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 }