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 12:13:01 -0400 (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 }