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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   * <em>Consider this class private.</em>
22   * Classes implementing this interface know how to supply a value.
23   *
24   * <p>This is a <a href="https://docs.oracle.com/javase/8/docs/api/java/util/function/package-summary.html">functional
25   * interface</a> intended to support lambda expressions in log4j 2.
26   *
27   * <p>Implementors are free to cache values or return a new or distinct value each time the supplier is invoked.
28   *
29   * <p><strong>DEPRECATED:</strong> this class will be removed in 3.0 to be replaced with the Java 8 interface.</p>
30   *
31   * @param <T> the type of values returned by this supplier
32   *
33   * @since 2.4
34   */
35  public interface Supplier<T> {
36  
37      /**
38       * Gets a value.
39       *
40       * @return a value
41       */
42      T get();
43  }