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