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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 (C) Exoffice Technologies Inc. All Rights Reserved. 42 * 43 * $Id: IdKeyComparator.java,v 1.4 2003/08/17 01:32:25 tanderson Exp $ 44 * 45 * Date Author Changes 46 * $Date jimm Created 47 */ 48 49 50 package org.exolab.jms.persistence; 51 52 import java.io.Serializable; 53 import java.util.Comparator; 54 55 import javax.jms.JMSException; 56 57 58 /*** 59 * A comparator class that iplements a string comparison. 60 * 61 * 62 * <P>Note this class assumes that id's are in some sort of order, such that 63 * an earlier generated id is less than a later generated id. 64 * 65 * @version $Revision: 1.4 $ $Date: 2003/08/17 01:32:25 $ 66 * @author <a href="mailto:mourikis@exolab.org">Jim Mourikis</a> 67 */ 68 public class IdKeyComparator implements Comparator, Serializable { 69 70 // All Message ID's are prefixed with "ID:" 71 private static final int PREFIX_LENGTH = 3; 72 73 /*** 74 * Default constructor does nothing. 75 * 76 */ 77 public IdKeyComparator() { 78 79 } 80 81 82 /*** 83 * Implements the compare operator. 84 * Compares its two arguments for order. Returns a negative integer, zero, 85 * or a positive integer as the first argument is less than, equal to, 86 * or greater than the second. 87 * 88 * @param Object object 1 to compare 89 * @param Object object 2 ro compare to. 90 * @return int returns -1, 0, 1 if the first argument is less than, 91 * equal to, or greater than the second. 92 * @exception ClassCastException if object types are unknown 93 * 94 */ 95 public int compare(Object o1, Object o2) 96 throws ClassCastException, NullPointerException { 97 int status = 0; 98 99 if (o1 == null && o2 == null) 100 status = 0; 101 else if (o1 == null) 102 status = -1; 103 else if (o2 == null) 104 status = 1; 105 else if (o1 instanceof String && 106 o2 instanceof String) { 107 String t1 = (String) o1; 108 String t2 = (String) o2; 109 try { 110 long l1 = strip(t1); 111 long l2 = strip(t2); 112 113 if (l1 == l2) 114 status = 0; 115 else if (l1 < l2) 116 status = -1; 117 else 118 status = 1; 119 } catch (NumberFormatException err) { 120 System.err.println("Invalid IDs " + t1 + ", " + t2); 121 } 122 } else { 123 throw new ClassCastException("Unknown Object"); 124 } 125 return status; 126 } 127 128 129 /*** 130 * Indicates whether some other object is "equal to" this Comparator. 131 * This method must obey the general contract of Object.equals(Object). 132 * 133 * @param Object the object to compare to 134 * @return boolean true iff objects are equal 135 * 136 */ 137 public boolean equals(Object ob) { 138 boolean status = false; 139 140 if (ob instanceof IdKeyComparator) status = true; 141 142 return status; 143 } 144 145 146 /*** 147 * Strip the "ID:" prefix from the string, and return the long number 148 * remaininng. 149 * 150 * @param st The string to strip. 151 * @return long the remaing long integer. 152 * 153 */ 154 private long strip(String st) throws NumberFormatException { 155 return Long.parseLong(st.substring(PREFIX_LENGTH)); 156 } 157 } // End IdKeyComparator 158 159 160

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