    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}