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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 47 /*** 48 * Utility class for casting from an SObject to a derived class, 49 * raising a TypeMismatchException if the operation is invalid. 50 * 51 * @version $Revision: 1.4 $ $Date: 2003/08/09 15:49:50 $ 52 * @author <a href="mailto:tma@netspace.net.au">Tim Anderson</a> 53 * @see Expression 54 * @see SBool 55 * @see SNumber 56 * @see SString 57 * @see TypeMismatchException 58 */ 59 final class TypeCaster { 60 61 /*** 62 * Private constructor 63 */ 64 private TypeCaster() { 65 } 66 67 /*** 68 * Cast an object to boolean 69 * 70 * @param obj the object to cast 71 * @param context the context where the object was created 72 * @return the cast object 73 * @throws TypeMismatchException if <code>obj</code> can't be cast 74 */ 75 public static SBool castToBool(final SObject obj, final String context) 76 throws TypeMismatchException { 77 78 SBool result = null; 79 if (obj instanceof SBool) { 80 result = (SBool) obj; 81 } else if (obj != null) { 82 typeMismatch(Type.BOOLEAN, obj, context); 83 } 84 return result; 85 } 86 87 /*** 88 * Cast an object to numeric 89 * 90 * @param obj the object to cast 91 * @param context the context where the object was created 92 * @return the cast object 93 * @throws TypeMismatchException if <code>obj</code> can't be cast 94 */ 95 public static SNumber castToNumber(final SObject obj, final String context) 96 throws TypeMismatchException { 97 98 SNumber result = null; 99 if (obj instanceof SNumber) { 100 result = (SNumber) obj; 101 } else if (obj != null) { 102 typeMismatch(Type.NUMERIC, obj, context); 103 } 104 return result; 105 } 106 107 /*** 108 * Cast an object to string 109 * 110 * @param obj the object to cast 111 * @param context the context where the object was created 112 * @return the cast object 113 * @throws TypeMismatchException if <code>obj</code> can't be cast 114 */ 115 public static SString castToString(final SObject obj, final String context) 116 throws TypeMismatchException { 117 118 SString result = null; 119 if (obj instanceof SString) { 120 result = (SString) obj; 121 } else if (obj != null) { 122 typeMismatch(Type.STRING, obj, context); 123 } 124 return result; 125 } 126 127 /*** 128 * Raises a type mismatch exception 129 * 130 * @param expected the expected type 131 * @param value the actual value 132 * @param context the context where <code>value</code> was created 133 * @throws TypeMismatchException corresponding to the expected and actual 134 * values 135 */ 136 private static void typeMismatch(final Type expected, final SObject value, 137 final String context) 138 throws TypeMismatchException { 139 140 StringBuffer msg = new StringBuffer(); 141 msg.append("expecting a "); 142 msg.append(expected); 143 msg.append(" expression"); 144 if (context != null) { 145 msg.append(" for "); 146 msg.append(context); 147 } 148 msg.append(", found a "); 149 msg.append(value.type()); 150 throw new TypeMismatchException(msg.toString()); 151 } 152 153 } //-- TypeCaster

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