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Java > Open Source Codes > org > mr > api > jms > selector > syntax > BetweenExpression


1 /*
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7  * 1.1 (the "License"); you may not use this file except in compliance with the
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16  * The Original Code is "MantaRay" (TM).
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18  * The Initial Developer of the Original Code is Coridan.
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33  * of this file under either the MPL or the GNU LESSER GENERAL PUBLIC LICENSE.
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38  * Lesser General Public License as published by the Free Software Foundation;
39  * either version 2.1 of the License, or any later version.
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41  * This library is distributed in the hope that it will be useful, but WITHOUT
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46 package org.mr.api.jms.selector.syntax;
47
48 import javax.jms.Message JavaDoc;
49
50
51 /**
52  * This class implements a 'between' expression.
53  * This is a boolean expression of the form:
54  * numeric-expr1 between numeric-expr2 and numeric-expr3
55  * This is equivalent to:
56  * numeric-expr1 >= numeric-expr2 and numeric-expr1 <= numeric-expr3
57  */
58 class BetweenExpression implements Expression {
59
60     
61     /**
62      * Corresponds to numeric-expr1
63      */
64     private final Expression number1;
65
66     /**
67      * Corresponds to numeric-expr2
68      */
69     private final Expression number2;
70
71     /**
72      * Corresponds to numeric-expr3
73      */
74     private final Expression number3;
75
76     /**
77      * The expression context, for error reporting purposes
78      */
79     private static final String JavaDoc CONTEXT = "between expression";
80
81
82     /**
83      * Construct an expression that returns num1 >= num2 and num1 <= num3
84      * when evaluated
85      *
86      * @param num1 arithmetic expression
87      * @param num2 arithmetic expression representing the lower bound
88      * @param num3 arithmetic expression representing the upper bound
89      */
90     public BetweenExpression(final Expression num1, final Expression num2,final Expression num3) {
91         number1 = num1;
92         number2 = num2;
93         number3 = num3;
94     }//BetweenExpression
95
96     
97     /**
98      * Evaluate the 'between' expression
99      *
100      * @param msg the message to evalulate the expression against
101      * @return an MantaBoolean instance
102      * @throws TypeMismatchException if any of the expressions are not numeric
103      */
104     public final MantaObject evaluate(final Message JavaDoc msg) throws TypeMismatchException {
105
106         MantaBoolean result = null;
107         MantaNumber val1 = TypeCaster.castToNumber(number1.evaluate(msg), CONTEXT);
108         
109         if (val1 != null) {
110             MantaNumber val2 = TypeCaster.castToNumber(number2.evaluate(msg), CONTEXT);
111             if (val2 != null) {
112                 MantaNumber val3 = TypeCaster.castToNumber(number3.evaluate(msg), CONTEXT);
113                 if (val3 != null) {
114                     if (val1.greaterEqual(val2).value() && val1.lessEqual(val3).value()) {
115                         result = MantaBoolean.TRUE;
116                     }//if
117 else {
118                         result = MantaBoolean.FALSE;
119                     }//else
120 }//if
121 }//if
122 }//if
123 return result;
124     }//evaluate
125
126     
127     /**
128      * Return a string representation of this expression
129      *
130      * @return a string representation of this expression
131      */
132     public final String JavaDoc toString() {
133         
134         StringBuffer JavaDoc result = new StringBuffer JavaDoc();
135         result.append('(');
136         result.append(number1.toString());
137         result.append(" between ");
138         result.append(number2.toString());
139         result.append(" and ");
140         result.append(number3.toString());
141         result.append(')');
142         return result.toString();
143     }//toString
144 }//BetweenExpression
145
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