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 file name.
034 * <p>
035 * This is a sample of VMS LIST output
036 * </p>
037 * <pre>
038 *  "1-JUN.LIS;1              9/9           2-JUN-1998 07:32:04  [GROUP,OWNER]    (RWED,RWED,RWED,RE)",
039 *  "1-JUN.LIS;2              9/9           2-JUN-1998 07:32:04  [GROUP,OWNER]    (RWED,RWED,RWED,RE)",
040 *  "DATA.DIR;1               1/9           2-JUN-1998 07:32:04  [GROUP,OWNER]    (RWED,RWED,RWED,RE)",
041 * </pre>
042 *
043 * @see org.apache.commons.net.ftp.FTPFileEntryParser FTPFileEntryParser (for usage instructions)
044 */
045public class VMSVersioningFTPEntryParser extends VMSFTPEntryParser
046{
047
048    private final Pattern preparsePattern;
049    private static final String PRE_PARSE_REGEX =
050        "(.*?);([0-9]+)\\s*.*";
051
052    /**
053     * Constructor for a VMSFTPEntryParser object.
054     *
055     * @throws IllegalArgumentException
056     * Thrown if the regular expression is unparseable.  Should not be seen
057     * under normal conditions.  It it is seen, this is a sign that
058     * <code>REGEX</code> is  not a valid regular expression.
059     */
060    public VMSVersioningFTPEntryParser()
061    {
062        this(null);
063    }
064
065    /**
066     * This constructor allows the creation of a VMSVersioningFTPEntryParser
067     * object with something other than the default configuration.
068     *
069     * @param config The {@link FTPClientConfig configuration} object used to
070     * configure this parser.
071     * @throws IllegalArgumentException
072     * Thrown if the regular expression is unparseable.  Should not be seen
073     * under normal conditions.  It it is seen, this is a sign that
074     * <code>REGEX</code> is  not a valid regular expression.
075     * @since 1.4
076     */
077    public VMSVersioningFTPEntryParser(final FTPClientConfig config)
078    {
079        configure(config);
080        try
081        {
082            //_preparse_matcher_ = new Perl5Matcher();
083            preparsePattern = Pattern.compile(PRE_PARSE_REGEX);
084        }
085        catch (final PatternSyntaxException pse)
086        {
087            throw new IllegalArgumentException (
088                "Unparseable regex supplied:  " + PRE_PARSE_REGEX);
089        }
090
091   }
092
093    /**
094     * Implement hook provided for those implementers (such as
095     * VMSVersioningFTPEntryParser, and possibly others) which return
096     * multiple files with the same name to remove the duplicates ..
097     *
098     * @param original Original list
099     *
100     * @return Original list purged of duplicates
101     */
102    @Override
103    public List<String> preParse(final List<String> original) {
104        final HashMap<String, Integer> existingEntries = new HashMap<>();
105        final ListIterator<String> iter = original.listIterator();
106        while (iter.hasNext()) {
107            final String entry = iter.next().trim();
108            MatchResult result = null;
109            final Matcher _preparse_matcher_ = preparsePattern.matcher(entry);
110            if (_preparse_matcher_.matches()) {
111                result = _preparse_matcher_.toMatchResult();
112                final String name = result.group(1);
113                final String version = result.group(2);
114                final Integer nv = Integer.valueOf(version);
115                final Integer existing = existingEntries.get(name);
116                if (null != existing) {
117                    if (nv.intValue() < existing.intValue()) {
118                        iter.remove();  // removes older version from original list.
119                        continue;
120                    }
121                }
122                existingEntries.put(name, nv);
123            }
124
125        }
126        // we've now removed all entries less than with less than the largest
127        // version number for each name that were listed after the largest.
128        // we now must remove those with smaller than the largest version number
129        // for each name that were found before the largest
130        while (iter.hasPrevious()) {
131            final String entry = iter.previous().trim();
132            MatchResult result = null;
133            final Matcher _preparse_matcher_ = preparsePattern.matcher(entry);
134            if (_preparse_matcher_.matches()) {
135                result = _preparse_matcher_.toMatchResult();
136                final String name = result.group(1);
137                final String version = result.group(2);
138                final Integer nv = Integer.valueOf(version);
139                final Integer existing = existingEntries.get(name);
140                if (null != existing) {
141                    if (nv.intValue() < existing.intValue()) {
142                        iter.remove(); // removes older version from original list.
143                    }
144                }
145            }
146
147        }
148        return original;
149    }
150
151
152    @Override
153    protected boolean isVersioning() {
154        return true;
155    }
156
157}