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.util.timer;
  
  public final class TimerTaskEntry {
      public final TimerTask timerTask;
      public final long expirationMs;
      volatile TimerTaskList list;
      TimerTaskEntry next;
      TimerTaskEntry prev;
  
      public TimerTaskEntry(
          TimerTask timerTask,
          long expirationMs
      ) {
          this.timerTask = timerTask;
          this.expirationMs = expirationMs;
  
          // if this timerTask is already held by an existing timer task entry,
          // setTimerTaskEntry will remove it.
          if (timerTask != null) {
              timerTask.setTimerTaskEntry(this);
          }
      }
  
      public boolean cancelled() {
          return timerTask.getTimerTaskEntry() != this;
      }
  
      public void remove() {
          TimerTaskList currentList = list;
          // If remove is called when another thread is moving the entry from a task entry list to another,
          // this may fail to remove the entry due to the change of value of list. Thus, we retry until the list becomes null.
          // In a rare case, this thread sees null and exits the loop, but the other thread insert the entry to another list later.
          while (currentList != null) {
              currentList.remove(this);
              currentList = list;
          }
      }
  }
  