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1   /*
2    * $Header: /home/projects/jaxen/scm/jaxen/src/java/main/org/jaxen/function/StringFunction.java,v 1.14 2005/01/29 21:00:51 elharo Exp $
3    * $Revision: 1.14 $
4    * $Date: 2005/01/29 21:00:51 $
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 1.14 2005/01/29 21:00:51 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             String retval = "";
108             if (obj == null) {
109                 return "";
110             }
111             if (obj instanceof List)
112             {
113                 List list = (List) obj;
114                 if (list.isEmpty())
115                 {
116                     return "";
117                 }
118                 // do not recurse: only first list should unwrap
119                 obj = list.get(0);
120             }
121             if (nav != null && (nav.isElement(obj) || nav.isDocument(obj)))
122             {
123                 Iterator descendantAxisIterator = nav.getDescendantAxisIterator(obj);
124                 StringBuffer sb = new StringBuffer();
125                 while (descendantAxisIterator.hasNext())
126                 {
127                     Object descendant = descendantAxisIterator.next();
128                     if (nav.isText(descendant))
129                     {
130                         sb.append(nav.getTextStringValue(descendant));
131                     }
132                 }
133                 retval = sb.toString();
134             }
135             else if (nav != null && nav.isAttribute(obj))
136             {
137                 retval = nav.getAttributeStringValue(obj);
138             }
139             else if (nav != null && nav.isText(obj))
140             {
141                 retval = nav.getTextStringValue(obj);
142             }
143             else if (nav != null && nav.isProcessingInstruction(obj))
144             {
145                 retval = nav.getProcessingInstructionData(obj);
146             }
147             else if (nav != null && nav.isComment(obj))
148             {
149                 retval = nav.getCommentStringValue(obj);
150             }
151             else if (nav != null && nav.isNamespace(obj))
152             {
153                 retval = nav.getNamespaceStringValue(obj);
154             }
155             else if (obj instanceof String)
156             {
157                 retval = (String) obj;
158             }
159             else if (obj instanceof Boolean)
160             {
161                 retval = stringValue(((Boolean) obj).booleanValue());
162             }
163             else if (obj instanceof Number)
164             {
165                 retval = stringValue(((Number) obj).doubleValue());
166             }
167             retval = retval == null ? "" : retval;
168             return retval;
169         }
170         catch (UnsupportedAxisException e)
171         {
172             throw new JaxenRuntimeException(e);
173         }
174 
175     }
176 
177     public static String stringValue(double value)
178     {
179         if (Double.isNaN(value))
180         {
181             return "NaN";
182         }
183         if (-0.0 == value || 0.0 == value)
184         {
185             return "0";
186         }
187         if (Double.isInfinite(value) && value < 0)
188         {
189             return "-Infinity";
190         }
191         if (Double.isInfinite(value) && value > 0)
192         {
193             return "Infinity";
194         }
195         if (((long) value) == value)
196         {
197             return Long.toString((long) value);
198         }
199         return Double.toString(value);
200     }
201 
202     public static String stringValue(boolean bool)
203     {
204         return bool ? "true" : "false";
205     }
206 
207 }