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.activemq.memory;
  
  public class CacheEntry {
  
      public final Object key;
      public final Object value;
  
      public CacheEntry next;
      public CacheEntry previous;
      public CacheEntryList owner;
  
      public CacheEntry(Object key, Object value) {
          this.key = key;
          this.value = value;
      }
  
      /**
       * @return false if you are trying to remove the tail pointer.
       */
      public boolean remove() {
  
          // Cannot remove if this is a tail pointer.
          // Or not linked.
          if (owner == null || this.key == null || this.next == null) {
              return false;
          }
  
          synchronized (owner.tail) {
              this.next.previous = this.previous;
              this.previous.next = this.next;
              this.owner = null;
              this.next = null;
              this.previous = null;
          }
  
          return true;
      }
  }
  