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3    * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4    *
5    * This code is free software; you can redistribute it and/or modify it
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7    * published by the Free Software Foundation.  Oracle designates this
8    * particular file as subject to the "Classpath" exception as provided
9    * by Oracle in the LICENSE file that accompanied this code.
10   *
11   * This code is distributed in the hope that it will be useful, but WITHOUT
12   * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13   * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
14   * version 2 for more details (a copy is included in the LICENSE file that
15   * accompanied this code).
16   *
17   * You should have received a copy of the GNU General Public License version
18   * 2 along with this work; if not, write to the Free Software Foundation,
19   * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20   *
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25  
26  /*
27   * (C) Copyright Taligent, Inc. 1996 - All Rights Reserved
28   * (C) Copyright IBM Corp. 1996 - All Rights Reserved
29   *
30   *   The original version of this source code and documentation is copyrighted
31   * and owned by Taligent, Inc., a wholly-owned subsidiary of IBM. These
32   * materials are provided under terms of a License Agreement between Taligent
33   * and Sun. This technology is protected by multiple US and International
34   * patents. This notice and attribution to Taligent may not be removed.
35   *   Taligent is a registered trademark of Taligent, Inc.
36   *
37   */
38  
39  package java.text;
40  
41  import java.io.IOException;
42  import java.io.ObjectOutputStream;
43  import java.io.Serializable;
44  import java.lang.ref.SoftReference;
45  import java.text.spi.DateFormatSymbolsProvider;
46  import java.util.Arrays;
47  import java.util.Locale;
48  import java.util.Objects;
49  import java.util.ResourceBundle;
50  import java.util.TimeZone;
51  import java.util.concurrent.ConcurrentHashMap;
52  import java.util.concurrent.ConcurrentMap;
53  import sun.util.locale.provider.LocaleProviderAdapter;
54  import sun.util.locale.provider.LocaleServiceProviderPool;
55  import sun.util.locale.provider.ResourceBundleBasedAdapter;
56  import sun.util.locale.provider.TimeZoneNameUtility;
57  
58  /**
59   * <code>DateFormatSymbols</code> is a public class for encapsulating
60   * localizable date-time formatting data, such as the names of the
61   * months, the names of the days of the week, and the time zone data.
62   * <code>SimpleDateFormat</code> uses
63   * <code>DateFormatSymbols</code> to encapsulate this information.
64   *
65   * <p>
66   * Typically you shouldn't use <code>DateFormatSymbols</code> directly.
67   * Rather, you are encouraged to create a date-time formatter with the
68   * <code>DateFormat</code> class's factory methods: <code>getTimeInstance</code>,
69   * <code>getDateInstance</code>, or <code>getDateTimeInstance</code>.
70   * These methods automatically create a <code>DateFormatSymbols</code> for
71   * the formatter so that you don't have to. After the
72   * formatter is created, you may modify its format pattern using the
73   * <code>setPattern</code> method. For more information about
74   * creating formatters using <code>DateFormat</code>'s factory methods,
75   * see {@link DateFormat}.
76   *
77   * <p>
78   * If you decide to create a date-time formatter with a specific
79   * format pattern for a specific locale, you can do so with:
80   * <blockquote>
81   * <pre>
82   * new SimpleDateFormat(aPattern, DateFormatSymbols.getInstance(aLocale)).
83   * </pre>
84   * </blockquote>
85   *
86   * <p>
87   * <code>DateFormatSymbols</code> objects are cloneable. When you obtain
88   * a <code>DateFormatSymbols</code> object, feel free to modify the
89   * date-time formatting data. For instance, you can replace the localized
90   * date-time format pattern characters with the ones that you feel easy
91   * to remember. Or you can change the representative cities
92   * to your favorite ones.
93   *
94   * <p>
95   * New <code>DateFormatSymbols</code> subclasses may be added to support
96   * <code>SimpleDateFormat</code> for date-time formatting for additional locales.
97  
98   * @see          DateFormat
99   * @see          SimpleDateFormat
100  * @see          java.util.SimpleTimeZone
101  * @author       Chen-Lieh Huang
102  */
103 public class DateFormatSymbols implements Serializable, Cloneable {
104 
105     /**
106      * Construct a DateFormatSymbols object by loading format data from
107      * resources for the default {@link java.util.Locale.Category#FORMAT FORMAT}
108      * locale. This constructor can only
109      * construct instances for the locales supported by the Java
110      * runtime environment, not for those supported by installed
111      * {@link java.text.spi.DateFormatSymbolsProvider DateFormatSymbolsProvider}
112      * implementations. For full locale coverage, use the
113      * {@link #getInstance(Locale) getInstance} method.
114      * <p>This is equivalent to calling
115      * {@link #DateFormatSymbols(Locale)
116      *     DateFormatSymbols(Locale.getDefault(Locale.Category.FORMAT))}.
117      * @see #getInstance()
118      * @see java.util.Locale#getDefault(java.util.Locale.Category)
119      * @see java.util.Locale.Category#FORMAT
120      * @exception  java.util.MissingResourceException
121      *             if the resources for the default locale cannot be
122      *             found or cannot be loaded.
123      */
124     public DateFormatSymbols()
125     {
126         initializeData(Locale.getDefault(Locale.Category.FORMAT));
127     }
128 
129     /**
130      * Construct a DateFormatSymbols object by loading format data from
131      * resources for the given locale. This constructor can only
132      * construct instances for the locales supported by the Java
133      * runtime environment, not for those supported by installed
134      * {@link java.text.spi.DateFormatSymbolsProvider DateFormatSymbolsProvider}
135      * implementations. For full locale coverage, use the
136      * {@link #getInstance(Locale) getInstance} method.
137      *
138      * @param locale the desired locale
139      * @see #getInstance(Locale)
140      * @exception  java.util.MissingResourceException
141      *             if the resources for the specified locale cannot be
142      *             found or cannot be loaded.
143      */
144     public DateFormatSymbols(Locale locale)
145     {
146         initializeData(locale);
147     }
148 
149     /**
150      * Era strings. For example: "AD" and "BC".  An array of 2 strings,
151      * indexed by <code>Calendar.BC</code> and <code>Calendar.AD</code>.
152      * @serial
153      */
154     String eras[] = null;
155 
156     /**
157      * Month strings. For example: "January", "February", etc.  An array
158      * of 13 strings (some calendars have 13 months), indexed by
159      * <code>Calendar.JANUARY</code>, <code>Calendar.FEBRUARY</code>, etc.
160      * @serial
161      */
162     String months[] = null;
163 
164     /**
165      * Short month strings. For example: "Jan", "Feb", etc.  An array of
166      * 13 strings (some calendars have 13 months), indexed by
167      * <code>Calendar.JANUARY</code>, <code>Calendar.FEBRUARY</code>, etc.
168 
169      * @serial
170      */
171     String shortMonths[] = null;
172 
173     /**
174      * Weekday strings. For example: "Sunday", "Monday", etc.  An array
175      * of 8 strings, indexed by <code>Calendar.SUNDAY</code>,
176      * <code>Calendar.MONDAY</code>, etc.
177      * The element <code>weekdays[0]</code> is ignored.
178      * @serial
179      */
180     String weekdays[] = null;
181 
182     /**
183      * Short weekday strings. For example: "Sun", "Mon", etc.  An array
184      * of 8 strings, indexed by <code>Calendar.SUNDAY</code>,
185      * <code>Calendar.MONDAY</code>, etc.
186      * The element <code>shortWeekdays[0]</code> is ignored.
187      * @serial
188      */
189     String shortWeekdays[] = null;
190 
191     /**
192      * AM and PM strings. For example: "AM" and "PM".  An array of
193      * 2 strings, indexed by <code>Calendar.AM</code> and
194      * <code>Calendar.PM</code>.
195      * @serial
196      */
197     String ampms[] = null;
198 
199     /**
200      * Localized names of time zones in this locale.  This is a
201      * two-dimensional array of strings of size <em>n</em> by <em>m</em>,
202      * where <em>m</em> is at least 5.  Each of the <em>n</em> rows is an
203      * entry containing the localized names for a single <code>TimeZone</code>.
204      * Each such row contains (with <code>i</code> ranging from
205      * 0..<em>n</em>-1):
206      * <ul>
207      * <li><code>zoneStrings[i][0]</code> - time zone ID</li>
208      * <li><code>zoneStrings[i][1]</code> - long name of zone in standard
209      * time</li>
210      * <li><code>zoneStrings[i][2]</code> - short name of zone in
211      * standard time</li>
212      * <li><code>zoneStrings[i][3]</code> - long name of zone in daylight
213      * saving time</li>
214      * <li><code>zoneStrings[i][4]</code> - short name of zone in daylight
215      * saving time</li>
216      * </ul>
217      * The zone ID is <em>not</em> localized; it's one of the valid IDs of
218      * the {@link java.util.TimeZone TimeZone} class that are not
219      * <a href="../java/util/TimeZone.html#CustomID">custom IDs</a>.
220      * All other entries are localized names.
221      * @see java.util.TimeZone
222      * @serial
223      */
224     String zoneStrings[][] = null;
225 
226     /**
227      * Indicates that zoneStrings is set externally with setZoneStrings() method.
228      */
229     transient boolean isZoneStringsSet = false;
230 
231     /**
232      * Unlocalized date-time pattern characters. For example: 'y', 'd', etc.
233      * All locales use the same these unlocalized pattern characters.
234      */
235     static final String  patternChars = "GyMdkHmsSEDFwWahKzZYuXL";
236 
237     static final int PATTERN_ERA                  =  0; // G
238     static final int PATTERN_YEAR                 =  1; // y
239     static final int PATTERN_MONTH                =  2; // M
240     static final int PATTERN_DAY_OF_MONTH         =  3; // d
241     static final int PATTERN_HOUR_OF_DAY1         =  4; // k
242     static final int PATTERN_HOUR_OF_DAY0         =  5; // H
243     static final int PATTERN_MINUTE               =  6; // m
244     static final int PATTERN_SECOND               =  7; // s
245     static final int PATTERN_MILLISECOND          =  8; // S
246     static final int PATTERN_DAY_OF_WEEK          =  9; // E
247     static final int PATTERN_DAY_OF_YEAR          = 10; // D
248     static final int PATTERN_DAY_OF_WEEK_IN_MONTH = 11; // F
249     static final int PATTERN_WEEK_OF_YEAR         = 12; // w
250     static final int PATTERN_WEEK_OF_MONTH        = 13; // W
251     static final int PATTERN_AM_PM                = 14; // a
252     static final int PATTERN_HOUR1                = 15; // h
253     static final int PATTERN_HOUR0                = 16; // K
254     static final int PATTERN_ZONE_NAME            = 17; // z
255     static final int PATTERN_ZONE_VALUE           = 18; // Z
256     static final int PATTERN_WEEK_YEAR            = 19; // Y
257     static final int PATTERN_ISO_DAY_OF_WEEK      = 20; // u
258     static final int PATTERN_ISO_ZONE             = 21; // X
259     static final int PATTERN_MONTH_STANDALONE     = 22; // L
260 
261     /**
262      * Localized date-time pattern characters. For example, a locale may
263      * wish to use 'u' rather than 'y' to represent years in its date format
264      * pattern strings.
265      * This string must be exactly 18 characters long, with the index of
266      * the characters described by <code>DateFormat.ERA_FIELD</code>,
267      * <code>DateFormat.YEAR_FIELD</code>, etc.  Thus, if the string were
268      * "Xz...", then localized patterns would use 'X' for era and 'z' for year.
269      * @serial
270      */
271     String  localPatternChars = null;
272 
273     /**
274      * The locale which is used for initializing this DateFormatSymbols object.
275      *
276      * @since 1.6
277      * @serial
278      */
279     Locale locale = null;
280 
281     /* use serialVersionUID from JDK 1.1.4 for interoperability */
282     static final long serialVersionUID = -5987973545549424702L;
283 
284     /**
285      * Returns an array of all locales for which the
286      * <code>getInstance</code> methods of this class can return
287      * localized instances.
288      * The returned array represents the union of locales supported by the
289      * Java runtime and by installed
290      * {@link java.text.spi.DateFormatSymbolsProvider DateFormatSymbolsProvider}
291      * implementations.  It must contain at least a <code>Locale</code>
292      * instance equal to {@link java.util.Locale#US Locale.US}.
293      *
294      * @return An array of locales for which localized
295      *         <code>DateFormatSymbols</code> instances are available.
296      * @since 1.6
297      */
298     public static Locale[] getAvailableLocales() {
299         LocaleServiceProviderPool pool=
300             LocaleServiceProviderPool.getPool(DateFormatSymbolsProvider.class);
301         return pool.getAvailableLocales();
302     }
303 
304     /**
305      * Gets the <code>DateFormatSymbols</code> instance for the default
306      * locale.  This method provides access to <code>DateFormatSymbols</code>
307      * instances for locales supported by the Java runtime itself as well
308      * as for those supported by installed
309      * {@link java.text.spi.DateFormatSymbolsProvider DateFormatSymbolsProvider}
310      * implementations.
311      * <p>This is equivalent to calling {@link #getInstance(Locale)
312      *     getInstance(Locale.getDefault(Locale.Category.FORMAT))}.
313      * @see java.util.Locale#getDefault(java.util.Locale.Category)
314      * @see java.util.Locale.Category#FORMAT
315      * @return a <code>DateFormatSymbols</code> instance.
316      * @since 1.6
317      */
318     public static final DateFormatSymbols getInstance() {
319         return getInstance(Locale.getDefault(Locale.Category.FORMAT));
320     }
321 
322     /**
323      * Gets the <code>DateFormatSymbols</code> instance for the specified
324      * locale.  This method provides access to <code>DateFormatSymbols</code>
325      * instances for locales supported by the Java runtime itself as well
326      * as for those supported by installed
327      * {@link java.text.spi.DateFormatSymbolsProvider DateFormatSymbolsProvider}
328      * implementations.
329      * @param locale the given locale.
330      * @return a <code>DateFormatSymbols</code> instance.
331      * @exception NullPointerException if <code>locale</code> is null
332      * @since 1.6
333      */
334     public static final DateFormatSymbols getInstance(Locale locale) {
335         DateFormatSymbols dfs = getProviderInstance(locale);
336         if (dfs != null) {
337             return dfs;
338         }
339         throw new RuntimeException("DateFormatSymbols instance creation failed.");
340     }
341 
342     /**
343      * Returns a DateFormatSymbols provided by a provider or found in
344      * the cache. Note that this method returns a cached instance,
345      * not its clone. Therefore, the instance should never be given to
346      * an application.
347      */
348     static final DateFormatSymbols getInstanceRef(Locale locale) {
349         DateFormatSymbols dfs = getProviderInstance(locale);
350         if (dfs != null) {
351             return dfs;
352         }
353         throw new RuntimeException("DateFormatSymbols instance creation failed.");
354     }
355 
356     private static DateFormatSymbols getProviderInstance(Locale locale) {
357         LocaleProviderAdapter adapter = LocaleProviderAdapter.getAdapter(DateFormatSymbolsProvider.class, locale);
358         DateFormatSymbolsProvider provider = adapter.getDateFormatSymbolsProvider();
359         DateFormatSymbols dfsyms = provider.getInstance(locale);
360         if (dfsyms == null) {
361             provider = LocaleProviderAdapter.forJRE().getDateFormatSymbolsProvider();
362             dfsyms = provider.getInstance(locale);
363         }
364         return dfsyms;
365     }
366 
367     /**
368      * Gets era strings. For example: "AD" and "BC".
369      * @return the era strings.
370      */
371     public String[] getEras() {
372         return Arrays.copyOf(eras, eras.length);
373     }
374 
375     /**
376      * Sets era strings. For example: "AD" and "BC".
377      * @param newEras the new era strings.
378      */
379     public void setEras(String[] newEras) {
380         eras = Arrays.copyOf(newEras, newEras.length);
381         cachedHashCode = 0;
382     }
383 
384     /**
385      * Gets month strings. For example: "January", "February", etc.
386      *
387      * <p>If the language requires different forms for formatting and
388      * stand-alone usages, this method returns month names in the
389      * formatting form. For example, the preferred month name for
390      * January in the Czech language is <em>ledna</em> in the
391      * formatting form, while it is <em>leden</em> in the stand-alone
392      * form. This method returns {@code "ledna"} in this case. Refer
393      * to the <a href="http://unicode.org/reports/tr35/#Calendar_Elements">
394      * Calendar Elements in the Unicode Locale Data Markup Language
395      * (LDML) specification</a> for more details.
396      *
397      * @return the month strings.
398      */
399     public String[] getMonths() {
400         return Arrays.copyOf(months, months.length);
401     }
402 
403     /**
404      * Sets month strings. For example: "January", "February", etc.
405      * @param newMonths the new month strings.
406      */
407     public void setMonths(String[] newMonths) {
408         months = Arrays.copyOf(newMonths, newMonths.length);
409         cachedHashCode = 0;
410     }
411 
412     /**
413      * Gets short month strings. For example: "Jan", "Feb", etc.
414      *
415      * <p>If the language requires different forms for formatting and
416      * stand-alone usages, This method returns short month names in
417      * the formatting form. For example, the preferred abbreviation
418      * for January in the Catalan language is <em>de gen.</em> in the
419      * formatting form, while it is <em>gen.</em> in the stand-alone
420      * form. This method returns {@code "de gen."} in this case. Refer
421      * to the <a href="http://unicode.org/reports/tr35/#Calendar_Elements">
422      * Calendar Elements in the Unicode Locale Data Markup Language
423      * (LDML) specification</a> for more details.
424      *
425      * @return the short month strings.
426      */
427     public String[] getShortMonths() {
428         return Arrays.copyOf(shortMonths, shortMonths.length);
429     }
430 
431     /**
432      * Sets short month strings. For example: "Jan", "Feb", etc.
433      * @param newShortMonths the new short month strings.
434      */
435     public void setShortMonths(String[] newShortMonths) {
436         shortMonths = Arrays.copyOf(newShortMonths, newShortMonths.length);
437         cachedHashCode = 0;
438     }
439 
440     /**
441      * Gets weekday strings. For example: "Sunday", "Monday", etc.
442      * @return the weekday strings. Use <code>Calendar.SUNDAY</code>,
443      * <code>Calendar.MONDAY</code>, etc. to index the result array.
444      */
445     public String[] getWeekdays() {
446         return Arrays.copyOf(weekdays, weekdays.length);
447     }
448 
449     /**
450      * Sets weekday strings. For example: "Sunday", "Monday", etc.
451      * @param newWeekdays the new weekday strings. The array should
452      * be indexed by <code>Calendar.SUNDAY</code>,
453      * <code>Calendar.MONDAY</code>, etc.
454      */
455     public void setWeekdays(String[] newWeekdays) {
456         weekdays = Arrays.copyOf(newWeekdays, newWeekdays.length);
457         cachedHashCode = 0;
458     }
459 
460     /**
461      * Gets short weekday strings. For example: "Sun", "Mon", etc.
462      * @return the short weekday strings. Use <code>Calendar.SUNDAY</code>,
463      * <code>Calendar.MONDAY</code>, etc. to index the result array.
464      */
465     public String[] getShortWeekdays() {
466         return Arrays.copyOf(shortWeekdays, shortWeekdays.length);
467     }
468 
469     /**
470      * Sets short weekday strings. For example: "Sun", "Mon", etc.
471      * @param newShortWeekdays the new short weekday strings. The array should
472      * be indexed by <code>Calendar.SUNDAY</code>,
473      * <code>Calendar.MONDAY</code>, etc.
474      */
475     public void setShortWeekdays(String[] newShortWeekdays) {
476         shortWeekdays = Arrays.copyOf(newShortWeekdays, newShortWeekdays.length);
477         cachedHashCode = 0;
478     }
479 
480     /**
481      * Gets ampm strings. For example: "AM" and "PM".
482      * @return the ampm strings.
483      */
484     public String[] getAmPmStrings() {
485         return Arrays.copyOf(ampms, ampms.length);
486     }
487 
488     /**
489      * Sets ampm strings. For example: "AM" and "PM".
490      * @param newAmpms the new ampm strings.
491      */
492     public void setAmPmStrings(String[] newAmpms) {
493         ampms = Arrays.copyOf(newAmpms, newAmpms.length);
494         cachedHashCode = 0;
495     }
496 
497     /**
498      * Gets time zone strings.  Use of this method is discouraged; use
499      * {@link java.util.TimeZone#getDisplayName() TimeZone.getDisplayName()}
500      * instead.
501      * <p>
502      * The value returned is a
503      * two-dimensional array of strings of size <em>n</em> by <em>m</em>,
504      * where <em>m</em> is at least 5.  Each of the <em>n</em> rows is an
505      * entry containing the localized names for a single <code>TimeZone</code>.
506      * Each such row contains (with <code>i</code> ranging from
507      * 0..<em>n</em>-1):
508      * <ul>
509      * <li><code>zoneStrings[i][0]</code> - time zone ID</li>
510      * <li><code>zoneStrings[i][1]</code> - long name of zone in standard
511      * time</li>
512      * <li><code>zoneStrings[i][2]</code> - short name of zone in
513      * standard time</li>
514      * <li><code>zoneStrings[i][3]</code> - long name of zone in daylight
515      * saving time</li>
516      * <li><code>zoneStrings[i][4]</code> - short name of zone in daylight
517      * saving time</li>
518      * </ul>
519      * The zone ID is <em>not</em> localized; it's one of the valid IDs of
520      * the {@link java.util.TimeZone TimeZone} class that are not
521      * <a href="../util/TimeZone.html#CustomID">custom IDs</a>.
522      * All other entries are localized names.  If a zone does not implement
523      * daylight saving time, the daylight saving time names should not be used.
524      * <p>
525      * If {@link #setZoneStrings(String[][]) setZoneStrings} has been called
526      * on this <code>DateFormatSymbols</code> instance, then the strings
527      * provided by that call are returned. Otherwise, the returned array
528      * contains names provided by the Java runtime and by installed
529      * {@link java.util.spi.TimeZoneNameProvider TimeZoneNameProvider}
530      * implementations.
531      *
532      * @return the time zone strings.
533      * @see #setZoneStrings(String[][])
534      */
535     public String[][] getZoneStrings() {
536         return getZoneStringsImpl(true);
537     }
538 
539     /**
540      * Sets time zone strings.  The argument must be a
541      * two-dimensional array of strings of size <em>n</em> by <em>m</em>,
542      * where <em>m</em> is at least 5.  Each of the <em>n</em> rows is an
543      * entry containing the localized names for a single <code>TimeZone</code>.
544      * Each such row contains (with <code>i</code> ranging from
545      * 0..<em>n</em>-1):
546      * <ul>
547      * <li><code>zoneStrings[i][0]</code> - time zone ID</li>
548      * <li><code>zoneStrings[i][1]</code> - long name of zone in standard
549      * time</li>
550      * <li><code>zoneStrings[i][2]</code> - short name of zone in
551      * standard time</li>
552      * <li><code>zoneStrings[i][3]</code> - long name of zone in daylight
553      * saving time</li>
554      * <li><code>zoneStrings[i][4]</code> - short name of zone in daylight
555      * saving time</li>
556      * </ul>
557      * The zone ID is <em>not</em> localized; it's one of the valid IDs of
558      * the {@link java.util.TimeZone TimeZone} class that are not
559      * <a href="../util/TimeZone.html#CustomID">custom IDs</a>.
560      * All other entries are localized names.
561      *
562      * @param newZoneStrings the new time zone strings.
563      * @exception IllegalArgumentException if the length of any row in
564      *    <code>newZoneStrings</code> is less than 5
565      * @exception NullPointerException if <code>newZoneStrings</code> is null
566      * @see #getZoneStrings()
567      */
568     public void setZoneStrings(String[][] newZoneStrings) {
569         String[][] aCopy = new String[newZoneStrings.length][];
570         for (int i = 0; i < newZoneStrings.length; ++i) {
571             int len = newZoneStrings[i].length;
572             if (len < 5) {
573                 throw new IllegalArgumentException();
574             }
575             aCopy[i] = Arrays.copyOf(newZoneStrings[i], len);
576         }
577         zoneStrings = aCopy;
578         isZoneStringsSet = true;
579         cachedHashCode = 0;
580     }
581 
582     /**
583      * Gets localized date-time pattern characters. For example: 'u', 't', etc.
584      * @return the localized date-time pattern characters.
585      */
586     public String getLocalPatternChars() {
587         return localPatternChars;
588     }
589 
590     /**
591      * Sets localized date-time pattern characters. For example: 'u', 't', etc.
592      * @param newLocalPatternChars the new localized date-time
593      * pattern characters.
594      */
595     public void setLocalPatternChars(String newLocalPatternChars) {
596         // Call toString() to throw an NPE in case the argument is null
597         localPatternChars = newLocalPatternChars.toString();
598         cachedHashCode = 0;
599     }
600 
601     /**
602      * Overrides Cloneable
603      */
604     public Object clone()
605     {
606         try
607         {
608             DateFormatSymbols other = (DateFormatSymbols)super.clone();
609             copyMembers(this, other);
610             return other;
611         } catch (CloneNotSupportedException e) {
612             throw new InternalError(e);
613         }
614     }
615 
616     /**
617      * Override hashCode.
618      * Generates a hash code for the DateFormatSymbols object.
619      */
620     @Override
621     public int hashCode() {
622         int hashCode = cachedHashCode;
623         if (hashCode == 0) {
624             hashCode = 5;
625             hashCode = 11 * hashCode + Arrays.hashCode(eras);
626             hashCode = 11 * hashCode + Arrays.hashCode(months);
627             hashCode = 11 * hashCode + Arrays.hashCode(shortMonths);
628             hashCode = 11 * hashCode + Arrays.hashCode(weekdays);
629             hashCode = 11 * hashCode + Arrays.hashCode(shortWeekdays);
630             hashCode = 11 * hashCode + Arrays.hashCode(ampms);
631             hashCode = 11 * hashCode + Arrays.deepHashCode(getZoneStringsWrapper());
632             hashCode = 11 * hashCode + Objects.hashCode(localPatternChars);
633             cachedHashCode = hashCode;
634         }
635 
636         return hashCode;
637     }
638 
639     /**
640      * Override equals
641      */
642     public boolean equals(Object obj)
643     {
644         if (this == obj) return true;
645         if (obj == null || getClass() != obj.getClass()) return false;
646         DateFormatSymbols that = (DateFormatSymbols) obj;
647         return (Arrays.equals(eras, that.eras)
648                 && Arrays.equals(months, that.months)
649                 && Arrays.equals(shortMonths, that.shortMonths)
650                 && Arrays.equals(weekdays, that.weekdays)
651                 && Arrays.equals(shortWeekdays, that.shortWeekdays)
652                 && Arrays.equals(ampms, that.ampms)
653                 && Arrays.deepEquals(getZoneStringsWrapper(), that.getZoneStringsWrapper())
654                 && ((localPatternChars != null
655                   && localPatternChars.equals(that.localPatternChars))
656                  || (localPatternChars == null
657                   && that.localPatternChars == null)));
658     }
659 
660     // =======================privates===============================
661 
662     /**
663      * Useful constant for defining time zone offsets.
664      */
665     static final int millisPerHour = 60*60*1000;
666 
667     /**
668      * Cache to hold DateFormatSymbols instances per Locale.
669      */
670     private static final ConcurrentMap<Locale, SoftReference<DateFormatSymbols>> cachedInstances
671         = new ConcurrentHashMap<>(3);
672 
673     private transient int lastZoneIndex = 0;
674 
675     /**
676      * Cached hash code
677      */
678     transient volatile int cachedHashCode = 0;
679 
680     private void initializeData(Locale desiredLocale) {
681         locale = desiredLocale;
682 
683         // Copy values of a cached instance if any.
684         SoftReference<DateFormatSymbols> ref = cachedInstances.get(locale);
685         DateFormatSymbols dfs;
686         if (ref != null && (dfs = ref.get()) != null) {
687             copyMembers(dfs, this);
688             return;
689         }
690 
691         // Initialize the fields from the ResourceBundle for locale.
692         LocaleProviderAdapter adapter = LocaleProviderAdapter.getAdapter(DateFormatSymbolsProvider.class, locale);
693         // Avoid any potential recursions
694         if (!(adapter instanceof ResourceBundleBasedAdapter)) {
695             adapter = LocaleProviderAdapter.getResourceBundleBased();
696         }
697         ResourceBundle resource = ((ResourceBundleBasedAdapter)adapter).getLocaleData().getDateFormatData(locale);
698 
699         // JRE and CLDR use different keys
700         // JRE: Eras, short.Eras and narrow.Eras
701         // CLDR: long.Eras, Eras and narrow.Eras
702         if (resource.containsKey("Eras")) {
703             eras = resource.getStringArray("Eras");
704         } else if (resource.containsKey("long.Eras")) {
705             eras = resource.getStringArray("long.Eras");
706         } else if (resource.containsKey("short.Eras")) {
707             eras = resource.getStringArray("short.Eras");
708         }
709         months = resource.getStringArray("MonthNames");
710         shortMonths = resource.getStringArray("MonthAbbreviations");
711         ampms = resource.getStringArray("AmPmMarkers");
712         localPatternChars = resource.getString("DateTimePatternChars");
713 
714         // Day of week names are stored in a 1-based array.
715         weekdays = toOneBasedArray(resource.getStringArray("DayNames"));
716         shortWeekdays = toOneBasedArray(resource.getStringArray("DayAbbreviations"));
717 
718         // Put a clone in the cache
719         ref = new SoftReference<>((DateFormatSymbols)this.clone());
720         SoftReference<DateFormatSymbols> x = cachedInstances.putIfAbsent(locale, ref);
721         if (x != null) {
722             DateFormatSymbols y = x.get();
723             if (y == null) {
724                 // Replace the empty SoftReference with ref.
725                 cachedInstances.put(locale, ref);
726             }
727         }
728     }
729 
730     private static String[] toOneBasedArray(String[] src) {
731         int len = src.length;
732         String[] dst = new String[len + 1];
733         dst[0] = "";
734         for (int i = 0; i < len; i++) {
735             dst[i + 1] = src[i];
736         }
737         return dst;
738     }
739 
740     /**
741      * Package private: used by SimpleDateFormat
742      * Gets the index for the given time zone ID to obtain the time zone
743      * strings for formatting. The time zone ID is just for programmatic
744      * lookup. NOT LOCALIZED!!!
745      * @param ID the given time zone ID.
746      * @return the index of the given time zone ID.  Returns -1 if
747      * the given time zone ID can't be located in the DateFormatSymbols object.
748      * @see java.util.SimpleTimeZone
749      */
750     final int getZoneIndex(String ID) {
751         String[][] zoneStrings = getZoneStringsWrapper();
752 
753         /*
754          * getZoneIndex has been re-written for performance reasons. instead of
755          * traversing the zoneStrings array every time, we cache the last used zone
756          * index
757          */
758         if (lastZoneIndex < zoneStrings.length && ID.equals(zoneStrings[lastZoneIndex][0])) {
759             return lastZoneIndex;
760         }
761 
762         /* slow path, search entire list */
763         for (int index = 0; index < zoneStrings.length; index++) {
764             if (ID.equals(zoneStrings[index][0])) {
765                 lastZoneIndex = index;
766                 return index;
767             }
768         }
769 
770         return -1;
771     }
772 
773     /**
774      * Wrapper method to the getZoneStrings(), which is called from inside
775      * the java.text package and not to mutate the returned arrays, so that
776      * it does not need to create a defensive copy.
777      */
778     final String[][] getZoneStringsWrapper() {
779         if (isSubclassObject()) {
780             return getZoneStrings();
781         } else {
782             return getZoneStringsImpl(false);
783         }
784     }
785 
786     private String[][] getZoneStringsImpl(boolean needsCopy) {
787         if (zoneStrings == null) {
788             zoneStrings = TimeZoneNameUtility.getZoneStrings(locale);
789         }
790 
791         if (!needsCopy) {
792             return zoneStrings;
793         }
794 
795         int len = zoneStrings.length;
796         String[][] aCopy = new String[len][];
797         for (int i = 0; i < len; i++) {
798             aCopy[i] = Arrays.copyOf(zoneStrings[i], zoneStrings[i].length);
799         }
800         return aCopy;
801     }
802 
803     private boolean isSubclassObject() {
804         return !getClass().getName().equals("java.text.DateFormatSymbols");
805     }
806 
807     /**
808      * Clones all the data members from the source DateFormatSymbols to
809      * the target DateFormatSymbols. This is only for subclasses.
810      * @param src the source DateFormatSymbols.
811      * @param dst the target DateFormatSymbols.
812      */
813     private void copyMembers(DateFormatSymbols src, DateFormatSymbols dst)
814     {
815         dst.eras = Arrays.copyOf(src.eras, src.eras.length);
816         dst.months = Arrays.copyOf(src.months, src.months.length);
817         dst.shortMonths = Arrays.copyOf(src.shortMonths, src.shortMonths.length);
818         dst.weekdays = Arrays.copyOf(src.weekdays, src.weekdays.length);
819         dst.shortWeekdays = Arrays.copyOf(src.shortWeekdays, src.shortWeekdays.length);
820         dst.ampms = Arrays.copyOf(src.ampms, src.ampms.length);
821         if (src.zoneStrings != null) {
822             dst.zoneStrings = src.getZoneStringsImpl(true);
823         } else {
824             dst.zoneStrings = null;
825         }
826         dst.localPatternChars = src.localPatternChars;
827         dst.cachedHashCode = 0;
828     }
829 
830     /**
831      * Write out the default serializable data, after ensuring the
832      * <code>zoneStrings</code> field is initialized in order to make
833      * sure the backward compatibility.
834      *
835      * @since 1.6
836      */
837     private void writeObject(ObjectOutputStream stream) throws IOException {
838         if (zoneStrings == null) {
839             zoneStrings = TimeZoneNameUtility.getZoneStrings(locale);
840         }
841         stream.defaultWriteObject();
842     }
843 }