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 636854 2008-03-13 19:55:01Z 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 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     */