1 /* 2 * Licensed to the Apache Software Foundation (ASF) under one or more 3 * contributor license agreements. See the NOTICE file distributed with 4 * this work for additional information regarding copyright ownership. 5 * The ASF licenses this file to You under the Apache License, Version 2.0 6 * (the "License"); you may not use this file except in compliance with 7 * the License. You may obtain a copy of the License at 8 * 9 * http://www.apache.org/licenses/LICENSE-2.0 10 * 11 * Unless required by applicable law or agreed to in writing, software 12 * distributed under the License is distributed on an "AS IS" BASIS, 13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 14 * See the License for the specific language governing permissions and 15 * limitations under the License. 16 */ 17 package org.apache.commons.io.filefilter; 18 19 import java.io.File; 20 21 /** 22 * This filter accepts <code>File</code>s that can be read. 23 * <p> 24 * Example, showing how to print out a list of the 25 * current directory's <i>readable</i> files: 26 * 27 * <pre> 28 * File dir = new File("."); 29 * String[] files = dir.list( CanReadFileFilter.CAN_READ ); 30 * for ( int i = 0; i < files.length; i++ ) { 31 * System.out.println(files[i]); 32 * } 33 * </pre> 34 * 35 * <p> 36 * Example, showing how to print out a list of the 37 * current directory's <i>un-readable</i> files: 38 * 39 * <pre> 40 * File dir = new File("."); 41 * String[] files = dir.list( CanReadFileFilter.CANNOT_READ ); 42 * for ( int i = 0; i < files.length; i++ ) { 43 * System.out.println(files[i]); 44 * } 45 * </pre> 46 * 47 * <p> 48 * Example, showing how to print out a list of the 49 * current directory's <i>read-only</i> files: 50 * 51 * <pre> 52 * File dir = new File("."); 53 * String[] files = dir.list( CanReadFileFilter.READ_ONLY ); 54 * for ( int i = 0; i < files.length; i++ ) { 55 * System.out.println(files[i]); 56 * } 57 * </pre> 58 * 59 * @since Commons IO 1.3 60 * @version $Revision: 437567 $ 61 */ 62 public class CanReadFileFilter extends AbstractFileFilter { 63 64 /** Singleton instance of <i>readable</i> filter */ 65 public static final IOFileFilter CAN_READ = new CanReadFileFilter(); 66 67 /** Singleton instance of not <i>readable</i> filter */ 68 public static final IOFileFilter CANNOT_READ = new NotFileFilter(CAN_READ); 69 70 /** Singleton instance of <i>read-only</i> filter */ 71 public static final IOFileFilter READ_ONLY = new AndFileFilter(CAN_READ, 72 CanWriteFileFilter.CANNOT_WRITE); 73 74 /** 75 * Restrictive consructor. 76 */ 77 protected CanReadFileFilter() { 78 } 79 80 /** 81 * Checks to see if the file can be read. 82 * 83 * @param file the File to check. 84 * @return <code>true</code> if the file can be 85 * read, otherwise <code>false</code>. 86 */ 87 public boolean accept(File file) { 88 return file.canRead(); 89 } 90 91 }