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 * Example of a <i>case-sensitive</i> file path sort using the
35 * {@link #PATH_COMPARATOR} singleton instance:
36 * <pre>
37 * List<File> list = ...
38 * ((AbstractFileComparator) PathFileComparator.PATH_COMPARATOR).sort(list);
39 * </pre>
40 * <p>
41 * Example of a <i>reverse case-insensitive</i> file path sort using the
42 * {@link #PATH_INSENSITIVE_REVERSE} singleton instance:
43 * <pre>
44 * File[] array = ...
45 * ((AbstractFileComparator) PathFileComparator.PATH_INSENSITIVE_REVERSE).sort(array);
46 * </pre>
47 * <p>
48 *
49 * @version $Id: PathFileComparator.java 1469107 2013-04-17 23:45:53Z sebb $
50 * @since 1.4
51 */
52 public class PathFileComparator extends AbstractFileComparator implements Serializable {
53
54 /** Case-sensitive path comparator instance (see {@link IOCase#SENSITIVE}) */
55 public static final Comparator<File> PATH_COMPARATOR = new PathFileComparator();
56
57 /** Reverse case-sensitive path comparator instance (see {@link IOCase#SENSITIVE}) */
58 public static final Comparator<File> PATH_REVERSE = new ReverseComparator(PATH_COMPARATOR);
59
60 /** Case-insensitive path comparator instance (see {@link IOCase#INSENSITIVE}) */
61 public static final Comparator<File> PATH_INSENSITIVE_COMPARATOR = new PathFileComparator(IOCase.INSENSITIVE);
62
63 /** Reverse case-insensitive path comparator instance (see {@link IOCase#INSENSITIVE}) */
64 public static final Comparator<File> PATH_INSENSITIVE_REVERSE = new ReverseComparator(PATH_INSENSITIVE_COMPARATOR);
65
66 /** System sensitive path comparator instance (see {@link IOCase#SYSTEM}) */
67 public static final Comparator<File> PATH_SYSTEM_COMPARATOR = new PathFileComparator(IOCase.SYSTEM);
68
69 /** Reverse system sensitive path comparator instance (see {@link IOCase#SYSTEM}) */
70 public static final Comparator<File> PATH_SYSTEM_REVERSE = new ReverseComparator(PATH_SYSTEM_COMPARATOR);
71
72 /** Whether the comparison is case sensitive. */
73 private final IOCase caseSensitivity;
74
75 /**
76 * Construct a case sensitive file path comparator instance.
77 */
78 public PathFileComparator() {
79 this.caseSensitivity = IOCase.SENSITIVE;
80 }
81
82 /**
83 * Construct a file path comparator instance with the specified case-sensitivity.
84 *
85 * @param caseSensitivity how to handle case sensitivity, null means case-sensitive
86 */
87 public PathFileComparator(final IOCase caseSensitivity) {
88 this.caseSensitivity = caseSensitivity == null ? IOCase.SENSITIVE : caseSensitivity;
89 }
90
91 /**
92 * Compare the paths of two files the specified case sensitivity.
93 *
94 * @param file1 The first file to compare
95 * @param file2 The second file to compare
96 * @return a negative value if the first file's path
97 * is less than the second, zero if the paths are the
98 * same and a positive value if the first files path
99 * is greater than the second file.
100 *
101 */
102 public int compare(final File file1, final File file2) {
103 return caseSensitivity.checkCompareTo(file1.getPath(), file2.getPath());
104 }
105
106 /**
107 * String representation of this file comparator.
108 *
109 * @return String representation of this file comparator
110 */
111 @Override
112 public String toString() {
113 return super.toString() + "[caseSensitivity=" + caseSensitivity + "]";
114 }
115 }