001    /**
002     * Licensed to the Apache Software Foundation (ASF) under one or more
003     * contributor license agreements.  See the NOTICE file distributed with
004     * this work for additional information regarding copyright ownership.
005     * The ASF licenses this file to You under the Apache License, Version 2.0
006     * (the "License"); you may not use this file except in compliance with
007     * the License.  You may obtain a copy of the License at
008     *
009     *      http://www.apache.org/licenses/LICENSE-2.0
010     *
011     * Unless required by applicable law or agreed to in writing, software
012     * distributed under the License is distributed on an "AS IS" BASIS,
013     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014     * See the License for the specific language governing permissions and
015     * limitations under the License.
016     */
017    package org.apache.activemq.memory;
018    
019    public class CacheEntry {
020    
021        public final Object key;
022        public final Object value;
023    
024        public CacheEntry next;
025        public CacheEntry previous;
026        public CacheEntryList owner;
027    
028        public CacheEntry(Object key, Object value) {
029            this.key = key;
030            this.value = value;
031        }
032    
033        /**
034         * 
035         * @param entry
036         * @return false if you are trying to remove the tail pointer.
037         */
038        public boolean remove() {
039    
040            // Cannot remove if this is a tail pointer.
041            // Or not linked.
042            if (owner == null || this.key == null || this.next == null) {
043                return false;
044            }
045    
046            synchronized (owner.tail) {
047                this.next.previous = this.previous;
048                this.previous.next = this.next;
049                this.owner = null;
050                this.next = null;
051                this.previous = null;
052            }
053    
054            return true;
055        }
056    
057    }