philipnee commented on code in PR #12663: URL: https://github.com/apache/kafka/pull/12663#discussion_r982820685
########## clients/src/main/java/org/apache/kafka/clients/consumer/internals/AbstractPrototypeAsyncConsumer.java: ########## @@ -0,0 +1,119 @@ +/* + * 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.clients.consumer.Consumer; +import org.apache.kafka.clients.consumer.ConsumerRecords; +import org.apache.kafka.clients.consumer.internals.events.ApplicationEvent; +import org.apache.kafka.clients.consumer.internals.events.BackgroundEvent; +import org.apache.kafka.clients.consumer.internals.events.EventHandler; +import org.apache.kafka.common.utils.Time; + +import java.time.Duration; +import java.util.Optional; +import java.util.concurrent.CompletableFuture; +import java.util.concurrent.ExecutionException; +import java.util.concurrent.TimeUnit; +import java.util.concurrent.TimeoutException; + +/** + * This is the prototype of the consumer that uses the {@link EventHandler} to process application events. + */ +public abstract class AbstractPrototypeAsyncConsumer<K, V> implements Consumer<K, V> { + private final EventHandler eventHandler; + private final Time time; + + public AbstractPrototypeAsyncConsumer(final Time time, final EventHandler eventHandler) { + this.eventHandler = eventHandler; + this.time = time; + } + + /** + * poll implementation using {@link EventHandler}. + * 1. Poll for background events. If there's a fetch response event, process the record and return it. If it is + * another type of event, process it. + * 2. Send fetches if needed. + * If the timeout expires, return an empty ConsumerRecord. + * @param timeout timeout of the poll loop + * @return ConsumerRecord. It can be empty if time timeout expires. + */ + @Override + public ConsumerRecords<K, V> poll(final Duration timeout) { + try { + do { + if (!eventHandler.isEmpty()) { + Optional<BackgroundEvent> backgroundEvent = eventHandler.poll(); + if (backgroundEvent.isPresent()) { + if (isFetchResult(backgroundEvent.get())) { + // return fetches + return processFetchResult(backgroundEvent.get()); + } + processEvent(backgroundEvent.get(), timeout); // might trigger callbacks or handle exceptions + } + } + + maybeSendFetches(); // send new fetches Review Comment: Thanks, @hachikuji - removed this line per your comment. -- 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
