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 * https://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 * Applies the {@link Function} on the object if the function is not {@code null}. Otherwise, does nothing and returns {@code null}. 31 * 32 * @param function the function to apply. 33 * @param object the object to apply the function. 34 * @param <T> the type of the argument the function applies. 35 * @param <R> the type of the result the function returns. 36 * @return the value the function returns if the function is not {@code null}; {@code null} otherwise. 37 * @since 3.15.0 38 */ 39 public static <T, R> R apply(final Function<T, R> function, final T object) { 40 return function != null ? function.apply(object) : null; 41 } 42 43 /** 44 * Starts a fluent chain like {@code function(foo::bar).andThen(...).andThen(...).apply(...);} 45 * 46 * @param <T> Input type. 47 * @param <R> Return type. 48 * @param function the argument to return. 49 * @return the argument 50 */ 51 public static <T, R> Function<T, R> function(final Function<T, R> function) { 52 return function; 53 } 54 55 private Functions() { 56 // no instances needed. 57 } 58 }