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