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 /**
21 * Provides mutable access to a value.
22 * <p>
23 * {@link Mutable} is used as a generic interface to the implementations in this package.
24 * </p>
25 * <p>
26 * A typical use case would be to enable a primitive or string to be passed to a method and allow that method to
27 * effectively change the value of the primitive/string. Another use case is to store a frequently changing primitive in
28 * a collection (for example a total in a map) without needing to create new Integer/Long wrapper objects.
29 * </p>
30 *
31 * @param <T> the type to set and get
32 * @since 2.1
33 */
34 public interface Mutable<T> {
35
36 /**
37 * Gets the value of this mutable.
38 *
39 * @return the stored value
40 */
41 T getValue();
42
43 /**
44 * Sets the value of this mutable.
45 *
46 * @param value
47 * the value to store
48 * @throws NullPointerException
49 * if the object is null and null is invalid
50 * @throws ClassCastException
51 * if the type is invalid
52 */
53 void setValue(T value);
54
55 }