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.Files;
023import java.nio.file.Path;
024import java.nio.file.attribute.BasicFileAttributes;
025
026/**
027 * This filter accepts {@code File}s that are files (not directories).
028 * <p>
029 * For example, here is how to print out a list of the real files
030 * within the current directory:
031 * </p>
032 * <h2>Using Classic IO</h2>
033 * <pre>
034 * File dir = new File(".");
035 * String[] files = dir.list(FileFileFilter.INSTANCE);
036 * for (String file : files) {
037 *     System.out.println(file);
038 * }
039 * </pre>
040 *
041 * <h2>Using NIO</h2>
042 * <pre>
043 * final Path dir = Paths.get("");
044 * final AccumulatorPathVisitor visitor = AccumulatorPathVisitor.withLongCounters(FileFileFilter.INSTANCE);
045 * //
046 * // Walk one dir
047 * Files.<b>walkFileTree</b>(dir, Collections.emptySet(), 1, visitor);
048 * System.out.println(visitor.getPathCounters());
049 * System.out.println(visitor.getFileList());
050 * //
051 * visitor.getPathCounters().reset();
052 * //
053 * // Walk dir tree
054 * Files.<b>walkFileTree</b>(dir, visitor);
055 * System.out.println(visitor.getPathCounters());
056 * System.out.println(visitor.getDirList());
057 * System.out.println(visitor.getFileList());
058 * </pre>
059 *
060 * @since 1.3
061 * @see FileFilterUtils#fileFileFilter()
062 */
063public class FileFileFilter extends AbstractFileFilter implements Serializable {
064
065    /**
066     * Singleton instance of file filter.
067     *
068     * @since 2.9.0
069     */
070    public static final IOFileFilter INSTANCE = new FileFileFilter();
071
072    /**
073     * Singleton instance of file filter.
074     *
075     * @deprecated Use {@link #INSTANCE}.
076     */
077    @Deprecated
078    public static final IOFileFilter FILE = INSTANCE;
079
080    private static final long serialVersionUID = 5345244090827540862L;
081
082    /**
083     * Restrictive constructor.
084     */
085    protected FileFileFilter() {
086    }
087
088    /**
089     * Checks to see if the file is a file.
090     *
091     * @param file  the File to check
092     * @return true if the file is a file
093     */
094    @Override
095    public boolean accept(final File file) {
096        return file.isFile();
097    }
098
099    /**
100     * Checks to see if the file is a file.
101     * @param file  the File to check
102     *
103     * @return true if the file is a file
104     * @since 2.9.0
105     */
106    @Override
107    public FileVisitResult accept(final Path file, final BasicFileAttributes attributes) {
108        return toFileVisitResult(Files.isRegularFile(file), file);
109    }
110
111}