dcapwell commented on code in PR #4556: URL: https://github.com/apache/cassandra/pull/4556#discussion_r2729713251
########## src/java/org/apache/cassandra/service/thresholds/CoordinatorWarningsState.java: ########## @@ -0,0 +1,192 @@ +/* + * 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.cassandra.service.thresholds; + +import java.util.function.BiConsumer; +import java.util.function.Consumer; +import java.util.function.Supplier; + +import javax.annotation.Nullable; + +import org.slf4j.Logger; + +import io.netty.util.concurrent.FastThreadLocal; + +/** + * Generic ThreadLocal state manager for coordinator warnings. + * Provides lifecycle management (init, update, done, reset) for accumulating + * warnings across a client request. + * + * @param <S> the type of state to manage (e.g., Map, custom holder class) + */ +public class CoordinatorWarningsState<S> +{ + private final FastThreadLocal<S> threadLocal; + private final S initSentinel; + private final S emptySentinel; + private final Supplier<S> stateFactory; + private final Logger logger; + private final String name; + private final boolean enableDefensiveChecks; + + /** + * Creates a new coordinator warnings state manager. + * + * @param name descriptive name for logging + * @param initSentinel sentinel value indicating initialized but empty state + * @param emptySentinel sentinel value indicating cleared state + * @param stateFactory factory to create new mutable state instances + * @param logger logger for diagnostic messages + * @param enableDefensiveChecks whether to enable defensive checks + */ + public CoordinatorWarningsState(String name, + S initSentinel, + @Nullable S emptySentinel, + Supplier<S> stateFactory, + Logger logger, + boolean enableDefensiveChecks) + { + this.name = name; + this.initSentinel = initSentinel; + this.emptySentinel = emptySentinel; + this.stateFactory = stateFactory; + this.logger = logger; + this.enableDefensiveChecks = enableDefensiveChecks; + this.threadLocal = new FastThreadLocal<>(); + } + + /** + * Initialize state for this thread. + * Must be called at the start of a client request. + */ + public void init() + { + if (logger.isTraceEnabled()) + logger.trace("{}.init()", name); + + S current = threadLocal.get(); + if (current != null && enableDefensiveChecks) + { + throw new AssertionError(name + ".init called while state is not null: " + current); + } + threadLocal.set(initSentinel); + } + + /** + * Reset/clear state for this thread. + */ + public void reset() + { + if (logger.isTraceEnabled()) + logger.trace("{}.reset()", name); + + if (emptySentinel != null) + threadLocal.set(emptySentinel); + else + threadLocal.remove(); + } + + /** + * Get current state, creating mutable state if needed. + * Transitions from initSentinel to mutable state on first access. + * + * @param fallbackSupplier supplies fallback state if not initialized + * @return current mutable state + */ + public S getMutableState(Supplier<S> fallbackSupplier) Review Comment: https://cassandra.apache.org/_/development/code_style.html We dislike `get` methods, and prefer names like `mutable` (`mutableState` is verbose as we are working with state, so redundant) -- 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: [email protected] For queries about this service, please contact Infrastructure at: [email protected] --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
