KickJava   Java API By Example, From Geeks To Geeks.

Java > Open Source Codes > org > exolab > jms > selector > Not


1 /**
2  * Redistribution and use of this software and associated documentation
3  * ("Software"), with or without modification, are permitted provided
4  * that the following conditions are met:
5  *
6  * 1. Redistributions of source code must retain copyright
7  * statements and notices. Redistributions must also contain a
8  * copy of this document.
9  *
10  * 2. Redistributions in binary form must reproduce the
11  * above copyright notice, this list of conditions and the
12  * following disclaimer in the documentation and/or other
13  * materials provided with the distribution.
14  *
15  * 3. The name "Exolab" must not be used to endorse or promote
16  * products derived from this Software without prior written
17  * permission of Exoffice Technologies. For written permission,
18  * please contact info@exolab.org.
19  *
20  * 4. Products derived from this Software may not be called "Exolab"
21  * nor may "Exolab" appear in their names without prior written
22  * permission of Exoffice Technologies. Exolab is a registered
23  * trademark of Exoffice Technologies.
24  *
25  * 5. Due credit should be given to the Exolab Project
26  * (http://www.exolab.org/).
27  *
28  * THIS SOFTWARE IS PROVIDED BY EXOFFICE TECHNOLOGIES AND CONTRIBUTORS
29  * ``AS IS'' AND ANY EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT
30  * NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
31  * FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
32  * EXOFFICE TECHNOLOGIES OR ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
33  * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
34  * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
35  * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
36  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
37  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
38  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
39  * OF THE POSSIBILITY OF SUCH DAMAGE.
40  *
41  * Copyright 2000-2001,2003 (C) Exoffice Technologies Inc. All Rights Reserved.
42  */
43
44 package org.exolab.jms.selector;
45
46
47 import javax.jms.Message JavaDoc;
48
49
50 /**
51  * This class implements a 'not' operator.
52  *
53  * @version $Revision: 1.1 $ $Date: 2004/11/26 01:50:44 $
54  * @author <a HREF="mailto:tma@netspace.net.au">Tim Anderson</a>
55  * @see Expression
56  * @see SBool
57  * @see UnaryOperator
58  */
59 class Not extends UnaryOperator {
60
61     /**
62      * The expression context, for error reporting purposes
63      */
64     private static final String JavaDoc CONTEXT = "not operator";
65
66
67     /**
68      * Construct a new <code>Not</code> operator
69      *
70      * @param operand the operand
71      */
72     public Not(final Expression operand) {
73         super("not", operand);
74     }
75
76     /**
77      * Evaluate the expression
78      *
79      * @param msg the message to evaluate this expression against
80      * @return the result of expression
81      * @throws TypeMismatchException if the operand doesn't evaluate to
82      * a boolean or null
83      */
84     public SObject evaluate(final Message JavaDoc msg) throws TypeMismatchException {
85         SBool result = null;
86         SBool value = TypeCaster.castToBool(operand().evaluate(msg), CONTEXT);
87         if (value != null) {
88             result = value.not();
89         }
90         return result;
91     }
92
93 } //-- Not
94
Popular Tags