    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.IOException;
    021import java.io.Serializable;
    022import java.nio.file.FileVisitResult;
    023import java.nio.file.Files;
    024import java.nio.file.Path;
    025import java.nio.file.attribute.BasicFileAttributes;
    026
    027/**
    028 * This filter accepts {@code File}s that are hidden.
    029 * <p>
    030 * Example, showing how to print out a list of the
    031 * current directory's <i>hidden</i> files:
    032 * </p>
    033 * <h2>Using Classic IO</h2>
    034 * <pre>
    035 * File dir = new File(".");
    036 * String[] files = dir.list(HiddenFileFilter.HIDDEN);
    037 * for (String file : files) {
    038 *     System.out.println(file);
    039 * }
    040 * </pre>
    041 *
    042 * <p>
    043 * Example, showing how to print out a list of the
    044 * current directory's <i>visible</i> (i.e. not hidden) files:
    045 * </p>
    046 *
    047 * <pre>
    048 * File dir = new File(".");
    049 * String[] files = dir.list(HiddenFileFilter.VISIBLE);
    050 * for (String file : files) {
    051 *     System.out.println(file);
    052 * }
    053 * </pre>
    054 *
    055 * <h2>Using NIO</h2>
    056 * <pre>
    057 * final Path dir = Paths.get("");
    058 * final AccumulatorPathVisitor visitor = AccumulatorPathVisitor.withLongCounters(HiddenFileFilter.HIDDEN);
    059 * //
    060 * // Walk one dir
    061 * Files.<b>walkFileTree</b>(dir, Collections.emptySet(), 1, visitor);
    062 * System.out.println(visitor.getPathCounters());
    063 * System.out.println(visitor.getFileList());
    064 * //
    065 * visitor.getPathCounters().reset();
    066 * //
    067 * // Walk dir tree
    068 * Files.<b>walkFileTree</b>(dir, visitor);
    069 * System.out.println(visitor.getPathCounters());
    070 * System.out.println(visitor.getDirList());
    071 * System.out.println(visitor.getFileList());
    072 * </pre>
    073 *
    074 * @since 1.3
    075 */
    076public class HiddenFileFilter extends AbstractFileFilter implements Serializable {
    077
    078    /** Singleton instance of <i>hidden</i> filter */
    079    public static final IOFileFilter HIDDEN  = new HiddenFileFilter();
    080
    081    private static final long serialVersionUID = 8930842316112759062L;
    082
    083    /** Singleton instance of <i>visible</i> filter */
    084    public static final IOFileFilter VISIBLE = HIDDEN.negate();
    085
    086    /**
    087     * Restrictive constructor.
    088     */
    089    protected HiddenFileFilter() {
    090    }
    091
    092    /**
    093     * Checks to see if the file is hidden.
    094     *
    095     * @param file  the File to check
    096     * @return {@code true} if the file is
    097     *  <i>hidden</i>, otherwise {@code false}.
    098     */
    099    @Override
    100    public boolean accept(final File file) {
    101        return file.isHidden();
    102    }
    103
    104    /**
    105     * Checks to see if the file is hidden.
    106     * @param file  the File to check
    107     *
    108     * @return {@code true} if the file is
    109     *  <i>hidden</i>, otherwise {@code false}.
    110     * @since 2.9.0
    111     */
    112    @Override
    113    public FileVisitResult accept(final Path file, final BasicFileAttributes attributes) {
    114        try {
    115            return toFileVisitResult(Files.isHidden(file), file);
    116        } catch (final IOException e) {
    117            return handle(e);
    118        }
    119    }
    120
    121}