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


1 /*
2  * Copyright 2002 by
3  * <a HREF="http://www.coridan.com">Coridan</a>
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6  * The contents of this file are subject to the Mozilla Public License Version
7  * 1.1 (the "License"); you may not use this file except in compliance with the
8  * License. You may obtain a copy of the License at
9  * http://www.mozilla.org/MPL/
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11  * Software distributed under the License is distributed on an "AS IS" basis,
12  * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
13  * for the specific language governing rights and limitations under the
14  * License.
15  *
16  * The Original Code is "MantaRay" (TM).
17  *
18  * The Initial Developer of the Original Code is Coridan.
19  * Portions created by the Initial Developer are Copyright (C) 2006
20  * Coridan Inc. All Rights Reserved.
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25  * Alternatively, the contents of this file may be used under the terms of the
26  * LGPL license (the "GNU LESSER GENERAL PUBLIC LICENSE"), in which case the
27  * provisions of LGPL are applicable instead of those above. If you wish to
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32  * If you do not delete the provisions above, a recipient may use your version
33  * of this file under either the MPL or the GNU LESSER GENERAL PUBLIC LICENSE.
34  
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36  * This library is free software; you can redistribute it and/or modify it
37  * under the terms of the MPL as stated above or under the terms of the GNU
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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43  * FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
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46 package org.mr.api.jms.selector.syntax;
47
48 import java.util.HashSet JavaDoc;
49 import java.util.Iterator JavaDoc;
50 import java.util.TreeSet JavaDoc;
51
52 import javax.jms.Message JavaDoc;
53
54
55 /**
56  * This class implements an 'in' expression.
57  * This is an expression that returns a boolean if a identifier's value is one
58  * a set of supplied values. If the identifier is null (undefined), then the
59  * expression evaluates to null.
60  *
61  */
62 class InExpression extends IdentifierExpression {
63
64     /**
65      * The set of values to compare against
66      */
67     private final HashSet JavaDoc values;
68
69
70     /**
71      * Construct a new InExpression
72      *
73      * @param ident the identifier
74      * @param values the values to check against
75      */
76     public InExpression(final Identifier ident, final HashSet JavaDoc values) {
77         super(ident);
78         this.values = values;
79     }//InExpression
80
81     /**
82      * Evaluate the expression
83      *
84      * @param msg the message to use to obtain any header identifier and property values
85      * @return the evaluated result, or null if the value of the expression is unknown
86      * @throws TypeMismatchException if the expression tries to evaluate mismatched types.
87      */
88     public final MantaObject evaluate(final Message JavaDoc msg)
89         throws TypeMismatchException {
90         MantaBoolean result = null;
91
92         MantaString value = TypeCaster.castToString(identifier().evaluate(msg), "in expression");
93         if (value != null) {
94             if (values.contains(value.getObject())) {
95                 result = MantaBoolean.TRUE;
96             }//if
97 else {
98                 result = MantaBoolean.FALSE;
99             }//else
100 }//if
101 return result;
102     }//evaluate
103
104
105     /**
106      * Return a string representation of this expression.
107      *
108      * @return a string representation of this expression
109      */
110     public final String JavaDoc toString() {
111         
112         StringBuffer JavaDoc result = new StringBuffer JavaDoc();
113         result.append('(');
114         result.append(identifier().toString());
115         result.append(" in (");
116         int i = 0;
117         
118         TreeSet JavaDoc sorted = new TreeSet JavaDoc(values);
119         // use a TreeSet to ensure that the result is the same for all
120 // runs/implementations. In general, the HashSet should be faster for
121 // individual lookups.
122 for (Iterator JavaDoc iter = sorted.iterator(); iter.hasNext(); i++) {
123             if (i > 0) {
124                 result.append(", ");
125             }//if
126 result.append("'");
127             result.append((String JavaDoc) iter.next());
128             result.append("'");
129         }//for
130 result.append("))");
131         return result.toString();
132     }//toString
133 }//InExpression
134
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