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.filefilter; 018 019import java.io.File; 020import java.io.IOException; 021import java.io.Serializable; 022import java.nio.file.FileVisitResult; 023import java.nio.file.Files; 024import java.nio.file.Path; 025import java.nio.file.attribute.BasicFileAttributes; 026 027/** 028 * Filters files based on size, can filter either smaller files or 029 * files equal to or larger than a given threshold. 030 * <p> 031 * For example, to print all files and directories in the 032 * current directory whose size is greater than 1 MB: 033 * </p> 034 * <h2>Using Classic IO</h2> 035 * <pre> 036 * File dir = new File("."); 037 * String[] files = dir.list(new SizeFileFilter(1024 * 1024)); 038 * for (String file : files) { 039 * System.out.println(file); 040 * } 041 * </pre> 042 * 043 * <h2>Using NIO</h2> 044 * <pre> 045 * final Path dir = Paths.get(""); 046 * final AccumulatorPathVisitor visitor = AccumulatorPathVisitor.withLongCounters(new SizeFileFilter(1024 * 1024)); 047 * // 048 * // Walk one dir 049 * Files.<b>walkFileTree</b>(dir, Collections.emptySet(), 1, visitor); 050 * System.out.println(visitor.getPathCounters()); 051 * System.out.println(visitor.getFileList()); 052 * // 053 * visitor.getPathCounters().reset(); 054 * // 055 * // Walk dir tree 056 * Files.<b>walkFileTree</b>(dir, visitor); 057 * System.out.println(visitor.getPathCounters()); 058 * System.out.println(visitor.getDirList()); 059 * System.out.println(visitor.getFileList()); 060 * </pre> 061 * 062 * @since 1.2 063 * @see FileFilterUtils#sizeFileFilter(long) 064 * @see FileFilterUtils#sizeFileFilter(long, boolean) 065 * @see FileFilterUtils#sizeRangeFileFilter(long, long) 066 */ 067public class SizeFileFilter extends AbstractFileFilter implements Serializable { 068 069 private static final long serialVersionUID = 7388077430788600069L; 070 071 /** Whether the files accepted will be larger or smaller. */ 072 private final boolean acceptLarger; 073 074 /** The size threshold. */ 075 private final long size; 076 077 /** 078 * Constructs a new size file filter for files equal to or 079 * larger than a certain size. 080 * 081 * @param size the threshold size of the files 082 * @throws IllegalArgumentException if the size is negative 083 */ 084 public SizeFileFilter(final long size) { 085 this(size, true); 086 } 087 088 /** 089 * Constructs a new size file filter for files based on a certain size 090 * threshold. 091 * 092 * @param size the threshold size of the files 093 * @param acceptLarger if true, files equal to or larger are accepted, 094 * otherwise smaller ones (but not equal to) 095 * @throws IllegalArgumentException if the size is negative 096 */ 097 public SizeFileFilter(final long size, final boolean acceptLarger) { 098 if (size < 0) { 099 throw new IllegalArgumentException("The size must be non-negative"); 100 } 101 this.size = size; 102 this.acceptLarger = acceptLarger; 103 } 104 105 /** 106 * Checks to see if the size of the file is favorable. 107 * <p> 108 * If size equals threshold and smaller files are required, 109 * file <b>IS NOT</b> selected. 110 * If size equals threshold and larger files are required, 111 * file <b>IS</b> selected. 112 * </p> 113 * 114 * @param file the File to check 115 * @return true if the file name matches 116 */ 117 @Override 118 public boolean accept(final File file) { 119 return accept(file.length()); 120 } 121 122 private boolean accept(final long length) { 123 return acceptLarger != length < size; 124 } 125 126 /** 127 * Checks to see if the size of the file is favorable. 128 * <p> 129 * If size equals threshold and smaller files are required, 130 * file <b>IS NOT</b> selected. 131 * If size equals threshold and larger files are required, 132 * file <b>IS</b> selected. 133 * </p> 134 * @param file the File to check 135 * 136 * @return true if the file name matches 137 */ 138 @Override 139 public FileVisitResult accept(final Path file, final BasicFileAttributes attributes) { 140 try { 141 return toFileVisitResult(accept(Files.size(file)), file); 142 } catch (final IOException e) { 143 return handle(e); 144 } 145 } 146 147 /** 148 * Provide a String representation of this file filter. 149 * 150 * @return a String representation 151 */ 152 @Override 153 public String toString() { 154 final String condition = acceptLarger ? ">=" : "<"; 155 return super.toString() + "(" + condition + size + ")"; 156 } 157 158 @Override 159 public FileVisitResult visitFile(final Path file, final BasicFileAttributes attrs) throws IOException { 160 return toFileVisitResult(accept(Files.size(file)), file); 161 } 162 163}