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1   /*
2    * $Header: /home/projects/jaxen/scm/jaxen/src/java/main/org/jaxen/function/LastFunction.java,v 1.8 2005/06/26 16:07:22 elharo Exp $
3    * $Revision: 1.8 $
4    * $Date: 2005/06/26 16:07:22 $
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: LastFunction.java,v 1.8 2005/06/26 16:07:22 elharo Exp $
60   */
61  
62  package org.jaxen.function;
63  
64  import java.util.List;
65  
66  import org.jaxen.Context;
67  import org.jaxen.Function;
68  import org.jaxen.FunctionCallException;
69  
70  /***
71   * <p><b>4.1</b> <code><i>number</i> last()</code> </p>
72   * 
73   * <blockquote src="http://www.w3.org/TR/xpath#function-last">
74   * The <b>last</b> function returns a number equal to 
75   * the context size from the expression evaluation context.
76   * </blockquote>
77   * 
78   * @author bob mcwhirter (bob @ werken.com)
79   * @see <a href="http://www.w3.org/TR/xpath#function-last" target="_top">Section 4.1 of the XPath Specification</a>
80   */
81  public class LastFunction implements Function
82  {
83  
84      /***
85       * Create a new <code>LastFunction</code> object.
86       */
87      public LastFunction() {}
88      
89      /***
90       * Returns the number of nodes in the context node-set.
91       * 
92       * @param context the context at the point in the
93       *         expression where the function is called
94       * @param args an empty list
95       * 
96       * @return a <code>Double</code> containing the context size
97       * 
98       * @throws FunctionCallException if <code>args</code> is not empty
99       * 
100      * @see Context#getSize()
101      */
102     public Object call(Context context,
103                        List args) throws FunctionCallException
104     {
105         if (args.size() == 0)
106         {
107             return evaluate( context );
108         }
109       
110         throw new FunctionCallException( "last() requires no arguments." );
111     }
112 
113     /***
114      * Returns the number of nodes in the context node-set.
115      * 
116      * @param context the context at the point in the
117      *         expression where the function is called
118      * 
119      * @return the context size
120      * 
121      * @see Context#getSize()
122      */
123     public static Double evaluate(Context context)
124     {
125         return new Double( context.getSize() );
126     }
127     
128 }