    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 *      https://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
    018package org.apache.commons.lang3.mutable;
    019
    020import java.util.function.Supplier;
    021
    022/**
    023 * Provides mutable access to a value.
    024 * <p>
    025 * {@link Mutable} is used as a generic interface to the implementations in this package.
    026 * </p>
    027 * <p>
    028 * A typical use case would be to enable a primitive or string to be passed to a method and allow that method to effectively change the value of the
    029 * primitive/object. Another use case is to store a frequently changing primitive in a collection (for example a total in a map) without needing to create new
    030 * Integer/Long wrapper objects.
    031 * </p>
    032 *
    033 * @param <T> the type to wrap.
    034 * @since 2.1
    035 */
    036public interface Mutable<T> extends Supplier<T> {
    037
    038    /**
    039     * Gets the value of this mutable.
    040     *
    041     * @return the stored value.
    042     * @since 3.18.0
    043     */
    044    @Override
    045    default T get() {
    046        return getValue();
    047    }
    048
    049    /**
    050     * Gets the value of this mutable.
    051     *
    052     * @return the stored value.
    053     * @deprecated Use {@link #get()}.
    054     */
    055    @Deprecated
    056    T getValue();
    057
    058    /**
    059     * Sets the value of this mutable.
    060     *
    061     * @param value the value to store.
    062     * @throws NullPointerException if the object is null and null is invalid.
    063     * @throws ClassCastException   if the type is invalid.
    064     */
    065    void setValue(T value);
    066}