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 * Example of sorting a list of files using the 33 * {@link #SIZE_COMPARATOR} singleton instance: 34 * <pre> 35 * List<File> list = ... 36 * Collections.sort(list, LengthFileComparator.LENGTH_COMPARATOR); 37 * </pre> 38 * <p> 39 * Example of doing a <i>reverse</i> sort of an array of files using the 40 * {@link #SIZE_REVERSE} singleton instance: 41 * <pre> 42 * File[] array = ... 43 * Arrays.sort(array, LengthFileComparator.LENGTH_REVERSE); 44 * </pre> 45 * <p> 46 * <strong>N.B.</strong> Directories are treated as <b>zero size</b> unless 47 * <code>sumDirectoryContents</code> is <code>true</code>. 48 * 49 * @version $Revision: 609243 $ $Date: 2008-01-06 00:30:42 +0000 (Sun, 06 Jan 2008) $ 50 * @since Commons IO 1.4 51 */ 52 public class SizeFileComparator implements Comparator<File>, Serializable { 53 54 /** Size comparator instance - directories are treated as zero size */ 55 public static final Comparator<File> SIZE_COMPARATOR = new SizeFileComparator(); 56 57 /** Reverse size comparator instance - directories are treated as zero size */ 58 public static final Comparator<File> SIZE_REVERSE = new ReverseComparator<File>(SIZE_COMPARATOR); 59 60 /** 61 * Size comparator instance which sums the size of a directory's contents 62 * using {@link FileUtils#sizeOfDirectory(File)} 63 */ 64 public static final Comparator<File> SIZE_SUMDIR_COMPARATOR = new SizeFileComparator(true); 65 66 /** 67 * Reverse size comparator instance which sums the size of a directory's contents 68 * using {@link FileUtils#sizeOfDirectory(File)} 69 */ 70 public static final Comparator<File> SIZE_SUMDIR_REVERSE = new ReverseComparator<File>(SIZE_SUMDIR_COMPARATOR); 71 72 /** Whether the sum of the directory's contents should be calculated. */ 73 private final boolean sumDirectoryContents; 74 75 /** 76 * Construct a file size comparator instance (directories treated as zero size). 77 */ SizeFileComparator()78 public SizeFileComparator() { 79 this.sumDirectoryContents = false; 80 } 81 82 /** 83 * Construct a file size comparator instance specifying whether the size of 84 * the directory contents should be aggregated. 85 * <p> 86 * If the <code>sumDirectoryContents</code> is <code>true</code> The size of 87 * directories is calculated using {@link FileUtils#sizeOfDirectory(File)}. 88 * 89 * @param sumDirectoryContents <code>true</code> if the sum of the directoryies contents 90 * should be calculated, otherwise <code>false</code> if directories should be treated 91 * as size zero (see {@link FileUtils#sizeOfDirectory(File)}). 92 */ SizeFileComparator(boolean sumDirectoryContents)93 public SizeFileComparator(boolean sumDirectoryContents) { 94 this.sumDirectoryContents = sumDirectoryContents; 95 } 96 97 /** 98 * Compare the length of two files. 99 * 100 * @param obj1 The first file to compare 101 * @param obj2 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 */ compare(File file1, File file2)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