1 /*
2 * Copyright (C) 2008, Charles O'Farrell <charleso@charleso.org>
3 * Copyright (C) 2010, Google Inc.
4 * and other copyright owners as documented in the project's IP log.
5 *
6 * This program and the accompanying materials are made available
7 * under the terms of the Eclipse Distribution License v1.0 which
8 * accompanies this distribution, is reproduced below, and is
9 * available at http://www.eclipse.org/org/documents/edl-v10.php
10 *
11 * All rights reserved.
12 *
13 * Redistribution and use in source and binary forms, with or
14 * without modification, are permitted provided that the following
15 * conditions are met:
16 *
17 * - Redistributions of source code must retain the above copyright
18 * notice, this list of conditions and the following disclaimer.
19 *
20 * - Redistributions in binary form must reproduce the above
21 * copyright notice, this list of conditions and the following
22 * disclaimer in the documentation and/or other materials provided
23 * with the distribution.
24 *
25 * - Neither the name of the Eclipse Foundation, Inc. nor the
26 * names of its contributors may be used to endorse or promote
27 * products derived from this software without specific prior
28 * written permission.
29 *
30 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
31 * CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
32 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
33 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
34 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
35 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
36 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
37 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
38 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
39 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
40 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
41 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
42 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
43 */
44
45 package org.eclipse.jgit.lib;
46
47 import java.util.ArrayList;
48 import java.util.Collection;
49 import java.util.Collections;
50 import java.util.Comparator;
51 import java.util.List;
52
53 /**
54 * Util for sorting (or comparing) Ref instances by name.
55 * <p>
56 * Useful for command line tools or writing out refs to file.
57 */
58 public class RefComparator implements Comparator<Ref> {
59
60 /** Singleton instance of RefComparator */
61 public static final RefComparator INSTANCE = new RefComparator();
62
63 @Override
64 public int compare(final Ref o1, final Ref o2) {
65 return compareTo(o1, o2);
66 }
67
68 /**
69 * Sorts the collection of refs, returning a new collection.
70 *
71 * @param refs
72 * collection to be sorted
73 * @return sorted collection of refs
74 */
75 public static Collection<Ref> sort(final Collection<Ref> refs) {
76 final List<Ref> r = new ArrayList<>(refs);
77 Collections.sort(r, INSTANCE);
78 return r;
79 }
80
81 /**
82 * Compare a reference to a name.
83 *
84 * @param o1
85 * the reference instance.
86 * @param o2
87 * the name to compare to.
88 * @return standard Comparator result of < 0, 0, > 0.
89 */
90 public static int compareTo(Ref o1, String o2) {
91 return o1.getName().compareTo(o2);
92 }
93
94 /**
95 * Compare two references by name.
96 *
97 * @param o1
98 * the reference instance.
99 * @param o2
100 * the other reference instance.
101 * @return standard Comparator result of < 0, 0, > 0.
102 */
103 public static int compareTo(final Ref o1, final Ref o2) {
104 return o1.getName().compareTo(o2.getName());
105 }
106 }