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 read. 024 * <p> 025 * Example, showing how to print out a list of the 026 * current directory's <i>readable</i> files: 027 * 028 * <pre> 029 * File dir = new File("."); 030 * String[] files = dir.list( CanReadFileFilter.CAN_READ ); 031 * for ( int i = 0; i < 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-readable</i> files: 039 * 040 * <pre> 041 * File dir = new File("."); 042 * String[] files = dir.list( CanReadFileFilter.CANNOT_READ ); 043 * for ( int i = 0; i < files.length; i++ ) { 044 * System.out.println(files[i]); 045 * } 046 * </pre> 047 * 048 * <p> 049 * Example, showing how to print out a list of the 050 * current directory's <i>read-only</i> files: 051 * 052 * <pre> 053 * File dir = new File("."); 054 * String[] files = dir.list( CanReadFileFilter.READ_ONLY ); 055 * for ( int i = 0; i < files.length; i++ ) { 056 * System.out.println(files[i]); 057 * } 058 * </pre> 059 * 060 * @since 1.3 061 * @version $Id: CanReadFileFilter.java 1307462 2012-03-30 15:13:11Z ggregory $ 062 */ 063 public class CanReadFileFilter extends AbstractFileFilter implements Serializable { 064 065 /** Singleton instance of <i>readable</i> filter */ 066 public static final IOFileFilter CAN_READ = new CanReadFileFilter(); 067 068 /** Singleton instance of not <i>readable</i> filter */ 069 public static final IOFileFilter CANNOT_READ = new NotFileFilter(CAN_READ); 070 071 /** Singleton instance of <i>read-only</i> filter */ 072 public static final IOFileFilter READ_ONLY = new AndFileFilter(CAN_READ, 073 CanWriteFileFilter.CANNOT_WRITE); 074 075 /** 076 * Restrictive consructor. 077 */ 078 protected CanReadFileFilter() { 079 } 080 081 /** 082 * Checks to see if the file can be read. 083 * 084 * @param file the File to check. 085 * @return {@code true} if the file can be 086 * read, otherwise {@code false}. 087 */ 088 @Override 089 public boolean accept(File file) { 090 return file.canRead(); 091 } 092 093 }