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Java > Open Source Codes > org > jaxen > function > NameFunction


1 /*
2  * $Header: /home/projects/jaxen/scm/jaxen/src/java/main/org/jaxen/function/NameFunction.java,v 1.9 2005/06/26 16:07:23 elharo Exp $
3  * $Revision: 1.9 $
4  * $Date: 2005/06/26 16:07:23 $
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: NameFunction.java,v 1.9 2005/06/26 16:07:23 elharo Exp $
60  */

61
62
63 package org.jaxen.function;
64
65 import java.util.List JavaDoc;
66
67 import org.jaxen.Context;
68 import org.jaxen.Function;
69 import org.jaxen.FunctionCallException;
70 import org.jaxen.Navigator;
71
72 /**
73  * <p><b>4.1</b> <code><i>string</i> name(<i>node-set?</i>)</code> </p>
74  *
75  *
76  * <blockquote SRC="http://www.w3.org/TR/xpath">
77  * The <b>name</b> function returns a string containing a QName representing
78  * the expanded-name of the node in the argument node-set that is first in document order.
79  * The QName must represent the expanded-name with respect to the namespace declarations
80  * in effect on the node whose expanded-name is being represented. Typically, this will
81  * be the QName that occurred in the XML source....If
82  * the argument node-set is empty or the first node has
83  * no expanded-name, an empty string is returned.
84  * If the argument it omitted, it defaults to a node-set with the context node as its only member.
85  * </blockquote>
86  *
87  * @author bob mcwhirter (bob @ werken.com)
88  *
89  * @see <a HREF="http://www.w3.org/TR/xpath#function-name" target="_top">Section 4.1 of the XPath Specification</a>
90  */

91 public class NameFunction implements Function
92 {
93     
94     
95     /**
96      * Create a new <code>NameFunction</code> object.
97      */

98     public NameFunction() {}
99     
100     /**
101      * Returns the name of the specified node or the name of the context node if
102      * no arguments are provided.
103      *
104      * @param context the context at the point in the
105      * expression where the function is called
106      * @param args a <code>List</code> containing zero or one items
107      *
108      * @return a <code>String</code> containing the name
109      *
110      * @throws FunctionCallException if <code>args</code> has more than one item
111      */

112     public Object JavaDoc call(Context context,
113                        List JavaDoc args) throws FunctionCallException
114     {
115         if ( args.size() == 0 )
116         {
117             return evaluate( context.getNodeSet(),
118                              context.getNavigator() );
119         }
120
121         if ( args.size() == 1 )
122         {
123             return evaluate( args,
124                              context.getNavigator() );
125         }
126
127         throw new FunctionCallException( "name() requires zero or one argument." );
128     }
129
130     /**
131      * Returns the name of <code>list.get(0)</code>
132      *
133      * @param list a list of nodes
134      * @param nav the <code>Navigator</code> used to retrieve the name
135      *
136      * @return the name of <code>list.get(0)</code>
137      *
138      * @throws FunctionCallException if <code>list.get(0)</code> is not a node
139      */

140     public static String JavaDoc evaluate(List JavaDoc list,
141                                   Navigator nav) throws FunctionCallException
142     {
143         if ( ! list.isEmpty() )
144         {
145             Object JavaDoc first = list.get(0);
146
147             if (first instanceof List JavaDoc)
148             {
149                 return evaluate( (List JavaDoc) first,
150                                  nav );
151             }
152             else if ( nav.isElement( first ) )
153             {
154                 return nav.getElementQName( first );
155             }
156             else if ( nav.isAttribute( first ) )
157             {
158                 return nav.getAttributeQName( first );
159             }
160             else if ( nav.isProcessingInstruction( first ) )
161             {
162                 return nav.getProcessingInstructionTarget( first );
163             }
164             else if ( nav.isNamespace( first ) )
165             {
166                 return nav.getNamespacePrefix( first );
167             }
168             else if ( nav.isDocument( first ) )
169             {
170                 return "";
171             }
172             else if ( nav.isComment( first ) )
173             {
174                 return "";
175             }
176             else if ( nav.isText( first ) )
177             {
178                 return "";
179             }
180             else {
181                 throw new FunctionCallException("The argument to the name function must be a node-set");
182             }
183         }
184
185         return "";
186
187     }
188     
189 }
190
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