rondagostino commented on code in PR #13280: URL: https://github.com/apache/kafka/pull/13280#discussion_r1161329362
########## server-common/src/main/java/org/apache/kafka/server/immutable/ImmutableMap.java: ########## @@ -0,0 +1,47 @@ +/* + * Licensed to the Apache Software Foundation (ASF) under one or more + * contributor license agreements. See the NOTICE file distributed with + * this work for additional information regarding copyright ownership. + * The ASF 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.apache.kafka.server.immutable; + +import java.util.Map; + +/** + * A persistent Hash-based Map wrapper. + * java.util.Map methods that mutate in-place will throw UnsupportedOperationException + * + * @param <K> the key type + * @param <V> the value type + */ +public interface ImmutableMap<K, V> extends Map<K, V> { Review Comment: If we add static methods here then those methods would have to hard-code which underlying library to use. Right now we just have PCollections because it meets a mandatory requirement for the ACL lock removal work, but it is possible we might find either a need or a significant performance advantage to using something else for some use case. Any static methods here might have to have the underlying library in the name. For example, a method name here might be `emptyMapPCollections()` (or `pCollectionsEmptyMap()`. I assumed it was easy for clients to just explicitly invoke `PCOLLECTIONS_FACTORY.emptySet()` (for example) -- or, more likely, they would have access to the factory already (like `TopicsImage` does as it declares `private static final ImmutableMapSetFactory FACTORY = ImmutableMapSetFactory.PCOLLECTIONS_FACTORY;`) and could invoke `FACTORY.emptySet()`. -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: jira-unsubscr...@kafka.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org
