TextComparer


1   package net.sf.saxon.sort;
2   import net.sf.saxon.om.Item;
3   import net.sf.saxon.trans.XPathException;
4   
5   import java.util.Comparator  ;
6   
7   /**
8    * A Comparer used for comparing sort keys when data-type="text". The items to be
9    * compared are converted to strings, and the strings are then compared using an
10   * underlying collator
11   *
12   * @author Michael H. Kay
13   *
14   */
15  
16  public class TextComparer implements Comparator  , java.io.Serializable   {
17  
18      private Comparator   collator;
19  
20      public TextComparer(Comparator   collator) {
21          this.collator = collator;
22      }
23  
24      /**
25      * Compare two Items by converting them to strings and comparing the string values.
26      * @param a the first Item to be compared.
27      * @param b the second Item to be compared.
28      * @return <0 if a<b, 0 if a=b, >0 if a>b
29      * @throws ClassCastException if the objects are not Items, or are items that cannot be convered
30      * to strings (e.g. QNames)
31      */
32  
33      public int compare(Object   a, Object   b) throws ClassCastException   {
34  
35          String   s1, s2;
36  
37          //try {
38              s1 = (a instanceof String   ? (String  )a : ((Item)a).getStringValue());
39          //} catch (XPathException err) {
40          //    throw new ClassCastException("Cannot convert sort key from " + a.getClass() + " to a string");
41          //}
42  
43          //try {
44              s2 = (b instanceof String   ? (String  )b : ((Item)b).getStringValue());
45          //} catch (XPathException err) {
46          //    throw new ClassCastException("Cannot convert sort key from " + b.getClass() + " to a string");
47          //}
48  
49          int x = collator.compare(s1, s2);
50          //System.err.println(((RuleBasedCollator)collator).getStrength() + " comparing " + s1 + " with " + s2 + " => " + x);
51          return x;
52  
53      }
54  
55  }
56  
57  //
58  // The contents of this file are subject to the Mozilla Public License Version 1.0 (the "License");
59  // you may not use this file except in compliance with the License. You may obtain a copy of the
60  // License at http://www.mozilla.org/MPL/
61  //
62  // Software distributed under the License is distributed on an "AS IS" basis,
63  // WITHOUT WARRANTY OF ANY KIND, either express or implied.
64  // See the License for the specific language governing rights and limitations under the License.
65  //
66  // The Original Code is: all this file.
67  //
68  // The Initial Developer of this module is Michael H. Kay
69  //
70  // Portions created by (your name) are Copyright (C) (your legal entity). All Rights Reserved.
71  //
72  // Contributor(s): none.
73  //
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