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


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.IterationContext;
22
23 /**
24  * The NumberLiteral class
25  *
26  *
27  * @author <a HREF='mailto:scott.hasse@isthmusgroup.com'>Scott Hasse</a>
28  * @version
29  */
30 public class NumberLiteral extends SimpleNode {
31
32     protected double val;
33
34     /**
35      * Used to create an instance of the NumberLiteral class
36      *
37      *
38      * @param id
39      *
40      */
41     public NumberLiteral(int id) {
42         super(id);
43     }
44
45     /**
46      * Used to create an instance of the NumberLiteral class
47      *
48      *
49      * @param p
50      * @param id
51      *
52      */
53     public NumberLiteral(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         return String.valueOf(val);
69     }
70
71     /**
72      * This method evaluates this node of the expression and all child nodes.
73      * It returns the result of the
74      * evaluation as an <tt>Object</tt>. If any problems are encountered
75      * during the evaluation, an <tt>EvaluationException</tt> is thrown.
76      *
77      *
78      * @param pageContext the current JSP PageContext
79      *
80      * @param icontext the Iteration Context of the expression. If there is
81      * no interation context, this should be null.
82      *
83      * @return the result of the expression evaluation as an object
84      *
85      * @throws EvaluationException if a problem is encountered during the
86      * evaluation
87      */
88     public Object JavaDoc evaluate(PageContext JavaDoc pageContext, IterationContext icontext)
89             throws EvaluationException {
90         return new Double JavaDoc(val);
91     }
92 }
93
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