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 1.0 037 * @version $Id: DirectoryFileFilter.java 1304052 2012-03-22 20:55:29Z ggregory $ 038 * 039 * @see FileFilterUtils#directoryFileFilter() 040 */ 041 public class DirectoryFileFilter extends AbstractFileFilter implements Serializable { 042 043 /** 044 * Singleton instance of directory filter. 045 * @since 1.3 046 */ 047 public static final IOFileFilter DIRECTORY = new DirectoryFileFilter(); 048 /** 049 * Singleton instance of directory filter. 050 * Please use the identical DirectoryFileFilter.DIRECTORY constant. 051 * The new name is more JDK 1.5 friendly as it doesn't clash with other 052 * values when using static imports. 053 */ 054 public static final IOFileFilter INSTANCE = DIRECTORY; 055 056 /** 057 * Restrictive consructor. 058 */ 059 protected DirectoryFileFilter() { 060 } 061 062 /** 063 * Checks to see if the file is a directory. 064 * 065 * @param file the File to check 066 * @return true if the file is a directory 067 */ 068 @Override 069 public boolean accept(File file) { 070 return file.isDirectory(); 071 } 072 073 }