292929
1 parent 9174a3d
commit 0292929
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Showing 2 changed files with 6 additions and 8 deletions.
diff --git a/server/src/main/java/org/elasticsearch/TransportVersion.java b/server/src/main/java/org/elasticsearch/TransportVersion.java
@@ -16,14 +16,14 @@
 import org.elasticsearch.plugins.ExtensionLoader;
 
 import java.io.IOException;
-import java.util.ArrayList;
 import java.util.Collection;
 import java.util.Collections;
 import java.util.List;
 import java.util.Map;
 import java.util.ServiceLoader;
 import java.util.function.Function;
 import java.util.stream.Collectors;
+import java.util.stream.Stream;
 
 /**
  * Represents the version of the wire protocol used to communicate between a pair of ES nodes.
@@ -172,14 +172,12 @@ private static class VersionsHolder {
             if (extendedVersions.isEmpty()) {
                 ALL_VERSIONS = TransportVersions.DEFINED_VERSIONS;
             } else {
-                List<TransportVersion> allVersions = new ArrayList<>(TransportVersions.DEFINED_VERSIONS.size() + extendedVersions.size());
-                allVersions.addAll(TransportVersions.DEFINED_VERSIONS);
-                allVersions.addAll(extendedVersions);
-                Collections.sort(allVersions);
-                ALL_VERSIONS = Collections.unmodifiableList(allVersions);
+                ALL_VERSIONS = Stream.concat(TransportVersions.DEFINED_VERSIONS.stream(), extendedVersions.stream())
+                    .sorted()
+                    .toList();
             }
 
-            ALL_VERSIONS_MAP = ALL_VERSIONS.stream().collect(Collectors.toMap(TransportVersion::id, Function.identity()));
+            ALL_VERSIONS_MAP = ALL_VERSIONS.stream().collect(Collectors.toUnmodifiableMap(TransportVersion::id, Function.identity()));
 
             CURRENT = ALL_VERSIONS.getLast();
         }

diff --git a/server/src/main/java/org/elasticsearch/TransportVersions.java b/server/src/main/java/org/elasticsearch/TransportVersions.java
@@ -260,7 +260,7 @@ public static List<TransportVersion> collectAllVersionIdsDefinedInClass(Class<?>
 
         Collections.sort(definedTransportVersions);
 
-        return Collections.unmodifiableList(definedTransportVersions);
+        return List.copyOf(definedTransportVersions);
     }
 
     static final IntFunction<String> VERSION_LOOKUP = ReleaseVersions.generateVersionsLookup(TransportVersions.class, LATEST_DEFINED.id());