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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.commons.lang3.function;
19  
20  import java.util.function.Function;
21  
22  /**
23   * Factory for {@link Function}.
24   *
25   * @since 3.14.0
26   */
27  public final class Functions {
28  
29      /**
30       * Starts a fluent chain like {@code function(foo::bar).andThen(...).andThen(...).apply(...);}
31       *
32       * @param <T>      Input type.
33       * @param <R>      Return type.
34       * @param function the argument to return.
35       * @return the argument
36       */
37      public static <T, R> Function<T, R> function(final Function<T, R> function) {
38          return function;
39      }
40  
41      private Functions() {
42          // no instances needed.
43      }
44  }