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 import org.apache.logging.log4j.message.Message; 21 import org.apache.logging.log4j.message.MessageFactory; 22 23 24 /** 25 * Utility class for lambda support. 26 */ 27 public final class LambdaUtil { 28 /** 29 * Private constructor: this class is not intended to be instantiated. 30 */ 31 private LambdaUtil() { 32 } 33 34 /** 35 * Converts an array of lambda expressions into an array of their evaluation results. 36 * 37 * @param suppliers an array of lambda expressions or {@code null} 38 * @return an array containing the results of evaluating the lambda expressions (or {@code null} if the suppliers 39 * array was {@code null} 40 */ 41 public static Object[] getAll(final Supplier<?>... suppliers) { 42 if (suppliers == null) { 43 return null; 44 } 45 final Object[] result = new Object[suppliers.length]; 46 for (int i = 0; i < result.length; i++) { 47 result[i] = get(suppliers[i]); 48 } 49 return result; 50 } 51 52 /** 53 * Returns the result of evaluating the specified function. If the supplied value is of type Message, this method 54 * returns the result of calling {@code #getFormattedMessage} on that Message. 55 * @param supplier a lambda expression or {@code null} 56 * @return the results of evaluating the lambda expression (or {@code null} if the supplier 57 * was {@code null} 58 */ 59 public static Object get(final Supplier<?> supplier) { 60 if (supplier == null) { 61 return null; 62 } 63 final Object result = supplier.get(); 64 return result instanceof Message ? ((Message) result).getFormattedMessage() : result; 65 } 66 67 /** 68 * Returns the Message supplied by the specified function. 69 * @param supplier a lambda expression or {@code null} 70 * @return the Message resulting from evaluating the lambda expression (or {@code null} if the supplier was 71 * {@code null} 72 */ 73 public static Message get(final MessageSupplier supplier) { 74 if (supplier == null) { 75 return null; 76 } 77 return supplier.get(); 78 } 79 80 /** 81 * Returns a Message, either the value supplied by the specified function, or a new Message created by the specified 82 * Factory. 83 * @param supplier a lambda expression or {@code null} 84 * @return the Message resulting from evaluating the lambda expression or the Message created by the factory for 85 * supplied values that are not of type Message 86 */ 87 public static Message getMessage(final Supplier<?> supplier, final MessageFactory messageFactory) { 88 if (supplier == null) { 89 return null; 90 } 91 final Object result = supplier.get(); 92 return result instanceof Message ? (Message) result : messageFactory.newMessage(result); 93 } 94 }