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 * <code>Mutable</code> is used as a generic interface to the implementations in this package.
24 * <p>
25 * A typical use case would be to enable a primitive or string to be passed to a method and allow that method to
26 * effectively change the value of the primitive/string. Another use case is to store a frequently changing primitive in
27 * a collection (for example a total in a map) without needing to create new Integer/Long wrapper objects.
28 *
29 * @since 2.1
30 * @param <T> the type to set and get
31 * @version $Id: Mutable.java 1153213 2011-08-02 17:35:39Z ggregory $
32 */
33 public interface Mutable<T> {
34
35 /**
36 * Gets the value of this mutable.
37 *
38 * @return the stored value
39 */
40 T getValue();
41
42 /**
43 * Sets the value of this mutable.
44 *
45 * @param value
46 * the value to store
47 * @throws NullPointerException
48 * if the object is null and null is invalid
49 * @throws ClassCastException
50 * if the type is invalid
51 */
52 void setValue(T value);
53
54 }