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;
021
022/**
023 * This filter accepts <code>File</code>s that can be written to.
024 * <p>
025 * Example, showing how to print out a list of the
026 * current directory's <i>writable</i> files:
027 *
028 * <pre>
029 * File dir = new File(".");
030 * String[] files = dir.list( CanWriteFileFilter.CAN_WRITE );
031 * for ( int i = 0; i &lt; files.length; i++ ) {
032 *     System.out.println(files[i]);
033 * }
034 * </pre>
035 *
036 * <p>
037 * Example, showing how to print out a list of the
038 * current directory's <i>un-writable</i> files:
039 *
040 * <pre>
041 * File dir = new File(".");
042 * String[] files = dir.list( CanWriteFileFilter.CANNOT_WRITE );
043 * for ( int i = 0; i &lt; files.length; i++ ) {
044 *     System.out.println(files[i]);
045 * }
046 * </pre>
047 *
048 * <p>
049 * <b>N.B.</b> For read-only files, use
050 *    <code>CanReadFileFilter.READ_ONLY</code>.
051 *
052 * @since 1.3
053 *
054 */
055public class CanWriteFileFilter extends AbstractFileFilter implements Serializable {
056
057    private static final long serialVersionUID = 5132005214688990379L;
058
059    /** Singleton instance of <i>writable</i> filter */
060    public static final IOFileFilter CAN_WRITE = new CanWriteFileFilter();
061
062    /** Singleton instance of not <i>writable</i> filter */
063    public static final IOFileFilter CANNOT_WRITE = new NotFileFilter(CAN_WRITE);
064
065    /**
066     * Restrictive constructor.
067     */
068    protected CanWriteFileFilter() {
069    }
070
071    /**
072     * Checks to see if the file can be written to.
073     *
074     * @param file  the File to check
075     * @return {@code true} if the file can be
076     *  written to, otherwise {@code false}.
077     */
078    @Override
079    public boolean accept(final File file) {
080        return file.canWrite();
081    }
082
083}