001 /** 002 * JDBM LICENSE v1.00 003 * 004 * Redistribution and use of this software and associated documentation 005 * ("Software"), with or without modification, are permitted provided 006 * that the following conditions are met: 007 * 008 * 1. Redistributions of source code must retain copyright 009 * statements and notices. Redistributions must also contain a 010 * copy of this document. 011 * 012 * 2. Redistributions in binary form must reproduce the 013 * above copyright notice, this list of conditions and the 014 * following disclaimer in the documentation and/or other 015 * materials provided with the distribution. 016 * 017 * 3. The name "JDBM" must not be used to endorse or promote 018 * products derived from this Software without prior written 019 * permission of Cees de Groot. For written permission, 020 * please contact cg@cdegroot.com. 021 * 022 * 4. Products derived from this Software may not be called "JDBM" 023 * nor may "JDBM" appear in their names without prior written 024 * permission of Cees de Groot. 025 * 026 * 5. Due credit should be given to the JDBM Project 027 * (http://jdbm.sourceforge.net/). 028 * 029 * THIS SOFTWARE IS PROVIDED BY THE JDBM PROJECT AND CONTRIBUTORS 030 * ``AS IS'' AND ANY EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT 031 * NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND 032 * FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL 033 * CEES DE GROOT OR ANY CONTRIBUTORS BE LIABLE FOR ANY DIRECT, 034 * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES 035 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR 036 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 037 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, 038 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 039 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED 040 * OF THE POSSIBILITY OF SUCH DAMAGE. 041 * 042 * Copyright 2001 (C) Alex Boisvert. All Rights Reserved. 043 * Contributions are Copyright (C) 2001 by their associated contributors. 044 * 045 */ 046 047 package jdbm.helper; 048 049 import java.io.IOException; 050 import java.io.Serializable; 051 import java.util.Comparator; 052 053 import org.apache.directory.server.i18n.I18n; 054 055 /** 056 * Comparator for objects which have been serialized into byte arrays. 057 * In effect, it wraps another Comparator which compares object and provides 058 * transparent deserialization from byte array to object. 059 * 060 * @author <a href="mailto:boisvert@intalio.com">Alex Boisvert</a> 061 * @version $Id: ObjectBAComparator.java,v 1.1 2002/05/31 06:33:20 boisvert Exp $ 062 */ 063 public final class ObjectBAComparator 064 implements Comparator, Serializable 065 { 066 067 /** 068 * Version id for serialization. 069 */ 070 final static long serialVersionUID = 1L; 071 072 073 /** 074 * Wrapped comparator. 075 */ 076 private Comparator _comparator; 077 078 079 /** 080 * Construct an ObjectByteArrayComparator which wraps an Object Comparator. 081 * 082 * @param comparator Object comparator. 083 */ 084 public ObjectBAComparator( Comparator comparator ) 085 { 086 if ( comparator == null ) { 087 throw new IllegalArgumentException( I18n.err( I18n.ERR_518 ) ); 088 } 089 090 _comparator = comparator; 091 } 092 093 094 /** 095 * Compare two objects. 096 * 097 * @param obj1 First object 098 * @param obj2 Second object 099 * @return 1 if obj1 > obj2, 0 if obj1 == obj2, -1 if obj1 < obj2 100 */ 101 public int compare( Object obj1, Object obj2 ) 102 { 103 if ( obj1 == null ) { 104 throw new IllegalArgumentException( I18n.err( I18n.ERR_525 ) ); 105 } 106 107 if ( obj2 == null ) { 108 throw new IllegalArgumentException( I18n.err( I18n.ERR_526 ) ); 109 } 110 111 try { 112 obj1 = Serialization.deserialize( (byte[]) obj1 ); 113 obj2 = Serialization.deserialize( (byte[]) obj2 ); 114 115 return _comparator.compare( obj1, obj2 ); 116 } catch ( IOException except ) { 117 throw new WrappedRuntimeException( except ); 118 } catch ( ClassNotFoundException except ) { 119 throw new WrappedRuntimeException( except ); 120 } 121 } 122 123 124 /** 125 * Compare two byte arrays. 126 */ 127 public static int compareByteArray( byte[] thisKey, byte[] otherKey ) 128 { 129 int len = Math.min( thisKey.length, otherKey.length ); 130 131 // compare the byte arrays 132 for ( int i=0; i<len; i++ ) { 133 if ( thisKey[i] >= 0 ) { 134 if ( otherKey[i] >= 0 ) { 135 // both positive 136 if ( thisKey[i] < otherKey[i] ) { 137 return -1; 138 } else if ( thisKey[i] > otherKey[i] ) { 139 return 1; 140 } 141 } else { 142 // otherKey is negative => greater (because MSB is 1) 143 return -1; 144 } 145 } else { 146 if ( otherKey[i] >= 0 ) { 147 // thisKey is negative => greater (because MSB is 1) 148 return 1; 149 } else { 150 // both negative 151 if ( thisKey[i] < otherKey[i] ) { 152 return -1; 153 } else if ( thisKey[i] > otherKey[i] ) { 154 return 1; 155 } 156 } 157 } 158 } 159 if ( thisKey.length == otherKey.length) { 160 return 0; 161 } 162 if ( thisKey.length < otherKey.length ) { 163 return -1; 164 } 165 return 1; 166 } 167 168 }