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.nio.file.FileVisitResult;
22 import java.nio.file.Files;
23 import java.nio.file.Path;
24 import java.nio.file.attribute.BasicFileAttributes;
25
26 /**
27 * This filter accepts {@link File}s that are hidden.
28 * <p>
29 * Example, showing how to print out a list of the
30 * current directory's <i>hidden</i> files:
31 * </p>
32 * <h2>Using Classic IO</h2>
33 * <pre>
34 * File dir = FileUtils.current();
35 * String[] files = dir.list(HiddenFileFilter.HIDDEN);
36 * for (String file : files) {
37 * System.out.println(file);
38 * }
39 * </pre>
40 *
41 * <p>
42 * Example, showing how to print out a list of the
43 * current directory's <i>visible</i> (i.e. not hidden) files:
44 * </p>
45 *
46 * <pre>
47 * File dir = FileUtils.current();
48 * String[] files = dir.list(HiddenFileFilter.VISIBLE);
49 * for (String file : files) {
50 * System.out.println(file);
51 * }
52 * </pre>
53 *
54 * <h2>Using NIO</h2>
55 * <pre>
56 * final Path dir = PathUtils.current();
57 * final AccumulatorPathVisitor visitor = AccumulatorPathVisitor.withLongCounters(HiddenFileFilter.HIDDEN);
58 * //
59 * // Walk one dir
60 * Files.<b>walkFileTree</b>(dir, Collections.emptySet(), 1, visitor);
61 * System.out.println(visitor.getPathCounters());
62 * System.out.println(visitor.getFileList());
63 * //
64 * visitor.getPathCounters().reset();
65 * //
66 * // Walk dir tree
67 * Files.<b>walkFileTree</b>(dir, visitor);
68 * System.out.println(visitor.getPathCounters());
69 * System.out.println(visitor.getDirList());
70 * System.out.println(visitor.getFileList());
71 * </pre>
72 * <h2>Deprecating Serialization</h2>
73 * <p>
74 * <em>Serialization is deprecated and will be removed in 3.0.</em>
75 * </p>
76 *
77 * @since 1.3
78 */
79 public class HiddenFileFilter extends AbstractFileFilter implements Serializable {
80
81 /** Singleton instance of <i>hidden</i> filter */
82 public static final IOFileFilter HIDDEN = new HiddenFileFilter();
83
84 private static final long serialVersionUID = 8930842316112759062L;
85
86 /** Singleton instance of <i>visible</i> filter */
87 public static final IOFileFilter VISIBLE = HIDDEN.negate();
88
89 /**
90 * Restrictive constructor.
91 */
92 protected HiddenFileFilter() {
93 }
94
95 /**
96 * Checks to see if the file is hidden.
97 *
98 * @param file the File to check
99 * @return {@code true} if the file is
100 * <i>hidden</i>, otherwise {@code false}.
101 */
102 @Override
103 public boolean accept(final File file) {
104 return file == null || file.isHidden();
105 }
106
107 /**
108 * Checks to see if the file is hidden.
109 * @param file the File to check
110 *
111 * @return {@code true} if the file is
112 * <i>hidden</i>, otherwise {@code false}.
113 * @since 2.9.0
114 */
115 @Override
116 public FileVisitResult accept(final Path file, final BasicFileAttributes attributes) {
117 return get(() -> toFileVisitResult(file == null || Files.isHidden(file)));
118 }
119
120 }