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: */package jdbm.helper;
046:
047: import java.io.IOException;
048: import java.io.Serializable;
049: import java.util.Comparator;
050:
051: /**
052: * Comparator for objects which have been serialized into byte arrays.
053: * In effect, it wraps another Comparator which compares object and provides
054: * transparent deserialization from byte array to object.
055: *
056: * @author <a href="mailto:boisvert@intalio.com">Alex Boisvert</a>
057: * @version $Id: ObjectBAComparator.java,v 1.1 2002/05/31 06:33:20 boisvert Exp $
058: */
059: public final class ObjectBAComparator implements Comparator,
060: Serializable {
061:
062: /**
063: * Version id for serialization.
064: */
065: final static long serialVersionUID = 1L;
066:
067: /**
068: * Wrapped comparator.
069: */
070: private Comparator _comparator;
071:
072: /**
073: * Construct an ObjectByteArrayComparator which wraps an Object Comparator.
074: *
075: * @param comparator Object comparator.
076: */
077: public ObjectBAComparator(Comparator comparator) {
078: if (comparator == null) {
079: throw new IllegalArgumentException(
080: "Argument 'comparator' is null");
081: }
082:
083: _comparator = comparator;
084: }
085:
086: /**
087: * Compare two objects.
088: *
089: * @param obj1 First object
090: * @param obj2 Second object
091: * @return 1 if obj1 > obj2, 0 if obj1 == obj2, -1 if obj1 < obj2
092: */
093: public int compare(Object obj1, Object obj2) {
094: if (obj1 == null) {
095: throw new IllegalArgumentException(
096: "Argument 'obj1' is null");
097: }
098:
099: if (obj2 == null) {
100: throw new IllegalArgumentException(
101: "Argument 'obj2' is null");
102: }
103:
104: try {
105: obj1 = Serialization.deserialize((byte[]) obj1);
106: obj2 = Serialization.deserialize((byte[]) obj2);
107:
108: return _comparator.compare(obj1, obj2);
109: } catch (IOException except) {
110: throw new WrappedRuntimeException(except);
111: } catch (ClassNotFoundException except) {
112: throw new WrappedRuntimeException(except);
113: }
114: }
115:
116: /**
117: * Compare two byte arrays.
118: */
119: public static int compareByteArray(byte[] this Key, byte[] otherKey) {
120: int len = Math.min(this Key.length, otherKey.length);
121:
122: // compare the byte arrays
123: for (int i = 0; i < len; i++) {
124: if (this Key[i] >= 0) {
125: if (otherKey[i] >= 0) {
126: // both positive
127: if (this Key[i] < otherKey[i]) {
128: return -1;
129: } else if (this Key[i] > otherKey[i]) {
130: return 1;
131: }
132: } else {
133: // otherKey is negative => greater (because MSB is 1)
134: return -1;
135: }
136: } else {
137: if (otherKey[i] >= 0) {
138: // thisKey is negative => greater (because MSB is 1)
139: return 1;
140: } else {
141: // both negative
142: if (this Key[i] < otherKey[i]) {
143: return -1;
144: } else if (this Key[i] > otherKey[i]) {
145: return 1;
146: }
147: }
148: }
149: }
150: if (this Key.length == otherKey.length) {
151: return 0;
152: }
153: if (this Key.length < otherKey.length) {
154: return -1;
155: }
156: return 1;
157: }
158:
159: }
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