001 /*
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements. See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache License, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License. You may obtain a copy of the License at
008 *
009 * http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 */
017 package org.apache.commons.io.comparator;
018
019 import java.io.File;
020 import java.io.Serializable;
021 import java.util.Comparator;
022
023 import org.apache.commons.io.FileUtils;
024
025 /**
026 * Compare the <b>length/size</b> of two files for order (see
027 * {@link File#length()} and {@link FileUtils#sizeOfDirectory(File)}).
028 * <p>
029 * This comparator can be used to sort lists or arrays of files
030 * by their length/size.
031 * <p>
032 * Example of sorting a list of files using the
033 * {@link #SIZE_COMPARATOR} singleton instance:
034 * <pre>
035 * List<File> list = ...
036 * SizeFileComparator.SIZE_COMPARATOR.sort(list);
037 * </pre>
038 * <p>
039 * Example of doing a <i>reverse</i> sort of an array of files using the
040 * {@link #SIZE_REVERSE} singleton instance:
041 * <pre>
042 * File[] array = ...
043 * SizeFileComparator.SIZE_REVERSE.sort(array);
044 * </pre>
045 * <p>
046 * <strong>N.B.</strong> Directories are treated as <b>zero size</b> unless
047 * <code>sumDirectoryContents</code> is {@code true}.
048 *
049 * @version $Id: SizeFileComparator.java 1307462 2012-03-30 15:13:11Z ggregory $
050 * @since 1.4
051 */
052 public class SizeFileComparator extends AbstractFileComparator implements Serializable {
053
054 /** Size comparator instance - directories are treated as zero size */
055 public static final Comparator<File> SIZE_COMPARATOR = new SizeFileComparator();
056
057 /** Reverse size comparator instance - directories are treated as zero size */
058 public static final Comparator<File> SIZE_REVERSE = new ReverseComparator(SIZE_COMPARATOR);
059
060 /**
061 * Size comparator instance which sums the size of a directory's contents
062 * using {@link FileUtils#sizeOfDirectory(File)}
063 */
064 public static final Comparator<File> SIZE_SUMDIR_COMPARATOR = new SizeFileComparator(true);
065
066 /**
067 * Reverse size comparator instance which sums the size of a directory's contents
068 * using {@link FileUtils#sizeOfDirectory(File)}
069 */
070 public static final Comparator<File> SIZE_SUMDIR_REVERSE = new ReverseComparator(SIZE_SUMDIR_COMPARATOR);
071
072 /** Whether the sum of the directory's contents should be calculated. */
073 private final boolean sumDirectoryContents;
074
075 /**
076 * Construct a file size comparator instance (directories treated as zero size).
077 */
078 public SizeFileComparator() {
079 this.sumDirectoryContents = false;
080 }
081
082 /**
083 * Construct a file size comparator instance specifying whether the size of
084 * the directory contents should be aggregated.
085 * <p>
086 * If the <code>sumDirectoryContents</code> is {@code true} The size of
087 * directories is calculated using {@link FileUtils#sizeOfDirectory(File)}.
088 *
089 * @param sumDirectoryContents {@code true} if the sum of the directoryies contents
090 * should be calculated, otherwise {@code false} if directories should be treated
091 * as size zero (see {@link FileUtils#sizeOfDirectory(File)}).
092 */
093 public SizeFileComparator(boolean sumDirectoryContents) {
094 this.sumDirectoryContents = sumDirectoryContents;
095 }
096
097 /**
098 * Compare the length of two files.
099 *
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 length
103 * is less than the second, zero if the lengths are the
104 * same and a positive value if the first files length
105 * is greater than the second file.
106 *
107 */
108 public int compare(File file1, File file2) {
109 long size1 = 0;
110 if (file1.isDirectory()) {
111 size1 = sumDirectoryContents && file1.exists() ? FileUtils.sizeOfDirectory(file1) : 0;
112 } else {
113 size1 = file1.length();
114 }
115 long size2 = 0;
116 if (file2.isDirectory()) {
117 size2 = sumDirectoryContents && file2.exists() ? FileUtils.sizeOfDirectory(file2) : 0;
118 } else {
119 size2 = file2.length();
120 }
121 long result = size1 - size2;
122 if (result < 0) {
123 return -1;
124 } else if (result > 0) {
125 return 1;
126 } else {
127 return 0;
128 }
129 }
130
131 /**
132 * String representation of this file comparator.
133 *
134 * @return String representation of this file comparator
135 */
136 @Override
137 public String toString() {
138 return super.toString() + "[sumDirectoryContents=" + sumDirectoryContents + "]";
139 }
140 }