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.function.Function; 025import java.util.regex.Pattern; 026 027import org.apache.commons.io.IOCase; 028 029/** 030 * Filters files using supplied regular expression(s). 031 * <p> 032 * See java.util.regex.Pattern for regex matching rules. 033 * </p> 034 * <h2>Using Classic IO</h2> 035 * <p> 036 * e.g. 037 * 038 * <pre> 039 * File dir = new File("."); 040 * FileFilter fileFilter = new RegexFileFilter("^.*[tT]est(-\\d+)?\\.java$"); 041 * File[] files = dir.listFiles(fileFilter); 042 * for (String file : files) { 043 * System.out.println(file); 044 * } 045 * </pre> 046 * 047 * <h2>Using NIO</h2> 048 * 049 * <pre> 050 * final Path dir = Paths.get(""); 051 * final AccumulatorPathVisitor visitor = AccumulatorPathVisitor.withLongCounters(new RegexFileFilter("^.*[tT]est(-\\d+)?\\.java$")); 052 * // 053 * // Walk one dir 054 * Files.<b>walkFileTree</b>(dir, Collections.emptySet(), 1, visitor); 055 * System.out.println(visitor.getPathCounters()); 056 * System.out.println(visitor.getFileList()); 057 * // 058 * visitor.getPathCounters().reset(); 059 * // 060 * // Walk dir tree 061 * Files.<b>walkFileTree</b>(dir, visitor); 062 * System.out.println(visitor.getPathCounters()); 063 * System.out.println(visitor.getDirList()); 064 * System.out.println(visitor.getFileList()); 065 * </pre> 066 * 067 * @since 1.4 068 */ 069public class RegexFileFilter extends AbstractFileFilter implements Serializable { 070 071 private static final long serialVersionUID = 4269646126155225062L; 072 073 /** 074 * Compiles the given pattern source. 075 * 076 * @param pattern the source pattern. 077 * @param flags the compilation flags. 078 * @return a new Pattern. 079 */ 080 private static Pattern compile(final String pattern, final int flags) { 081 if (pattern == null) { 082 throw new IllegalArgumentException("Pattern is missing"); 083 } 084 return Pattern.compile(pattern, flags); 085 } 086 087 /** 088 * Converts IOCase to Pattern compilation flags. 089 * 090 * @param caseSensitivity case-sensitivity. 091 * @return Pattern compilation flags. 092 */ 093 private static int toFlags(final IOCase caseSensitivity) { 094 return IOCase.isCaseSensitive(caseSensitivity) ? Pattern.CASE_INSENSITIVE : 0; 095 } 096 097 /** The regular expression pattern that will be used to match file names. */ 098 private final Pattern pattern; 099 100 /** How convert a path to a string. */ 101 private final Function<Path, String> pathToString; 102 103 /** 104 * Constructs a new regular expression filter for a compiled regular expression 105 * 106 * @param pattern regular expression to match. 107 * @throws IllegalArgumentException if the pattern is null. 108 */ 109 public RegexFileFilter(final Pattern pattern) { 110 this(pattern, p -> p.getFileName().toString()); 111 } 112 113 /** 114 * Constructs a new regular expression filter for a compiled regular expression 115 * 116 * @param pattern regular expression to match. 117 * @param pathToString How convert a path to a string. 118 * @throws IllegalArgumentException if the pattern is null. 119 * @since 2.10.0 120 */ 121 public RegexFileFilter(final Pattern pattern, final Function<Path, String> pathToString) { 122 if (pattern == null) { 123 throw new IllegalArgumentException("Pattern is missing"); 124 } 125 this.pattern = pattern; 126 this.pathToString = pathToString; 127 } 128 129 /** 130 * Constructs a new regular expression filter. 131 * 132 * @param pattern regular string expression to match 133 * @throws IllegalArgumentException if the pattern is null 134 */ 135 public RegexFileFilter(final String pattern) { 136 this(pattern, 0); 137 } 138 139 /** 140 * Constructs a new regular expression filter with the specified flags. 141 * 142 * @param pattern regular string expression to match 143 * @param flags pattern flags - e.g. {@link Pattern#CASE_INSENSITIVE} 144 * @throws IllegalArgumentException if the pattern is null 145 */ 146 public RegexFileFilter(final String pattern, final int flags) { 147 this(compile(pattern, flags)); 148 } 149 150 /** 151 * Constructs a new regular expression filter with the specified flags case sensitivity. 152 * 153 * @param pattern regular string expression to match 154 * @param caseSensitivity how to handle case sensitivity, null means case-sensitive 155 * @throws IllegalArgumentException if the pattern is null 156 */ 157 public RegexFileFilter(final String pattern, final IOCase caseSensitivity) { 158 this(compile(pattern, toFlags(caseSensitivity))); 159 } 160 161 /** 162 * Checks to see if the file name matches one of the regular expressions. 163 * 164 * @param dir the file directory (ignored) 165 * @param name the file name 166 * @return true if the file name matches one of the regular expressions 167 */ 168 @Override 169 public boolean accept(final File dir, final String name) { 170 return pattern.matcher(name).matches(); 171 } 172 173 /** 174 * Checks to see if the file name matches one of the regular expressions. 175 * 176 * @param path the path 177 * @param attributes the path attributes 178 * @return true if the file name matches one of the regular expressions 179 */ 180 @Override 181 public FileVisitResult accept(final Path path, final BasicFileAttributes attributes) { 182 return toFileVisitResult(pattern.matcher(pathToString.apply(path)).matches(), path); 183 } 184 185 /** 186 * Returns a debug string. 187 * 188 * @since 2.10.0 189 */ 190 @Override 191 public String toString() { 192 return "RegexFileFilter [pattern=" + pattern + "]"; 193 } 194 195}