content: /*
   * 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.server;
  
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  import java.util.concurrent.ConcurrentLinkedQueue;
  
  /**
   * This queue is used to collect actions which need to be executed later. One use case is that ReplicaManager#appendRecords
   * produces record changes, so we need to check and complete delayed requests. In order to avoid conflicting locking,
   * we add those actions to this queue and then complete them at the end of KafkaApis.handle() or DelayedJoin.onExpiration.
   */
  public class DelayedActionQueue implements ActionQueue {
      private static final Logger LOGGER = LoggerFactory.getLogger(DelayedActionQueue.class);
      private final ConcurrentLinkedQueue<Runnable> queue = new ConcurrentLinkedQueue<>();
  
      @Override
      public void add(Runnable action) {
          queue.add(action);
      }
  
      @Override
      public void tryCompleteActions() {
          int maxToComplete = queue.size();
          for (int count = 0; count < maxToComplete; count++) {
              try {
                  Runnable action = queue.poll();
                  if (action == null) return;
                  action.run();
              } catch (Throwable e) {
                  LOGGER.error("failed to complete delayed actions", e);
              }
          }
      }
  }
  