kirktrue commented on code in PR #14359: URL: https://github.com/apache/kafka/pull/14359#discussion_r1325038436
########## clients/src/main/java/org/apache/kafka/clients/consumer/internals/FetchBuffer.java: ########## @@ -0,0 +1,143 @@ +/* + * 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.clients.consumer.internals; + +import org.apache.kafka.common.TopicPartition; +import org.apache.kafka.common.internals.IdempotentCloser; +import org.apache.kafka.common.utils.LogContext; +import org.slf4j.Logger; + +import java.io.Closeable; +import java.util.Collection; +import java.util.HashSet; +import java.util.Set; +import java.util.concurrent.ConcurrentLinkedQueue; +import java.util.function.Predicate; + +/** + * {@code FetchBuffer} buffers up the results from the broker responses as they are received. It is essentially a + * wrapper around a {@link java.util.Queue} of {@link CompletedFetch}. + * + * <p/> + * + * <em>Note</em>: this class is not thread-safe and is intended to only be used from a single thread. + */ +public class FetchBuffer implements Closeable { + + private final Logger log; + private final ConcurrentLinkedQueue<CompletedFetch> completedFetches; + private final IdempotentCloser idempotentCloser = new IdempotentCloser(); + + private CompletedFetch nextInLineFetch; + + public FetchBuffer(final LogContext logContext) { + this.log = logContext.logger(FetchBuffer.class); + this.completedFetches = new ConcurrentLinkedQueue<>(); + } + + /** + * Returns {@code true} if there are no completed fetches pending to return to the user. + * + * @return {@code true} if the buffer is empty, {@code false} otherwise + */ + boolean isEmpty() { + return completedFetches.isEmpty(); + } + + /** + * Return whether we have any completed fetches pending return to the user. This method is thread-safe. Has + * visibility for testing. + * + * @return {@code true} if there are completed fetches that match the {@link Predicate}, {@code false} otherwise + */ + boolean hasCompletedFetches(Predicate<CompletedFetch> predicate) { + return completedFetches.stream().anyMatch(predicate); + } + + void add(CompletedFetch completedFetch) { + completedFetches.add(completedFetch); + } + + void addAll(Collection<CompletedFetch> completedFetches) { + this.completedFetches.addAll(completedFetches); + } + + CompletedFetch nextInLineFetch() { + return nextInLineFetch; + } + + void setNextInLineFetch(CompletedFetch completedFetch) { + this.nextInLineFetch = completedFetch; + } + + CompletedFetch peek() { + return completedFetches.peek(); + } + + CompletedFetch poll() { + return completedFetches.poll(); + } + + /** + * Updates the buffer to retain only the fetch data that corresponds to the given partitions. Any previously + * {@link CompletedFetch fetched data} is removed if its partition is not in the given set of partitions. + * + * @param partitions {@link Set} of {@link TopicPartition}s for which any buffered data should be kept + */ + void retainAll(final Set<TopicPartition> partitions) { + completedFetches.removeIf(cf -> maybeDrain(partitions, cf)); + + if (maybeDrain(partitions, nextInLineFetch)) + nextInLineFetch = null; + } + + boolean maybeDrain(final Set<TopicPartition> partitions, final CompletedFetch completedFetch) { + if (completedFetch != null && !partitions.contains(completedFetch.partition)) { + log.debug("Removing {} from buffered fetch data as it is not in the set of partitions to retain ({})", completedFetch.partition, partitions); + completedFetch.drain(); + return true; + } else { + return false; + } + } + + Set<TopicPartition> partitions() { Review Comment: Done. -- 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
