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1   /*
2    * $Header: /home/projects/jaxen/scm/jaxen/src/java/main/org/jaxen/function/CeilingFunction.java,v 1.11 2006/02/05 21:47:41 elharo Exp $
3    * $Revision: 1.11 $
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: CeilingFunction.java,v 1.11 2006/02/05 21:47:41 elharo Exp $
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> 
60   * <blockquote src="http://www.w3.org/TR/xpath">
61   * <p>
62   *
63   * <p><q>The ceiling function returns the smallest 
64   *   (closest to negative infinity) number that is not less 
65   *   than the argument and that is an integer....If the argument 
66   *   is NaN, then NaN is returned. If the argument is positive infinity, 
67   *   then positive infinity is returned. If the argument is negative infinity, 
68   *   then negative infinity is returned. If the argument is positive zero, 
69   *   then positive zero is returned. 
70   *   If the argument is negative zero, then negative zero is returned. 
71   *   If the argument is less than zero, but greater than -1, 
72   *   then negative zero is returned.</q>
73   * </p>
74   * 
75   *  @author bob mcwhirter (bob @ werken.com)
76   *  
77   *  @see <a href="http://www.w3.org/TR/xpath#function-ceiling">Section 4.4 of the XPath Specification</a>
78   *  @see <a href="http://www.w3.org/1999/11/REC-xpath-19991116-errata/">XPath Specification Errata</a>
79   *  
80   */
81  public class CeilingFunction implements Function
82  {
83  
84      /***
85       * Create a new <code>CeilingFunction</code> object.
86       */
87      public CeilingFunction() {}
88      
89      /*** Returns the smallest integer greater than or equal to a number.
90       *
91       * @param context the context at the point in the
92       *         expression when the function is called
93       * @param args a list with exactly one item which will be converted to a 
94       *     <code>Double</code> as if by the XPath <code>number()</code> function
95       * 
96       * @return a <code>Double</code> containing the smallest integer greater than or equal
97       *     <code>args.get(0)</code>
98       * 
99       * @throws FunctionCallException if <code>args</code> has more or less than one item
100      */
101     public Object call(Context context,
102                        List args) throws FunctionCallException
103     {
104         if (args.size() == 1)
105         {
106             return evaluate( args.get(0),
107                              context.getNavigator() );
108         }
109 
110         throw new FunctionCallException("ceiling() requires one argument.");
111     }
112 
113     /*** Returns the smallest integer greater than or equal to the argument.
114      * If necessary, the argument is first converted to a <code>Double</code>
115      * as if by the XPath <code>number()</code> function.
116      * 
117      * @param obj the object whose ceiling is returned
118      * @param nav ignored
119      * 
120      * @return a <code>Double</code> containing the smallest integer 
121      *     greater than or equal to <code>obj</code>
122      */
123     public static Double evaluate(Object obj,
124                                   Navigator nav)
125     {
126         Double value = NumberFunction.evaluate( obj,
127                                                 nav );
128 
129         return new Double( Math.ceil( value.doubleValue() ) );
130     }
131 }