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.parser;
019
020import java.util.HashMap;
021import java.util.List;
022import java.util.ListIterator;
023import java.util.regex.MatchResult;
024import java.util.regex.Matcher;
025import java.util.regex.Pattern;
026import java.util.regex.PatternSyntaxException;
027
028import org.apache.commons.net.ftp.FTPClientConfig;
029
030/**
031 * Special implementation VMSFTPEntryParser with versioning turned on.
032 * This parser removes all duplicates and only leaves the version with the highest
033 * version number for each filename.
034 *
035 * This is a sample of VMS LIST output
036 *
037 *  "1-JUN.LIS;1              9/9           2-JUN-1998 07:32:04  [GROUP,OWNER]    (RWED,RWED,RWED,RE)",
038 *  "1-JUN.LIS;2              9/9           2-JUN-1998 07:32:04  [GROUP,OWNER]    (RWED,RWED,RWED,RE)",
039 *  "DATA.DIR;1               1/9           2-JUN-1998 07:32:04  [GROUP,OWNER]    (RWED,RWED,RWED,RE)",
040 * <P>
041 *
042 * @author  <a href="Winston.Ojeda@qg.com">Winston Ojeda</a>
043 * @author <a href="sestegra@free.fr">Stephane ESTE-GRACIAS</a>
044 * @version $Id: VMSVersioningFTPEntryParser.java 636854 2008-03-13 19:55:01Z sebb $
045 *
046 * @see org.apache.commons.net.ftp.FTPFileEntryParser FTPFileEntryParser (for usage instructions)
047 */
048public class VMSVersioningFTPEntryParser extends VMSFTPEntryParser
049{
050
051    private Matcher _preparse_matcher_;
052    private Pattern _preparse_pattern_;
053    private static final String PRE_PARSE_REGEX =
054        "(.*);([0-9]+)\\s*.*";
055
056    /**
057     * Constructor for a VMSFTPEntryParser object.  Sets the versioning member
058     * to the supplied value.
059     *
060     * @exception IllegalArgumentException
061     * Thrown if the regular expression is unparseable.  Should not be seen
062     * under normal conditions.  It it is seen, this is a sign that
063     * <code>REGEX</code> is  not a valid regular expression.
064     */
065    public VMSVersioningFTPEntryParser()
066    {
067        this(null);
068    }
069
070    /**
071     * This constructor allows the creation of a VMSVersioningFTPEntryParser 
072     * object with something other than the default configuration.
073     *
074     * @param config The {@link FTPClientConfig configuration} object used to 
075     * configure this parser.
076     * @exception IllegalArgumentException
077     * Thrown if the regular expression is unparseable.  Should not be seen
078     * under normal conditions.  It it is seen, this is a sign that
079     * <code>REGEX</code> is  not a valid regular expression.
080     * @since 1.4
081     */
082    public VMSVersioningFTPEntryParser(FTPClientConfig config)
083    {
084        super();
085        configure(config);
086        try
087        {
088            //_preparse_matcher_ = new Perl5Matcher();
089            _preparse_pattern_ = Pattern.compile(PRE_PARSE_REGEX);
090        }
091        catch (PatternSyntaxException pse)
092        {
093            throw new IllegalArgumentException (
094                "Unparseable regex supplied:  " + PRE_PARSE_REGEX);
095        }
096
097   }
098
099
100
101    private static class NameVersion {
102        String name;
103        int versionNumber;
104        NameVersion(String name, String vers) {
105            this.name = name;
106            this.versionNumber = Integer.parseInt(vers);
107        }
108    }
109
110    /**
111     * Implement hook provided for those implementers (such as
112     * VMSVersioningFTPEntryParser, and possibly others) which return
113     * multiple files with the same name to remove the duplicates ..
114     *
115     * @param original Original list
116     *
117     * @return Original list purged of duplicates
118     */
119    @Override
120    public List<String> preParse(List<String> original) {
121        original = super.preParse(original);
122        HashMap<String, NameVersion> existingEntries = new HashMap<String, NameVersion>();
123        ListIterator<String> iter = original.listIterator();
124        while (iter.hasNext()) {
125            String entry = iter.next().trim();
126            MatchResult result = null;
127            _preparse_matcher_ = _preparse_pattern_.matcher(entry);
128            if (_preparse_matcher_.matches()) {
129                result = _preparse_matcher_.toMatchResult();
130                String name = result.group(1);
131                String version = result.group(2);
132                NameVersion nv = new NameVersion(name, version);
133                NameVersion existing = existingEntries.get(name);
134                if (null != existing) {
135                    if (nv.versionNumber < existing.versionNumber) {
136                        iter.remove();  // removal removes from original list.
137                        continue;
138                    }
139                }
140                existingEntries.put(name, nv);
141            }
142
143        }
144        // we've now removed all entries less than with less than the largest
145        // version number for each name that were listed after the largest.
146        // we now must remove those with smaller than the largest version number
147        // for each name that were found before the largest
148        while (iter.hasPrevious()) {
149            String entry = iter.previous().trim();
150            MatchResult result = null;
151            _preparse_matcher_ = _preparse_pattern_.matcher(entry);
152            if (_preparse_matcher_.matches()) {
153                result = _preparse_matcher_.toMatchResult();
154                String name = result.group(1);
155                String version = result.group(2);
156                NameVersion nv = new NameVersion(name, version);
157                NameVersion existing = existingEntries.get(name);
158                if (null != existing) {
159                    if (nv.versionNumber < existing.versionNumber) {
160                        iter.remove(); // removal removes from original list.
161                    }
162                }
163            }
164
165        }
166        return original;
167    }
168
169
170    @Override
171    protected boolean isVersioning() {
172        return true;
173    }
174
175}
176
177/* Emacs configuration
178 * Local variables:        **
179 * mode:             java  **
180 * c-basic-offset:   4     **
181 * indent-tabs-mode: nil   **
182 * End:                    **
183 */