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.regex.Pattern;
022
023 import org.apache.commons.io.IOCase;
024
025 /**
026 * Filters files using supplied regular expression(s).
027 * <p/>
028 * See java.util.regex.Pattern for regex matching rules
029 * <p/>
030 *
031 * <p/>
032 * e.g.
033 * <pre>
034 * File dir = new File(".");
035 * FileFilter fileFilter = new RegexFileFilter("^.*[tT]est(-\\d+)?\\.java$");
036 * File[] files = dir.listFiles(fileFilter);
037 * for (int i = 0; i < files.length; i++) {
038 * System.out.println(files[i]);
039 * }
040 * </pre>
041 *
042 * @author Oliver Siegmar
043 * @version $Revision: 659817 $
044 * @since Commons IO 1.4
045 */
046 public class RegexFileFilter extends AbstractFileFilter implements Serializable {
047
048 /** The regular expression pattern that will be used to match filenames */
049 private final Pattern pattern;
050
051 /**
052 * Construct a new regular expression filter.
053 *
054 * @param pattern regular string expression to match
055 * @throws IllegalArgumentException if the pattern is null
056 */
057 public RegexFileFilter(String pattern) {
058 if (pattern == null) {
059 throw new IllegalArgumentException("Pattern is missing");
060 }
061
062 this.pattern = Pattern.compile(pattern);
063 }
064
065 /**
066 * Construct a new regular expression filter with the specified flags case sensitivity.
067 *
068 * @param pattern regular string expression to match
069 * @param caseSensitivity how to handle case sensitivity, null means case-sensitive
070 * @throws IllegalArgumentException if the pattern is null
071 */
072 public RegexFileFilter(String pattern, IOCase caseSensitivity) {
073 if (pattern == null) {
074 throw new IllegalArgumentException("Pattern is missing");
075 }
076 int flags = 0;
077 if (caseSensitivity != null && !caseSensitivity.isCaseSensitive()) {
078 flags = Pattern.CASE_INSENSITIVE;
079 }
080 this.pattern = Pattern.compile(pattern, flags);
081 }
082
083 /**
084 * Construct a new regular expression filter with the specified flags.
085 *
086 * @param pattern regular string expression to match
087 * @param flags pattern flags - e.g. {@link Pattern#CASE_INSENSITIVE}
088 * @throws IllegalArgumentException if the pattern is null
089 */
090 public RegexFileFilter(String pattern, int flags) {
091 if (pattern == null) {
092 throw new IllegalArgumentException("Pattern is missing");
093 }
094 this.pattern = Pattern.compile(pattern, flags);
095 }
096
097 /**
098 * Construct a new regular expression filter for a compiled regular expression
099 *
100 * @param pattern regular expression to match
101 * @throws IllegalArgumentException if the pattern is null
102 */
103 public RegexFileFilter(Pattern pattern) {
104 if (pattern == null) {
105 throw new IllegalArgumentException("Pattern is missing");
106 }
107
108 this.pattern = pattern;
109 }
110
111 /**
112 * Checks to see if the filename matches one of the regular expressions.
113 *
114 * @param dir the file directory
115 * @param name the filename
116 * @return true if the filename matches one of the regular expressions
117 */
118 @Override
119 public boolean accept(File dir, String name) {
120 return (pattern.matcher(name).matches());
121 }
122
123 }