1 /*
2 * $Header: /home/projects/jaxen/scm/jaxen/src/java/main/org/jaxen/function/NameFunction.java,v 1.10 2005/06/28 13:44:45 elharo Exp $
3 * $Revision: 1.10 $
4 * $Date: 2005/06/28 13:44:45 $
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 1.10 2005/06/28 13:44:45 elharo Exp $
60 */
61
62
63 package org.jaxen.function;
64
65 import java.util.List;
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 call(Context context,
113 List 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 evaluate(List list,
141 Navigator nav) throws FunctionCallException
142 {
143 if ( ! list.isEmpty() )
144 {
145 Object first = list.get(0);
146
147 if (first instanceof List)
148 {
149 return evaluate( (List) 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 }