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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  
18  package org.apache.commons.net.ftp;
19  import java.io.BufferedReader;
20  import java.io.IOException;
21  import java.util.List;
22  
23  /**
24   * FTPFileEntryParser defines the interface for parsing a single FTP file
25   * listing and converting that information into an
26   * {@link org.apache.commons.net.ftp.FTPFile} instance.
27   * Sometimes you will want to parse unusual listing formats, in which
28   * case you would create your own implementation of FTPFileEntryParser and
29   * if necessary, subclass FTPFile.
30   * <p>
31   * Here are some examples showing how to use one of the classes that
32   * implement this interface.
33   * <p>
34   *
35   * The first example uses the <code>FTPClient.listFiles()</code>
36   * API to pull the whole list from the subfolder <code>subfolder</code> in
37   * one call, attempting to automatically detect the parser type.  This
38   * method, without a parserKey parameter, indicates that autodection should
39   * be used.
40   *
41   * <pre>
42   *    FTPClient f=FTPClient();
43   *    f.connect(server);
44   *    f.login(username, password);
45   *    FTPFile[] files = f.listFiles("subfolder");
46   * </pre>
47   *
48   * The secondr example uses the <code>FTPClient.listFiles()</code>>
49   * API to pull the whole list from the current working directory in one call,
50   * but specifying by classname the parser to be used.  For this particular
51   * parser class, this approach is necessary since there is no way to
52   * autodetect this server type.
53   *
54   * <pre>
55   *    FTPClient f=FTPClient();
56   *    f.connect(server);
57   *    f.login(username, password);
58   *    FTPFile[] files = f.listFiles(
59   *      "org.apache.commons.net.ftp.parser.EnterpriseUnixFTPFileEntryParser",
60   *      ".");
61   * </pre>
62   *
63   * The third example uses the <code>FTPClient.listFiles()</code>
64   * API to pull a single file listing in an arbitrary directory in one call,
65   * specifying by KEY the parser to be used, in this case, VMS.
66   *
67   * <pre>
68   *    FTPClient f=FTPClient();
69   *    f.connect(server);
70   *    f.login(username, password);
71   *    FTPFile[] files = f.listFiles("VMS", "subfolder/foo.java");
72   * </pre>
73   *
74   * For an alternative approach, see the {@link FTPListParseEngine} class
75   * which provides iterative access.
76   *
77   * @author <a href="mailto:scohen@apache.org">Steve Cohen</a>
78   * @version $Id: FTPFileEntryParser.java 1299238 2012-03-10 17:12:28Z sebb $
79   * @see org.apache.commons.net.ftp.FTPFile
80   * @see org.apache.commons.net.ftp.FTPClient#listFiles()
81   */
82  public interface FTPFileEntryParser
83  {
84      /**
85       * Parses a line of an FTP server file listing and converts it into a usable
86       * format in the form of an <code> FTPFile </code> instance.  If the
87       * file listing line doesn't describe a file, <code> null </code> should be
88       * returned, otherwise a <code> FTPFile </code> instance representing the
89       * files in the directory is returned.
90       * <p>
91       * @param listEntry A line of text from the file listing
92       * @return An FTPFile instance corresponding to the supplied entry
93       */
94      FTPFile parseFTPEntry(String listEntry);
95  
96      /**
97       * Reads the next entry using the supplied BufferedReader object up to
98       * whatever delemits one entry from the next.  Implementors must define
99       * this for the particular ftp system being parsed.  In many but not all
100      * cases, this can be defined simply by calling BufferedReader.readLine().
101      *
102      * @param reader The BufferedReader object from which entries are to be
103      * read.
104      *
105      * @return A string representing the next ftp entry or null if none found.
106      * @exception IOException thrown on any IO Error reading from the reader.
107      */
108     String readNextEntry(BufferedReader reader) throws IOException;
109 
110 
111     /**
112      * This method is a hook for those implementors (such as
113      * VMSVersioningFTPEntryParser, and possibly others) which need to
114      * perform some action upon the FTPFileList after it has been created
115      * from the server stream, but before any clients see the list.
116      *
117      * The default implementation can be a no-op.
118      *
119      * @param original Original list after it has been created from the server stream
120      *
121      * @return Original list as processed by this method.
122      */
123     List<String> preParse(List<String> original);
124 
125 
126 }
127 
128 
129 /* Emacs configuration
130  * Local variables:        **
131  * mode:             java  **
132  * c-basic-offset:   4     **
133  * indent-tabs-mode: nil   **
134  * End:                    **
135  */