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
018package org.apache.logging.log4j.util;
019
020/**
021 * <em>Consider this class private.</em>
022 * Classes implementing this interface know how to supply a value.
023 *
024 * <p>This is a <a href="https://docs.oracle.com/javase/8/docs/api/java/util/function/package-summary.html">functional
025 * interface</a> intended to support lambda expressions in log4j 2.
026 *
027 * <p>Implementors are free to cache values or return a new or distinct value each time the supplier is invoked.
028 *
029 * <p><strong>DEPRECATED:</strong> this class will be removed in 3.0 to be replaced with the Java 8 interface.</p>
030 *
031 * @param <T> the type of values returned by this supplier
032 *
033 * @since 2.4
034 */
035public interface Supplier<T> {
036
037    /**
038     * Gets a value.
039     *
040     * @return a value
041     */
042    T get();
043}