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 018package org.apache.commons.net.ftp; 019import java.io.BufferedReader; 020import java.io.IOException; 021import java.util.List; 022 023/** 024 * FTPFileEntryParser defines the interface for parsing a single FTP file 025 * listing and converting that information into an 026 * {@link org.apache.commons.net.ftp.FTPFile} instance. 027 * Sometimes you will want to parse unusual listing formats, in which 028 * case you would create your own implementation of FTPFileEntryParser and 029 * if necessary, subclass FTPFile. 030 * <p> 031 * Here are some examples showing how to use one of the classes that 032 * implement this interface. 033 * <p> 034 * 035 * The first example uses the <code>FTPClient.listFiles()</code> 036 * API to pull the whole list from the subfolder <code>subfolder</code> in 037 * one call, attempting to automatically detect the parser type. This 038 * method, without a parserKey parameter, indicates that autodection should 039 * be used. 040 * 041 * <pre> 042 * FTPClient f=FTPClient(); 043 * f.connect(server); 044 * f.login(username, password); 045 * FTPFile[] files = f.listFiles("subfolder"); 046 * </pre> 047 * 048 * The second example uses the <code>FTPClient.listFiles()</code> 049 * API to pull the whole list from the current working directory in one call, 050 * but specifying by classname the parser to be used. For this particular 051 * parser class, this approach is necessary since there is no way to 052 * autodetect this server type. 053 * 054 * <pre> 055 * FTPClient f=FTPClient(); 056 * f.connect(server); 057 * f.login(username, password); 058 * FTPFile[] files = f.listFiles( 059 * "org.apache.commons.net.ftp.parser.EnterpriseUnixFTPFileEntryParser", 060 * "."); 061 * </pre> 062 * 063 * The third example uses the <code>FTPClient.listFiles()</code> 064 * API to pull a single file listing in an arbitrary directory in one call, 065 * specifying by KEY the parser to be used, in this case, VMS. 066 * 067 * <pre> 068 * FTPClient f=FTPClient(); 069 * f.connect(server); 070 * f.login(username, password); 071 * FTPFile[] files = f.listFiles("VMS", "subfolder/foo.java"); 072 * </pre> 073 * 074 * For an alternative approach, see the {@link FTPListParseEngine} class 075 * which provides iterative access. 076 * 077 * @see org.apache.commons.net.ftp.FTPFile 078 * @see org.apache.commons.net.ftp.FTPClient#listFiles() 079 */ 080public interface FTPFileEntryParser 081{ 082 /** 083 * Parses a line of an FTP server file listing and converts it into a usable 084 * format in the form of an <code> FTPFile </code> instance. If the 085 * file listing line doesn't describe a file, <code> null </code> should be 086 * returned, otherwise a <code> FTPFile </code> instance representing the 087 * files in the directory is returned. 088 * 089 * @param listEntry A line of text from the file listing 090 * @return An FTPFile instance corresponding to the supplied entry 091 */ 092 FTPFile parseFTPEntry(String listEntry); 093 094 /** 095 * Reads the next entry using the supplied BufferedReader object up to 096 * whatever delemits one entry from the next. Implementors must define 097 * this for the particular ftp system being parsed. In many but not all 098 * cases, this can be defined simply by calling BufferedReader.readLine(). 099 * 100 * @param reader The BufferedReader object from which entries are to be 101 * read. 102 * 103 * @return A string representing the next ftp entry or null if none found. 104 * @throws IOException thrown on any IO Error reading from the reader. 105 */ 106 String readNextEntry(BufferedReader reader) throws IOException; 107 108 109 /** 110 * This method is a hook for those implementors (such as 111 * VMSVersioningFTPEntryParser, and possibly others) which need to 112 * perform some action upon the FTPFileList after it has been created 113 * from the server stream, but before any clients see the list. 114 * 115 * The default implementation can be a no-op. 116 * 117 * @param original Original list after it has been created from the server stream 118 * 119 * @return Original list as processed by this method. 120 */ 121 List<String> preParse(List<String> original); 122 123 124}