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1   /*
2    * $Header$
3    * $Revision: 1128 $
4    * $Date: 2006-02-05 13:49:04 -0800 (Sun, 05 Feb 2006) $
5    *
6    * ====================================================================
7    *
8    * Copyright 2000-2002 bob mcwhirter & James Strachan.
9    * All rights reserved.
10   *
11   * Redistribution and use in source and binary forms, with or without
12   * modification, are permitted provided that the following conditions are
13   * met:
14   * 
15   *   * Redistributions of source code must retain the above copyright
16   *     notice, this list of conditions and the following disclaimer.
17   * 
18   *   * Redistributions in binary form must reproduce the above copyright
19   *     notice, this list of conditions and the following disclaimer in the
20   *     documentation and/or other materials provided with the distribution.
21   * 
22   *   * Neither the name of the Jaxen Project nor the names of its
23   *     contributors may be used to endorse or promote products derived 
24   *     from this software without specific prior written permission.
25   * 
26   * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
27   * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
28   * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
29   * PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER
30   * OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
31   * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
32   * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
33   * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
34   * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
35   * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
36   * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
37   *
38   * ====================================================================
39   * This software consists of voluntary contributions made by many 
40   * individuals on behalf of the Jaxen Project and was originally 
41   * created by bob mcwhirter <bob@werken.com> and 
42   * James Strachan <jstrachan@apache.org>.  For more information on the 
43   * Jaxen Project, please see <http://www.jaxen.org/>.
44   * 
45   * $Id: LowerFunction.java 1128 2006-02-05 21:49:04Z elharo $
46   */
47  
48  package org.jaxen.function.ext;
49  
50  import java.util.List;
51  import java.util.Locale;
52  
53  import org.jaxen.Context;
54  import org.jaxen.FunctionCallException;
55  import org.jaxen.Navigator;
56  import org.jaxen.function.StringFunction;
57  
58  /**
59   * <p><code><i>string</i> lower-case(<i>string</i>)</code>
60   *
61   * This function can take a second parameter of the 
62   * <code>Locale</code> to use for the String conversion.
63   * </p>
64   *
65   * <p>
66   * For example
67   *
68   * <code>lower-case( /foo/bar )</code>
69   * <code>lower-case( /foo/@name, $myLocale )</code>
70   * </p>
71   *
72   * @author mark wilson (markw@wilsoncom.de)
73   * @author <a href="mailto:jstrachan@apache.org">James Strachan</a>
74   */
75  public class LowerFunction extends LocaleFunctionSupport
76  {
77  
78      public Object call(Context context,
79                         List args) throws FunctionCallException
80      {
81          Navigator navigator = context.getNavigator();
82          int size = args.size();
83          if (size > 0)
84          {
85              Object text = args.get(0);
86              Locale locale = null;
87              if (size > 1)
88              {  
89                  locale = getLocale( args.get(1), navigator );
90              }
91              return evaluate( text, locale, navigator );
92          }
93          throw new FunctionCallException( "lower-case() requires at least one argument." );
94      }
95  
96      /**
97       * Converts the given string value to lower case using an optional Locale
98       * 
99       * @param strArg the value which gets converted to a String
100      * @param locale the Locale to use for the conversion or null
101      *        English should be used
102      * @param nav the Navigator to use
103      */
104     public static String evaluate(Object strArg,
105                                   Locale locale,
106                                   Navigator nav)
107     {
108 
109         String str   = StringFunction.evaluate( strArg,
110                                                 nav );
111         // it might be possible to use the xml:lang attribute to
112         // pick a default locale
113         if (locale == null) locale = Locale.ENGLISH;
114         return str.toLowerCase(locale);
115         
116     }
117 }