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 */
17package org.apache.commons.io.filefilter;
18
19import java.io.File;
20import java.io.Serializable;
21import java.util.regex.Pattern;
22
23import org.apache.commons.io.IOCase;
24
25/**
26 * Filters files using supplied regular expression(s).
27 * <p/>
28 * See java.util.regex.Pattern for regex matching rules
29 * <p/>
30 *
31 * <p/>
32 * e.g.
33 * <pre>
34 * File dir = new File(".");
35 * FileFilter fileFilter = new RegexFileFilter("^.*[tT]est(-\\d+)?\\.java$");
36 * File[] files = dir.listFiles(fileFilter);
37 * for (int i = 0; i < files.length; i++) {
38 *   System.out.println(files[i]);
39 * }
40 * </pre>
41 *
42 * @author Oliver Siegmar
43 * @version $Revision: 606381 $
44 * @since Commons IO 1.4
45 */
46public class RegexFileFilter extends AbstractFileFilter implements Serializable {
47
48    /** The regular expression pattern that will be used to match filenames */
49    private final Pattern pattern;
50
51    /**
52     * Construct a new regular expression filter.
53     *
54     * @param pattern regular string expression to match
55     * @throws IllegalArgumentException if the pattern is null
56     */
57    public RegexFileFilter(String pattern) {
58        if (pattern == null) {
59            throw new IllegalArgumentException("Pattern is missing");
60        }
61
62        this.pattern = Pattern.compile(pattern);
63    }
64
65    /**
66     * Construct a new regular expression filter with the specified flags case sensitivity.
67     *
68     * @param pattern regular string expression to match
69     * @param caseSensitivity  how to handle case sensitivity, null means case-sensitive
70     * @throws IllegalArgumentException if the pattern is null
71     */
72    public RegexFileFilter(String pattern, IOCase caseSensitivity) {
73        if (pattern == null) {
74            throw new IllegalArgumentException("Pattern is missing");
75        }
76        int flags = 0;
77        if (caseSensitivity != null && !caseSensitivity.isCaseSensitive()) {
78            flags = Pattern.CASE_INSENSITIVE;
79        }
80        this.pattern = Pattern.compile(pattern, flags);
81    }
82
83    /**
84     * Construct a new regular expression filter with the specified flags.
85     *
86     * @param pattern regular string expression to match
87     * @param flags pattern flags - e.g. {@link Pattern#CASE_INSENSITIVE}
88     * @throws IllegalArgumentException if the pattern is null
89     */
90    public RegexFileFilter(String pattern, int flags) {
91        if (pattern == null) {
92            throw new IllegalArgumentException("Pattern is missing");
93        }
94        this.pattern = Pattern.compile(pattern, flags);
95    }
96
97    /**
98     * Construct a new regular expression filter for a compiled regular expression
99     *
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    public boolean accept(File dir, String name) {
119        return (pattern.matcher(name).matches());
120    }
121
122}
123