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.filefilter; 018 019 import java.io.File; 020 import java.io.Serializable; 021 022 /** 023 * Filters files based on size, can filter either smaller files or 024 * files equal to or larger than a given threshold. 025 * <p> 026 * For example, to print all files and directories in the 027 * current directory whose size is greater than 1 MB: 028 * 029 * <pre> 030 * File dir = new File("."); 031 * String[] files = dir.list( new SizeFileFilter(1024 * 1024) ); 032 * for ( int i = 0; i < files.length; i++ ) { 033 * System.out.println(files[i]); 034 * } 035 * </pre> 036 * 037 * @author Rahul Akolkar 038 * @version $Id: SizeFileFilter.java 591058 2007-11-01 15:47:05Z niallp $ 039 * @since Commons IO 1.2 040 */ 041 public class SizeFileFilter extends AbstractFileFilter implements Serializable { 042 043 /** The size threshold. */ 044 private final long size; 045 /** Whether the files accepted will be larger or smaller. */ 046 private final boolean acceptLarger; 047 048 /** 049 * Constructs a new size file filter for files equal to or 050 * larger than a certain size. 051 * 052 * @param size the threshold size of the files 053 * @throws IllegalArgumentException if the size is negative 054 */ 055 public SizeFileFilter(long size) { 056 this(size, true); 057 } 058 059 /** 060 * Constructs a new size file filter for files based on a certain size 061 * threshold. 062 * 063 * @param size the threshold size of the files 064 * @param acceptLarger if true, files equal to or larger are accepted, 065 * otherwise smaller ones (but not equal to) 066 * @throws IllegalArgumentException if the size is negative 067 */ 068 public SizeFileFilter(long size, boolean acceptLarger) { 069 if (size < 0) { 070 throw new IllegalArgumentException("The size must be non-negative"); 071 } 072 this.size = size; 073 this.acceptLarger = acceptLarger; 074 } 075 076 //----------------------------------------------------------------------- 077 /** 078 * Checks to see if the size of the file is favorable. 079 * <p> 080 * If size equals threshold and smaller files are required, 081 * file <b>IS NOT</b> selected. 082 * If size equals threshold and larger files are required, 083 * file <b>IS</b> selected. 084 * 085 * @param file the File to check 086 * @return true if the filename matches 087 */ 088 public boolean accept(File file) { 089 boolean smaller = file.length() < size; 090 return acceptLarger ? !smaller : smaller; 091 } 092 093 /** 094 * Provide a String representaion of this file filter. 095 * 096 * @return a String representaion 097 */ 098 public String toString() { 099 String condition = acceptLarger ? ">=" : "<"; 100 return super.toString() + "(" + condition + size + ")"; 101 } 102 103 }