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.vfs2.filter;
18
19 import java.io.Serializable;
20 import java.util.ArrayList;
21 import java.util.Arrays;
22 import java.util.List;
23
24 import org.apache.commons.vfs2.FileFilter;
25 import org.apache.commons.vfs2.FileSelectInfo;
26
27 /**
28 * Filters file names for a certain prefix.
29 * <p>
30 * For example, to print all files and directories in the current directory
31 * whose name starts with a {@code .}:
32 * </p>
33 *
34 * <pre>
35 * FileSystemManager fsManager = VFS.getManager();
36 * FileObject dir = fsManager.toFileObject(new File("."));
37 * FileObject[] files = dir.findFiles(new FileFilterSelector(new PrefixFileFilter(".")));
38 * for (int i = 0; i < files.length; i++) {
39 * System.out.println(files[i]);
40 * }
41 * </pre>
42 *
43 * @author This code was originally ported from Apache Commons IO File Filter
44 * @see "http://commons.apache.org/proper/commons-io/"
45 * @since 2.4
46 */
47 public class PrefixFileFilter implements FileFilter, Serializable {
48
49 private static final long serialVersionUID = 1L;
50
51 /** Whether the comparison is case sensitive. */
52 private final IOCase caseSensitivity;
53
54 /** The file name prefixes to search for. */
55 private final List<String> prefixes;
56
57 /**
58 * Constructs a new Prefix file filter for a list of prefixes.
59 *
60 * @param prefixes the prefixes to allow, must not be null
61 */
62 public PrefixFileFilter(final List<String> prefixes) {
63 this(IOCase.SENSITIVE, prefixes);
64 }
65
66 /**
67 * Constructs a new Prefix file filter for a list of prefixes specifying
68 * case-sensitivity.
69 *
70 * @param caseSensitivity how to handle case sensitivity, null means
71 * case-sensitive
72 * @param prefixes the prefixes to allow, must not be null
73 */
74 public PrefixFileFilter(final IOCase caseSensitivity, final List<String> prefixes) {
75 if (prefixes == null) {
76 throw new IllegalArgumentException("The list of prefixes must not be null");
77 }
78 this.prefixes = new ArrayList<>(prefixes);
79 this.caseSensitivity = caseSensitivity == null ? IOCase.SENSITIVE : caseSensitivity;
80 }
81
82 /**
83 * Constructs a new Prefix file filter for any of an array of prefixes.
84 * <p>
85 * The array is not cloned, so could be changed after constructing the instance.
86 * This would be inadvisable however.
87 *
88 * @param prefixes the prefixes to allow, must not be null
89 */
90 public PrefixFileFilter(final String... prefixes) {
91 this(IOCase.SENSITIVE, prefixes);
92 }
93
94 /**
95 * Constructs a new Prefix file filter for any of an array of prefixes
96 * specifying case-sensitivity.
97 *
98 * @param prefixes the prefixes to allow, must not be null
99 * @param caseSensitivity how to handle case sensitivity, null means
100 * case-sensitive
101 */
102 public PrefixFileFilter(final IOCase caseSensitivity, final String... prefixes) {
103 if (prefixes == null) {
104 throw new IllegalArgumentException("The array of prefixes must not be null");
105 }
106 this.prefixes = new ArrayList<>(Arrays.asList(prefixes));
107 this.caseSensitivity = caseSensitivity == null ? IOCase.SENSITIVE : caseSensitivity;
108 }
109
110 /**
111 * Checks to see if the file name starts with the prefix.
112 *
113 * @param fileSelectInfo the File to check
114 *
115 * @return true if the file name starts with one of our prefixes
116 */
117 @Override
118 public boolean accept(final FileSelectInfo fileSelectInfo) {
119 final String name = fileSelectInfo.getFile().getName().getBaseName();
120 for (final String prefix : this.prefixes) {
121 if (caseSensitivity.checkStartsWith(name, prefix)) {
122 return true;
123 }
124 }
125 return false;
126 }
127
128 /**
129 * Provide a String representation of this file filter.
130 *
131 * @return a String representation
132 */
133 @Override
134 public String toString() {
135 final StringBuilder buffer = new StringBuilder();
136 buffer.append(super.toString());
137 buffer.append("(");
138 if (prefixes != null) {
139 for (int i = 0; i < prefixes.size(); i++) {
140 if (i > 0) {
141 buffer.append(",");
142 }
143 buffer.append(prefixes.get(i));
144 }
145 }
146 buffer.append(")");
147 return buffer.toString();
148 }
149
150 }