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 /** 31 * A set of utility methods to help produce consistent 32 * {@link Object#equals equals} and {@link Object#hashCode hashCode} methods. 33 * 34 * 35 * @since 4.0 36 */ 37 public final class LangUtils { 38 39 public static final int HASH_SEED = 17; 40 public static final int HASH_OFFSET = 37; 41 42 /** Disabled default constructor. */ 43 private LangUtils() { 44 } 45 46 public static int hashCode(final int seed, final int hashcode) { 47 return seed * HASH_OFFSET + hashcode; 48 } 49 50 public static int hashCode(final int seed, final boolean b) { 51 return hashCode(seed, b ? 1 : 0); 52 } 53 54 public static int hashCode(final int seed, final Object obj) { 55 return hashCode(seed, obj != null ? obj.hashCode() : 0); 56 } 57 58 /** 59 * Check if two objects are equal. 60 * 61 * @param obj1 first object to compare, may be {@code null} 62 * @param obj2 second object to compare, may be {@code null} 63 * @return {@code true} if the objects are equal or both null 64 */ 65 public static boolean equals(final Object obj1, final Object obj2) { 66 return obj1 == null ? obj2 == null : obj1.equals(obj2); 67 } 68 69 /** 70 * Check if two object arrays are equal. 71 * <ul> 72 * <li>If both parameters are null, return {@code true}</li> 73 * <li>If one parameter is null, return {@code false}</li> 74 * <li>If the array lengths are different, return {@code false}</li> 75 * <li>Compare array elements using .equals(); return {@code false} if any comparisons fail.</li> 76 * <li>Return {@code true}</li> 77 * </ul> 78 * 79 * @param a1 first array to compare, may be {@code null} 80 * @param a2 second array to compare, may be {@code null} 81 * @return {@code true} if the arrays are equal or both null 82 */ 83 public static boolean equals(final Object[] a1, final Object[] a2) { 84 if (a1 == null) { 85 return a2 == null; 86 } 87 if (a2 != null && a1.length == a2.length) { 88 for (int i = 0; i < a1.length; i++) { 89 if (!equals(a1[i], a2[i])) { 90 return false; 91 } 92 } 93 return true; 94 } 95 return false; 96 } 97 98 }