Github user fmthoma commented on a diff in the pull request: https://github.com/apache/flink/pull/6021#discussion_r192861127 --- Diff: flink-connectors/flink-connector-kinesis/src/main/java/org/apache/flink/streaming/connectors/kinesis/util/TimeoutLatch.java --- @@ -0,0 +1,41 @@ +/* + * 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.flink.streaming.connectors.kinesis.util; + +public class TimeoutLatch { + + private final Object lock = new Object(); + private volatile boolean waiting; + + public void await(long timeout) throws InterruptedException { + synchronized (lock) { + waiting = true; + lock.wait(timeout); + } + } + + public void trigger() { + if (waiting) { + synchronized (lock) { + waiting = false; --- End diff -- Why? I don't think a double-check lock is necessary here: There is no harm in setting a variable to `false` that is already `false`, and neither in `notify`ing a lock for which nobody is `wait`ing. But sure, it wouldn't harm, either. Do you insist?
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