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     */
017    package org.apache.commons.io.filefilter;
018    
019    import java.io.File;
020    import 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     * @version $Id: CanWriteFileFilter.java 1307462 2012-03-30 15:13:11Z ggregory $
054     */
055    public class CanWriteFileFilter extends AbstractFileFilter implements Serializable {
056        
057        /** Singleton instance of <i>writable</i> filter */
058        public static final IOFileFilter CAN_WRITE = new CanWriteFileFilter();
059    
060        /** Singleton instance of not <i>writable</i> filter */
061        public static final IOFileFilter CANNOT_WRITE = new NotFileFilter(CAN_WRITE);
062    
063        /**
064         * Restrictive consructor.
065         */
066        protected CanWriteFileFilter() {
067        }
068        
069        /**
070         * Checks to see if the file can be written to.
071         * 
072         * @param file  the File to check
073         * @return {@code true} if the file can be
074         *  written to, otherwise {@code false}.
075         */
076        @Override
077        public boolean accept(File file) {
078            return file.canWrite();
079        }
080        
081    }