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 can be executed.
028 * <p>
029 * Example, showing how to print out a list of the
030 * current directory's <i>executable</i> files:
031 * </p>
032 * <h2>Using Classic IO</h2>
033 * <pre>
034 * File dir = new File(".");
035 * String[] files = dir.list(CanExecuteFileFilter.CAN_EXECUTE);
036 * for (String file : files) {
037 *     System.out.println(file);
038 * }
039 * </pre>
040 *
041 * <p>
042 * Example, showing how to print out a list of the
043 * current directory's <i>non-executable</i> files:
044 * </p>
045 *
046 * <pre>
047 * File dir = new File(".");
048 * String[] files = dir.list(CanExecuteFileFilter.CANNOT_EXECUTE);
049 * for (int i = 0; i &lt; files.length; i++) {
050 *     System.out.println(files[i]);
051 * }
052 * </pre>
053 *
054 * @since 2.7
055 */
056public class CanExecuteFileFilter extends AbstractFileFilter implements Serializable {
057
058    /** Singleton instance of <i>executable</i> filter */
059    public static final IOFileFilter CAN_EXECUTE = new CanExecuteFileFilter();
060
061    /** Singleton instance of not <i>executable</i> filter */
062    public static final IOFileFilter CANNOT_EXECUTE = CAN_EXECUTE.negate();
063
064    private static final long serialVersionUID = 3179904805251622989L;
065
066    /**
067     * Restrictive constructor.
068     */
069    protected CanExecuteFileFilter() {
070        // empty.
071    }
072
073    /**
074     * Checks to see if the file can be executed.
075     *
076     * @param file  the File to check.
077     * @return {@code true} if the file can be executed, otherwise {@code false}.
078     */
079    @Override
080    public boolean accept(final File file) {
081        return file.canExecute();
082    }
083
084    /**
085     * Checks to see if the file can be executed.
086     * @param file  the File to check.
087     *
088     * @return {@code true} if the file can be executed, otherwise {@code false}.
089     * @since 2.9.0
090     */
091    @Override
092    public FileVisitResult accept(final Path file, final BasicFileAttributes attributes) {
093        return toFileVisitResult(Files.isExecutable(file), file);
094    }
095
096}