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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 }