DefaultComparator


1   /**
2    * Licensed under the Artistic License; you may not use this file
3    * except in compliance with the License.
4    * You may obtain a copy of the License at
5    *
6    *      http://displaytag.sourceforge.net/license.html
7    *
8    * THIS PACKAGE IS PROVIDED "AS IS" AND WITHOUT ANY EXPRESS OR
9    * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
10   * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
11   */
12  package org.displaytag.model;
13  
14  import java.text.Collator  ;
15  import java.util.Comparator  ;
16  
17  
18  /**
19   * Default comparator. Was previously part of RowSorter.
20   * @author fguist
21   * @author rapruitt
22   * @version $Revision: 986 $ ($Author: fgiust $)
23   */
24  public class DefaultComparator implements Comparator  
25  {
26  
27      /**
28       * Use this collator.
29       */
30      private Collator   collator;
31  
32      /**
33       * Instantiate a default comparator with no collator specified.
34       */
35      public DefaultComparator()
36      {
37          this.collator = Collator.getInstance();
38          collator.setStrength(Collator.PRIMARY); // ignore case and accents
39      }
40  
41      /**
42       * Instantiate a default comparator with a specified collator.
43       * @param collatorToUse collator instance
44       */
45      public DefaultComparator(Collator   collatorToUse)
46      {
47          this.collator = collatorToUse;
48      }
49  
50      /**
51       * Compares two given objects. Not comparable objects are compared using their string representation. String
52       * comparisons are done using a Collator.
53       * @param object1 first parameter
54       * @param object2 second parameter
55       * @return the value
56       */
57      public int compare(Object   object1, Object   object2)
58      {
59          int returnValue;
60          if (object1 instanceof String   && object2 instanceof String  )
61          {
62              returnValue = collator.compare(object1, object2);
63          }
64          else if (object1 instanceof Comparable   && object2 instanceof Comparable  )
65          {
66              returnValue = ((Comparable  ) object1).compareTo(object2);
67          }
68          else
69          {
70              // if object are not null and don't implement comparable, compare using string values
71              returnValue = collator.compare(object1.toString(), object2.toString());
72          }
73          return returnValue;
74      }
75  }
76
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