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.lang3.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 1436770 2013-01-22 07:09:45Z ggregory $
27 */
28 public class MutableObject<T> implements Mutable<T>, 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 T 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 the initial value to store
51 */
52 public MutableObject(final T value) {
53 super();
54 this.value = value;
55 }
56
57 //-----------------------------------------------------------------------
58 /**
59 * Gets the value.
60 *
61 * @return the value, may be null
62 */
63 @Override
64 public T getValue() {
65 return this.value;
66 }
67
68 /**
69 * Sets the value.
70 *
71 * @param value the value to set
72 */
73 @Override
74 public void setValue(final T value) {
75 this.value = value;
76 }
77
78 //-----------------------------------------------------------------------
79 /**
80 * <p>
81 * Compares this object against the specified object. The result is <code>true</code> if and only if the argument
82 * is not <code>null</code> and is a <code>MutableObject</code> object that contains the same <code>T</code>
83 * value as this object.
84 * </p>
85 *
86 * @param obj the object to compare with, <code>null</code> returns <code>false</code>
87 * @return <code>true</code> if the objects are the same;
88 * <code>true</code> if the objects have equivalent <code>value</code> fields;
89 * <code>false</code> otherwise.
90 */
91 @Override
92 public boolean equals(final Object obj) {
93 if (obj == null) {
94 return false;
95 }
96 if (this == obj) {
97 return true;
98 }
99 if (this.getClass() == obj.getClass()) {
100 final MutableObject<?> that = (MutableObject<?>) obj;
101 return this.value.equals(that.value);
102 } else {
103 return false;
104 }
105 }
106
107 /**
108 * Returns the value's hash code or <code>0</code> if the value is <code>null</code>.
109 *
110 * @return the value's hash code or <code>0</code> if the value is <code>null</code>.
111 */
112 @Override
113 public int hashCode() {
114 return value == null ? 0 : value.hashCode();
115 }
116
117 //-----------------------------------------------------------------------
118 /**
119 * Returns the String value of this mutable.
120 *
121 * @return the mutable value as a string
122 */
123 @Override
124 public String toString() {
125 return value == null ? "null" : value.toString();
126 }
127
128 }