1 /*
2 * Licensed to the Apache Software Foundation (ASF) under one or more
3 * contributor license agreements. See the NOTICE file distributed with
4 * this work for additional information regarding copyright ownership.
5 * The ASF licenses this file to You under the Apache License, Version 2.0
6 * (the "License"); you may not use this file except in compliance with
7 * the License. You may obtain a copy of the License at
8 *
9 * http://www.apache.org/licenses/LICENSE-2.0
10 *
11 * Unless required by applicable law or agreed to in writing, software
12 * distributed under the License is distributed on an "AS IS" BASIS,
13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 * See the License for the specific language governing permissions and
15 * limitations under the License.
16 */
17 package org.apache.commons.io.comparator;
18
19 import java.io.File;
20 import java.io.Serializable;
21 import java.util.Comparator;
22
23 import org.apache.commons.io.IOCase;
24
25 /**
26 * Compare the <b>path</b> of two files for order (see {@link File#getPath()}).
27 * <p>
28 * This comparator can be used to sort lists or arrays of files
29 * by their path either in a case-sensitive, case-insensitive or
30 * system dependent case-sensitive way. A number of singleton instances
31 * are provided for the various case sensitivity options (using {@link IOCase})
32 * and the reverse of those options.
33 * </p>
34 * <p>
35 * Example of a <i>case-sensitive</i> file path sort using the
36 * {@link #PATH_COMPARATOR} singleton instance:
37 * </p>
38 * <pre>
39 * List<File> list = ...
40 * ((AbstractFileComparator) PathFileComparator.PATH_COMPARATOR).sort(list);
41 * </pre>
42 * <p>
43 * Example of a <i>reverse case-insensitive</i> file path sort using the
44 * {@link #PATH_INSENSITIVE_REVERSE} singleton instance:
45 * </p>
46 * <pre>
47 * File[] array = ...
48 * ((AbstractFileComparator) PathFileComparator.PATH_INSENSITIVE_REVERSE).sort(array);
49 * </pre>
50 * <h2>Deprecating Serialization</h2>
51 * <p>
52 * <em>Serialization is deprecated and will be removed in 3.0.</em>
53 * </p>
54 * @since 1.4
55 */
56 public class PathFileComparator extends AbstractFileComparator implements Serializable {
57
58 private static final long serialVersionUID = 6527501707585768673L;
59
60 /** Case-sensitive path comparator instance (see {@link IOCase#SENSITIVE}) */
61 public static final Comparator<File> PATH_COMPARATOR = new PathFileComparator();
62
63 /** Reverse case-sensitive path comparator instance (see {@link IOCase#SENSITIVE}) */
64 public static final Comparator<File> PATH_REVERSE = new ReverseFileComparator(PATH_COMPARATOR);
65
66 /** Case-insensitive path comparator instance (see {@link IOCase#INSENSITIVE}) */
67 public static final Comparator<File> PATH_INSENSITIVE_COMPARATOR = new PathFileComparator(IOCase.INSENSITIVE);
68
69 /** Reverse case-insensitive path comparator instance (see {@link IOCase#INSENSITIVE}) */
70 public static final Comparator<File> PATH_INSENSITIVE_REVERSE = new ReverseFileComparator(PATH_INSENSITIVE_COMPARATOR);
71
72 /** System sensitive path comparator instance (see {@link IOCase#SYSTEM}) */
73 public static final Comparator<File> PATH_SYSTEM_COMPARATOR = new PathFileComparator(IOCase.SYSTEM);
74
75 /** Reverse system sensitive path comparator instance (see {@link IOCase#SYSTEM}) */
76 public static final Comparator<File> PATH_SYSTEM_REVERSE = new ReverseFileComparator(PATH_SYSTEM_COMPARATOR);
77
78 /** Whether the comparison is case-sensitive. */
79 private final IOCase ioCase;
80
81 /**
82 * Constructs a case-sensitive file path comparator instance.
83 */
84 public PathFileComparator() {
85 this.ioCase = IOCase.SENSITIVE;
86 }
87
88 /**
89 * Constructs a file path comparator instance with the specified case-sensitivity.
90 *
91 * @param ioCase how to handle case sensitivity, null means case-sensitive
92 */
93 public PathFileComparator(final IOCase ioCase) {
94 this.ioCase = IOCase.value(ioCase, IOCase.SENSITIVE);
95 }
96
97 /**
98 * Compares the paths of two files the specified case sensitivity.
99 *
100 * @param file1 The first file to compare
101 * @param file2 The second file to compare
102 * @return a negative value if the first file's path
103 * is less than the second, zero if the paths are the
104 * same and a positive value if the first files path
105 * is greater than the second file.
106 */
107 @Override
108 public int compare(final File file1, final File file2) {
109 return ioCase.checkCompareTo(file1.getPath(), file2.getPath());
110 }
111
112 /**
113 * String representation of this file comparator.
114 *
115 * @return String representation of this file comparator
116 */
117 @Override
118 public String toString() {
119 return super.toString() + "[ioCase=" + ioCase + "]";
120 }
121 }