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Java > Open Source Codes > org > apache > taglibs > standard > lang > jpath > expression > CeilingFunction


1 /*
2  * Copyright 1999,2004 The Apache Software Foundation.
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  * http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16
17 package org.apache.taglibs.standard.lang.jpath.expression;
18
19 import javax.servlet.jsp.PageContext JavaDoc;
20
21 import org.apache.taglibs.standard.lang.jpath.adapter.ConversionException;
22 import org.apache.taglibs.standard.lang.jpath.adapter.Convert;
23 import org.apache.taglibs.standard.lang.jpath.adapter.IterationContext;
24
25 /**
26  * The CeilingFunction class
27  *
28  *
29  * @author <a HREF='mailto:scott.hasse@isthmusgroup.com'>Scott Hasse</a>
30  * @version
31  */
32 public class CeilingFunction extends SimpleNode {
33
34     /**
35      * Used to create an instance of the CeilingFunction class
36      *
37      *
38      * @param id
39      *
40      */
41     public CeilingFunction(int id) {
42         super(id);
43     }
44
45     /**
46      * Used to create an instance of the CeilingFunction class
47      *
48      *
49      * @param p
50      * @param id
51      *
52      */
53     public CeilingFunction(Parser p, int id) {
54         super(p, id);
55     }
56
57     /**
58      * Provides a method to print a normalized version of the original
59      * expression. The normalized version has standardized spacing and
60      * parenthesis, and can be used to compare expressions formatted
61      * in different ways to see if they are actually the same expression.
62      *
63      *
64      * @return The normalized version of the original expression
65      *
66      */
67     public String JavaDoc toNormalizedString() {
68
69         String JavaDoc normalized = "";
70
71         normalized = "ceiling(" + jjtGetChild(0).toNormalizedString() + ")";
72
73         return normalized;
74     }
75
76     /**
77      * This method evaluates this node of the expression and all child nodes.
78      * It returns the result of the
79      * evaluation as an <tt>Object</tt>. If any problems are encountered
80      * during the evaluation, an <tt>EvaluationException</tt> is thrown.
81      *
82      *
83      * @param pageContext the current JSP PageContext
84      *
85      * @param icontext the Iteration Context of the expression. If there is
86      * no interation context, this should be null.
87      *
88      * @return the result of the expression evaluation as an object
89      *
90      * @throws EvaluationException if a problem is encountered during the
91      * evaluation
92      */
93     public Object JavaDoc evaluate(PageContext JavaDoc pageContext, IterationContext icontext)
94             throws EvaluationException {
95
96         Double JavaDoc result;
97
98         try {
99             result = Convert.toDouble(jjtGetChild(0).evaluate(pageContext,
100                     icontext));
101         } catch (ConversionException ce) {
102             throw new EvaluationException(this, ce.getMessage());
103         }
104
105         return new Double JavaDoc(Math.ceil(result.doubleValue()));
106     }
107 }
108
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