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