1 /* 2 * ==================================================================== 3 * Licensed to the Apache Software Foundation (ASF) under one 4 * or more contributor license agreements. See the NOTICE file 5 * distributed with this work for additional information 6 * regarding copyright ownership. The ASF licenses this file 7 * to you under the Apache License, Version 2.0 (the 8 * "License"); you may not use this file except in compliance 9 * with the License. You may obtain a copy of the License at 10 * 11 * http://www.apache.org/licenses/LICENSE-2.0 12 * 13 * Unless required by applicable law or agreed to in writing, 14 * software distributed under the License is distributed on an 15 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY 16 * KIND, either express or implied. See the License for the 17 * specific language governing permissions and limitations 18 * under the License. 19 * ==================================================================== 20 * 21 * This software consists of voluntary contributions made by many 22 * individuals on behalf of the Apache Software Foundation. For more 23 * information on the Apache Software Foundation, please see 24 * <http://www.apache.org/>. 25 * 26 */ 27 28 package org.apache.hc.core5.util; 29 30 import java.util.Objects; 31 32 /** 33 * A set of utility methods to help produce consistent 34 * {@link Object#equals equals} and {@link Object#hashCode hashCode} methods. 35 * 36 * 37 * @since 4.0 38 */ 39 public final class LangUtils { 40 41 public static final int HASH_SEED = 17; 42 public static final int HASH_OFFSET = 37; 43 44 /** Disabled default constructor. */ 45 private LangUtils() { 46 } 47 48 public static int hashCode(final int seed, final int hashcode) { 49 return seed * HASH_OFFSET + hashcode; 50 } 51 52 public static int hashCode(final int seed, final boolean b) { 53 return hashCode(seed, b ? 1 : 0); 54 } 55 56 public static int hashCode(final int seed, final Object obj) { 57 return hashCode(seed, obj != null ? obj.hashCode() : 0); 58 } 59 60 /** 61 * Check if two objects are equal. 62 * 63 * @param obj1 first object to compare, may be {@code null} 64 * @param obj2 second object to compare, may be {@code null} 65 * @return {@code true} if the objects are equal or both null 66 */ 67 public static boolean equals(final Object obj1, final Object obj2) { 68 return Objects.equals(obj1, obj2); 69 } 70 71 /** 72 * Check if two object arrays are equal. 73 * <ul> 74 * <li>If both parameters are null, return {@code true}</li> 75 * <li>If one parameter is null, return {@code false}</li> 76 * <li>If the array lengths are different, return {@code false}</li> 77 * <li>Compare array elements using .equals(); return {@code false} if any comparisons fail.</li> 78 * <li>Return {@code true}</li> 79 * </ul> 80 * 81 * @param a1 first array to compare, may be {@code null} 82 * @param a2 second array to compare, may be {@code null} 83 * @return {@code true} if the arrays are equal or both null 84 */ 85 public static boolean equals(final Object[] a1, final Object[] a2) { 86 if (a1 == null) { 87 return a2 == null; 88 } 89 if (a2 != null && a1.length == a2.length) { 90 for (int i = 0; i < a1.length; i++) { 91 if (!equals(a1[i], a2[i])) { 92 return false; 93 } 94 } 95 return true; 96 } 97 return false; 98 } 99 100 }