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1   /*
2    * $Header$
3    * $Revision$
4    * $Date$
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   * $Id$
46   */
47  
48  
49  package org.jaxen.function;
50  
51  import java.util.List;
52  
53  import org.jaxen.Context;
54  import org.jaxen.Function;
55  import org.jaxen.FunctionCallException;
56  import org.jaxen.Navigator;
57  
58  /**
59   *  <p><b>4.4</b> <code><i>number</i> ceiling(<i>number</i>)</code></p>
60   * <blockquote cite="http://www.w3.org/TR/xpath">
61   *
62   * <p>The ceiling function returns the smallest 
63   *   (closest to negative infinity) number that is not less 
64   *   than the argument and that is an integer....If the argument 
65   *   is NaN, then NaN is returned. If the argument is positive infinity, 
66   *   then positive infinity is returned. If the argument is negative infinity, 
67   *   then negative infinity is returned. If the argument is positive zero, 
68   *   then positive zero is returned. 
69   *   If the argument is negative zero, then negative zero is returned. 
70   *   If the argument is less than zero, but greater than -1, 
71   *   then negative zero is returned.
72   * </p></blockquote>
73   * 
74   *  @author bob mcwhirter (bob @ werken.com)
75   *  
76   *  @see <a href="https://www.w3.org/TR/xpath#function-ceiling">Section 4.4 of the XPath Specification</a>
77   *  @see <a href="https://www.w3.org/1999/11/REC-xpath-19991116-errata/">XPath Specification Errata</a>
78   *  
79   */
80  public class CeilingFunction implements Function
81  {
82  
83      /**
84       * Create a new <code>CeilingFunction</code> object.
85       */
86      public CeilingFunction() {}
87      
88      /** Returns the smallest integer greater than or equal to a number.
89       *
90       * @param context the context at the point in the
91       *         expression when the function is called
92       * @param args a list with exactly one item which will be converted to a 
93       *     <code>Double</code> as if by the XPath <code>number()</code> function
94       * 
95       * @return a <code>Double</code> containing the smallest integer greater than or equal
96       *     <code>args.get(0)</code>
97       * 
98       * @throws FunctionCallException if <code>args</code> has more or less than one item
99       */
100     public Object call(Context context,
101                        List args) throws FunctionCallException
102     {
103         if (args.size() == 1)
104         {
105             return evaluate( args.get(0),
106                              context.getNavigator() );
107         }
108 
109         throw new FunctionCallException("ceiling() requires one argument.");
110     }
111 
112     /** Returns the smallest integer greater than or equal to the argument.
113      * If necessary, the argument is first converted to a <code>Double</code>
114      * as if by the XPath <code>number()</code> function.
115      * 
116      * @param obj the object whose ceiling is returned
117      * @param nav ignored
118      * 
119      * @return a <code>Double</code> containing the smallest integer 
120      *     greater than or equal to <code>obj</code>
121      */
122     public static Double evaluate(Object obj,
123                                   Navigator nav)
124     {
125         Double value = NumberFunction.evaluate( obj,
126                                                 nav );
127 
128         return new Double( Math.ceil( value.doubleValue() ) );
129     }
130 }