001package org.apache.commons.jcs3.engine; 002 003/* 004 * Licensed to the Apache Software Foundation (ASF) under one 005 * or more contributor license agreements. See the NOTICE file 006 * distributed with this work for additional information 007 * regarding copyright ownership. The ASF licenses this file 008 * to you under the Apache License, Version 2.0 (the 009 * "License"); you may not use this file except in compliance 010 * with the License. You may obtain a copy of the License at 011 * 012 * http://www.apache.org/licenses/LICENSE-2.0 013 * 014 * Unless required by applicable law or agreed to in writing, 015 * software distributed under the License is distributed on an 016 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY 017 * KIND, either express or implied. See the License for the 018 * specific language governing permissions and limitations 019 * under the License. 020 */ 021 022import java.util.Objects; 023 024import org.apache.commons.jcs3.engine.behavior.ICacheElement; 025import org.apache.commons.jcs3.engine.behavior.IElementAttributes; 026 027/** 028 * Generic element wrapper. Often stuffed inside another. 029 */ 030public class CacheElement<K, V> 031 implements ICacheElement<K, V> 032{ 033 /** Don't change */ 034 private static final long serialVersionUID = -6062305728297627263L; 035 036 /** The name of the cache region. This is a namespace. */ 037 private final String cacheName; 038 039 /** This is the cache key by which the value can be referenced. */ 040 private final K key; 041 042 /** This is the cached value, reference by the key. */ 043 private final V val; 044 045 /** 046 * These attributes hold information about the element and what it is 047 * allowed to do. 048 */ 049 private IElementAttributes attr; 050 051 /** 052 * Constructor for the CacheElement object 053 * <p> 054 * @param cacheName 055 * @param key 056 * @param val 057 */ 058 public CacheElement( final String cacheName, final K key, final V val ) 059 { 060 this.cacheName = cacheName; 061 this.key = key; 062 this.val = val; 063 } 064 065 /** 066 * Constructor for the CacheElement object 067 * <p> 068 * @param cacheName 069 * @param key 070 * @param val 071 * @param attrArg 072 */ 073 public CacheElement( final String cacheName, final K key, final V val, final IElementAttributes attrArg ) 074 { 075 this(cacheName, key, val); 076 this.attr = attrArg; 077 } 078 079 /** 080 * Gets the cacheName attribute of the CacheElement object 081 * <p> 082 * @return The cacheName value 083 */ 084 @Override 085 public String getCacheName() 086 { 087 return this.cacheName; 088 } 089 090 /** 091 * Gets the key attribute of the CacheElement object 092 * <p> 093 * @return The key value 094 */ 095 @Override 096 public K getKey() 097 { 098 return this.key; 099 } 100 101 /** 102 * Gets the val attribute of the CacheElement object 103 * <p> 104 * @return The val value 105 */ 106 @Override 107 public V getVal() 108 { 109 return this.val; 110 } 111 112 /** 113 * Sets the attributes attribute of the CacheElement object 114 * <p> 115 * @param attr 116 * The new IElementAttributes value 117 */ 118 @Override 119 public void setElementAttributes( final IElementAttributes attr ) 120 { 121 this.attr = attr; 122 } 123 124 /** 125 * Gets the IElementAttributes attribute of the CacheElement object 126 * <p> 127 * @return The IElementAttributes value, never null 128 */ 129 @Override 130 public IElementAttributes getElementAttributes() 131 { 132 // create default attributes if they are null 133 // this shouldn't happen, but could if a corrupt 134 // object was sent over the wire. 135 if ( this.attr == null ) 136 { 137 this.attr = new ElementAttributes(); 138 } 139 return this.attr; 140 } 141 142 /** 143 * @param obj other object 144 * @return true if this object key equals the key of obj 145 */ 146 @Override 147 public boolean equals(final Object obj) 148 { 149 if (this == obj) 150 { 151 return true; 152 } 153 if (!(obj instanceof CacheElement)) 154 { 155 return false; 156 } 157 final CacheElement<?,?> other = (CacheElement<?,?>) obj; 158 return Objects.equals(key, other.key); 159 } 160 161 /** 162 * @return a hash of the key only 163 */ 164 @Override 165 public int hashCode() 166 { 167 return key.hashCode(); 168 } 169 170 /** 171 * For debugging only. 172 * <p> 173 * @return String representation 174 */ 175 @Override 176 public String toString() 177 { 178 return "[CacheElement: cacheName [" + cacheName + "], key [" + key + "], val [" + val + "], attr [" + attr 179 + "]"; 180 } 181}