01: /* ====================================================================
02: * The LateralNZ Software License, Version 1.0
03: *
04: * Copyright (c) 2003 LateralNZ. All rights reserved.
05: *
06: * Redistribution and use in source and binary forms, with or without
07: * modification, are permitted provided that the following conditions
08: * are met:
09: *
10: * 1. Redistributions of source code must retain the above copyright
11: * notice, this list of conditions and the following disclaimer.
12: *
13: * 2. Redistributions in binary form must reproduce the above copyright
14: * notice, this list of conditions and the following disclaimer in
15: * the documentation and/or other materials provided with the
16: * distribution.
17: *
18: * 3. The end-user documentation included with the redistribution,
19: * if any, must include the following acknowledgment:
20: * "This product includes software developed by
21: * LateralNZ (http://www.lateralnz.org/) and other third parties."
22: * Alternately, this acknowledgment may appear in the software itself,
23: * if and wherever such third-party acknowledgments normally appear.
24: *
25: * 4. The names "LateralNZ" must not be used to endorse or promote
26: * products derived from this software without prior written
27: * permission. For written permission, please
28: * contact oss@lateralnz.org.
29: *
30: * 5. Products derived from this software may not be called "Panther",
31: * or "Lateral" or "LateralNZ", nor may "PANTHER" or "LATERAL" or
32: * "LATERALNZ" appear in their name, without prior written
33: * permission of LateralNZ.
34: *
35: * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
36: * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
37: * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
38: * DISCLAIMED. IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
39: * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
40: * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
41: * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
42: * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
43: * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
44: * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
45: * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
46: * SUCH DAMAGE.
47: * ====================================================================
48: *
49: * This software consists of voluntary contributions made by many
50: * individuals on behalf of LateralNZ. For more
51: * information on Lateral, please see http://www.lateralnz.com/ or
52: * http://www.lateralnz.org
53: *
54: */
55: package org.lateralnz.common.util;
56:
57: import java.util.Comparator;
58:
59: /**
60: * a comparator that can be reversed (i.e. ascending becomes descending order)
61: *
62: * @author J R Briggs
63: */
64: public abstract class ReversibleComparator implements Comparator {
65: private ReversibleComparator comp = null;
66: private Comparator reverse = null;
67:
68: public ReversibleComparator() {
69: this .comp = this ;
70: }
71:
72: /**
73: * return the reverse of the current comparator
74: */
75: public Comparator getReverse() {
76: if (reverse == null) {
77: reverse = new Comparator() {
78: public int compare(Object obj1, Object obj2) {
79: return comp.compare(obj2, obj1);
80: }
81: };
82: }
83:
84: return reverse;
85: }
86: }
|