cmccabe commented on a change in pull request #10030: URL: https://github.com/apache/kafka/pull/10030#discussion_r569818530
########## File path: metadata/src/main/java/org/apache/kafka/queue/KafkaEventQueue.java ########## @@ -0,0 +1,420 @@ +/* + * 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.queue; + +import java.util.HashMap; +import java.util.Map; +import java.util.Objects; +import java.util.TreeMap; +import java.util.concurrent.TimeUnit; +import java.util.concurrent.locks.Condition; +import java.util.concurrent.locks.ReentrantLock; +import java.util.function.Function; +import org.apache.kafka.common.errors.TimeoutException; +import org.apache.kafka.common.utils.KafkaThread; +import org.apache.kafka.common.utils.LogContext; +import org.apache.kafka.common.utils.Time; +import org.slf4j.Logger; + + +public final class KafkaEventQueue implements EventQueue { + /** + * A context object that wraps events. + */ + private static class EventContext { + /** + * The caller-supplied event. + */ + private final Event event; + + /** + * How this event was inserted. + */ + private final EventInsertionType insertionType; + + /** + * The previous pointer of our circular doubly-linked list. + */ + private EventContext prev = this; + + /** + * The next pointer in our circular doubly-linked list. + */ + private EventContext next = this; + + /** + * If this event is in the delay map, this is the key it is there under. + * If it is not in the map, this is null. + */ + private Long deadlineNs = null; + + /** + * The tag associated with this event. + */ + private String tag; + + EventContext(Event event, EventInsertionType insertionType, String tag) { + this.event = event; + this.insertionType = insertionType; + this.tag = tag; + } + + /** + * Insert a new node in the circularly linked list after this node. Review comment: I think it's pretty standard for linked list insertion functions to overwrite the existing prev and next pointers of the object being inserted ---------------------------------------------------------------- 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. For queries about this service, please contact Infrastructure at: us...@infra.apache.org
