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1   /*
2    * $Header: /home/projects/jaxen/scm/jaxen/src/java/main/org/jaxen/function/StringFunction.java,v 1.16 2005/04/12 13:16:46 elharo Exp $
3    * $Revision: 1.16 $
4    * $Date: 2005/04/12 13:16:46 $
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 1.16 2005/04/12 13:16:46 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.util.List;
73  import java.util.Iterator;
74  
75  /***
76   * <p><b>4.2</b> <code><i>string</i> string(<i>object</i>)</code>
77   *
78   * @author bob mcwhirter (bob @ werken.com)
79   */
80  public class StringFunction implements Function
81  {
82      
83      public Object call(Context context,
84                         List args) throws FunctionCallException
85      {
86          int size = args.size();
87  
88          if ( size == 0 )
89          {
90              return evaluate( context.getNodeSet(),
91                               context.getNavigator() );
92          }
93          else if ( size == 1 )
94          {
95              return evaluate( args.get(0),
96                               context.getNavigator() );
97          }
98  
99          throw new FunctionCallException( "string() requires one argument." );
100     }
101     
102     public static String evaluate(Object obj,
103                                   Navigator nav)
104     {
105         try
106         {
107             if (obj == null) {
108                 return "";
109             }
110             
111             // Workaround because XOM uses lists for Text nodes
112             // so we need to check for that first
113             if (nav != null && nav.isText(obj))
114             {
115                 return nav.getTextStringValue(obj);
116             }
117             
118             if (obj instanceof List)
119             {
120                 List list = (List) obj;
121                 if (list.isEmpty())
122                 {
123                     return "";
124                 }
125                 // do not recurse: only first list should unwrap
126                 obj = list.get(0);
127             }
128             
129             if (nav != null && (nav.isElement(obj) || nav.isDocument(obj)))
130             {
131                 Iterator descendantAxisIterator = nav.getDescendantAxisIterator(obj);
132                 StringBuffer sb = new StringBuffer();
133                 while (descendantAxisIterator.hasNext())
134                 {
135                     Object descendant = descendantAxisIterator.next();
136                     if (nav.isText(descendant))
137                     {
138                         sb.append(nav.getTextStringValue(descendant));
139                     }
140                 }
141                 return sb.toString();
142             }
143             else if (nav != null && nav.isAttribute(obj))
144             {
145                 return nav.getAttributeStringValue(obj);
146             }
147             else if (nav != null && nav.isText(obj))
148             {
149                 return nav.getTextStringValue(obj);
150             }
151             else if (nav != null && nav.isProcessingInstruction(obj))
152             {
153                 return nav.getProcessingInstructionData(obj);
154             }
155             else if (nav != null && nav.isComment(obj))
156             {
157                 return nav.getCommentStringValue(obj);
158             }
159             else if (nav != null && nav.isNamespace(obj))
160             {
161                 return nav.getNamespaceStringValue(obj);
162             }
163             else if (obj instanceof String)
164             {
165                 return (String) obj;
166             }
167             else if (obj instanceof Boolean)
168             {
169                 return stringValue(((Boolean) obj).booleanValue());
170             }
171             else if (obj instanceof Number)
172             {
173                 return stringValue(((Number) obj).doubleValue());
174             }
175             return "";
176         }
177         catch (UnsupportedAxisException e)
178         {
179             throw new JaxenRuntimeException(e);
180         }
181 
182     }
183 
184     public static String stringValue(double value)
185     {
186         if (Double.isNaN(value))
187         {
188             return "NaN";
189         }
190         if (-0.0 == value || 0.0 == value)
191         {
192             return "0";
193         }
194         if (Double.isInfinite(value) && value < 0)
195         {
196             return "-Infinity";
197         }
198         if (Double.isInfinite(value) && value > 0)
199         {
200             return "Infinity";
201         }
202         if (((long) value) == value)
203         {
204             return Long.toString((long) value);
205         }
206         return Double.toString(value);
207     }
208 
209     public static String stringValue(boolean bool)
210     {
211         return bool ? "true" : "false";
212     }
213 
214 }