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 */ 017package org.apache.commons.vfs2.filter; 018 019import java.io.Serializable; 020 021import org.apache.commons.vfs2.FileFilter; 022import org.apache.commons.vfs2.FileSelectInfo; 023import org.apache.commons.vfs2.FileSystemException; 024 025/** 026 * This filter accepts {@code File}s that are symbolic links. 027 * <p> 028 * Example, showing how to print out a list of the current directory's 029 * <em>symbolic link</em> files: 030 * </p> 031 * 032 * <pre> 033 * FileSystemManager fsManager = VFS.getManager(); 034 * FileObject dir = fsManager.toFileObject(new File(".")); 035 * FileObject[] files = dir.findFiles(new FileFilterSelector(SymbolicLinkFileFilter.SYMBOLIC)); 036 * for (int i = 0; i < files.length; i++) { 037 * System.out.println(files[i]); 038 * } 039 * </pre> 040 * 041 * <p> 042 * Example, showing how to print out a list of the current directory's 043 * <em>actual</em> (i.e. symbolic link) files: 044 * </p> 045 * 046 * <pre> 047 * FileSystemManager fsManager = VFS.getManager(); 048 * FileObject dir = fsManager.toFileObject(new File(".")); 049 * FileObject[] files = dir.findFiles(new FileFilterSelector(SymbolicLinkFileFilter.ACTUAL)); 050 * for (int i = 0; i < files.length; i++) { 051 * System.out.println(files[i]); 052 * } 053 * </pre> 054 * 055 * @since 2.4 056 */ 057public class SymbolicLinkFileFilter implements FileFilter, Serializable { 058 059 /** Singleton instance of <em>hidden</em> filter. */ 060 public static final FileFilter SYMBOLIC = new SymbolicLinkFileFilter(); 061 062 /** Singleton instance of <em>visible</em> filter. */ 063 public static final FileFilter ACTUAL = new NotFileFilter(SYMBOLIC); 064 065 private static final long serialVersionUID = 1L; 066 067 /** 068 * Restrictive constructor. 069 */ 070 protected SymbolicLinkFileFilter() { 071 } 072 073 /** 074 * Checks to see if the file is a symbolic link. Non-existing files won't be accepted. 075 * 076 * @param fileSelectInfo the file to check 077 * @return {@code true} if the file is <em>symbolic link</em>, otherwise {@code false}. 078 * @throws FileSystemException Thrown for file system errors. 079 */ 080 @Override 081 public boolean accept(final FileSelectInfo fileSelectInfo) throws FileSystemException { 082 if (!fileSelectInfo.getFile().exists()) { 083 return false; 084 } 085 return fileSelectInfo.getFile().isSymbolicLink(); 086 } 087 088}