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Java > Open Source Codes > org > apache > commons > net > ftp > parser > VMSVersioningFTPEntryParser


1 /*
2  * Copyright 2001-2005 The Apache Software Foundation
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  * http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16 package org.apache.commons.net.ftp.parser;
17
18 import java.util.HashMap JavaDoc;
19 import java.util.List JavaDoc;
20 import java.util.ListIterator JavaDoc;
21
22 import org.apache.commons.net.ftp.FTPClientConfig;
23 import org.apache.oro.text.regex.MalformedPatternException;
24 import org.apache.oro.text.regex.MatchResult;
25 import org.apache.oro.text.regex.Pattern;
26 import org.apache.oro.text.regex.Perl5Compiler;
27 import org.apache.oro.text.regex.Perl5Matcher;
28
29 /**
30  * Special implementation VMSFTPEntryParser with versioning turned on.
31  * This parser removes all duplicates and only leaves the version with the highest
32  * version number for each filename.
33  *
34  * This is a sample of VMS LIST output
35  *
36  * "1-JUN.LIS;1 9/9 2-JUN-1998 07:32:04 [GROUP,OWNER] (RWED,RWED,RWED,RE)",
37  * "1-JUN.LIS;2 9/9 2-JUN-1998 07:32:04 [GROUP,OWNER] (RWED,RWED,RWED,RE)",
38  * "DATA.DIR;1 1/9 2-JUN-1998 07:32:04 [GROUP,OWNER] (RWED,RWED,RWED,RE)",
39  * <P>
40  *
41  * @author <a HREF="Winston.Ojeda@qg.com">Winston Ojeda</a>
42  * @author <a HREF="sestegra@free.fr">Stephane ESTE-GRACIAS</a>
43  * @version $Id: VMSVersioningFTPEntryParser.java 155429 2005-02-26 13:13:04Z dirkv $
44  *
45  * @see org.apache.commons.net.ftp.FTPFileEntryParser FTPFileEntryParser (for usage instructions)
46  */
47 public class VMSVersioningFTPEntryParser extends VMSFTPEntryParser
48 {
49
50     private Perl5Matcher _preparse_matcher_;
51     private Pattern _preparse_pattern_;
52     private static final String JavaDoc PRE_PARSE_REGEX =
53         "(.*);([0-9]+)\\s*.*";
54
55     /**
56      * Constructor for a VMSFTPEntryParser object. Sets the versioning member
57      * to the supplied value.
58      *
59      * @exception IllegalArgumentException
60      * Thrown if the regular expression is unparseable. Should not be seen
61      * under normal conditions. It it is seen, this is a sign that
62      * <code>REGEX</code> is not a valid regular expression.
63      */
64     public VMSVersioningFTPEntryParser()
65     {
66         this(null);
67     }
68
69     /**
70      * This constructor allows the creation of a VMSVersioningFTPEntryParser
71      * object with something other than the default configuration.
72      *
73      * @param config The {@link FTPClientConfig configuration} object used to
74      * configure this parser.
75      * @exception IllegalArgumentException
76      * Thrown if the regular expression is unparseable. Should not be seen
77      * under normal conditions. It it is seen, this is a sign that
78      * <code>REGEX</code> is not a valid regular expression.
79      * @since 1.4
80      */
81     public VMSVersioningFTPEntryParser(FTPClientConfig config)
82     {
83         super();
84         configure(config);
85         try
86         {
87             _preparse_matcher_ = new Perl5Matcher();
88             _preparse_pattern_ = new Perl5Compiler().compile(PRE_PARSE_REGEX);
89         }
90         catch (MalformedPatternException e)
91         {
92             throw new IllegalArgumentException JavaDoc (
93                 "Unparseable regex supplied: " + PRE_PARSE_REGEX);
94         }
95
96    }
97
98
99
100     private class NameVersion {
101         String JavaDoc name;
102         int versionNumber;
103         NameVersion(String JavaDoc name, String JavaDoc vers) {
104             this.name = name;
105             this.versionNumber = Integer.parseInt(vers);
106         }
107     }
108
109     /**
110      * Implement hook provided for those implementers (such as
111      * VMSVersioningFTPEntryParser, and possibly others) which return
112      * multiple files with the same name to remove the duplicates ..
113      *
114      * @param original Original list
115      *
116      * @return Original list purged of duplicates
117      */
118     public List JavaDoc preParse(List JavaDoc original) {
119         original = super.preParse(original);
120         HashMap JavaDoc existingEntries = new HashMap JavaDoc();
121         ListIterator JavaDoc iter = original.listIterator();
122         while (iter.hasNext()) {
123             String JavaDoc entry = ((String JavaDoc)iter.next()).trim();
124             MatchResult result = null;
125             if (_preparse_matcher_.matches(entry, _preparse_pattern_)) {
126                 result = _preparse_matcher_.getMatch();
127                 String JavaDoc name = result.group(1);
128                 String JavaDoc version = result.group(2);
129                 NameVersion nv = new NameVersion(name, version);
130                 NameVersion existing = (NameVersion) existingEntries.get(name);
131                 if (null != existing) {
132                     if (nv.versionNumber < existing.versionNumber) {
133                         iter.remove(); // removal removes from original list.
134 continue;
135                     }
136                 }
137                 existingEntries.put(name, nv);
138             }
139
140         }
141         // we've now removed all entries less than with less than the largest
142 // version number for each name that were listed after the largest.
143 // we now must remove those with smaller than the largest version number
144 // for each name that were found before the largest
145 while (iter.hasPrevious()) {
146             String JavaDoc entry = ((String JavaDoc)iter.previous()).trim();
147             MatchResult result = null;
148             if (_preparse_matcher_.matches(entry, _preparse_pattern_)) {
149                 result = _preparse_matcher_.getMatch();
150                 String JavaDoc name = result.group(1);
151                 String JavaDoc version = result.group(2);
152                 NameVersion nv = new NameVersion(name, version);
153                 NameVersion existing = (NameVersion) existingEntries.get(name);
154                 if (null != existing) {
155                     if (nv.versionNumber < existing.versionNumber) {
156                         iter.remove(); // removal removes from original list.
157 }
158                 }
159             }
160
161         }
162         return original;
163     }
164
165     protected boolean isVersioning() {
166         return true;
167     }
168
169 }
170
171 /* Emacs configuration
172  * Local variables: **
173  * mode: java **
174  * c-basic-offset: 4 **
175  * indent-tabs-mode: nil **
176  * End: **
177  */
178
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