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;
019
020import java.text.DateFormatSymbols;
021import java.util.Collection;
022import java.util.Locale;
023import java.util.Map;
024import java.util.StringTokenizer;
025import java.util.TreeMap;
026
027/**
028 * <p>
029 * This class implements an alternate means of configuring the
030 * {@link  org.apache.commons.net.ftp.FTPClient  FTPClient} object and
031 * also subordinate objects which it uses.  Any class implementing the
032 * {@link  org.apache.commons.net.ftp.Configurable  Configurable }
033 * interface can be configured by this object.
034 * </p><p>
035 * In particular this class was designed primarily to support configuration
036 * of FTP servers which express file timestamps in formats and languages
037 * other than those for the US locale, which although it is the most common
038 * is not universal.  Unfortunately, nothing in the FTP spec allows this to
039 * be determined in an automated way, so manual configuration such as this
040 * is necessary.
041 * </p><p>
042 * This functionality was designed to allow existing clients to work exactly
043 * as before without requiring use of this component.  This component should
044 * only need to be explicitly invoked by the user of this package for problem
045 * cases that previous implementations could not solve.
046 * </p>
047 * <h3>Examples of use of FTPClientConfig</h3>
048 * Use cases:
049 * You are trying to access a server that
050 * <ul>
051 * <li>lists files with timestamps that use month names in languages other
052 * than English</li>
053 * <li>lists files with timestamps that use date formats other
054 * than the American English "standard" <code>MM dd yyyy</code></li>
055 * <li>is in different timezone and you need accurate timestamps for
056 * dependency checking as in Ant</li>
057 * </ul>
058 * <p>
059 * Unpaged (whole list) access on a UNIX server that uses French month names
060 * but uses the "standard" <code>MMM d yyyy</code> date formatting
061 * <pre>
062 *    FTPClient f=FTPClient();
063 *    FTPClientConfig conf = new FTPClientConfig(FTPClientConfig.SYST_UNIX);
064 *    conf.setServerLanguageCode("fr");
065 *    f.configure(conf);
066 *    f.connect(server);
067 *    f.login(username, password);
068 *    FTPFile[] files = listFiles(directory);
069 * </pre>
070 * <p>
071 * Paged access on a UNIX server that uses Danish month names
072 * and "European" date formatting in Denmark's time zone, when you
073 * are in some other time zone.
074 * <pre>
075 *    FTPClient f=FTPClient();
076 *    FTPClientConfig conf = new FTPClientConfig(FTPClientConfig.SYST_UNIX);
077 *    conf.setServerLanguageCode("da");
078 *    conf.setDefaultDateFormat("d MMM yyyy");
079 *    conf.setRecentDateFormat("d MMM HH:mm");
080 *    conf.setTimeZoneId("Europe/Copenhagen");
081 *    f.configure(conf);
082 *    f.connect(server);
083 *    f.login(username, password);
084 *    FTPListParseEngine engine =
085 *       f.initiateListParsing("com.whatever.YourOwnParser", directory);
086 *
087 *    while (engine.hasNext()) {
088 *       FTPFile[] files = engine.getNext(25);  // "page size" you want
089 *       //do whatever you want with these files, display them, etc.
090 *       //expensive FTPFile objects not created until needed.
091 *    }
092 * </pre>
093 * <p>
094 * Unpaged (whole list) access on a VMS server that uses month names
095 * in a language not {@link #getSupportedLanguageCodes() supported} by the system.
096 * but uses the "standard" <code>MMM d yyyy</code> date formatting
097 * <pre>
098 *    FTPClient f=FTPClient();
099 *    FTPClientConfig conf = new FTPClientConfig(FTPClientConfig.SYST_VMS);
100 *    conf.setShortMonthNames(
101 *        "jan|feb|mar|apr|ma\u00ED|j\u00FAn|j\u00FAl|\u00e1g\u00FA|sep|okt|n\u00F3v|des");
102 *    f.configure(conf);
103 *    f.connect(server);
104 *    f.login(username, password);
105 *    FTPFile[] files = listFiles(directory);
106 * </pre>
107 * <p>
108 * Unpaged (whole list) access on a Windows-NT server in a different time zone.
109 * (Note, since the NT Format uses numeric date formatting, language issues
110 * are irrelevant here).
111 * <pre>
112 *    FTPClient f=FTPClient();
113 *    FTPClientConfig conf = new FTPClientConfig(FTPClientConfig.SYST_NT);
114 *    conf.setTimeZoneId("America/Denver");
115 *    f.configure(conf);
116 *    f.connect(server);
117 *    f.login(username, password);
118 *    FTPFile[] files = listFiles(directory);
119 * </pre>
120 * Unpaged (whole list) access on a Windows-NT server in a different time zone
121 * but which has been configured to use a unix-style listing format.
122 * <pre>
123 *    FTPClient f=FTPClient();
124 *    FTPClientConfig conf = new FTPClientConfig(FTPClientConfig.SYST_UNIX);
125 *    conf.setTimeZoneId("America/Denver");
126 *    f.configure(conf);
127 *    f.connect(server);
128 *    f.login(username, password);
129 *    FTPFile[] files = listFiles(directory);
130 * </pre>
131 *
132 * @since 1.4
133 * @see org.apache.commons.net.ftp.Configurable
134 * @see org.apache.commons.net.ftp.FTPClient
135 * @see org.apache.commons.net.ftp.parser.FTPTimestampParserImpl#configure(FTPClientConfig)
136 * @see org.apache.commons.net.ftp.parser.ConfigurableFTPFileEntryParserImpl
137 */
138public class FTPClientConfig
139{
140
141    /**
142     * Identifier by which a unix-based ftp server is known throughout
143     * the commons-net ftp system.
144     */
145    public static final String SYST_UNIX  = "UNIX";
146
147    /**
148     * Identifier for alternate UNIX parser; same as {@link #SYST_UNIX} but leading spaces are
149     * trimmed from file names. This is to maintain backwards compatibility with
150     * the original behaviour of the parser which ignored multiple spaces between the date
151     * and the start of the file name.
152     * @since 3.4
153     */
154    public static final String SYST_UNIX_TRIM_LEADING  = "UNIX_LTRIM";
155
156    /**
157     * Identifier by which a vms-based ftp server is known throughout
158     * the commons-net ftp system.
159     */
160    public static final String SYST_VMS   = "VMS";
161
162    /**
163     * Identifier by which a WindowsNT-based ftp server is known throughout
164     * the commons-net ftp system.
165     */
166    public static final String SYST_NT    = "WINDOWS";
167
168    /**
169     * Identifier by which an OS/2-based ftp server is known throughout
170     * the commons-net ftp system.
171     */
172    public static final String SYST_OS2   = "OS/2";
173
174    /**
175     * Identifier by which an OS/400-based ftp server is known throughout
176     * the commons-net ftp system.
177     */
178    public static final String SYST_OS400 = "OS/400";
179
180    /**
181     * Identifier by which an AS/400-based ftp server is known throughout
182     * the commons-net ftp system.
183     */
184    public static final String SYST_AS400 = "AS/400";
185
186    /**
187     * Identifier by which an MVS-based ftp server is known throughout
188     * the commons-net ftp system.
189     */
190    public static final String SYST_MVS = "MVS";
191
192    /**
193     * Some servers return an "UNKNOWN Type: L8" message
194     * in response to the SYST command. We set these to be a Unix-type system.
195     * This may happen if the ftpd in question was compiled without system
196     * information.
197     *
198     * NET-230 - Updated to be UPPERCASE so that the check done in
199     * createFileEntryParser will succeed.
200     *
201     * @since 1.5
202     */
203    public static final String SYST_L8 = "TYPE: L8";
204
205    /**
206     * Identifier by which an Netware-based ftp server is known throughout
207     * the commons-net ftp system.
208     *
209     * @since 1.5
210     */
211    public static final String SYST_NETWARE = "NETWARE";
212
213    /**
214     * Identifier by which a Mac pre OS-X -based ftp server is known throughout
215     * the commons-net ftp system.
216     *
217     * @since 3.1
218     */
219    // Full string is "MACOS Peter's Server"; the substring below should be enough
220    public static final String SYST_MACOS_PETER  = "MACOS PETER"; // NET-436
221
222    private final String serverSystemKey;
223    private String defaultDateFormatStr = null;
224    private String recentDateFormatStr = null;
225    private boolean lenientFutureDates = true; // NET-407
226    private String serverLanguageCode = null;
227    private String shortMonthNames = null;
228    private String serverTimeZoneId = null;
229    private boolean saveUnparseableEntries = false;
230
231
232    /**
233     * The main constructor for an FTPClientConfig object
234     * @param systemKey key representing system type of the  server being
235     * connected to. See {@link #getServerSystemKey() serverSystemKey}
236     * If set to the empty string, then FTPClient uses the system type returned by the server.
237     * However this is not recommended for general use;
238     * the correct system type should be set if it is known.
239     */
240    public FTPClientConfig(String systemKey) {
241        this.serverSystemKey = systemKey;
242    }
243
244    /**
245     * Convenience constructor mainly for use in testing.
246     * Constructs a UNIX configuration.
247     */
248    public FTPClientConfig() {
249        this(SYST_UNIX);
250    }
251
252    /**
253     * Constructor which allows setting of most member fields
254     * @param systemKey key representing system type of the  server being
255     * connected to. See
256     *  {@link #getServerSystemKey() serverSystemKey}
257     * @param defaultDateFormatStr See
258     *  {@link  #setDefaultDateFormatStr(String)  defaultDateFormatStr}
259     * @param recentDateFormatStr See
260     *  {@link  #setRecentDateFormatStr(String)  recentDateFormatStr}
261     * @param serverLanguageCode See
262     *  {@link  #setServerLanguageCode(String)  serverLanguageCode}
263     * @param shortMonthNames See
264     *  {@link  #setShortMonthNames(String)  shortMonthNames}
265     * @param serverTimeZoneId See
266     *  {@link  #setServerTimeZoneId(String)  serverTimeZoneId}
267     */
268    public FTPClientConfig(String systemKey,
269                           String defaultDateFormatStr,
270                           String recentDateFormatStr,
271                           String serverLanguageCode,
272                           String shortMonthNames,
273                           String serverTimeZoneId)
274    {
275        this(systemKey);
276        this.defaultDateFormatStr = defaultDateFormatStr;
277        this.recentDateFormatStr = recentDateFormatStr;
278        this.serverLanguageCode = serverLanguageCode;
279        this.shortMonthNames = shortMonthNames;
280        this.serverTimeZoneId = serverTimeZoneId;
281    }
282
283    /**
284     * Constructor which allows setting of all member fields
285     * @param systemKey key representing system type of the  server being
286     * connected to. See
287     *  {@link #getServerSystemKey() serverSystemKey}
288     * @param defaultDateFormatStr See
289     *  {@link  #setDefaultDateFormatStr(String)  defaultDateFormatStr}
290     * @param recentDateFormatStr See
291     *  {@link  #setRecentDateFormatStr(String)  recentDateFormatStr}
292     * @param serverLanguageCode See
293     *  {@link  #setServerLanguageCode(String)  serverLanguageCode}
294     * @param shortMonthNames See
295     *  {@link  #setShortMonthNames(String)  shortMonthNames}
296     * @param serverTimeZoneId See
297     *  {@link  #setServerTimeZoneId(String)  serverTimeZoneId}
298     * @param lenientFutureDates See
299     * {@link  #setLenientFutureDates(boolean)  lenientFutureDates}
300     * @param saveUnparseableEntries See
301     * {@link  #setUnparseableEntries(boolean)  saveUnparseableEntries}
302     */
303    public FTPClientConfig(String systemKey,
304                           String defaultDateFormatStr,
305                           String recentDateFormatStr,
306                           String serverLanguageCode,
307                           String shortMonthNames,
308                           String serverTimeZoneId,
309                           boolean lenientFutureDates,
310                           boolean saveUnparseableEntries)
311    {
312        this(systemKey);
313        this.defaultDateFormatStr = defaultDateFormatStr;
314        this.lenientFutureDates = lenientFutureDates;
315        this.recentDateFormatStr = recentDateFormatStr;
316        this.saveUnparseableEntries = saveUnparseableEntries;
317        this.serverLanguageCode = serverLanguageCode;
318        this.shortMonthNames = shortMonthNames;
319        this.serverTimeZoneId = serverTimeZoneId;
320    }
321
322    // Copy constructor, intended for use by FTPClient only
323    FTPClientConfig(String systemKey, FTPClientConfig config) {
324        this.serverSystemKey = systemKey;
325        this.defaultDateFormatStr = config.defaultDateFormatStr;
326        this.lenientFutureDates = config.lenientFutureDates;
327        this.recentDateFormatStr = config.recentDateFormatStr;
328        this.saveUnparseableEntries = config.saveUnparseableEntries;
329        this.serverLanguageCode = config.serverLanguageCode;
330        this.serverTimeZoneId = config.serverTimeZoneId;
331        this.shortMonthNames = config.shortMonthNames;
332    }
333
334    private static final Map<String, Object> LANGUAGE_CODE_MAP = new TreeMap<String, Object>();
335    static {
336
337        // if there are other commonly used month name encodings which
338        // correspond to particular locales, please add them here.
339
340
341
342        // many locales code short names for months as all three letters
343        // these we handle simply.
344        LANGUAGE_CODE_MAP.put("en", Locale.ENGLISH);
345        LANGUAGE_CODE_MAP.put("de",Locale.GERMAN);
346        LANGUAGE_CODE_MAP.put("it",Locale.ITALIAN);
347        LANGUAGE_CODE_MAP.put("es", new Locale("es", "", "")); // spanish
348        LANGUAGE_CODE_MAP.put("pt", new Locale("pt", "", "")); // portuguese
349        LANGUAGE_CODE_MAP.put("da", new Locale("da", "", "")); // danish
350        LANGUAGE_CODE_MAP.put("sv", new Locale("sv", "", "")); // swedish
351        LANGUAGE_CODE_MAP.put("no", new Locale("no", "", "")); // norwegian
352        LANGUAGE_CODE_MAP.put("nl", new Locale("nl", "", "")); // dutch
353        LANGUAGE_CODE_MAP.put("ro", new Locale("ro", "", "")); // romanian
354        LANGUAGE_CODE_MAP.put("sq", new Locale("sq", "", "")); // albanian
355        LANGUAGE_CODE_MAP.put("sh", new Locale("sh", "", "")); // serbo-croatian
356        LANGUAGE_CODE_MAP.put("sk", new Locale("sk", "", "")); // slovak
357        LANGUAGE_CODE_MAP.put("sl", new Locale("sl", "", "")); // slovenian
358
359
360        // some don't
361        LANGUAGE_CODE_MAP.put("fr",
362                "jan|f\u00e9v|mar|avr|mai|jun|jui|ao\u00fb|sep|oct|nov|d\u00e9c");  //french
363
364    }
365
366    /**
367     * Getter for the serverSystemKey property.  This property
368     * specifies the general type of server to which the client connects.
369     * Should be either one of the <code>FTPClientConfig.SYST_*</code> codes
370     * or else the fully qualified class name of a parser implementing both
371     * the <code>FTPFileEntryParser</code> and <code>Configurable</code>
372     * interfaces.
373     * @return Returns the serverSystemKey property.
374     */
375    public String getServerSystemKey() {
376        return serverSystemKey;
377    }
378
379    /**
380     * getter for the {@link  #setDefaultDateFormatStr(String)  defaultDateFormatStr}
381     * property.
382     * @return Returns the defaultDateFormatStr property.
383     */
384    public String getDefaultDateFormatStr() {
385        return defaultDateFormatStr;
386    }
387
388    /**
389     * getter for the {@link  #setRecentDateFormatStr(String)  recentDateFormatStr} property.
390     * @return Returns the recentDateFormatStr property.
391     */
392
393    public String getRecentDateFormatStr() {
394        return recentDateFormatStr;
395    }
396
397    /**
398     * getter for the {@link  #setServerTimeZoneId(String)  serverTimeZoneId} property.
399     * @return Returns the serverTimeZoneId property.
400     */
401    public String getServerTimeZoneId() {
402        return serverTimeZoneId;
403    }
404
405    /**
406     * <p>
407     * getter for the {@link  #setShortMonthNames(String)  shortMonthNames}
408     * property.
409     * </p>
410     * @return Returns the shortMonthNames.
411     */
412    public String getShortMonthNames() {
413        return shortMonthNames;
414    }
415
416    /**
417     * <p>
418     * getter for the {@link  #setServerLanguageCode(String)  serverLanguageCode} property.
419     * </p>
420     * @return Returns the serverLanguageCode property.
421     */
422    public String getServerLanguageCode() {
423        return serverLanguageCode;
424    }
425
426    /**
427     * <p>
428     * getter for the {@link  #setLenientFutureDates(boolean)  lenientFutureDates} property.
429     * </p>
430     * @return Returns the lenientFutureDates.
431     * @since 1.5
432     */
433    public boolean isLenientFutureDates() {
434        return lenientFutureDates;
435    }
436    /**
437     * <p>
438     * setter for the defaultDateFormatStr property.  This property
439     * specifies the main date format that will be used by a parser configured
440     * by this configuration to parse file timestamps.  If this is not
441     * specified, such a parser will use as a default value, the most commonly
442     * used format which will be in as used in <code>en_US</code> locales.
443     * </p><p>
444     * This should be in the format described for
445     * <code>java.text.SimpleDateFormat</code>.
446     * property.
447     * </p>
448     * @param defaultDateFormatStr The defaultDateFormatStr to set.
449     */
450    public void setDefaultDateFormatStr(String defaultDateFormatStr) {
451        this.defaultDateFormatStr = defaultDateFormatStr;
452    }
453
454    /**
455     * <p>
456     * setter for the recentDateFormatStr property.  This property
457     * specifies a secondary date format that will be used by a parser
458     * configured by this configuration to parse file timestamps, typically
459     * those less than a year old.  If this is  not specified, such a parser
460     * will not attempt to parse using an alternate format.
461     * </p>
462     * <p>
463     * This is used primarily in unix-based systems.
464     * </p>
465     * <p>
466     * This should be in the format described for
467     * <code>java.text.SimpleDateFormat</code>.
468     * </p>
469     * @param recentDateFormatStr The recentDateFormatStr to set.
470     */
471    public void setRecentDateFormatStr(String recentDateFormatStr) {
472        this.recentDateFormatStr = recentDateFormatStr;
473    }
474
475    /**
476     * <p>
477     * setter for the lenientFutureDates property.  This boolean property
478     * (default: false) only has meaning when a
479     * {@link  #setRecentDateFormatStr(String)  recentDateFormatStr} property
480     * has been set.  In that case, if this property is set true, then the
481     * parser, when it encounters a listing parseable with the recent date
482     * format, will only consider a date to belong to the previous year if
483     * it is more than one day in the future.  This will allow all
484     * out-of-synch situations (whether based on "slop" - i.e. servers simply
485     * out of synch with one another or because of time zone differences -
486     * but in the latter case it is highly recommended to use the
487     * {@link  #setServerTimeZoneId(String)  serverTimeZoneId} property
488     * instead) to resolve correctly.
489     * </p><p>
490     * This is used primarily in unix-based systems.
491     * </p>
492     * @param lenientFutureDates set true to compensate for out-of-synch
493     * conditions.
494     */
495    public void setLenientFutureDates(boolean lenientFutureDates) {
496        this.lenientFutureDates = lenientFutureDates;
497    }
498    /**
499     * <p>
500     * setter for the serverTimeZoneId property.  This property
501     * allows a time zone to be specified corresponding to that known to be
502     * used by an FTP server in file listings.  This might be particularly
503     * useful to clients such as Ant that try to use these timestamps for
504     * dependency checking.
505     * </p><p>
506     * This should be one of the identifiers used by
507     * <code>java.util.TimeZone</code> to refer to time zones, for example,
508     * <code>America/Chicago</code> or <code>Asia/Rangoon</code>.
509     * </p>
510     * @param serverTimeZoneId The serverTimeZoneId to set.
511     */
512    public void setServerTimeZoneId(String serverTimeZoneId) {
513        this.serverTimeZoneId = serverTimeZoneId;
514    }
515
516    /**
517     * <p>
518     * setter for the shortMonthNames property.
519     * This property allows the user to specify a set of month names
520     * used by the server that is different from those that may be
521     * specified using the {@link  #setServerLanguageCode(String)  serverLanguageCode}
522     * property.
523     * </p><p>
524     * This should be a string containing twelve strings each composed of
525     * three characters, delimited by pipe (|) characters.  Currently,
526     * only 8-bit ASCII characters are known to be supported.  For example,
527     * a set of month names used by a hypothetical Icelandic FTP server might
528     * conceivably be specified as
529     * <code>"jan|feb|mar|apr|ma&#xED;|j&#xFA;n|j&#xFA;l|&#xE1;g&#xFA;|sep|okt|n&#xF3;v|des"</code>.
530     * </p>
531     * @param shortMonthNames The value to set to the shortMonthNames property.
532     */
533    public void setShortMonthNames(String shortMonthNames) {
534        this.shortMonthNames = shortMonthNames;
535    }
536
537    /**
538     * <p>
539     * setter for the serverLanguageCode property.  This property allows
540     * user to specify a
541     * <a href="http://www.ics.uci.edu/pub/ietf/http/related/iso639.txt">
542     * two-letter ISO-639 language code</a> that will be used to
543     * configure the set of month names used by the file timestamp parser.
544     * If neither this nor the {@link #setShortMonthNames(String) shortMonthNames}
545     * is specified, parsing will assume English month names, which may or
546     * may not be significant, depending on whether the date format(s)
547     * specified via {@link  #setDefaultDateFormatStr(String)  defaultDateFormatStr}
548     * and/or {@link  #setRecentDateFormatStr(String)  recentDateFormatStr} are using
549     * numeric or alphabetic month names.
550     * </p>
551     * <p>If the code supplied is not supported here, <code>en_US</code>
552     * month names will be used.  We are supporting here those language
553     * codes which, when a <code> java.util.Locale</code> is constucted
554     * using it, and a <code>java.text.SimpleDateFormat</code> is
555     * constructed using that Locale, the array returned by the
556     * SimpleDateFormat's <code>getShortMonths()</code> method consists
557     * solely of three 8-bit ASCII character strings.  Additionally,
558     * languages which do not meet this requirement are included if a
559     * common alternative set of short month names is known to be used.
560     * This means that users who can tell us of additional such encodings
561     * may get them added to the list of supported languages by contacting
562     * the Apache Commons Net team.
563     * </p>
564     * <p><strong>
565     * Please note that this attribute will NOT be used to determine a
566     * locale-based date format for the language.  </strong>
567     * Experience has shown that many if not most FTP servers outside the
568     * United States employ the standard <code>en_US</code> date format
569     * orderings of <code>MMM d yyyy</code> and <code>MMM d HH:mm</code>
570     * and attempting to deduce this automatically here would cause more
571     * problems than it would solve.  The date format must be changed
572     * via the {@link  #setDefaultDateFormatStr(String)  defaultDateFormatStr} and/or
573     * {@link  #setRecentDateFormatStr(String)  recentDateFormatStr} parameters.
574     * </p>
575     * @param serverLanguageCode The value to set to the serverLanguageCode property.
576     */
577    public void setServerLanguageCode(String serverLanguageCode) {
578        this.serverLanguageCode = serverLanguageCode;
579    }
580
581    /**
582     * Looks up the supplied language code in the internally maintained table of
583     * language codes.  Returns a DateFormatSymbols object configured with
584     * short month names corresponding to the code.  If there is no corresponding
585     * entry in the table, the object returned will be that for
586     * <code>Locale.US</code>
587     * @param languageCode See {@link  #setServerLanguageCode(String)  serverLanguageCode}
588     * @return a DateFormatSymbols object configured with short month names
589     * corresponding to the supplied code, or with month names for
590     * <code>Locale.US</code> if there is no corresponding entry in the internal
591     * table.
592     */
593    public static DateFormatSymbols lookupDateFormatSymbols(String languageCode)
594    {
595        Object lang = LANGUAGE_CODE_MAP.get(languageCode);
596        if (lang != null) {
597            if (lang instanceof Locale) {
598                return new DateFormatSymbols((Locale) lang);
599            } else if (lang instanceof String){
600                return getDateFormatSymbols((String) lang);
601            }
602        }
603        return new DateFormatSymbols(Locale.US);
604    }
605
606    /**
607     * Returns a DateFormatSymbols object configured with short month names
608     * as in the supplied string
609     * @param shortmonths This  should be as described in
610     *  {@link  #setShortMonthNames(String)  shortMonthNames}
611     * @return a DateFormatSymbols object configured with short month names
612     * as in the supplied string
613     */
614    public static DateFormatSymbols getDateFormatSymbols(String shortmonths)
615    {
616        String[] months = splitShortMonthString(shortmonths);
617        DateFormatSymbols dfs = new DateFormatSymbols(Locale.US);
618        dfs.setShortMonths(months);
619        return dfs;
620    }
621
622    private static String[] splitShortMonthString(String shortmonths) {
623        StringTokenizer st = new StringTokenizer(shortmonths, "|");
624        int monthcnt = st.countTokens();
625        if (12 != monthcnt) {
626            throw new IllegalArgumentException(
627                    "expecting a pipe-delimited string containing 12 tokens");
628        }
629        String[] months = new String[13];
630        int pos = 0;
631        while(st.hasMoreTokens()) {
632            months[pos++] = st.nextToken();
633        }
634        months[pos]="";
635        return months;
636    }
637
638    /**
639     * Returns a Collection of all the language codes currently supported
640     * by this class. See {@link  #setServerLanguageCode(String)  serverLanguageCode}
641     * for a functional descrption of language codes within this system.
642     *
643     * @return a Collection of all the language codes currently supported
644     * by this class
645     */
646    public static Collection<String> getSupportedLanguageCodes() {
647        return LANGUAGE_CODE_MAP.keySet();
648    }
649
650    /**
651     * Allow list parsing methods to create basic FTPFile entries if parsing fails.
652     * <p>
653     * In this case, the FTPFile will contain only the unparsed entry {@link FTPFile#getRawListing()}
654     * and {@link FTPFile#isValid()} will return {@code false}
655     * @param saveUnparseable if true, then create FTPFile entries if parsing fails
656     * @since 3.4
657     */
658    public void setUnparseableEntries(boolean saveUnparseable) {
659        this.saveUnparseableEntries = saveUnparseable;
660    }
661
662    /**
663     * @return true if list parsing should return FTPFile entries even for unparseable response lines
664     * <p>
665     * If true, the FTPFile for any unparseable entries will contain only the unparsed entry
666     * {@link FTPFile#getRawListing()} and {@link FTPFile#isValid()} will return {@code false}
667     * @since 3.4
668     */
669    public boolean getUnparseableEntries() {
670        return this.saveUnparseableEntries;
671    }
672
673}