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    
018    package org.apache.commons.net.ftp.parser;
019    
020    import java.util.HashMap;
021    import java.util.List;
022    import java.util.ListIterator;
023    import java.util.regex.MatchResult;
024    import java.util.regex.Matcher;
025    import java.util.regex.Pattern;
026    import java.util.regex.PatternSyntaxException;
027    
028    import 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 999923 2010-09-22 13:03:51Z sebb $
045     *
046     * @see org.apache.commons.net.ftp.FTPFileEntryParser FTPFileEntryParser (for usage instructions)
047     */
048    public class VMSVersioningFTPEntryParser extends VMSFTPEntryParser
049    {
050    
051        private final Pattern _preparse_pattern_;
052        private static final String PRE_PARSE_REGEX =
053            "(.*);([0-9]+)\\s*.*";
054    
055        /**
056         * Constructor for a VMSFTPEntryParser object.
057         *
058         * @exception IllegalArgumentException
059         * Thrown if the regular expression is unparseable.  Should not be seen
060         * under normal conditions.  It it is seen, this is a sign that
061         * <code>REGEX</code> is  not a valid regular expression.
062         */
063        public VMSVersioningFTPEntryParser()
064        {
065            this(null);
066        }
067    
068        /**
069         * This constructor allows the creation of a VMSVersioningFTPEntryParser 
070         * object with something other than the default configuration.
071         *
072         * @param config The {@link FTPClientConfig configuration} object used to 
073         * configure this parser.
074         * @exception IllegalArgumentException
075         * Thrown if the regular expression is unparseable.  Should not be seen
076         * under normal conditions.  It it is seen, this is a sign that
077         * <code>REGEX</code> is  not a valid regular expression.
078         * @since 1.4
079         */
080        public VMSVersioningFTPEntryParser(FTPClientConfig config)
081        {
082            super();
083            configure(config);
084            try
085            {
086                //_preparse_matcher_ = new Perl5Matcher();
087                _preparse_pattern_ = Pattern.compile(PRE_PARSE_REGEX);
088            }
089            catch (PatternSyntaxException pse)
090            {
091                throw new IllegalArgumentException (
092                    "Unparseable regex supplied:  " + PRE_PARSE_REGEX);
093            }
094    
095       }
096    
097        /**
098         * Implement hook provided for those implementers (such as
099         * VMSVersioningFTPEntryParser, and possibly others) which return
100         * multiple files with the same name to remove the duplicates ..
101         *
102         * @param original Original list
103         *
104         * @return Original list purged of duplicates
105         */
106        @Override
107        public List<String> preParse(List<String> original) {
108            original = super.preParse(original);
109            HashMap<String, Integer> existingEntries = new HashMap<String, Integer>();
110            ListIterator<String> iter = original.listIterator();
111            while (iter.hasNext()) {
112                String entry = iter.next().trim();
113                MatchResult result = null;
114                Matcher _preparse_matcher_ = _preparse_pattern_.matcher(entry);
115                if (_preparse_matcher_.matches()) {
116                    result = _preparse_matcher_.toMatchResult();
117                    String name = result.group(1);
118                    String version = result.group(2);
119                    Integer nv = Integer.valueOf(version);
120                    Integer existing = existingEntries.get(name);
121                    if (null != existing) {
122                        if (nv.intValue() < existing.intValue()) {
123                            iter.remove();  // removes older version from original list.
124                            continue;
125                        }
126                    }
127                    existingEntries.put(name, nv);
128                }
129    
130            }
131            // we've now removed all entries less than with less than the largest
132            // version number for each name that were listed after the largest.
133            // we now must remove those with smaller than the largest version number
134            // for each name that were found before the largest
135            while (iter.hasPrevious()) {
136                String entry = iter.previous().trim();
137                MatchResult result = null;
138                Matcher _preparse_matcher_ = _preparse_pattern_.matcher(entry);
139                if (_preparse_matcher_.matches()) {
140                    result = _preparse_matcher_.toMatchResult();
141                    String name = result.group(1);
142                    String version = result.group(2);
143                    Integer nv = Integer.valueOf(version);
144                    Integer existing = existingEntries.get(name);
145                    if (null != existing) {
146                        if (nv.intValue() < existing.intValue()) {
147                            iter.remove(); // removes older version from original list.
148                        }
149                    }
150                }
151    
152            }
153            return original;
154        }
155    
156    
157        @Override
158        protected boolean isVersioning() {
159            return true;
160        }
161    
162    }
163    
164    /* Emacs configuration
165     * Local variables:        **
166     * mode:             java  **
167     * c-basic-offset:   4     **
168     * indent-tabs-mode: nil   **
169     * End:                    **
170     */