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.commons.lang3.function;
019
020import java.util.function.Function;
021
022/**
023 * Factory for {@link Function}.
024 *
025 * @since 3.14.0
026 */
027public final class Functions {
028
029    /**
030     * Starts a fluent chain like {@code function(foo::bar).andThen(...).andThen(...).apply(...);}
031     *
032     * @param <T>      Input type.
033     * @param <R>      Return type.
034     * @param function the argument to return.
035     * @return the argument
036     */
037    public static <T, R> Function<T, R> function(final Function<T, R> function) {
038        return function;
039    }
040
041    private Functions() {
042        // no instances needed.
043    }
044}