turboFei commented on code in PR #3158: URL: https://github.com/apache/celeborn/pull/3158#discussion_r2004744738
########## common/src/main/scala/org/apache/celeborn/common/util/KeyLock.scala: ########## @@ -0,0 +1,70 @@ +/* + * 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.celeborn.common.util + +import java.util.concurrent.{Callable, ConcurrentHashMap} + +/** + * This class is copied from Apache Spark. + * A special locking mechanism to provide locking with a given key. By providing the same key + * (identity is tested using the `equals` method), we ensure there is only one `func` running at + * the same time. + * + * @tparam K the type of key to identify a lock. This type must implement `equals` and `hashCode` + * correctly as it will be the key type of an internal Map. + */ +class KeyLock[K] { + + private val lockMap = new ConcurrentHashMap[K, AnyRef]() + + private def acquireLock(key: K): Unit = { + while (true) { + val lock = lockMap.putIfAbsent(key, new Object) + if (lock == null) return + lock.synchronized { + while (lockMap.get(key) eq lock) { + lock.wait() + } + } + } + } + + private def releaseLock(key: K): Unit = { + val lock = lockMap.remove(key) + lock.synchronized { + lock.notifyAll() + } + } + + /** + * Run `func` under a lock identified by the given key. Multiple calls with the same key + * (identity is tested using the `equals` method) will be locked properly to ensure there is only + * one `func` running at the same time. + */ + def withLock[T](key: K)(func: Callable[T]): T = { + if (key == null) { + throw new NullPointerException("key must not be null") + } + acquireLock(key) + try { + func.call() + } finally { + releaseLock(key) + } + } +} Review Comment: copied from https://github.com/apache/spark/blob/8d260084b8a50ff59a127c7292c0cdb6737981b0/core/src/main/scala/org/apache/spark/util/KeyLock.scala for spark-2 -- 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]
