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1   /*
2    * $Header: /home/projects/jaxen/scm/jaxen/src/java/main/org/jaxen/function/CeilingFunction.java,v 1.9 2005/06/26 16:07:23 elharo Exp $
3    * $Revision: 1.9 $
4    * $Date: 2005/06/26 16:07:23 $
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: CeilingFunction.java,v 1.9 2005/06/26 16:07:23 elharo Exp $
60   */
61  
62  
63  package org.jaxen.function;
64  
65  import java.util.List;
66  
67  import org.jaxen.Context;
68  import org.jaxen.Function;
69  import org.jaxen.FunctionCallException;
70  import org.jaxen.Navigator;
71  
72  /***
73   *  <p><b>4.4</b> <code><i>number</i> ceiling(<i>number</i>)</code> 
74   * <blockquote src="http://www.w3.org/TR/xpath">
75   * <p>
76   *
77   * <p><q>The ceiling function returns the smallest 
78   *   (closest to negative infinity) number that is not less 
79   *   than the argument and that is an integer....If the argument 
80   *   is NaN, then NaN is returned. If the argument is positive infinity, 
81   *   then positive infinity is returned. If the argument is negative infinity, 
82   *   then negative infinity is returned. If the argument is positive zero, 
83   *   then positive zero is returned. 
84   *   If the argument is negative zero, then negative zero is returned. 
85   *   If the argument is less than zero, but greater than -1, 
86   *   then negative zero is returned.</q>
87   * </p>
88   * 
89   *  @author bob mcwhirter (bob @ werken.com)
90   *  
91   *  @see <a href="http://www.w3.org/TR/xpath#function-ceiling">Section 4.4 of the XPath Specification</a>
92   *  @see <a href="http://www.w3.org/1999/11/REC-xpath-19991116-errata/">XPath Specification Errata</a>
93   *  
94   */
95  public class CeilingFunction implements Function
96  {
97  
98      /***
99       * Create a new <code>CeilingFunction</code> object.
100      */
101     public CeilingFunction() {}
102     
103     /*** Returns the smallest integer greater than or equal to a number.
104      *
105      * @param context the context at the point in the
106      *         expression when the function is called
107      * @param args a list with exactly one item which will be converted to a 
108      *     <code>Double</code> as if by the XPath <code>number()</code> function
109      * 
110      * @return a <code>Double</code> containing the smallest integer greater than or equal
111      *     <code>args.get(0)</code>
112      * 
113      * @throws FunctionCallException if <code>args</code> has more or less than one item
114      */
115     public Object call(Context context,
116                        List args) throws FunctionCallException
117     {
118         if (args.size() == 1)
119         {
120             return evaluate( args.get(0),
121                              context.getNavigator() );
122         }
123 
124         throw new FunctionCallException("ceiling() requires one argument.");
125     }
126 
127     /*** Returns the smallest integer greater than or equal to the argument.
128      * If necessary, the argument is first converted to a <code>Double</code>
129      * as if by the XPath <code>number()</code> function.
130      * 
131      * @param obj the object whose ceiling is returned
132      * @param nav ignored
133      * 
134      * @return a <code>Double</code> containing the smallest integer 
135      *     greater than or equal to <code>obj</code>
136      */
137     public static Double evaluate(Object obj,
138                                   Navigator nav)
139     {
140         Double value = NumberFunction.evaluate( obj,
141                                                 nav );
142 
143         return new Double( Math.ceil( value.doubleValue() ) );
144     }
145 }