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 are directories.
024 * <p>
025 * For example, here is how to print out a list of the
026 * current directory's subdirectories:
027 *
028 * <pre>
029 * File dir = new File(".");
030 * String[] files = dir.list( DirectoryFileFilter.INSTANCE );
031 * for ( int i = 0; i < files.length; i++ ) {
032 * System.out.println(files[i]);
033 * }
034 * </pre>
035 *
036 * @since Commons IO 1.0
037 * @version $Revision: 1005099 $ $Date: 2010-10-06 17:13:01 +0100 (Wed, 06 Oct 2010) $
038 *
039 * @author Stephen Colebourne
040 * @author Peter Donald
041 * @see FileFilterUtils#directoryFileFilter()
042 */
043 public class DirectoryFileFilter extends AbstractFileFilter implements Serializable {
044
045 /**
046 * Singleton instance of directory filter.
047 * @since Commons IO 1.3
048 */
049 public static final IOFileFilter DIRECTORY = new DirectoryFileFilter();
050 /**
051 * Singleton instance of directory filter.
052 * Please use the identical DirectoryFileFilter.DIRECTORY constant.
053 * The new name is more JDK 1.5 friendly as it doesn't clash with other
054 * values when using static imports.
055 */
056 public static final IOFileFilter INSTANCE = DIRECTORY;
057
058 /**
059 * Restrictive consructor.
060 */
061 protected DirectoryFileFilter() {
062 }
063
064 /**
065 * Checks to see if the file is a directory.
066 *
067 * @param file the File to check
068 * @return true if the file is a directory
069 */
070 @Override
071 public boolean accept(File file) {
072 return file.isDirectory();
073 }
074
075 }