    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;
    024
    025/**
    026 * A file filter that always returns false.
    027 *
    028 * @since 1.0
    029 * @see FileFilterUtils#falseFileFilter()
    030 */
    031public class FalseFileFilter implements IOFileFilter, Serializable {
    032
    033    private static final String TO_STRING = Boolean.FALSE.toString();
    034
    035    /**
    036     * Singleton instance of false filter.
    037     *
    038     * @since 1.3
    039     */
    040    public static final IOFileFilter FALSE = new FalseFileFilter();
    041
    042    /**
    043     * Singleton instance of false filter. Please use the identical FalseFileFilter.FALSE constant. The new name is more
    044     * JDK 1.5 friendly as it doesn't clash with other values when using static imports.
    045     */
    046    public static final IOFileFilter INSTANCE = FALSE;
    047
    048    private static final long serialVersionUID = 6210271677940926200L;
    049
    050    /**
    051     * Restrictive constructor.
    052     */
    053    protected FalseFileFilter() {
    054    }
    055
    056    /**
    057     * Returns false.
    058     *
    059     * @param file the file to check (ignored)
    060     * @return false
    061     */
    062    @Override
    063    public boolean accept(final File file) {
    064        return false;
    065    }
    066
    067    /**
    068     * Returns false.
    069     *
    070     * @param dir the directory to check (ignored)
    071     * @param name the file name (ignored)
    072     * @return false
    073     */
    074    @Override
    075    public boolean accept(final File dir, final String name) {
    076        return false;
    077    }
    078
    079    /**
    080     * Returns false.
    081     *
    082     * @param file the file to check (ignored)
    083     *
    084     * @return false
    085     * @since 2.9.0
    086     */
    087    @Override
    088    public FileVisitResult accept(final Path file, final BasicFileAttributes attributes) {
    089        return FileVisitResult.TERMINATE;
    090    }
    091
    092    @Override
    093    public IOFileFilter negate() {
    094        return TrueFileFilter.INSTANCE;
    095    }
    096
    097    @Override
    098    public String toString() {
    099        return TO_STRING;
    100    }
    101
    102    @Override
    103    public IOFileFilter and(final IOFileFilter fileFilter) {
    104        // FALSE AND expression <=> FALSE
    105        return INSTANCE;
    106    }
    107
    108    @Override
    109    public IOFileFilter or(final IOFileFilter fileFilter) {
    110        // FALSE OR expression <=> expression
    111        return fileFilter;
    112    }
    113}