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.List;
025import java.util.Objects;
026import java.util.stream.Stream;
027
028import org.apache.commons.io.IOCase;
029import org.apache.commons.io.file.PathUtils;
030
031/**
032 * Filters file names for a certain prefix.
033 * <p>
034 * For example, to print all files and directories in the
035 * current directory whose name starts with {@code Test}:
036 * </p>
037 * <h2>Using Classic IO</h2>
038 * <pre>
039 * File dir = FileUtils.current();
040 * String[] files = dir.list(new PrefixFileFilter("Test"));
041 * for (String file : files) {
042 *     System.out.println(file);
043 * }
044 * </pre>
045 *
046 * <h2>Using NIO</h2>
047 * <pre>
048 * final Path dir = PathUtils.current();
049 * final AccumulatorPathVisitor visitor = AccumulatorPathVisitor.withLongCounters(new PrefixFileFilter("Test"));
050 * //
051 * // Walk one dir
052 * Files.<b>walkFileTree</b>(dir, Collections.emptySet(), 1, visitor);
053 * System.out.println(visitor.getPathCounters());
054 * System.out.println(visitor.getFileList());
055 * //
056 * visitor.getPathCounters().reset();
057 * //
058 * // Walk dir tree
059 * Files.<b>walkFileTree</b>(dir, visitor);
060 * System.out.println(visitor.getPathCounters());
061 * System.out.println(visitor.getDirList());
062 * System.out.println(visitor.getFileList());
063 * </pre>
064 * <h2>Deprecating Serialization</h2>
065 * <p>
066 * <em>Serialization is deprecated and will be removed in 3.0.</em>
067 * </p>
068 *
069 * @since 1.0
070 * @see FileFilterUtils#prefixFileFilter(String)
071 * @see FileFilterUtils#prefixFileFilter(String, IOCase)
072 */
073public class PrefixFileFilter extends AbstractFileFilter implements Serializable {
074
075    private static final long serialVersionUID = 8533897440809599867L;
076
077    /** The file name prefixes to search for */
078    private final String[] prefixes;
079
080    /** Whether the comparison is case-sensitive. */
081    private final IOCase isCase;
082
083    /**
084     * Constructs a new Prefix file filter for a list of prefixes.
085     *
086     * @param prefixes  the prefixes to allow, must not be null
087     * @throws NullPointerException if the prefix list is null
088     * @throws ClassCastException if the list does not contain Strings
089     */
090    public PrefixFileFilter(final List<String> prefixes) {
091        this(prefixes, IOCase.SENSITIVE);
092    }
093
094    /**
095     * Constructs a new Prefix file filter for a list of prefixes
096     * specifying case-sensitivity.
097     *
098     * @param prefixes  the prefixes to allow, must not be null
099     * @param ioCase  how to handle case sensitivity, null means case-sensitive
100     * @throws NullPointerException if the prefix list is null
101     * @throws ClassCastException if the list does not contain Strings
102     * @since 1.4
103     */
104    public PrefixFileFilter(final List<String> prefixes, final IOCase ioCase) {
105        Objects.requireNonNull(prefixes, "prefixes");
106        this.prefixes = prefixes.toArray(EMPTY_STRING_ARRAY);
107        this.isCase = IOCase.value(ioCase, IOCase.SENSITIVE);
108    }
109
110    /**
111     * Constructs a new Prefix file filter for a single prefix.
112     *
113     * @param prefix  the prefix to allow, must not be null
114     * @throws IllegalArgumentException if the prefix is null
115     */
116    public PrefixFileFilter(final String prefix) {
117        this(prefix, IOCase.SENSITIVE);
118    }
119
120    /**
121     * Constructs a new Prefix file filter for any of an array of prefixes.
122     * <p>
123     * The array is not cloned, so could be changed after constructing the
124     * instance. This would be inadvisable however.
125     *
126     * @param prefixes  the prefixes to allow, must not be null
127     * @throws IllegalArgumentException if the prefix array is null
128     */
129    public PrefixFileFilter(final String... prefixes) {
130        this(prefixes, IOCase.SENSITIVE);
131    }
132
133    /**
134     * Constructs a new Prefix file filter for a single prefix
135     * specifying case-sensitivity.
136     *
137     * @param prefix  the prefix to allow, must not be null
138     * @param ioCase  how to handle case sensitivity, null means case-sensitive
139     * @throws IllegalArgumentException if the prefix is null
140     * @since 1.4
141     */
142    public PrefixFileFilter(final String prefix, final IOCase ioCase) {
143        Objects.requireNonNull(prefix, "prefix");
144        this.prefixes = new String[] {prefix};
145        this.isCase = IOCase.value(ioCase, IOCase.SENSITIVE);
146    }
147
148    /**
149     * Constructs a new Prefix file filter for any of an array of prefixes
150     * specifying case-sensitivity.
151     *
152     * @param prefixes  the prefixes to allow, must not be null
153     * @param ioCase  how to handle case sensitivity, null means case-sensitive
154     * @throws IllegalArgumentException if the prefix is null
155     * @since 1.4
156     */
157    public PrefixFileFilter(final String[] prefixes, final IOCase ioCase) {
158        Objects.requireNonNull(prefixes, "prefixes");
159        this.prefixes = prefixes.clone();
160        this.isCase = IOCase.value(ioCase, IOCase.SENSITIVE);
161    }
162
163    /**
164     * Checks to see if the file name starts with the prefix.
165     *
166     * @param file  the File to check
167     * @return true if the file name starts with one of our prefixes
168     */
169    @Override
170    public boolean accept(final File file) {
171        return accept(file == null ? null : file.getName());
172    }
173
174    /**
175     * Checks to see if the file name starts with the prefix.
176     *
177     * @param file  the File directory
178     * @param name  the file name
179     * @return true if the file name starts with one of our prefixes
180     */
181    @Override
182    public boolean accept(final File file, final String name) {
183        return accept(name);
184    }
185
186    /**
187     * Checks to see if the file name starts with the prefix.
188     * @param file  the File to check
189     *
190     * @return true if the file name starts with one of our prefixes
191     * @since 2.9.0
192     */
193    @Override
194    public FileVisitResult accept(final Path file, final BasicFileAttributes attributes) {
195        return toFileVisitResult(accept(PathUtils.getFileName(file, Path::toFile)));
196    }
197
198    private boolean accept(final String name) {
199        return Stream.of(prefixes).anyMatch(prefix -> isCase.checkStartsWith(name, prefix));
200    }
201
202    /**
203     * Provide a String representation of this file filter.
204     *
205     * @return a String representation
206     */
207    @Override
208    public String toString() {
209        final StringBuilder buffer = new StringBuilder();
210        buffer.append(super.toString());
211        buffer.append("(");
212        append(prefixes, buffer);
213        buffer.append(")");
214        return buffer.toString();
215    }
216
217}