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 /**
21 * Classes implementing this interface know how to supply a value.
22 *
23 * <p>This is a <a href="https://docs.oracle.com/javase/8/docs/api/java/util/function/package-summary.html">functional
24 * interface</a> intended to support lambda expressions in log4j 2.
25 *
26 * <p>Implementors are free to cache values or return a new or distinct value each time the supplier is invoked.
27 *
28 * @param <T> the type of values returned by this supplier
29 *
30 * @since 2.4
31 */
32 public interface Supplier<T> {
33
34 /**
35 * Gets a value.
36 *
37 * @return a value
38 */
39 T get();
40 }