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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 import javax.jms.Message; 47 48 49 /*** 50 * This class implements a unary minus operator. 51 * 52 * @version $Revision: 1.4 $ $Date: 2003/08/09 15:49:50 $ 53 * @author <a href="mailto:tma@netspace.net.au">Tim Anderson</a> 54 * @see Expression 55 * @see SNumber 56 * @see UnaryOperator 57 */ 58 class UnaryMinus extends UnaryOperator { 59 60 /*** 61 * The expression context, for error reporting purposes 62 */ 63 private static final String CONTEXT = "unary minus"; 64 65 /*** 66 * Helper for -1 67 */ 68 private static final SLong MINUS1 = new SLong(-1); 69 70 /*** 71 * Construct a new <code>UnaryMinus</code> operator 72 * 73 * @param operand the operand 74 */ 75 public UnaryMinus(final Expression operand) { 76 super("-", operand); 77 } 78 79 /*** 80 * Evaluate the expression 81 * 82 * @param msg the message to evaluate this expression against 83 * @return the result of expression 84 * @throws TypeMismatchException if the operand doesn't evaluate to 85 * a numeric or null 86 */ 87 public final SObject evaluate(final Message msg) 88 throws TypeMismatchException { 89 SObject result = null; 90 SNumber value = TypeCaster.castToNumber(operand().evaluate(msg), 91 CONTEXT); 92 if (value != null) { 93 result = value.multiply(MINUS1); 94 } 95 return result; 96 } 97 98 } //-- UnaryMinus

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