szetszwo commented on code in PR #5853: URL: https://github.com/apache/ozone/pull/5853#discussion_r1435717402
########## hadoop-hdds/common/src/main/java/org/apache/hadoop/hdds/resource/LeakDetector.java: ########## @@ -0,0 +1,102 @@ +/* + * 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.hadoop.hdds.resource; + +import org.slf4j.Logger; +import org.slf4j.LoggerFactory; + +import java.lang.ref.ReferenceQueue; +import java.util.Collections; +import java.util.Set; +import java.util.concurrent.ConcurrentHashMap; + +/** + * Simple general resource leak detector using {@link ReferenceQueue} and {@link java.lang.ref.WeakReference} to + * observe resource object life-cycle and assert proper resource closure before they are GCed. + * + * <p> + * Example usage: + * + * <pre> {@code + * class MyResource implements AutoClosable { + * static final LeakDetector LEAK_DETECTOR = new LeakDetector("MyResource"); + * + * private final LeakTracker leakTracker = LEAK_DETECTOR.track(this, () -> { + * // report leaks, don't refer to the original object (MyResource) here. + * System.out.println("MyResource is not closed before being discarded."); + * }); + * + * @Override + * public void close() { + * // proper resources cleanup... + * // inform tracker that this object is closed properly. + * leakTracker.close(); + * } + * } + * + * }</pre> + */ +public class LeakDetector implements Runnable { + public static final Logger LOG = LoggerFactory.getLogger(LeakDetector.class); + private final ReferenceQueue<Object> queue = new ReferenceQueue<>(); + private final Set<LeakTracker> allLeaks = Collections.newSetFromMap(new ConcurrentHashMap<>()); Review Comment: Thanks for the info! Good to know. Then, we will need a data structure to hold the references. -- 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]
