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 */ 017package org.apache.commons.io.comparator; 018 019import java.io.File; 020import java.io.Serializable; 021import java.util.Comparator; 022 023import 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 * ((AbstractFileComparator) 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 * ((AbstractFileComparator) 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 * @since 1.4 050 */ 051public class SizeFileComparator extends AbstractFileComparator implements Serializable { 052 053 private static final long serialVersionUID = -1201561106411416190L; 054 055 /** Size comparator instance - directories are treated as zero size */ 056 public static final Comparator<File> SIZE_COMPARATOR = new SizeFileComparator(); 057 058 /** Reverse size comparator instance - directories are treated as zero size */ 059 public static final Comparator<File> SIZE_REVERSE = new ReverseComparator(SIZE_COMPARATOR); 060 061 /** 062 * Size comparator instance which sums the size of a directory's contents 063 * using {@link FileUtils#sizeOfDirectory(File)} 064 */ 065 public static final Comparator<File> SIZE_SUMDIR_COMPARATOR = new SizeFileComparator(true); 066 067 /** 068 * Reverse size comparator instance which sums the size of a directory's contents 069 * using {@link FileUtils#sizeOfDirectory(File)} 070 */ 071 public static final Comparator<File> SIZE_SUMDIR_REVERSE = new ReverseComparator(SIZE_SUMDIR_COMPARATOR); 072 073 /** Whether the sum of the directory's contents should be calculated. */ 074 private final boolean sumDirectoryContents; 075 076 /** 077 * Construct a file size comparator instance (directories treated as zero size). 078 */ 079 public SizeFileComparator() { 080 this.sumDirectoryContents = false; 081 } 082 083 /** 084 * Construct a file size comparator instance specifying whether the size of 085 * the directory contents should be aggregated. 086 * <p> 087 * If the <code>sumDirectoryContents</code> is {@code true} The size of 088 * directories is calculated using {@link FileUtils#sizeOfDirectory(File)}. 089 * 090 * @param sumDirectoryContents {@code true} if the sum of the directories' contents 091 * should be calculated, otherwise {@code false} if directories should be treated 092 * as size zero (see {@link FileUtils#sizeOfDirectory(File)}). 093 */ 094 public SizeFileComparator(final boolean sumDirectoryContents) { 095 this.sumDirectoryContents = sumDirectoryContents; 096 } 097 098 /** 099 * Compare the length of two files. 100 * 101 * @param file1 The first file to compare 102 * @param file2 The second file to compare 103 * @return a negative value if the first file's length 104 * is less than the second, zero if the lengths are the 105 * same and a positive value if the first files length 106 * is greater than the second file. 107 * 108 */ 109 @Override 110 public int compare(final File file1, final File file2) { 111 long size1 = 0; 112 if (file1.isDirectory()) { 113 size1 = sumDirectoryContents && file1.exists() ? FileUtils.sizeOfDirectory(file1) : 0; 114 } else { 115 size1 = file1.length(); 116 } 117 long size2 = 0; 118 if (file2.isDirectory()) { 119 size2 = sumDirectoryContents && file2.exists() ? FileUtils.sizeOfDirectory(file2) : 0; 120 } else { 121 size2 = file2.length(); 122 } 123 final long result = size1 - size2; 124 if (result < 0) { 125 return -1; 126 } else if (result > 0) { 127 return 1; 128 } else { 129 return 0; 130 } 131 } 132 133 /** 134 * String representation of this file comparator. 135 * 136 * @return String representation of this file comparator 137 */ 138 @Override 139 public String toString() { 140 return super.toString() + "[sumDirectoryContents=" + sumDirectoryContents + "]"; 141 } 142}