1 /*
2 * $Header: /home/projects/jaxen/scm/jaxen/src/java/main/org/jaxen/function/LastFunction.java,v 1.10 2006/02/05 21:47:41 elharo Exp $
3 * $Revision: 1.10 $
4 * $Date: 2006/02/05 21:47:41 $
5 *
6 * ====================================================================
7 *
8 * Copyright 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 are
13 * met:
14 *
15 * * Redistributions of source code must retain the above copyright
16 * notice, this list of conditions and the following disclaimer.
17 *
18 * * Redistributions in binary form must reproduce the above copyright
19 * notice, this list of conditions and the following disclaimer in the
20 * documentation and/or other materials provided with the distribution.
21 *
22 * * Neither the name of the Jaxen Project nor the names of its
23 * contributors may be used to endorse or promote products derived
24 * from this software without specific prior written permission.
25 *
26 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
27 * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
28 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
29 * PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER
30 * OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
31 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
32 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
33 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
34 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
35 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
36 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
37 *
38 * ====================================================================
39 * This software consists of voluntary contributions made by many
40 * individuals on behalf of the Jaxen Project and was originally
41 * created by bob mcwhirter <bob@werken.com> and
42 * James Strachan <jstrachan@apache.org>. For more information on the
43 * Jaxen Project, please see <http://www.jaxen.org/>.
44 *
45 * $Id: LastFunction.java,v 1.10 2006/02/05 21:47:41 elharo Exp $
46 */
47
48 package org.jaxen.function;
49
50 import java.util.List;
51
52 import org.jaxen.Context;
53 import org.jaxen.Function;
54 import org.jaxen.FunctionCallException;
55
56 /***
57 * <p><b>4.1</b> <code><i>number</i> last()</code> </p>
58 *
59 * <blockquote src="http://www.w3.org/TR/xpath#function-last">
60 * The <b>last</b> function returns a number equal to
61 * the context size from the expression evaluation context.
62 * </blockquote>
63 *
64 * @author bob mcwhirter (bob @ werken.com)
65 * @see <a href="http://www.w3.org/TR/xpath#function-last" target="_top">Section 4.1 of the XPath Specification</a>
66 */
67 public class LastFunction implements Function
68 {
69
70 /***
71 * Create a new <code>LastFunction</code> object.
72 */
73 public LastFunction() {}
74
75 /***
76 * Returns the number of nodes in the context node-set.
77 *
78 * @param context the context at the point in the
79 * expression where the function is called
80 * @param args an empty list
81 *
82 * @return a <code>Double</code> containing the context size
83 *
84 * @throws FunctionCallException if <code>args</code> is not empty
85 *
86 * @see Context#getSize()
87 */
88 public Object call(Context context,
89 List args) throws FunctionCallException
90 {
91 if (args.size() == 0)
92 {
93 return evaluate( context );
94 }
95
96 throw new FunctionCallException( "last() requires no arguments." );
97 }
98
99 /***
100 * Returns the number of nodes in the context node-set.
101 *
102 * @param context the context at the point in the
103 * expression where the function is called
104 *
105 * @return the context size
106 *
107 * @see Context#getSize()
108 */
109 public static Double evaluate(Context context)
110 {
111 return new Double( context.getSize() );
112 }
113
114 }