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.filefilter; 18 19 import java.io.File; 20 import java.io.Serializable; 21 import java.util.List; 22 23 import org.apache.commons.io.IOCase; 24 25 /** 26 * Filters filenames for a certain prefix. 27 * <p> 28 * For example, to print all files and directories in the 29 * current directory whose name starts with <code>Test</code>: 30 * 31 * <pre> 32 * File dir = new File("."); 33 * String[] files = dir.list( new PrefixFileFilter("Test") ); 34 * for ( int i = 0; i < files.length; i++ ) { 35 * System.out.println(files[i]); 36 * } 37 * </pre> 38 * 39 * @since Commons IO 1.0 40 * @version $Revision: 606381 $ $Date: 2007-12-22 02:03:16 +0000 (Sat, 22 Dec 2007) $ 41 * 42 * @author Stephen Colebourne 43 * @author Federico Barbieri 44 * @author Serge Knystautas 45 * @author Peter Donald 46 */ 47 public class PrefixFileFilter extends AbstractFileFilter implements Serializable { 48 49 /** The filename prefixes to search for */ 50 private final String[] prefixes; 51 52 /** Whether the comparison is case sensitive. */ 53 private final IOCase caseSensitivity; 54 55 /** 56 * Constructs a new Prefix file filter for a single prefix. 57 * 58 * @param prefix the prefix to allow, must not be null 59 * @throws IllegalArgumentException if the prefix is null 60 */ 61 public PrefixFileFilter(String prefix) { 62 this(prefix, IOCase.SENSITIVE); 63 } 64 65 /** 66 * Constructs a new Prefix file filter for a single prefix 67 * specifying case-sensitivity. 68 * 69 * @param prefix the prefix to allow, must not be null 70 * @param caseSensitivity how to handle case sensitivity, null means case-sensitive 71 * @throws IllegalArgumentException if the prefix is null 72 * @since Commons IO 1.4 73 */ 74 public PrefixFileFilter(String prefix, IOCase caseSensitivity) { 75 if (prefix == null) { 76 throw new IllegalArgumentException("The prefix must not be null"); 77 } 78 this.prefixes = new String[] {prefix}; 79 this.caseSensitivity = (caseSensitivity == null ? IOCase.SENSITIVE : caseSensitivity); 80 } 81 82 /** 83 * Constructs a new Prefix file filter for any of an array of prefixes. 84 * <p> 85 * The array is not cloned, so could be changed after constructing the 86 * instance. This would be inadvisable however. 87 * 88 * @param prefixes the prefixes to allow, must not be null 89 * @throws IllegalArgumentException if the prefix array is null 90 */ 91 public PrefixFileFilter(String[] prefixes) { 92 this(prefixes, IOCase.SENSITIVE); 93 } 94 95 /** 96 * Constructs a new Prefix file filter for any of an array of prefixes 97 * specifying case-sensitivity. 98 * <p> 99 * 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<String> 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<String> prefixes, IOCase caseSensitivity) { 137 if (prefixes == null) { 138 throw new IllegalArgumentException("The list of prefixes must not be null"); 139 } 140 this.prefixes = 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 @Override 151 public boolean accept(File file) { 152 String name = file.getName(); 153 for (int i = 0; i < this.prefixes.length; i++) { 154 if (caseSensitivity.checkStartsWith(name, prefixes[i])) { 155 return true; 156 } 157 } 158 return false; 159 } 160 161 /** 162 * Checks to see if the filename starts with the prefix. 163 * 164 * @param file the File directory 165 * @param name the filename 166 * @return true if the filename starts with one of our prefixes 167 */ 168 @Override 169 public boolean accept(File file, String name) { 170 for (int i = 0; i < prefixes.length; i++) { 171 if (caseSensitivity.checkStartsWith(name, prefixes[i])) { 172 return true; 173 } 174 } 175 return false; 176 } 177 178 /** 179 * Provide a String representaion of this file filter. 180 * 181 * @return a String representaion 182 */ 183 @Override 184 public String toString() { 185 StringBuffer buffer = new StringBuffer(); 186 buffer.append(super.toString()); 187 buffer.append("("); 188 if (prefixes != null) { 189 for (int i = 0; i < prefixes.length; i++) { 190 if (i > 0) { 191 buffer.append(","); 192 } 193 buffer.append(prefixes[i]); 194 } 195 } 196 buffer.append(")"); 197 return buffer.toString(); 198 } 199 200 } 201
