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 import java.util.Objects;
22
23 /**
24 * A mutable {@link Object} wrapper.
25 *
26 * @param <T> the type to set and get
27 * @since 2.1
28 */
29 public class MutableObject<T> implements Mutable<T>, Serializable {
30
31 /**
32 * Required for serialization support.
33 *
34 * @see java.io.Serializable
35 */
36 private static final long serialVersionUID = 86241875189L;
37
38 /** The mutable value. */
39 private T value;
40
41 /**
42 * Constructs a new MutableObject with the default value of {@code null}.
43 */
44 public MutableObject() {
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 this.value = value;
54 }
55
56 /**
57 * Compares this object against the specified object. The result is {@code true} if and only if the argument
58 * is not {@code null} and is a {@link MutableObject} object that contains the same {@link T}
59 * value as this object.
60 *
61 * @param obj the object to compare with, {@code null} returns {@code false}
62 * @return {@code true} if the objects are the same;
63 * {@code true} if the objects have equivalent {@code value} fields;
64 * {@code false} otherwise.
65 */
66 @Override
67 public boolean equals(final Object obj) {
68 if (obj == null) {
69 return false;
70 }
71 if (this == obj) {
72 return true;
73 }
74 if (this.getClass() == obj.getClass()) {
75 final MutableObject<?> that = (MutableObject<?>) obj;
76 return Objects.equals(this.value, that.value);
77 }
78 return false;
79 }
80
81 /**
82 * Gets the value.
83 *
84 * @return the value, may be null
85 */
86 @Override
87 public T getValue() {
88 return this.value;
89 }
90
91 /**
92 * Returns the value's hash code or {@code 0} if the value is {@code null}.
93 *
94 * @return the value's hash code or {@code 0} if the value is {@code null}.
95 */
96 @Override
97 public int hashCode() {
98 return Objects.hashCode(value);
99 }
100
101 /**
102 * Sets the value.
103 *
104 * @param value the value to set
105 */
106 @Override
107 public void setValue(final T value) {
108 this.value = value;
109 }
110
111 /**
112 * Returns the String value of this mutable.
113 *
114 * @return the mutable value as a string
115 */
116 @Override
117 public String toString() {
118 return Objects.toString(value);
119 }
120
121 }