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.Serializable; 021import java.nio.file.FileVisitResult; 022import java.nio.file.Path; 023import java.nio.file.attribute.BasicFileAttributes; 024import java.util.List; 025import java.util.Objects; 026import java.util.stream.Stream; 027 028import org.apache.commons.io.IOCase; 029import org.apache.commons.io.file.PathUtils; 030 031/** 032 * Filters file names for a certain prefix. 033 * <p> 034 * For example, to print all files and directories in the 035 * current directory whose name starts with {@code Test}: 036 * </p> 037 * <h2>Using Classic IO</h2> 038 * <pre> 039 * File dir = FileUtils.current(); 040 * String[] files = dir.list(new PrefixFileFilter("Test")); 041 * for (String file : files) { 042 * System.out.println(file); 043 * } 044 * </pre> 045 * 046 * <h2>Using NIO</h2> 047 * <pre> 048 * final Path dir = PathUtils.current(); 049 * final AccumulatorPathVisitor visitor = AccumulatorPathVisitor.withLongCounters(new PrefixFileFilter("Test")); 050 * // 051 * // Walk one dir 052 * Files.<b>walkFileTree</b>(dir, Collections.emptySet(), 1, visitor); 053 * System.out.println(visitor.getPathCounters()); 054 * System.out.println(visitor.getFileList()); 055 * // 056 * visitor.getPathCounters().reset(); 057 * // 058 * // Walk dir tree 059 * Files.<b>walkFileTree</b>(dir, visitor); 060 * System.out.println(visitor.getPathCounters()); 061 * System.out.println(visitor.getDirList()); 062 * System.out.println(visitor.getFileList()); 063 * </pre> 064 * <h2>Deprecating Serialization</h2> 065 * <p> 066 * <em>Serialization is deprecated and will be removed in 3.0.</em> 067 * </p> 068 * 069 * @since 1.0 070 * @see FileFilterUtils#prefixFileFilter(String) 071 * @see FileFilterUtils#prefixFileFilter(String, IOCase) 072 */ 073public class PrefixFileFilter extends AbstractFileFilter implements Serializable { 074 075 private static final long serialVersionUID = 8533897440809599867L; 076 077 /** The file name prefixes to search for */ 078 private final String[] prefixes; 079 080 /** Whether the comparison is case-sensitive. */ 081 private final IOCase isCase; 082 083 /** 084 * Constructs a new Prefix file filter for a list of prefixes. 085 * 086 * @param prefixes the prefixes to allow, must not be null 087 * @throws NullPointerException if the prefix list is null 088 * @throws ClassCastException if the list does not contain Strings 089 */ 090 public PrefixFileFilter(final List<String> prefixes) { 091 this(prefixes, IOCase.SENSITIVE); 092 } 093 094 /** 095 * Constructs a new Prefix file filter for a list of prefixes 096 * specifying case-sensitivity. 097 * 098 * @param prefixes the prefixes to allow, must not be null 099 * @param ioCase how to handle case sensitivity, null means case-sensitive 100 * @throws NullPointerException if the prefix list is null 101 * @throws ClassCastException if the list does not contain Strings 102 * @since 1.4 103 */ 104 public PrefixFileFilter(final List<String> prefixes, final IOCase ioCase) { 105 Objects.requireNonNull(prefixes, "prefixes"); 106 this.prefixes = prefixes.toArray(EMPTY_STRING_ARRAY); 107 this.isCase = IOCase.value(ioCase, IOCase.SENSITIVE); 108 } 109 110 /** 111 * Constructs a new Prefix file filter for a single prefix. 112 * 113 * @param prefix the prefix to allow, must not be null 114 * @throws IllegalArgumentException if the prefix is null 115 */ 116 public PrefixFileFilter(final String prefix) { 117 this(prefix, IOCase.SENSITIVE); 118 } 119 120 /** 121 * Constructs a new Prefix file filter for any of an array of prefixes. 122 * <p> 123 * The array is not cloned, so could be changed after constructing the 124 * instance. This would be inadvisable however. 125 * 126 * @param prefixes the prefixes to allow, must not be null 127 * @throws IllegalArgumentException if the prefix array is null 128 */ 129 public PrefixFileFilter(final String... prefixes) { 130 this(prefixes, IOCase.SENSITIVE); 131 } 132 133 /** 134 * Constructs a new Prefix file filter for a single prefix 135 * specifying case-sensitivity. 136 * 137 * @param prefix the prefix to allow, must not be null 138 * @param ioCase how to handle case sensitivity, null means case-sensitive 139 * @throws IllegalArgumentException if the prefix is null 140 * @since 1.4 141 */ 142 public PrefixFileFilter(final String prefix, final IOCase ioCase) { 143 Objects.requireNonNull(prefix, "prefix"); 144 this.prefixes = new String[] {prefix}; 145 this.isCase = IOCase.value(ioCase, IOCase.SENSITIVE); 146 } 147 148 /** 149 * Constructs a new Prefix file filter for any of an array of prefixes 150 * specifying case-sensitivity. 151 * 152 * @param prefixes the prefixes to allow, must not be null 153 * @param ioCase how to handle case sensitivity, null means case-sensitive 154 * @throws IllegalArgumentException if the prefix is null 155 * @since 1.4 156 */ 157 public PrefixFileFilter(final String[] prefixes, final IOCase ioCase) { 158 Objects.requireNonNull(prefixes, "prefixes"); 159 this.prefixes = prefixes.clone(); 160 this.isCase = IOCase.value(ioCase, IOCase.SENSITIVE); 161 } 162 163 /** 164 * Checks to see if the file name starts with the prefix. 165 * 166 * @param file the File to check 167 * @return true if the file name starts with one of our prefixes 168 */ 169 @Override 170 public boolean accept(final File file) { 171 return accept(file == null ? null : file.getName()); 172 } 173 174 /** 175 * Checks to see if the file name starts with the prefix. 176 * 177 * @param file the File directory 178 * @param name the file name 179 * @return true if the file name starts with one of our prefixes 180 */ 181 @Override 182 public boolean accept(final File file, final String name) { 183 return accept(name); 184 } 185 186 /** 187 * Checks to see if the file name starts with the prefix. 188 * @param file the File to check 189 * 190 * @return true if the file name starts with one of our prefixes 191 * @since 2.9.0 192 */ 193 @Override 194 public FileVisitResult accept(final Path file, final BasicFileAttributes attributes) { 195 return toFileVisitResult(accept(PathUtils.getFileName(file, Path::toFile))); 196 } 197 198 private boolean accept(final String name) { 199 return Stream.of(prefixes).anyMatch(prefix -> isCase.checkStartsWith(name, prefix)); 200 } 201 202 /** 203 * Provide a String representation of this file filter. 204 * 205 * @return a String representation 206 */ 207 @Override 208 public String toString() { 209 final StringBuilder buffer = new StringBuilder(); 210 buffer.append(super.toString()); 211 buffer.append("("); 212 append(prefixes, buffer); 213 buffer.append(")"); 214 return buffer.toString(); 215 } 216 217}