1 /*
2 * $Header: /home/projects/jaxen/scm/jaxen/src/java/main/org/jaxen/function/FloorFunction.java,v 1.8 2005/06/26 16:07:23 elharo Exp $
3 * $Revision: 1.8 $
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: FloorFunction.java,v 1.8 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> floor(<i>number</i>)</code>
74 *
75 *
76 * <blockquote src="http://www.w3.org/TR/xpath">
77 * The floor function returns the largest (closest to positive infinity)
78 * number that is not greater than the argument and that is an integer....
79 * If the argument is NaN, then NaN is returned.
80 * If the argument is positive infinity, then positive infinity is returned.
81 * If the argument is negative infinity, then negative infinity is returned.
82 * If the argument is positive zero, then positive zero is returned.
83 * If the argument is negative zero, then negative zero is returned.
84 * If the argument is greater than zero, but less than 1, then positive zero is returned.
85 * </blockquote>
86 *
87 * @author bob mcwhirter (bob @ werken.com)
88 *
89 * @see <a href="http://www.w3.org/TR/xpath#function-floor" target="_top">Section 4.4 of the XPath Specification</a>
90 * @see <a href="http://www.w3.org/1999/11/REC-xpath-19991116-errata/" target="_top">XPath Errata</a>
91 */
92 public class FloorFunction implements Function
93 {
94
95 /***
96 * Create a new <code>FloorFunction</code> object.
97 */
98 public FloorFunction() {}
99
100 /*** Returns the largest integer less than or equal to a number.
101 *
102 * @param context the context at the point in the
103 * expression when the function is called
104 * @param args a list with exactly one item which will be converted to a
105 * <code>Double</code> as if by the XPath <code>number()</code> function
106 *
107 * @return a <code>Double</code> containing the largest integer less than or equal
108 * to <code>args.get(0)</code>
109 *
110 * @throws FunctionCallException if <code>args</code> has more or less than one item
111 */
112 public Object call(Context context,
113 List args) throws FunctionCallException
114 {
115 if (args.size() == 1)
116 {
117 return evaluate( args.get(0),
118 context.getNavigator() );
119 }
120
121 throw new FunctionCallException( "floor() requires one argument." );
122 }
123
124 /*** Returns the largest integer less than or equal to the argument.
125 * If necessary, the argument is first converted to a <code>Double</code>
126 * as if by the XPath <code>number()</code> function.
127 *
128 * @param obj the object whose floor is returned
129 * @param nav ignored
130 *
131 * @return a <code>Double</code> containing the largest integer less
132 * than or equal to <code>obj</code>
133 */
134 public static Double evaluate(Object obj,
135 Navigator nav)
136 {
137 Double value = NumberFunction.evaluate( obj,
138 nav );
139
140 return new Double( Math.floor( value.doubleValue() ) );
141 }
142 }
143