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      1 /*
      2  * $HeadURL: http://svn.apache.org/repos/asf/httpcomponents/httpcore/trunk/module-main/src/main/java/org/apache/http/util/LangUtils.java $
      3  * $Revision: 503413 $
      4  * $Date: 2007-02-04 06:22:14 -0800 (Sun, 04 Feb 2007) $
      5  *
      6  * ====================================================================
      7  * Licensed to the Apache Software Foundation (ASF) under one
      8  * or more contributor license agreements.  See the NOTICE file
      9  * distributed with this work for additional information
     10  * regarding copyright ownership.  The ASF licenses this file
     11  * to you under the Apache License, Version 2.0 (the
     12  * "License"); you may not use this file except in compliance
     13  * with the License.  You may obtain a copy of the License at
     14  *
     15  *   http://www.apache.org/licenses/LICENSE-2.0
     16  *
     17  * Unless required by applicable law or agreed to in writing,
     18  * software distributed under the License is distributed on an
     19  * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
     20  * KIND, either express or implied.  See the License for the
     21  * specific language governing permissions and limitations
     22  * under the License.
     23  * ====================================================================
     24  *
     25  * This software consists of voluntary contributions made by many
     26  * individuals on behalf of the Apache Software Foundation.  For more
     27  * information on the Apache Software Foundation, please see
     28  * <http://www.apache.org/>.
     29  *
     30  */
     31 
     32 package org.apache.http.util;
     33 
     34 /**
     35  * A set of utility methods to help produce consistent
     36  * {@link Object#equals equals} and {@link Object#hashCode hashCode} methods.
     37  *
     38  * @author <a href="mailto:oleg at ural.ru">Oleg Kalnichevski</a>
     39  *
     40  * @since 4.0
     41  */
     42 public final class LangUtils {
     43 
     44     public static final int HASH_SEED = 17;
     45     public static final int HASH_OFFSET = 37;
     46 
     47     /** Disabled default constructor. */
     48     private LangUtils() {
     49     }
     50 
     51     public static int hashCode(final int seed, final int hashcode) {
     52         return seed * HASH_OFFSET + hashcode;
     53     }
     54 
     55     public static int hashCode(final int seed, final boolean b) {
     56         return hashCode(seed, b ? 1 : 0);
     57     }
     58 
     59     public static int hashCode(final int seed, final Object obj) {
     60         return hashCode(seed, obj != null ? obj.hashCode() : 0);
     61     }
     62 
     63     public static boolean equals(final Object obj1, final Object obj2) {
     64         return obj1 == null ? obj2 == null : obj1.equals(obj2);
     65     }
     66 
     67     public static boolean equals(final Object[] a1, final Object[] a2) {
     68         if (a1 == null) {
     69             if (a2 == null) {
     70                 return true;
     71             } else {
     72                 return false;
     73             }
     74         } else {
     75             if (a2 != null && a1.length == a2.length) {
     76                 for (int i = 0; i < a1.length; i++) {
     77                     if (!equals(a1[i], a2[i])) {
     78                         return false;
     79                     }
     80                 }
     81                 return true;
     82             } else {
     83                 return false;
     84             }
     85         }
     86     }
     87 
     88 }
     89