1 package org.apache.commons.jcs3.engine;
2
3 /*
4 * Licensed to the Apache Software Foundation (ASF) under one
5 * or more contributor license agreements. See the NOTICE file
6 * distributed with this work for additional information
7 * regarding copyright ownership. The ASF licenses this file
8 * to you under the Apache License, Version 2.0 (the
9 * "License"); you may not use this file except in compliance
10 * with the License. You may obtain a copy of the License at
11 *
12 * http://www.apache.org/licenses/LICENSE-2.0
13 *
14 * Unless required by applicable law or agreed to in writing,
15 * software distributed under the License is distributed on an
16 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
17 * KIND, either express or implied. See the License for the
18 * specific language governing permissions and limitations
19 * under the License.
20 */
21
22 import java.util.Objects;
23
24 import org.apache.commons.jcs3.engine.behavior.ICacheElement;
25 import org.apache.commons.jcs3.engine.behavior.IElementAttributes;
26
27 /**
28 * Generic element wrapper. Often stuffed inside another.
29 */
30 public class CacheElement<K, V>
31 implements ICacheElement<K, V>
32 {
33 /** Don't change */
34 private static final long serialVersionUID = -6062305728297627263L;
35
36 /** The name of the cache region. This is a namespace. */
37 private final String cacheName;
38
39 /** This is the cache key by which the value can be referenced. */
40 private final K key;
41
42 /** This is the cached value, reference by the key. */
43 private final V val;
44
45 /**
46 * These attributes hold information about the element and what it is
47 * allowed to do.
48 */
49 private IElementAttributes attr;
50
51 /**
52 * Constructor for the CacheElement object
53 * <p>
54 * @param cacheName
55 * @param key
56 * @param val
57 */
58 public CacheElement( final String cacheName, final K key, final V val )
59 {
60 this.cacheName = cacheName;
61 this.key = key;
62 this.val = val;
63 }
64
65 /**
66 * Constructor for the CacheElement object
67 * <p>
68 * @param cacheName
69 * @param key
70 * @param val
71 * @param attrArg
72 */
73 public CacheElement( final String cacheName, final K key, final V val, final IElementAttributes attrArg )
74 {
75 this(cacheName, key, val);
76 this.attr = attrArg;
77 }
78
79 /**
80 * Gets the cacheName attribute of the CacheElement object
81 * <p>
82 * @return The cacheName value
83 */
84 @Override
85 public String getCacheName()
86 {
87 return this.cacheName;
88 }
89
90 /**
91 * Gets the key attribute of the CacheElement object
92 * <p>
93 * @return The key value
94 */
95 @Override
96 public K getKey()
97 {
98 return this.key;
99 }
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 }