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.FileUtils;
24
25 /**
26 * Compare the <b>length/size</b> of two files for order (see
27 * {@link File#length()} and {@link FileUtils#sizeOfDirectory(File)}).
28 * <p>
29 * This comparator can be used to sort lists or arrays of files
30 * by their length/size.
31 * </p>
32 * <p>
33 * Example of sorting a list of files using the
34 * {@link #SIZE_COMPARATOR} singleton instance:
35 * </p>
36 * <pre>
37 * List<File> list = ...
38 * ((AbstractFileComparator) SizeFileComparator.SIZE_COMPARATOR).sort(list);
39 * </pre>
40 * <p>
41 * Example of doing a <i>reverse</i> sort of an array of files using the
42 * {@link #SIZE_REVERSE} singleton instance:
43 * </p>
44 * <pre>
45 * File[] array = ...
46 * ((AbstractFileComparator) SizeFileComparator.SIZE_REVERSE).sort(array);
47 * </pre>
48 * <p>
49 * <strong>N.B.</strong> Directories are treated as <b>zero size</b> unless
50 * {@code sumDirectoryContents} is {@code true}.
51 * </p>
52 * <h2>Deprecating Serialization</h2>
53 * <p>
54 * <em>Serialization is deprecated and will be removed in 3.0.</em>
55 * </p>
56 *
57 * @since 1.4
58 */
59 public class SizeFileComparator extends AbstractFileComparator implements Serializable {
60
61 private static final long serialVersionUID = -1201561106411416190L;
62
63 /** Size comparator instance - directories are treated as zero size */
64 public static final Comparator<File> SIZE_COMPARATOR = new SizeFileComparator();
65
66 /** Reverse size comparator instance - directories are treated as zero size */
67 public static final Comparator<File> SIZE_REVERSE = new ReverseFileComparator(SIZE_COMPARATOR);
68
69 /**
70 * Size comparator instance which sums the size of a directory's contents
71 * using {@link FileUtils#sizeOfDirectory(File)}
72 */
73 public static final Comparator<File> SIZE_SUMDIR_COMPARATOR = new SizeFileComparator(true);
74
75 /**
76 * Reverse size comparator instance which sums the size of a directory's contents
77 * using {@link FileUtils#sizeOfDirectory(File)}
78 */
79 public static final Comparator<File> SIZE_SUMDIR_REVERSE = new ReverseFileComparator(SIZE_SUMDIR_COMPARATOR);
80
81 /** Whether the sum of the directory's contents should be calculated. */
82 private final boolean sumDirectoryContents;
83
84 /**
85 * Constructs a file size comparator instance (directories treated as zero size).
86 */
87 public SizeFileComparator() {
88 this.sumDirectoryContents = false;
89 }
90
91 /**
92 * Constructs a file size comparator instance specifying whether the size of
93 * the directory contents should be aggregated.
94 * <p>
95 * If the {@code sumDirectoryContents} is {@code true} The size of
96 * directories is calculated using {@link FileUtils#sizeOfDirectory(File)}.
97 * </p>
98 *
99 * @param sumDirectoryContents {@code true} if the sum of the directories' contents
100 * should be calculated, otherwise {@code false} if directories should be treated
101 * as size zero (see {@link FileUtils#sizeOfDirectory(File)}).
102 */
103 public SizeFileComparator(final boolean sumDirectoryContents) {
104 this.sumDirectoryContents = sumDirectoryContents;
105 }
106
107 /**
108 * Compares the length of two files.
109 *
110 * @param file1 The first file to compare
111 * @param file2 The second file to compare
112 * @return a negative value if the first file's length
113 * is less than the second, zero if the lengths are the
114 * same and a positive value if the first files length
115 * is greater than the second file.
116 */
117 @Override
118 public int compare(final File file1, final File file2) {
119 final long size1;
120 if (file1.isDirectory()) {
121 size1 = sumDirectoryContents && file1.exists() ? FileUtils.sizeOfDirectory(file1) : 0;
122 } else {
123 size1 = file1.length();
124 }
125 final long size2;
126 if (file2.isDirectory()) {
127 size2 = sumDirectoryContents && file2.exists() ? FileUtils.sizeOfDirectory(file2) : 0;
128 } else {
129 size2 = file2.length();
130 }
131 final long result = size1 - size2;
132 if (result < 0) {
133 return -1;
134 }
135 if (result > 0) {
136 return 1;
137 }
138 return 0;
139 }
140
141 /**
142 * String representation of this file comparator.
143 *
144 * @return String representation of this file comparator
145 */
146 @Override
147 public String toString() {
148 return super.toString() + "[sumDirectoryContents=" + sumDirectoryContents + "]";
149 }
150 }