kirktrue commented on code in PR #14359: URL: https://github.com/apache/kafka/pull/14359#discussion_r1327394904
########## clients/src/main/java/org/apache/kafka/common/internals/IdempotentCloser.java: ########## @@ -0,0 +1,127 @@ +/* + * 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.common.internals; + +import java.util.concurrent.atomic.AtomicBoolean; +import java.util.function.Supplier; + +/** + * {@code IdempotentCloser} encapsulates some basic logic to ensure that a given resource is only closed once. + * It provides methods to invoke callbacks (via optional {@link Runnable}s) for either the <em>initial</em> close + * and/or any <em>subsequent</em> closes. + * + * <p/> + * + * Here's an example: + * + * <pre> + * + * public class MyDataFile implements Closeable { + * + * private final IdempotentCloser closer = new IdempotentCloser(); + * + * private final File file; + * + * . . . + * + * public boolean write() { + * closer.maybeThrowIllegalStateException(() -> String.format("Data file %s already closed!", file)); + * writeToFile(); + * } + * + * + * public boolean isClosed() { + * return closer.isClosed(); + * } + * + * @Override + * public void close() { + * Runnable onInitialClose = () -> { + * cleanUpFile(file); + * log.debug("Data file {} closed", file); + * }; + * Runnable onSubsequentClose = () -> { + * log.warn("Data file {} already closed!", file); + * }; + * closer.close(onInitialClose, onSubsequentClose); + * } + * } + * </pre> + * + * Note that the callbacks are optional and if unused operates as a simple means to ensure resources + * are only closed once. + */ +public class IdempotentCloser implements AutoCloseable { + + private final AtomicBoolean isClosed; + + /** + * Creates an {@code IdempotentCloser} that is not yet closed. + */ + public IdempotentCloser() { + this(false); + } + + /** + * Creates an {@code IdempotentCloser} with the given initial state. + * + * @param isClosed Initial value for underlying state + */ + public IdempotentCloser(boolean isClosed) { + this.isClosed = new AtomicBoolean(isClosed); + } + + public void maybeThrowIllegalStateException(Supplier<String> message) { Review Comment: Agreed! -- 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
