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.logging.log4j.util; 19 20 import org.apache.logging.log4j.message.Message; 21 22 /** 23 * Classes implementing this interface know how to supply {@link Message}s. 24 * 25 * <p>This is a <a href="https://docs.oracle.com/javase/8/docs/api/java/util/function/package-summary.html">functional 26 * interface</a> intended to support lambda expressions in log4j 2. 27 * 28 * <p>Implementors are free to cache values or return a new or distinct value each time the supplier is invoked. 29 * 30 * <p><strong>DEPRECATED:</strong> this class should not normally be used outside a Java 8+ lambda syntax. Instead, 31 * {@link Supplier Supplier<Message>} should be used as an anonymous class. Both this and {@link Supplier} will be 32 * removed in 3.0. 33 * </p> 34 * 35 * @since 2.4 36 */ 37 public interface MessageSupplier { 38 39 /** 40 * Gets a Message. 41 * 42 * @return a Message 43 */ 44 Message get(); 45 }