001/* 002 * ==================================================================== 003 * Licensed to the Apache Software Foundation (ASF) under one 004 * or more contributor license agreements. See the NOTICE file 005 * distributed with this work for additional information 006 * regarding copyright ownership. The ASF licenses this file 007 * to you under the Apache License, Version 2.0 (the 008 * "License"); you may not use this file except in compliance 009 * with the License. You may obtain a copy of the License at 010 * 011 * http://www.apache.org/licenses/LICENSE-2.0 012 * 013 * Unless required by applicable law or agreed to in writing, 014 * software distributed under the License is distributed on an 015 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY 016 * KIND, either express or implied. See the License for the 017 * specific language governing permissions and limitations 018 * under the License. 019 * ==================================================================== 020 * 021 * This software consists of voluntary contributions made by many 022 * individuals on behalf of the Apache Software Foundation. For more 023 * information on the Apache Software Foundation, please see 024 * <http://www.apache.org/>. 025 * 026 */ 027 028package org.apache.http.util; 029 030/** 031 * A set of utility methods to help produce consistent 032 * {@link Object#equals equals} and {@link Object#hashCode hashCode} methods. 033 * 034 * 035 * @since 4.0 036 */ 037public final class LangUtils { 038 039 public static final int HASH_SEED = 17; 040 public static final int HASH_OFFSET = 37; 041 042 /** Disabled default constructor. */ 043 private LangUtils() { 044 } 045 046 public static int hashCode(final int seed, final int hashcode) { 047 return seed * HASH_OFFSET + hashcode; 048 } 049 050 public static int hashCode(final int seed, final boolean b) { 051 return hashCode(seed, b ? 1 : 0); 052 } 053 054 public static int hashCode(final int seed, final Object obj) { 055 return hashCode(seed, obj != null ? obj.hashCode() : 0); 056 } 057 058 /** 059 * Check if two objects are equal. 060 * 061 * @param obj1 first object to compare, may be {@code null} 062 * @param obj2 second object to compare, may be {@code null} 063 * @return {@code true} if the objects are equal or both null 064 */ 065 public static boolean equals(final Object obj1, final Object obj2) { 066 return obj1 == null ? obj2 == null : obj1.equals(obj2); 067 } 068 069 /** 070 * Check if two object arrays are equal. 071 * <ul> 072 * <li>If both parameters are null, return {@code true}</li> 073 * <li>If one parameter is null, return {@code false}</li> 074 * <li>If the array lengths are different, return {@code false}</li> 075 * <li>Compare array elements using .equals(); return {@code false} if any comparisons fail.</li> 076 * <li>Return {@code true}</li> 077 * </ul> 078 * 079 * @param a1 first array to compare, may be {@code null} 080 * @param a2 second array to compare, may be {@code null} 081 * @return {@code true} if the arrays are equal or both null 082 */ 083 public static boolean equals(final Object[] a1, final Object[] a2) { 084 if (a1 == null) { 085 return a2 == null; 086 } else { 087 if (a2 != null && a1.length == a2.length) { 088 for (int i = 0; i < a1.length; i++) { 089 if (!equals(a1[i], a2[i])) { 090 return false; 091 } 092 } 093 return true; 094 } else { 095 return false; 096 } 097 } 098 } 099 100}