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1   /*
2    * $Header: /home/projects/jaxen/scm/jaxen/src/java/main/org/jaxen/function/StringFunction.java,v 1.18 2005/04/16 14:18:12 elharo Exp $
3    * $Revision: 1.18 $
4    * $Date: 2005/04/16 14:18:12 $
5    *
6    * ====================================================================
7    *
8    * Copyright (C) 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
13   * are met:
14   * 
15   * 1. Redistributions of source code must retain the above copyright
16   *    notice, this list of conditions, and the following disclaimer.
17   *
18   * 2. Redistributions in binary form must reproduce the above copyright
19   *    notice, this list of conditions, and the disclaimer that follows 
20   *    these conditions in the documentation and/or other materials 
21   *    provided with the distribution.
22   *
23   * 3. The name "Jaxen" must not be used to endorse or promote products
24   *    derived from this software without prior written permission.  For
25   *    written permission, please contact license@jaxen.org.
26   * 
27   * 4. Products derived from this software may not be called "Jaxen", nor
28   *    may "Jaxen" appear in their name, without prior written permission
29   *    from the Jaxen Project Management (pm@jaxen.org).
30   * 
31   * In addition, we request (but do not require) that you include in the 
32   * end-user documentation provided with the redistribution and/or in the 
33   * software itself an acknowledgement equivalent to the following:
34   *     "This product includes software developed by the
35   *      Jaxen Project (http://www.jaxen.org/)."
36   * Alternatively, the acknowledgment may be graphical using the logos 
37   * available at http://www.jaxen.org/
38   *
39   * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
40   * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
41   * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
42   * DISCLAIMED.  IN NO EVENT SHALL THE Jaxen AUTHORS OR THE PROJECT
43   * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
44   * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
45   * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
46   * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
47   * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
48   * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
49   * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
50   * SUCH DAMAGE.
51   *
52   * ====================================================================
53   * This software consists of voluntary contributions made by many 
54   * individuals on behalf of the Jaxen Project and was originally 
55   * created by bob mcwhirter <bob@werken.com> and 
56   * James Strachan <jstrachan@apache.org>.  For more information on the 
57   * Jaxen Project, please see <http://www.jaxen.org/>.
58   * 
59   * $Id: StringFunction.java,v 1.18 2005/04/16 14:18:12 elharo Exp $
60   */
61  
62  
63  package org.jaxen.function;
64  
65  import org.jaxen.Context;
66  import org.jaxen.Function;
67  import org.jaxen.FunctionCallException;
68  import org.jaxen.Navigator;
69  import org.jaxen.UnsupportedAxisException;
70  import org.jaxen.JaxenRuntimeException;
71  
72  import java.text.NumberFormat;
73  import java.util.List;
74  import java.util.Iterator;
75  import java.util.Locale;
76  
77  /***
78   * <p><b>4.2</b> <code><i>string</i> string(<i>object</i>)</code>
79   *
80   * @author bob mcwhirter (bob @ werken.com)
81   */
82  public class StringFunction implements Function
83  {
84      
85      private static NumberFormat format = NumberFormat.getInstance(Locale.ENGLISH);
86      
87      static {
88          format.setGroupingUsed(false);
89          format.setMaximumFractionDigits(32);
90      }
91  
92      public Object call(Context context,
93                         List args) throws FunctionCallException
94      {
95          int size = args.size();
96  
97          if ( size == 0 )
98          {
99              return evaluate( context.getNodeSet(),
100                              context.getNavigator() );
101         }
102         else if ( size == 1 )
103         {
104             return evaluate( args.get(0),
105                              context.getNavigator() );
106         }
107 
108         throw new FunctionCallException( "string() requires one argument." );
109     }
110     
111     public static String evaluate(Object obj,
112                                   Navigator nav)
113     {
114         try
115         {
116             if (obj == null) {
117                 return "";
118             }
119             
120             // Workaround because XOM uses lists for Text nodes
121             // so we need to check for that first
122             if (nav != null && nav.isText(obj))
123             {
124                 return nav.getTextStringValue(obj);
125             }
126             
127             if (obj instanceof List)
128             {
129                 List list = (List) obj;
130                 if (list.isEmpty())
131                 {
132                     return "";
133                 }
134                 // do not recurse: only first list should unwrap
135                 obj = list.get(0);
136             }
137             
138             if (nav != null && (nav.isElement(obj) || nav.isDocument(obj)))
139             {
140                 Iterator descendantAxisIterator = nav.getDescendantAxisIterator(obj);
141                 StringBuffer sb = new StringBuffer();
142                 while (descendantAxisIterator.hasNext())
143                 {
144                     Object descendant = descendantAxisIterator.next();
145                     if (nav.isText(descendant))
146                     {
147                         sb.append(nav.getTextStringValue(descendant));
148                     }
149                 }
150                 return sb.toString();
151             }
152             else if (nav != null && nav.isAttribute(obj))
153             {
154                 return nav.getAttributeStringValue(obj);
155             }
156             else if (nav != null && nav.isText(obj))
157             {
158                 return nav.getTextStringValue(obj);
159             }
160             else if (nav != null && nav.isProcessingInstruction(obj))
161             {
162                 return nav.getProcessingInstructionData(obj);
163             }
164             else if (nav != null && nav.isComment(obj))
165             {
166                 return nav.getCommentStringValue(obj);
167             }
168             else if (nav != null && nav.isNamespace(obj))
169             {
170                 return nav.getNamespaceStringValue(obj);
171             }
172             else if (obj instanceof String)
173             {
174                 return (String) obj;
175             }
176             else if (obj instanceof Boolean)
177             {
178                 return stringValue(((Boolean) obj).booleanValue());
179             }
180             else if (obj instanceof Number)
181             {
182                 return stringValue(((Number) obj).doubleValue());
183             }
184             return "";
185         }
186         catch (UnsupportedAxisException e)
187         {
188             throw new JaxenRuntimeException(e);
189         }
190 
191     }
192 
193     public static String stringValue(double value)
194     {
195         return format.format(value);
196     }
197 
198     public static String stringValue(boolean bool)
199     {
200         return bool ? "true" : "false";
201     }
202 
203 }