1 /*
2 * Licensed to the Apache Software Foundation (ASF) under one or more
3 * contributor license agreements. See the NOTICE file distributed with
4 * this work for additional information regarding copyright ownership.
5 * The ASF licenses this file to You under the Apache License, Version 2.0
6 * (the "License"); you may not use this file except in compliance with
7 * the License. You may obtain a copy of the License at
8 *
9 * http://www.apache.org/licenses/LICENSE-2.0
10 *
11 * Unless required by applicable law or agreed to in writing, software
12 * distributed under the License is distributed on an "AS IS" BASIS,
13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 * See the License for the specific language governing permissions and
15 * limitations under the License.
16 */
17
18 package org.apache.commons.lang.mutable;
19
20 import java.io.Serializable;
21
22 /**
23 * A mutable <code>Object</code> wrapper.
24 *
25 * @since 2.1
26 * @version $Id: MutableObject.java 437554 2006-08-28 06:21:41Z bayard $
27 */
28 public class MutableObject implements Mutable, Serializable {
29
30 /**
31 * Required for serialization support.
32 *
33 * @see java.io.Serializable
34 */
35 private static final long serialVersionUID = 86241875189L;
36
37 /** The mutable value. */
38 private Object value;
39
40 /**
41 * Constructs a new MutableObject with the default value of <code>null</code>.
42 */
43 public MutableObject() {
44 super();
45 }
46
47 /**
48 * Constructs a new MutableObject with the specified value.
49 *
50 * @param value
51 * a value.
52 */
53 public MutableObject(Object value) {
54 super();
55 this.value = value;
56 }
57
58 //-----------------------------------------------------------------------
59 /**
60 * Gets the value.
61 *
62 * @return the value
63 */
64 public Object getValue() {
65 return this.value;
66 }
67
68 /**
69 * Sets the value.
70 *
71 * @param value
72 * the value to set
73 */
74 public void setValue(Object value) {
75 this.value = value;
76 }
77
78 //-----------------------------------------------------------------------
79 /**
80 * Compares this object against the specified object. The result is <code>true</code> if and only if the argument
81 * is not <code>null</code> and is a <code>MutableObject</code> object that contains the same <code>Object</code>
82 * value as this object.
83 *
84 * @param obj
85 * the object to compare with.
86 * @return <code>true</code> if the objects are the same; <code>false</code> otherwise.
87 */
88 public boolean equals(Object obj) {
89 if (obj instanceof MutableObject) {
90 Object other = ((MutableObject) obj).value;
91 return value == other || (value != null && value.equals(other));
92 }
93 return false;
94 }
95
96 /**
97 * Returns the value's hash code or <code>0</code> if the value is <code>null</code>.
98 *
99 * @return the value's hash code or <code>0</code> if the value is <code>null</code>.
100 */
101 public int hashCode() {
102 return value == null ? 0 : value.hashCode();
103 }
104
105 /**
106 * Returns the String value of this mutable.
107 *
108 * @return the mutable value as a string
109 */
110 public String toString() {
111 return value == null ? "null" : value.toString();
112 }
113
114 }