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 import java.util.List; 022 023 import org.apache.commons.io.IOCase; 024 025 /** 026 * Filters filenames for a certain prefix. 027 * <p> 028 * For example, to print all files and directories in the 029 * current directory whose name starts with <code>Test</code>: 030 * 031 * <pre> 032 * File dir = new File("."); 033 * String[] files = dir.list( new PrefixFileFilter("Test") ); 034 * for ( int i = 0; i < files.length; i++ ) { 035 * System.out.println(files[i]); 036 * } 037 * </pre> 038 * 039 * @since Commons IO 1.0 040 * @version $Revision: 606381 $ $Date: 2007-12-22 02:03:16 +0000 (Sat, 22 Dec 2007) $ 041 * 042 * @author Stephen Colebourne 043 * @author Federico Barbieri 044 * @author Serge Knystautas 045 * @author Peter Donald 046 */ 047 public class PrefixFileFilter extends AbstractFileFilter implements Serializable { 048 049 /** The filename prefixes to search for */ 050 private final String[] prefixes; 051 052 /** Whether the comparison is case sensitive. */ 053 private final IOCase caseSensitivity; 054 055 /** 056 * Constructs a new Prefix file filter for a single prefix. 057 * 058 * @param prefix the prefix to allow, must not be null 059 * @throws IllegalArgumentException if the prefix is null 060 */ 061 public PrefixFileFilter(String prefix) { 062 this(prefix, IOCase.SENSITIVE); 063 } 064 065 /** 066 * Constructs a new Prefix file filter for a single prefix 067 * specifying case-sensitivity. 068 * 069 * @param prefix the prefix to allow, must not be null 070 * @param caseSensitivity how to handle case sensitivity, null means case-sensitive 071 * @throws IllegalArgumentException if the prefix is null 072 * @since Commons IO 1.4 073 */ 074 public PrefixFileFilter(String prefix, IOCase caseSensitivity) { 075 if (prefix == null) { 076 throw new IllegalArgumentException("The prefix must not be null"); 077 } 078 this.prefixes = new String[] {prefix}; 079 this.caseSensitivity = (caseSensitivity == null ? IOCase.SENSITIVE : caseSensitivity); 080 } 081 082 /** 083 * Constructs a new Prefix file filter for any of an array of prefixes. 084 * <p> 085 * The array is not cloned, so could be changed after constructing the 086 * instance. This would be inadvisable however. 087 * 088 * @param prefixes the prefixes to allow, must not be null 089 * @throws IllegalArgumentException if the prefix array is null 090 */ 091 public PrefixFileFilter(String[] prefixes) { 092 this(prefixes, IOCase.SENSITIVE); 093 } 094 095 /** 096 * Constructs a new Prefix file filter for any of an array of prefixes 097 * specifying case-sensitivity. 098 * <p> 099 * The array is not cloned, so could be changed after constructing the 100 * instance. This would be inadvisable however. 101 * 102 * @param prefixes the prefixes to allow, must not be null 103 * @param caseSensitivity how to handle case sensitivity, null means case-sensitive 104 * @throws IllegalArgumentException if the prefix is null 105 * @since Commons IO 1.4 106 */ 107 public PrefixFileFilter(String[] prefixes, IOCase caseSensitivity) { 108 if (prefixes == null) { 109 throw new IllegalArgumentException("The array of prefixes must not be null"); 110 } 111 this.prefixes = prefixes; 112 this.caseSensitivity = (caseSensitivity == null ? IOCase.SENSITIVE : caseSensitivity); 113 } 114 115 /** 116 * Constructs a new Prefix file filter for a list of prefixes. 117 * 118 * @param prefixes the prefixes to allow, must not be null 119 * @throws IllegalArgumentException if the prefix list is null 120 * @throws ClassCastException if the list does not contain Strings 121 */ 122 public PrefixFileFilter(List prefixes) { 123 this(prefixes, IOCase.SENSITIVE); 124 } 125 126 /** 127 * Constructs a new Prefix file filter for a list of prefixes 128 * specifying case-sensitivity. 129 * 130 * @param prefixes the prefixes to allow, must not be null 131 * @param caseSensitivity how to handle case sensitivity, null means case-sensitive 132 * @throws IllegalArgumentException if the prefix list is null 133 * @throws ClassCastException if the list does not contain Strings 134 * @since Commons IO 1.4 135 */ 136 public PrefixFileFilter(List prefixes, IOCase caseSensitivity) { 137 if (prefixes == null) { 138 throw new IllegalArgumentException("The list of prefixes must not be null"); 139 } 140 this.prefixes = (String[]) prefixes.toArray(new String[prefixes.size()]); 141 this.caseSensitivity = (caseSensitivity == null ? IOCase.SENSITIVE : caseSensitivity); 142 } 143 144 /** 145 * Checks to see if the filename starts with the prefix. 146 * 147 * @param file the File to check 148 * @return true if the filename starts with one of our prefixes 149 */ 150 public boolean accept(File file) { 151 String name = file.getName(); 152 for (int i = 0; i < this.prefixes.length; i++) { 153 if (caseSensitivity.checkStartsWith(name, prefixes[i])) { 154 return true; 155 } 156 } 157 return false; 158 } 159 160 /** 161 * Checks to see if the filename starts with the prefix. 162 * 163 * @param file the File directory 164 * @param name the filename 165 * @return true if the filename starts with one of our prefixes 166 */ 167 public boolean accept(File file, String name) { 168 for (int i = 0; i < prefixes.length; i++) { 169 if (caseSensitivity.checkStartsWith(name, prefixes[i])) { 170 return true; 171 } 172 } 173 return false; 174 } 175 176 /** 177 * Provide a String representaion of this file filter. 178 * 179 * @return a String representaion 180 */ 181 public String toString() { 182 StringBuffer buffer = new StringBuffer(); 183 buffer.append(super.toString()); 184 buffer.append("("); 185 if (prefixes != null) { 186 for (int i = 0; i < prefixes.length; i++) { 187 if (i > 0) { 188 buffer.append(","); 189 } 190 buffer.append(prefixes[i]); 191 } 192 } 193 buffer.append(")"); 194 return buffer.toString(); 195 } 196 197 }