001 /*
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements. See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache License, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License. You may obtain a copy of the License at
008 *
009 * http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 */
017
018 package org.apache.commons.lang.mutable;
019
020 /**
021 * Provides mutable access to a value.
022 * <p>
023 * <code>Mutable</code> is used as a generic interface to the implementations in this package.
024 * <p>
025 * A typical use case would be to enable a primitive or string to be passed to a method and allow that method to
026 * effectively change the value of the primitive/string. Another use case is to store a frequently changing primitive in
027 * a collection (for example a total in a map) without needing to create new Integer/Long wrapper objects.
028 *
029 * @author Apache Software Foundation
030 * @author Matthew Hawthorne
031 * @since 2.1
032 * @version $Id: Mutable.java 905636 2010-02-02 14:03:32Z niallp $
033 */
034 public interface Mutable {
035
036 /**
037 * Gets the value of this mutable.
038 *
039 * @return the stored value
040 */
041 Object getValue();
042
043 /**
044 * Sets the value of this mutable.
045 *
046 * @param value
047 * the value to store
048 * @throws NullPointerException
049 * if the object is null and null is invalid
050 * @throws ClassCastException
051 * if the type is invalid
052 */
053 void setValue(Object value);
054
055 }