1 /*
   2  * Copyright (c) 1996, 2016, Oracle and/or its affiliates. All rights reserved.
   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
   6  * under the terms of the GNU General Public License version 2 only, as
   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  *
  21  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  22  * or visit www.oracle.com if you need additional information or have any
  23  * questions.
  24  */
  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.concurrent.ConcurrentHashMap;
  51 import java.util.concurrent.ConcurrentMap;
  52 import sun.util.locale.provider.LocaleProviderAdapter;
  53 import sun.util.locale.provider.LocaleServiceProviderPool;
  54 import sun.util.locale.provider.ResourceBundleBasedAdapter;
  55 import sun.util.locale.provider.TimeZoneNameUtility;
  56 
  57 /**
  58  * <code>DateFormatSymbols</code> is a public class for encapsulating
  59  * localizable date-time formatting data, such as the names of the
  60  * months, the names of the days of the week, and the time zone data.
  61  * <code>SimpleDateFormat</code> uses
  62  * <code>DateFormatSymbols</code> to encapsulate this information.
  63  *
  64  * <p>
  65  * Typically you shouldn't use <code>DateFormatSymbols</code> directly.
  66  * Rather, you are encouraged to create a date-time formatter with the
  67  * <code>DateFormat</code> class's factory methods: <code>getTimeInstance</code>,
  68  * <code>getDateInstance</code>, or <code>getDateTimeInstance</code>.
  69  * These methods automatically create a <code>DateFormatSymbols</code> for
  70  * the formatter so that you don't have to. After the
  71  * formatter is created, you may modify its format pattern using the
  72  * <code>setPattern</code> method. For more information about
  73  * creating formatters using <code>DateFormat</code>'s factory methods,
  74  * see {@link DateFormat}.
  75  *
  76  * <p>
  77  * If you decide to create a date-time formatter with a specific
  78  * format pattern for a specific locale, you can do so with:
  79  * <blockquote>
  80  * <pre>
  81  * new SimpleDateFormat(aPattern, DateFormatSymbols.getInstance(aLocale)).
  82  * </pre>
  83  * </blockquote>
  84  *
  85  * <p>
  86  * <code>DateFormatSymbols</code> objects are cloneable. When you obtain
  87  * a <code>DateFormatSymbols</code> object, feel free to modify the
  88  * date-time formatting data. For instance, you can replace the localized
  89  * date-time format pattern characters with the ones that you feel easy
  90  * to remember. Or you can change the representative cities
  91  * to your favorite ones.
  92  *
  93  * <p>
  94  * New <code>DateFormatSymbols</code> subclasses may be added to support
  95  * <code>SimpleDateFormat</code> for date-time formatting for additional locales.
  96 
  97  * @see          DateFormat
  98  * @see          SimpleDateFormat
  99  * @see          java.util.SimpleTimeZone
 100  * @author       Chen-Lieh Huang
 101  * @since 1.1
 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      * Constructs an uninitialized DateFormatSymbols.
 151      */
 152     private DateFormatSymbols(boolean flag) {
 153     }
 154 
 155     /**
 156      * Era strings. For example: "AD" and "BC".  An array of 2 strings,
 157      * indexed by <code>Calendar.BC</code> and <code>Calendar.AD</code>.
 158      * @serial
 159      */
 160     String eras[] = null;
 161 
 162     /**
 163      * Month strings. For example: "January", "February", etc.  An array
 164      * of 13 strings (some calendars have 13 months), indexed by
 165      * <code>Calendar.JANUARY</code>, <code>Calendar.FEBRUARY</code>, etc.
 166      * @serial
 167      */
 168     String months[] = null;
 169 
 170     /**
 171      * Short month strings. For example: "Jan", "Feb", etc.  An array of
 172      * 13 strings (some calendars have 13 months), indexed by
 173      * <code>Calendar.JANUARY</code>, <code>Calendar.FEBRUARY</code>, etc.
 174 
 175      * @serial
 176      */
 177     String shortMonths[] = null;
 178 
 179     /**
 180      * Weekday strings. For example: "Sunday", "Monday", etc.  An array
 181      * of 8 strings, indexed by <code>Calendar.SUNDAY</code>,
 182      * <code>Calendar.MONDAY</code>, etc.
 183      * The element <code>weekdays[0]</code> is ignored.
 184      * @serial
 185      */
 186     String weekdays[] = null;
 187 
 188     /**
 189      * Short weekday strings. For example: "Sun", "Mon", etc.  An array
 190      * of 8 strings, indexed by <code>Calendar.SUNDAY</code>,
 191      * <code>Calendar.MONDAY</code>, etc.
 192      * The element <code>shortWeekdays[0]</code> is ignored.
 193      * @serial
 194      */
 195     String shortWeekdays[] = null;
 196 
 197     /**
 198      * AM and PM strings. For example: "AM" and "PM".  An array of
 199      * 2 strings, indexed by <code>Calendar.AM</code> and
 200      * <code>Calendar.PM</code>.
 201      * @serial
 202      */
 203     String ampms[] = null;
 204 
 205     /**
 206      * Localized names of time zones in this locale.  This is a
 207      * two-dimensional array of strings of size <em>n</em> by <em>m</em>,
 208      * where <em>m</em> is at least 5.  Each of the <em>n</em> rows is an
 209      * entry containing the localized names for a single <code>TimeZone</code>.
 210      * Each such row contains (with <code>i</code> ranging from
 211      * 0..<em>n</em>-1):
 212      * <ul>
 213      * <li><code>zoneStrings[i][0]</code> - time zone ID</li>
 214      * <li><code>zoneStrings[i][1]</code> - long name of zone in standard
 215      * time</li>
 216      * <li><code>zoneStrings[i][2]</code> - short name of zone in
 217      * standard time</li>
 218      * <li><code>zoneStrings[i][3]</code> - long name of zone in daylight
 219      * saving time</li>
 220      * <li><code>zoneStrings[i][4]</code> - short name of zone in daylight
 221      * saving time</li>
 222      * </ul>
 223      * The zone ID is <em>not</em> localized; it's one of the valid IDs of
 224      * the {@link java.util.TimeZone TimeZone} class that are not
 225      * <a href="../util/TimeZone.html#CustomID">custom IDs</a>.
 226      * All other entries are localized names.
 227      * @see java.util.TimeZone
 228      * @serial
 229      */
 230     String zoneStrings[][] = null;
 231 
 232     /**
 233      * Indicates that zoneStrings is set externally with setZoneStrings() method.
 234      */
 235     transient boolean isZoneStringsSet = false;
 236 
 237     /**
 238      * Unlocalized date-time pattern characters. For example: 'y', 'd', etc.
 239      * All locales use the same these unlocalized pattern characters.
 240      */
 241     static final String  patternChars = "GyMdkHmsSEDFwWahKzZYuXL";
 242 
 243     static final int PATTERN_ERA                  =  0; // G
 244     static final int PATTERN_YEAR                 =  1; // y
 245     static final int PATTERN_MONTH                =  2; // M
 246     static final int PATTERN_DAY_OF_MONTH         =  3; // d
 247     static final int PATTERN_HOUR_OF_DAY1         =  4; // k
 248     static final int PATTERN_HOUR_OF_DAY0         =  5; // H
 249     static final int PATTERN_MINUTE               =  6; // m
 250     static final int PATTERN_SECOND               =  7; // s
 251     static final int PATTERN_MILLISECOND          =  8; // S
 252     static final int PATTERN_DAY_OF_WEEK          =  9; // E
 253     static final int PATTERN_DAY_OF_YEAR          = 10; // D
 254     static final int PATTERN_DAY_OF_WEEK_IN_MONTH = 11; // F
 255     static final int PATTERN_WEEK_OF_YEAR         = 12; // w
 256     static final int PATTERN_WEEK_OF_MONTH        = 13; // W
 257     static final int PATTERN_AM_PM                = 14; // a
 258     static final int PATTERN_HOUR1                = 15; // h
 259     static final int PATTERN_HOUR0                = 16; // K
 260     static final int PATTERN_ZONE_NAME            = 17; // z
 261     static final int PATTERN_ZONE_VALUE           = 18; // Z
 262     static final int PATTERN_WEEK_YEAR            = 19; // Y
 263     static final int PATTERN_ISO_DAY_OF_WEEK      = 20; // u
 264     static final int PATTERN_ISO_ZONE             = 21; // X
 265     static final int PATTERN_MONTH_STANDALONE     = 22; // L
 266 
 267     /**
 268      * Localized date-time pattern characters. For example, a locale may
 269      * wish to use 'u' rather than 'y' to represent years in its date format
 270      * pattern strings.
 271      * This string must be exactly 18 characters long, with the index of
 272      * the characters described by <code>DateFormat.ERA_FIELD</code>,
 273      * <code>DateFormat.YEAR_FIELD</code>, etc.  Thus, if the string were
 274      * "Xz...", then localized patterns would use 'X' for era and 'z' for year.
 275      * @serial
 276      */
 277     String  localPatternChars = null;
 278 
 279     /**
 280      * The locale which is used for initializing this DateFormatSymbols object.
 281      *
 282      * @since 1.6
 283      * @serial
 284      */
 285     Locale locale = null;
 286 
 287     /* use serialVersionUID from JDK 1.1.4 for interoperability */
 288     static final long serialVersionUID = -5987973545549424702L;
 289 
 290     /**
 291      * Returns an array of all locales for which the
 292      * <code>getInstance</code> methods of this class can return
 293      * localized instances.
 294      * The returned array represents the union of locales supported by the
 295      * Java runtime and by installed
 296      * {@link java.text.spi.DateFormatSymbolsProvider DateFormatSymbolsProvider}
 297      * implementations.  It must contain at least a <code>Locale</code>
 298      * instance equal to {@link java.util.Locale#US Locale.US}.
 299      *
 300      * @return An array of locales for which localized
 301      *         <code>DateFormatSymbols</code> instances are available.
 302      * @since 1.6
 303      */
 304     public static Locale[] getAvailableLocales() {
 305         LocaleServiceProviderPool pool=
 306             LocaleServiceProviderPool.getPool(DateFormatSymbolsProvider.class);
 307         return pool.getAvailableLocales();
 308     }
 309 
 310     /**
 311      * Gets the <code>DateFormatSymbols</code> instance for the default
 312      * locale.  This method provides access to <code>DateFormatSymbols</code>
 313      * instances for locales supported by the Java runtime itself as well
 314      * as for those supported by installed
 315      * {@link java.text.spi.DateFormatSymbolsProvider DateFormatSymbolsProvider}
 316      * implementations.
 317      * <p>This is equivalent to calling {@link #getInstance(Locale)
 318      *     getInstance(Locale.getDefault(Locale.Category.FORMAT))}.
 319      * @see java.util.Locale#getDefault(java.util.Locale.Category)
 320      * @see java.util.Locale.Category#FORMAT
 321      * @return a <code>DateFormatSymbols</code> instance.
 322      * @since 1.6
 323      */
 324     public static final DateFormatSymbols getInstance() {
 325         return getInstance(Locale.getDefault(Locale.Category.FORMAT));
 326     }
 327 
 328     /**
 329      * Gets the <code>DateFormatSymbols</code> instance for the specified
 330      * locale.  This method provides access to <code>DateFormatSymbols</code>
 331      * instances for locales supported by the Java runtime itself as well
 332      * as for those supported by installed
 333      * {@link java.text.spi.DateFormatSymbolsProvider DateFormatSymbolsProvider}
 334      * implementations.
 335      * @param locale the given locale.
 336      * @return a <code>DateFormatSymbols</code> instance.
 337      * @exception NullPointerException if <code>locale</code> is null
 338      * @since 1.6
 339      */
 340     public static final DateFormatSymbols getInstance(Locale locale) {
 341         DateFormatSymbols dfs = getProviderInstance(locale);
 342         if (dfs != null) {
 343             return dfs;
 344         }
 345         throw new RuntimeException("DateFormatSymbols instance creation failed.");
 346     }
 347 
 348     /**
 349      * Returns a DateFormatSymbols provided by a provider or found in
 350      * the cache. Note that this method returns a cached instance,
 351      * not its clone. Therefore, the instance should never be given to
 352      * an application.
 353      */
 354     static final DateFormatSymbols getInstanceRef(Locale locale) {
 355         DateFormatSymbols dfs = getProviderInstance(locale);
 356         if (dfs != null) {
 357             return dfs;
 358         }
 359         throw new RuntimeException("DateFormatSymbols instance creation failed.");
 360     }
 361 
 362     private static DateFormatSymbols getProviderInstance(Locale locale) {
 363         LocaleProviderAdapter adapter = LocaleProviderAdapter.getAdapter(DateFormatSymbolsProvider.class, locale);
 364         DateFormatSymbolsProvider provider = adapter.getDateFormatSymbolsProvider();
 365         DateFormatSymbols dfsyms = provider.getInstance(locale);
 366         if (dfsyms == null) {
 367             provider = LocaleProviderAdapter.forJRE().getDateFormatSymbolsProvider();
 368             dfsyms = provider.getInstance(locale);
 369         }
 370         return dfsyms;
 371     }
 372 
 373     /**
 374      * Gets era strings. For example: "AD" and "BC".
 375      * @return the era strings.
 376      */
 377     public String[] getEras() {
 378         return Arrays.copyOf(eras, eras.length);
 379     }
 380 
 381     /**
 382      * Sets era strings. For example: "AD" and "BC".
 383      * @param newEras the new era strings.
 384      */
 385     public void setEras(String[] newEras) {
 386         eras = Arrays.copyOf(newEras, newEras.length);
 387         cachedHashCode = 0;
 388     }
 389 
 390     /**
 391      * Gets month strings. For example: "January", "February", etc.
 392      *
 393      * <p>If the language requires different forms for formatting and
 394      * stand-alone usages, this method returns month names in the
 395      * formatting form. For example, the preferred month name for
 396      * January in the Czech language is <em>ledna</em> in the
 397      * formatting form, while it is <em>leden</em> in the stand-alone
 398      * form. This method returns {@code "ledna"} in this case. Refer
 399      * to the <a href="http://unicode.org/reports/tr35/#Calendar_Elements">
 400      * Calendar Elements in the Unicode Locale Data Markup Language
 401      * (LDML) specification</a> for more details.
 402      *
 403      * @return the month strings. Use
 404      * {@link java.util.Calendar#JANUARY Calendar.JANUARY},
 405      * {@link java.util.Calendar#FEBRUARY Calendar.FEBRUARY},
 406      * etc. to index the result array.
 407      */
 408     public String[] getMonths() {
 409         return Arrays.copyOf(months, months.length);
 410     }
 411 
 412     /**
 413      * Sets month strings. For example: "January", "February", etc.
 414      * @param newMonths the new month strings. The array should
 415      * be indexed by {@link java.util.Calendar#JANUARY Calendar.JANUARY},
 416      * {@link java.util.Calendar#FEBRUARY Calendar.FEBRUARY}, etc.
 417      */
 418     public void setMonths(String[] newMonths) {
 419         months = Arrays.copyOf(newMonths, newMonths.length);
 420         cachedHashCode = 0;
 421     }
 422 
 423     /**
 424      * Gets short month strings. For example: "Jan", "Feb", etc.
 425      *
 426      * <p>If the language requires different forms for formatting and
 427      * stand-alone usages, this method returns short month names in
 428      * the formatting form. For example, the preferred abbreviation
 429      * for January in the Catalan language is <em>de gen.</em> in the
 430      * formatting form, while it is <em>gen.</em> in the stand-alone
 431      * form. This method returns {@code "de gen."} in this case. Refer
 432      * to the <a href="http://unicode.org/reports/tr35/#Calendar_Elements">
 433      * Calendar Elements in the Unicode Locale Data Markup Language
 434      * (LDML) specification</a> for more details.
 435      *
 436      * @return the short month strings. Use
 437      * {@link java.util.Calendar#JANUARY Calendar.JANUARY},
 438      * {@link java.util.Calendar#FEBRUARY Calendar.FEBRUARY},
 439      * etc. to index the result array.
 440      */
 441     public String[] getShortMonths() {
 442         return Arrays.copyOf(shortMonths, shortMonths.length);
 443     }
 444 
 445     /**
 446      * Sets short month strings. For example: "Jan", "Feb", etc.
 447      * @param newShortMonths the new short month strings. The array should
 448      * be indexed by {@link java.util.Calendar#JANUARY Calendar.JANUARY},
 449      * {@link java.util.Calendar#FEBRUARY Calendar.FEBRUARY}, etc.
 450      */
 451     public void setShortMonths(String[] newShortMonths) {
 452         shortMonths = Arrays.copyOf(newShortMonths, newShortMonths.length);
 453         cachedHashCode = 0;
 454     }
 455 
 456     /**
 457      * Gets weekday strings. For example: "Sunday", "Monday", etc.
 458      * @return the weekday strings. Use
 459      * {@link java.util.Calendar#SUNDAY Calendar.SUNDAY},
 460      * {@link java.util.Calendar#MONDAY Calendar.MONDAY}, etc. to index
 461      * the result array.
 462      */
 463     public String[] getWeekdays() {
 464         return Arrays.copyOf(weekdays, weekdays.length);
 465     }
 466 
 467     /**
 468      * Sets weekday strings. For example: "Sunday", "Monday", etc.
 469      * @param newWeekdays the new weekday strings. The array should
 470      * be indexed by {@link java.util.Calendar#SUNDAY Calendar.SUNDAY},
 471      * {@link java.util.Calendar#MONDAY Calendar.MONDAY}, etc.
 472      */
 473     public void setWeekdays(String[] newWeekdays) {
 474         weekdays = Arrays.copyOf(newWeekdays, newWeekdays.length);
 475         cachedHashCode = 0;
 476     }
 477 
 478     /**
 479      * Gets short weekday strings. For example: "Sun", "Mon", etc.
 480      * @return the short weekday strings. Use
 481      * {@link java.util.Calendar#SUNDAY Calendar.SUNDAY},
 482      * {@link java.util.Calendar#MONDAY Calendar.MONDAY}, etc. to index
 483      * the result array.
 484      */
 485     public String[] getShortWeekdays() {
 486         return Arrays.copyOf(shortWeekdays, shortWeekdays.length);
 487     }
 488 
 489     /**
 490      * Sets short weekday strings. For example: "Sun", "Mon", etc.
 491      * @param newShortWeekdays the new short weekday strings. The array should
 492      * be indexed by {@link java.util.Calendar#SUNDAY Calendar.SUNDAY},
 493      * {@link java.util.Calendar#MONDAY Calendar.MONDAY}, etc.
 494      */
 495     public void setShortWeekdays(String[] newShortWeekdays) {
 496         shortWeekdays = Arrays.copyOf(newShortWeekdays, newShortWeekdays.length);
 497         cachedHashCode = 0;
 498     }
 499 
 500     /**
 501      * Gets ampm strings. For example: "AM" and "PM".
 502      * @return the ampm strings.
 503      */
 504     public String[] getAmPmStrings() {
 505         return Arrays.copyOf(ampms, ampms.length);
 506     }
 507 
 508     /**
 509      * Sets ampm strings. For example: "AM" and "PM".
 510      * @param newAmpms the new ampm strings.
 511      */
 512     public void setAmPmStrings(String[] newAmpms) {
 513         ampms = Arrays.copyOf(newAmpms, newAmpms.length);
 514         cachedHashCode = 0;
 515     }
 516 
 517     /**
 518      * Gets time zone strings.  Use of this method is discouraged; use
 519      * {@link java.util.TimeZone#getDisplayName() TimeZone.getDisplayName()}
 520      * instead.
 521      * <p>
 522      * The value returned is a
 523      * two-dimensional array of strings of size <em>n</em> by <em>m</em>,
 524      * where <em>m</em> is at least 5.  Each of the <em>n</em> rows is an
 525      * entry containing the localized names for a single <code>TimeZone</code>.
 526      * Each such row contains (with <code>i</code> ranging from
 527      * 0..<em>n</em>-1):
 528      * <ul>
 529      * <li><code>zoneStrings[i][0]</code> - time zone ID</li>
 530      * <li><code>zoneStrings[i][1]</code> - long name of zone in standard
 531      * time</li>
 532      * <li><code>zoneStrings[i][2]</code> - short name of zone in
 533      * standard time</li>
 534      * <li><code>zoneStrings[i][3]</code> - long name of zone in daylight
 535      * saving time</li>
 536      * <li><code>zoneStrings[i][4]</code> - short name of zone in daylight
 537      * saving time</li>
 538      * </ul>
 539      * The zone ID is <em>not</em> localized; it's one of the valid IDs of
 540      * the {@link java.util.TimeZone TimeZone} class that are not
 541      * <a href="../util/TimeZone.html#CustomID">custom IDs</a>.
 542      * All other entries are localized names.  If a zone does not implement
 543      * daylight saving time, the daylight saving time names should not be used.
 544      * <p>
 545      * If {@link #setZoneStrings(String[][]) setZoneStrings} has been called
 546      * on this <code>DateFormatSymbols</code> instance, then the strings
 547      * provided by that call are returned. Otherwise, the returned array
 548      * contains names provided by the Java runtime and by installed
 549      * {@link java.util.spi.TimeZoneNameProvider TimeZoneNameProvider}
 550      * implementations.
 551      *
 552      * @return the time zone strings.
 553      * @see #setZoneStrings(String[][])
 554      */
 555     public String[][] getZoneStrings() {
 556         return getZoneStringsImpl(true);
 557     }
 558 
 559     /**
 560      * Sets time zone strings.  The argument must be a
 561      * two-dimensional array of strings of size <em>n</em> by <em>m</em>,
 562      * where <em>m</em> is at least 5.  Each of the <em>n</em> rows is an
 563      * entry containing the localized names for a single <code>TimeZone</code>.
 564      * Each such row contains (with <code>i</code> ranging from
 565      * 0..<em>n</em>-1):
 566      * <ul>
 567      * <li><code>zoneStrings[i][0]</code> - time zone ID</li>
 568      * <li><code>zoneStrings[i][1]</code> - long name of zone in standard
 569      * time</li>
 570      * <li><code>zoneStrings[i][2]</code> - short name of zone in
 571      * standard time</li>
 572      * <li><code>zoneStrings[i][3]</code> - long name of zone in daylight
 573      * saving time</li>
 574      * <li><code>zoneStrings[i][4]</code> - short name of zone in daylight
 575      * saving time</li>
 576      * </ul>
 577      * The zone ID is <em>not</em> localized; it's one of the valid IDs of
 578      * the {@link java.util.TimeZone TimeZone} class that are not
 579      * <a href="../util/TimeZone.html#CustomID">custom IDs</a>.
 580      * All other entries are localized names.
 581      *
 582      * @param newZoneStrings the new time zone strings.
 583      * @exception IllegalArgumentException if the length of any row in
 584      *    <code>newZoneStrings</code> is less than 5
 585      * @exception NullPointerException if <code>newZoneStrings</code> is null
 586      * @see #getZoneStrings()
 587      */
 588     public void setZoneStrings(String[][] newZoneStrings) {
 589         String[][] aCopy = new String[newZoneStrings.length][];
 590         for (int i = 0; i < newZoneStrings.length; ++i) {
 591             int len = newZoneStrings[i].length;
 592             if (len < 5) {
 593                 throw new IllegalArgumentException();
 594             }
 595             aCopy[i] = Arrays.copyOf(newZoneStrings[i], len);
 596         }
 597         zoneStrings = aCopy;
 598         isZoneStringsSet = true;
 599         cachedHashCode = 0;
 600     }
 601 
 602     /**
 603      * Gets localized date-time pattern characters. For example: 'u', 't', etc.
 604      * @return the localized date-time pattern characters.
 605      */
 606     public String getLocalPatternChars() {
 607         return localPatternChars;
 608     }
 609 
 610     /**
 611      * Sets localized date-time pattern characters. For example: 'u', 't', etc.
 612      * @param newLocalPatternChars the new localized date-time
 613      * pattern characters.
 614      */
 615     public void setLocalPatternChars(String newLocalPatternChars) {
 616         // Call toString() to throw an NPE in case the argument is null
 617         localPatternChars = newLocalPatternChars.toString();
 618         cachedHashCode = 0;
 619     }
 620 
 621     /**
 622      * Overrides Cloneable
 623      */
 624     public Object clone()
 625     {
 626         try
 627         {
 628             DateFormatSymbols other = (DateFormatSymbols)super.clone();
 629             copyMembers(this, other);
 630             return other;
 631         } catch (CloneNotSupportedException e) {
 632             throw new InternalError(e);
 633         }
 634     }
 635 
 636     /**
 637      * Override hashCode.
 638      * Generates a hash code for the DateFormatSymbols object.
 639      */
 640     @Override
 641     public int hashCode() {
 642         int hashCode = cachedHashCode;
 643         if (hashCode == 0) {
 644             hashCode = 5;
 645             hashCode = 11 * hashCode + Arrays.hashCode(eras);
 646             hashCode = 11 * hashCode + Arrays.hashCode(months);
 647             hashCode = 11 * hashCode + Arrays.hashCode(shortMonths);
 648             hashCode = 11 * hashCode + Arrays.hashCode(weekdays);
 649             hashCode = 11 * hashCode + Arrays.hashCode(shortWeekdays);
 650             hashCode = 11 * hashCode + Arrays.hashCode(ampms);
 651             hashCode = 11 * hashCode + Arrays.deepHashCode(getZoneStringsWrapper());
 652             hashCode = 11 * hashCode + Objects.hashCode(localPatternChars);
 653             if (hashCode != 0) {
 654                 cachedHashCode = hashCode;
 655             }
 656         }
 657 
 658         return hashCode;
 659     }
 660 
 661     /**
 662      * Override equals
 663      */
 664     public boolean equals(Object obj)
 665     {
 666         if (this == obj) return true;
 667         if (obj == null || getClass() != obj.getClass()) return false;
 668         DateFormatSymbols that = (DateFormatSymbols) obj;
 669         return (Arrays.equals(eras, that.eras)
 670                 && Arrays.equals(months, that.months)
 671                 && Arrays.equals(shortMonths, that.shortMonths)
 672                 && Arrays.equals(weekdays, that.weekdays)
 673                 && Arrays.equals(shortWeekdays, that.shortWeekdays)
 674                 && Arrays.equals(ampms, that.ampms)
 675                 && Arrays.deepEquals(getZoneStringsWrapper(), that.getZoneStringsWrapper())
 676                 && ((localPatternChars != null
 677                   && localPatternChars.equals(that.localPatternChars))
 678                  || (localPatternChars == null
 679                   && that.localPatternChars == null)));
 680     }
 681 
 682     // =======================privates===============================
 683 
 684     /**
 685      * Useful constant for defining time zone offsets.
 686      */
 687     static final int millisPerHour = 60*60*1000;
 688 
 689     /**
 690      * Cache to hold DateFormatSymbols instances per Locale.
 691      */
 692     private static final ConcurrentMap<Locale, SoftReference<DateFormatSymbols>> cachedInstances
 693         = new ConcurrentHashMap<>(3);
 694 
 695     private transient int lastZoneIndex;
 696 
 697     /**
 698      * Cached hash code
 699      */
 700     transient volatile int cachedHashCode;
 701 
 702     /**
 703      * Initializes this DateFormatSymbols with the locale data. This method uses
 704      * a cached DateFormatSymbols instance for the given locale if available. If
 705      * there's no cached one, this method creates an uninitialized instance and
 706      * populates its fields from the resource bundle for the locale, and caches
 707      * the instance. Note: zoneStrings isn't initialized in this method.
 708      */
 709     private void initializeData(Locale locale) {
 710         SoftReference<DateFormatSymbols> ref = cachedInstances.get(locale);
 711         DateFormatSymbols dfs;
 712         if (ref == null || (dfs = ref.get()) == null) {
 713             if (ref != null) {
 714                 // Remove the empty SoftReference
 715                 cachedInstances.remove(locale, ref);
 716             }
 717             dfs = new DateFormatSymbols(false);
 718 
 719             // Initialize the fields from the ResourceBundle for locale.
 720             LocaleProviderAdapter adapter
 721                 = LocaleProviderAdapter.getAdapter(DateFormatSymbolsProvider.class, locale);
 722             // Avoid any potential recursions
 723             if (!(adapter instanceof ResourceBundleBasedAdapter)) {
 724                 adapter = LocaleProviderAdapter.getResourceBundleBased();
 725             }
 726             ResourceBundle resource
 727                 = ((ResourceBundleBasedAdapter)adapter).getLocaleData().getDateFormatData(locale);
 728 
 729             dfs.locale = locale;
 730             // JRE and CLDR use different keys
 731             // JRE: Eras, short.Eras and narrow.Eras
 732             // CLDR: long.Eras, Eras and narrow.Eras
 733             if (resource.containsKey("Eras")) {
 734                 dfs.eras = resource.getStringArray("Eras");
 735             } else if (resource.containsKey("long.Eras")) {
 736                 dfs.eras = resource.getStringArray("long.Eras");
 737             } else if (resource.containsKey("short.Eras")) {
 738                 dfs.eras = resource.getStringArray("short.Eras");
 739             }
 740             dfs.months = resource.getStringArray("MonthNames");
 741             dfs.shortMonths = resource.getStringArray("MonthAbbreviations");
 742             dfs.ampms = resource.getStringArray("AmPmMarkers");
 743             dfs.localPatternChars = resource.getString("DateTimePatternChars");
 744 
 745             // Day of week names are stored in a 1-based array.
 746             dfs.weekdays = toOneBasedArray(resource.getStringArray("DayNames"));
 747             dfs.shortWeekdays = toOneBasedArray(resource.getStringArray("DayAbbreviations"));
 748 
 749             // Put dfs in the cache
 750             ref = new SoftReference<>(dfs);
 751             SoftReference<DateFormatSymbols> x = cachedInstances.putIfAbsent(locale, ref);
 752             if (x != null) {
 753                 DateFormatSymbols y = x.get();
 754                 if (y == null) {
 755                     // Replace the empty SoftReference with ref.
 756                     cachedInstances.replace(locale, x, ref);
 757                 } else {
 758                     ref = x;
 759                     dfs = y;
 760                 }
 761             }
 762         }
 763 
 764         // Copy the field values from dfs to this instance.
 765         copyMembers(dfs, this);
 766     }
 767 
 768     private static String[] toOneBasedArray(String[] src) {
 769         int len = src.length;
 770         String[] dst = new String[len + 1];
 771         dst[0] = "";
 772         for (int i = 0; i < len; i++) {
 773             dst[i + 1] = src[i];
 774         }
 775         return dst;
 776     }
 777 
 778     /**
 779      * Package private: used by SimpleDateFormat
 780      * Gets the index for the given time zone ID to obtain the time zone
 781      * strings for formatting. The time zone ID is just for programmatic
 782      * lookup. NOT LOCALIZED!!!
 783      * @param ID the given time zone ID.
 784      * @return the index of the given time zone ID.  Returns -1 if
 785      * the given time zone ID can't be located in the DateFormatSymbols object.
 786      * @see java.util.SimpleTimeZone
 787      */
 788     final int getZoneIndex(String ID) {
 789         String[][] zoneStrings = getZoneStringsWrapper();
 790 
 791         /*
 792          * getZoneIndex has been re-written for performance reasons. instead of
 793          * traversing the zoneStrings array every time, we cache the last used zone
 794          * index
 795          */
 796         if (lastZoneIndex < zoneStrings.length && ID.equals(zoneStrings[lastZoneIndex][0])) {
 797             return lastZoneIndex;
 798         }
 799 
 800         /* slow path, search entire list */
 801         for (int index = 0; index < zoneStrings.length; index++) {
 802             if (ID.equals(zoneStrings[index][0])) {
 803                 lastZoneIndex = index;
 804                 return index;
 805             }
 806         }
 807 
 808         return -1;
 809     }
 810 
 811     /**
 812      * Wrapper method to the getZoneStrings(), which is called from inside
 813      * the java.text package and not to mutate the returned arrays, so that
 814      * it does not need to create a defensive copy.
 815      */
 816     final String[][] getZoneStringsWrapper() {
 817         if (isSubclassObject()) {
 818             return getZoneStrings();
 819         } else {
 820             return getZoneStringsImpl(false);
 821         }
 822     }
 823 
 824     private String[][] getZoneStringsImpl(boolean needsCopy) {
 825         if (zoneStrings == null) {
 826             zoneStrings = TimeZoneNameUtility.getZoneStrings(locale);
 827         }
 828 
 829         if (!needsCopy) {
 830             return zoneStrings;
 831         }
 832 
 833         int len = zoneStrings.length;
 834         String[][] aCopy = new String[len][];
 835         for (int i = 0; i < len; i++) {
 836             aCopy[i] = Arrays.copyOf(zoneStrings[i], zoneStrings[i].length);
 837         }
 838         return aCopy;
 839     }
 840 
 841     private boolean isSubclassObject() {
 842         return !getClass().getName().equals("java.text.DateFormatSymbols");
 843     }
 844 
 845     /**
 846      * Clones all the data members from the source DateFormatSymbols to
 847      * the target DateFormatSymbols.
 848      *
 849      * @param src the source DateFormatSymbols.
 850      * @param dst the target DateFormatSymbols.
 851      */
 852     private void copyMembers(DateFormatSymbols src, DateFormatSymbols dst)
 853     {
 854         dst.locale = src.locale;
 855         dst.eras = Arrays.copyOf(src.eras, src.eras.length);
 856         dst.months = Arrays.copyOf(src.months, src.months.length);
 857         dst.shortMonths = Arrays.copyOf(src.shortMonths, src.shortMonths.length);
 858         dst.weekdays = Arrays.copyOf(src.weekdays, src.weekdays.length);
 859         dst.shortWeekdays = Arrays.copyOf(src.shortWeekdays, src.shortWeekdays.length);
 860         dst.ampms = Arrays.copyOf(src.ampms, src.ampms.length);
 861         if (src.zoneStrings != null) {
 862             dst.zoneStrings = src.getZoneStringsImpl(true);
 863         } else {
 864             dst.zoneStrings = null;
 865         }
 866         dst.localPatternChars = src.localPatternChars;
 867         dst.cachedHashCode = 0;
 868     }
 869 
 870     /**
 871      * Write out the default serializable data, after ensuring the
 872      * <code>zoneStrings</code> field is initialized in order to make
 873      * sure the backward compatibility.
 874      *
 875      * @since 1.6
 876      */
 877     private void writeObject(ObjectOutputStream stream) throws IOException {
 878         if (zoneStrings == null) {
 879             zoneStrings = TimeZoneNameUtility.getZoneStrings(locale);
 880         }
 881         stream.defaultWriteObject();
 882     }
 883 }