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1   /*
2    * $Id: CompareUtil.java 787720 2009-06-23 15:39:21Z apetrelli $
3    *
4    * Licensed to the Apache Software Foundation (ASF) under one
5    * or more contributor license agreements.  See the NOTICE file
6    * distributed with this work for additional information
7    * regarding copyright ownership.  The ASF licenses this file
8    * to you under the Apache License, Version 2.0 (the
9    * "License"); you may not use this file except in compliance
10   * with the License.  You may obtain a copy of the License at
11   *
12   * http://www.apache.org/licenses/LICENSE-2.0
13   *
14   * Unless required by applicable law or agreed to in writing,
15   * software distributed under the License is distributed on an
16   * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
17   * KIND, either express or implied.  See the License for the
18   * specific language governing permissions and limitations
19   * under the License.
20   */
21  
22  package org.apache.tiles;
23  
24  /**
25   * Utilities to work with comparation between objects.
26   *
27   * @version $Rev: 787720 $ $Date: 2009-06-24 01:39:21 +1000 (Wed, 24 Jun 2009) $
28   * @since 2.2.0
29   */
30  public final class CompareUtil {
31  
32      /**
33       * Private constructor to avoid instantiation.
34       */
35      private CompareUtil() { }
36  
37      /**
38       * Checks if two objects (eventually null) are the same. They are considered the same
39       * even if they are both null.
40       *
41       * @param obj1 The first object to check.
42       * @param obj2 The second object to check.
43       * @return <code>true</code> if the objects are the same.
44       * @since 2.2.0
45       */
46      public static boolean nullSafeEquals(Object obj1, Object obj2) {
47          if (obj1 != null) {
48              return obj1.equals(obj2);
49          }
50          return obj2 == null;
51      }
52  
53      /**
54       * Returns <code>0</code> if the object is null, the hash code of the object
55       * otherwise.
56       *
57       * @param obj The object from which the hash code must be calculated..
58       * @return The hash code.
59       * @since 2.2.0
60       */
61      public static int nullSafeHashCode(Object obj) {
62          if (obj != null) {
63              return obj.hashCode();
64          }
65          return 0;
66      }
67  }