1 /*
   2  * Copyright (c) 1996, 2013, 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. 1996-1998 - All Rights Reserved
  28  * (C) Copyright IBM Corp. 1996-1998 - 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.util;
  40 
  41 import java.io.IOException;
  42 import java.io.ObjectInputStream;
  43 import java.io.ObjectOutputStream;
  44 import java.io.OptionalDataException;
  45 import java.io.Serializable;
  46 import java.security.AccessControlContext;
  47 import java.security.AccessController;
  48 import java.security.PermissionCollection;
  49 import java.security.PrivilegedActionException;
  50 import java.security.PrivilegedExceptionAction;
  51 import java.security.ProtectionDomain;
  52 import java.text.DateFormat;
  53 import java.text.DateFormatSymbols;
  54 import java.time.Instant;
  55 import java.util.concurrent.ConcurrentHashMap;
  56 import java.util.concurrent.ConcurrentMap;
  57 import sun.util.BuddhistCalendar;
  58 import sun.util.calendar.ZoneInfo;
  59 import sun.util.locale.provider.CalendarDataUtility;
  60 import sun.util.locale.provider.LocaleProviderAdapter;
  61 import sun.util.spi.CalendarProvider;
  62 
  63 /**
  64  * The <code>Calendar</code> class is an abstract class that provides methods
  65  * for converting between a specific instant in time and a set of {@link
  66  * #fields calendar fields} such as <code>YEAR</code>, <code>MONTH</code>,
  67  * <code>DAY_OF_MONTH</code>, <code>HOUR</code>, and so on, and for
  68  * manipulating the calendar fields, such as getting the date of the next
  69  * week. An instant in time can be represented by a millisecond value that is
  70  * an offset from the <a name="Epoch"><em>Epoch</em></a>, January 1, 1970
  71  * 00:00:00.000 GMT (Gregorian).
  72  *
  73  * <p>The class also provides additional fields and methods for
  74  * implementing a concrete calendar system outside the package. Those
  75  * fields and methods are defined as <code>protected</code>.
  76  *
  77  * <p>
  78  * Like other locale-sensitive classes, <code>Calendar</code> provides a
  79  * class method, <code>getInstance</code>, for getting a generally useful
  80  * object of this type. <code>Calendar</code>'s <code>getInstance</code> method
  81  * returns a <code>Calendar</code> object whose
  82  * calendar fields have been initialized with the current date and time:
  83  * <blockquote>
  84  * <pre>
  85  *     Calendar rightNow = Calendar.getInstance();
  86  * </pre>
  87  * </blockquote>
  88  *
  89  * <p>A <code>Calendar</code> object can produce all the calendar field values
  90  * needed to implement the date-time formatting for a particular language and
  91  * calendar style (for example, Japanese-Gregorian, Japanese-Traditional).
  92  * <code>Calendar</code> defines the range of values returned by
  93  * certain calendar fields, as well as their meaning.  For example,
  94  * the first month of the calendar system has value <code>MONTH ==
  95  * JANUARY</code> for all calendars.  Other values are defined by the
  96  * concrete subclass, such as <code>ERA</code>.  See individual field
  97  * documentation and subclass documentation for details.
  98  *
  99  * <h3>Getting and Setting Calendar Field Values</h3>
 100  *
 101  * <p>The calendar field values can be set by calling the <code>set</code>
 102  * methods. Any field values set in a <code>Calendar</code> will not be
 103  * interpreted until it needs to calculate its time value (milliseconds from
 104  * the Epoch) or values of the calendar fields. Calling the
 105  * <code>get</code>, <code>getTimeInMillis</code>, <code>getTime</code>,
 106  * <code>add</code> and <code>roll</code> involves such calculation.
 107  *
 108  * <h4>Leniency</h4>
 109  *
 110  * <p><code>Calendar</code> has two modes for interpreting the calendar
 111  * fields, <em>lenient</em> and <em>non-lenient</em>.  When a
 112  * <code>Calendar</code> is in lenient mode, it accepts a wider range of
 113  * calendar field values than it produces.  When a <code>Calendar</code>
 114  * recomputes calendar field values for return by <code>get()</code>, all of
 115  * the calendar fields are normalized. For example, a lenient
 116  * <code>GregorianCalendar</code> interprets <code>MONTH == JANUARY</code>,
 117  * <code>DAY_OF_MONTH == 32</code> as February 1.
 118 
 119  * <p>When a <code>Calendar</code> is in non-lenient mode, it throws an
 120  * exception if there is any inconsistency in its calendar fields. For
 121  * example, a <code>GregorianCalendar</code> always produces
 122  * <code>DAY_OF_MONTH</code> values between 1 and the length of the month. A
 123  * non-lenient <code>GregorianCalendar</code> throws an exception upon
 124  * calculating its time or calendar field values if any out-of-range field
 125  * value has been set.
 126  *
 127  * <h4><a name="first_week">First Week</a></h4>
 128  *
 129  * <code>Calendar</code> defines a locale-specific seven day week using two
 130  * parameters: the first day of the week and the minimal days in first week
 131  * (from 1 to 7).  These numbers are taken from the locale resource data when a
 132  * <code>Calendar</code> is constructed.  They may also be specified explicitly
 133  * through the methods for setting their values.
 134  *
 135  * <p>When setting or getting the <code>WEEK_OF_MONTH</code> or
 136  * <code>WEEK_OF_YEAR</code> fields, <code>Calendar</code> must determine the
 137  * first week of the month or year as a reference point.  The first week of a
 138  * month or year is defined as the earliest seven day period beginning on
 139  * <code>getFirstDayOfWeek()</code> and containing at least
 140  * <code>getMinimalDaysInFirstWeek()</code> days of that month or year.  Weeks
 141  * numbered ..., -1, 0 precede the first week; weeks numbered 2, 3,... follow
 142  * it.  Note that the normalized numbering returned by <code>get()</code> may be
 143  * different.  For example, a specific <code>Calendar</code> subclass may
 144  * designate the week before week 1 of a year as week <code><i>n</i></code> of
 145  * the previous year.
 146  *
 147  * <h4>Calendar Fields Resolution</h4>
 148  *
 149  * When computing a date and time from the calendar fields, there
 150  * may be insufficient information for the computation (such as only
 151  * year and month with no day of month), or there may be inconsistent
 152  * information (such as Tuesday, July 15, 1996 (Gregorian) -- July 15,
 153  * 1996 is actually a Monday). <code>Calendar</code> will resolve
 154  * calendar field values to determine the date and time in the
 155  * following way.
 156  *
 157  * <p><a name="resolution">If there is any conflict in calendar field values,
 158  * <code>Calendar</code> gives priorities to calendar fields that have been set
 159  * more recently.</a> The following are the default combinations of the
 160  * calendar fields. The most recent combination, as determined by the
 161  * most recently set single field, will be used.
 162  *
 163  * <p><a name="date_resolution">For the date fields</a>:
 164  * <blockquote>
 165  * <pre>
 166  * YEAR + MONTH + DAY_OF_MONTH
 167  * YEAR + MONTH + WEEK_OF_MONTH + DAY_OF_WEEK
 168  * YEAR + MONTH + DAY_OF_WEEK_IN_MONTH + DAY_OF_WEEK
 169  * YEAR + DAY_OF_YEAR
 170  * YEAR + DAY_OF_WEEK + WEEK_OF_YEAR
 171  * </pre></blockquote>
 172  *
 173  * <a name="time_resolution">For the time of day fields</a>:
 174  * <blockquote>
 175  * <pre>
 176  * HOUR_OF_DAY
 177  * AM_PM + HOUR
 178  * </pre></blockquote>
 179  *
 180  * <p>If there are any calendar fields whose values haven't been set in the selected
 181  * field combination, <code>Calendar</code> uses their default values. The default
 182  * value of each field may vary by concrete calendar systems. For example, in
 183  * <code>GregorianCalendar</code>, the default of a field is the same as that
 184  * of the start of the Epoch: i.e., <code>YEAR = 1970</code>, <code>MONTH =
 185  * JANUARY</code>, <code>DAY_OF_MONTH = 1</code>, etc.
 186  *
 187  * <p>
 188  * <strong>Note:</strong> There are certain possible ambiguities in
 189  * interpretation of certain singular times, which are resolved in the
 190  * following ways:
 191  * <ol>
 192  *     <li> 23:59 is the last minute of the day and 00:00 is the first
 193  *          minute of the next day. Thus, 23:59 on Dec 31, 1999 &lt; 00:00 on
 194  *          Jan 1, 2000 &lt; 00:01 on Jan 1, 2000.
 195  *
 196  *     <li> Although historically not precise, midnight also belongs to "am",
 197  *          and noon belongs to "pm", so on the same day,
 198  *          12:00 am (midnight) &lt; 12:01 am, and 12:00 pm (noon) &lt; 12:01 pm
 199  * </ol>
 200  *
 201  * <p>
 202  * The date or time format strings are not part of the definition of a
 203  * calendar, as those must be modifiable or overridable by the user at
 204  * runtime. Use {@link DateFormat}
 205  * to format dates.
 206  *
 207  * <h4>Field Manipulation</h4>
 208  *
 209  * The calendar fields can be changed using three methods:
 210  * <code>set()</code>, <code>add()</code>, and <code>roll()</code>.
 211  *
 212  * <p><strong><code>set(f, value)</code></strong> changes calendar field
 213  * <code>f</code> to <code>value</code>.  In addition, it sets an
 214  * internal member variable to indicate that calendar field <code>f</code> has
 215  * been changed. Although calendar field <code>f</code> is changed immediately,
 216  * the calendar's time value in milliseconds is not recomputed until the next call to
 217  * <code>get()</code>, <code>getTime()</code>, <code>getTimeInMillis()</code>,
 218  * <code>add()</code>, or <code>roll()</code> is made. Thus, multiple calls to
 219  * <code>set()</code> do not trigger multiple, unnecessary
 220  * computations. As a result of changing a calendar field using
 221  * <code>set()</code>, other calendar fields may also change, depending on the
 222  * calendar field, the calendar field value, and the calendar system. In addition,
 223  * <code>get(f)</code> will not necessarily return <code>value</code> set by
 224  * the call to the <code>set</code> method
 225  * after the calendar fields have been recomputed. The specifics are determined by
 226  * the concrete calendar class.</p>
 227  *
 228  * <p><em>Example</em>: Consider a <code>GregorianCalendar</code>
 229  * originally set to August 31, 1999. Calling <code>set(Calendar.MONTH,
 230  * Calendar.SEPTEMBER)</code> sets the date to September 31,
 231  * 1999. This is a temporary internal representation that resolves to
 232  * October 1, 1999 if <code>getTime()</code>is then called. However, a
 233  * call to <code>set(Calendar.DAY_OF_MONTH, 30)</code> before the call to
 234  * <code>getTime()</code> sets the date to September 30, 1999, since
 235  * no recomputation occurs after <code>set()</code> itself.</p>
 236  *
 237  * <p><strong><code>add(f, delta)</code></strong> adds <code>delta</code>
 238  * to field <code>f</code>.  This is equivalent to calling <code>set(f,
 239  * get(f) + delta)</code> with two adjustments:</p>
 240  *
 241  * <blockquote>
 242  *   <p><strong>Add rule 1</strong>. The value of field <code>f</code>
 243  *   after the call minus the value of field <code>f</code> before the
 244  *   call is <code>delta</code>, modulo any overflow that has occurred in
 245  *   field <code>f</code>. Overflow occurs when a field value exceeds its
 246  *   range and, as a result, the next larger field is incremented or
 247  *   decremented and the field value is adjusted back into its range.</p>
 248  *
 249  *   <p><strong>Add rule 2</strong>. If a smaller field is expected to be
 250  *   invariant, but it is impossible for it to be equal to its
 251  *   prior value because of changes in its minimum or maximum after field
 252  *   <code>f</code> is changed or other constraints, such as time zone
 253  *   offset changes, then its value is adjusted to be as close
 254  *   as possible to its expected value. A smaller field represents a
 255  *   smaller unit of time. <code>HOUR</code> is a smaller field than
 256  *   <code>DAY_OF_MONTH</code>. No adjustment is made to smaller fields
 257  *   that are not expected to be invariant. The calendar system
 258  *   determines what fields are expected to be invariant.</p>
 259  * </blockquote>
 260  *
 261  * <p>In addition, unlike <code>set()</code>, <code>add()</code> forces
 262  * an immediate recomputation of the calendar's milliseconds and all
 263  * fields.</p>
 264  *
 265  * <p><em>Example</em>: Consider a <code>GregorianCalendar</code>
 266  * originally set to August 31, 1999. Calling <code>add(Calendar.MONTH,
 267  * 13)</code> sets the calendar to September 30, 2000. <strong>Add rule
 268  * 1</strong> sets the <code>MONTH</code> field to September, since
 269  * adding 13 months to August gives September of the next year. Since
 270  * <code>DAY_OF_MONTH</code> cannot be 31 in September in a
 271  * <code>GregorianCalendar</code>, <strong>add rule 2</strong> sets the
 272  * <code>DAY_OF_MONTH</code> to 30, the closest possible value. Although
 273  * it is a smaller field, <code>DAY_OF_WEEK</code> is not adjusted by
 274  * rule 2, since it is expected to change when the month changes in a
 275  * <code>GregorianCalendar</code>.</p>
 276  *
 277  * <p><strong><code>roll(f, delta)</code></strong> adds
 278  * <code>delta</code> to field <code>f</code> without changing larger
 279  * fields. This is equivalent to calling <code>add(f, delta)</code> with
 280  * the following adjustment:</p>
 281  *
 282  * <blockquote>
 283  *   <p><strong>Roll rule</strong>. Larger fields are unchanged after the
 284  *   call. A larger field represents a larger unit of
 285  *   time. <code>DAY_OF_MONTH</code> is a larger field than
 286  *   <code>HOUR</code>.</p>
 287  * </blockquote>
 288  *
 289  * <p><em>Example</em>: See {@link java.util.GregorianCalendar#roll(int, int)}.
 290  *
 291  * <p><strong>Usage model</strong>. To motivate the behavior of
 292  * <code>add()</code> and <code>roll()</code>, consider a user interface
 293  * component with increment and decrement buttons for the month, day, and
 294  * year, and an underlying <code>GregorianCalendar</code>. If the
 295  * interface reads January 31, 1999 and the user presses the month
 296  * increment button, what should it read? If the underlying
 297  * implementation uses <code>set()</code>, it might read March 3, 1999. A
 298  * better result would be February 28, 1999. Furthermore, if the user
 299  * presses the month increment button again, it should read March 31,
 300  * 1999, not March 28, 1999. By saving the original date and using either
 301  * <code>add()</code> or <code>roll()</code>, depending on whether larger
 302  * fields should be affected, the user interface can behave as most users
 303  * will intuitively expect.</p>
 304  *
 305  * @see          java.lang.System#currentTimeMillis()
 306  * @see          Date
 307  * @see          GregorianCalendar
 308  * @see          TimeZone
 309  * @see          java.text.DateFormat
 310  * @author Mark Davis, David Goldsmith, Chen-Lieh Huang, Alan Liu
 311  * @since JDK1.1
 312  */
 313 public abstract class Calendar implements Serializable, Cloneable, Comparable<Calendar> {
 314 
 315     // Data flow in Calendar
 316     // ---------------------
 317 
 318     // The current time is represented in two ways by Calendar: as UTC
 319     // milliseconds from the epoch (1 January 1970 0:00 UTC), and as local
 320     // fields such as MONTH, HOUR, AM_PM, etc.  It is possible to compute the
 321     // millis from the fields, and vice versa.  The data needed to do this
 322     // conversion is encapsulated by a TimeZone object owned by the Calendar.
 323     // The data provided by the TimeZone object may also be overridden if the
 324     // user sets the ZONE_OFFSET and/or DST_OFFSET fields directly. The class
 325     // keeps track of what information was most recently set by the caller, and
 326     // uses that to compute any other information as needed.
 327 
 328     // If the user sets the fields using set(), the data flow is as follows.
 329     // This is implemented by the Calendar subclass's computeTime() method.
 330     // During this process, certain fields may be ignored.  The disambiguation
 331     // algorithm for resolving which fields to pay attention to is described
 332     // in the class documentation.
 333 
 334     //   local fields (YEAR, MONTH, DATE, HOUR, MINUTE, etc.)
 335     //           |
 336     //           | Using Calendar-specific algorithm
 337     //           V
 338     //   local standard millis
 339     //           |
 340     //           | Using TimeZone or user-set ZONE_OFFSET / DST_OFFSET
 341     //           V
 342     //   UTC millis (in time data member)
 343 
 344     // If the user sets the UTC millis using setTime() or setTimeInMillis(),
 345     // the data flow is as follows.  This is implemented by the Calendar
 346     // subclass's computeFields() method.
 347 
 348     //   UTC millis (in time data member)
 349     //           |
 350     //           | Using TimeZone getOffset()
 351     //           V
 352     //   local standard millis
 353     //           |
 354     //           | Using Calendar-specific algorithm
 355     //           V
 356     //   local fields (YEAR, MONTH, DATE, HOUR, MINUTE, etc.)
 357 
 358     // In general, a round trip from fields, through local and UTC millis, and
 359     // back out to fields is made when necessary.  This is implemented by the
 360     // complete() method.  Resolving a partial set of fields into a UTC millis
 361     // value allows all remaining fields to be generated from that value.  If
 362     // the Calendar is lenient, the fields are also renormalized to standard
 363     // ranges when they are regenerated.
 364 
 365     /**
 366      * Field number for <code>get</code> and <code>set</code> indicating the
 367      * era, e.g., AD or BC in the Julian calendar. This is a calendar-specific
 368      * value; see subclass documentation.
 369      *
 370      * @see GregorianCalendar#AD
 371      * @see GregorianCalendar#BC
 372      */
 373     public final static int ERA = 0;
 374 
 375     /**
 376      * Field number for <code>get</code> and <code>set</code> indicating the
 377      * year. This is a calendar-specific value; see subclass documentation.
 378      */
 379     public final static int YEAR = 1;
 380 
 381     /**
 382      * Field number for <code>get</code> and <code>set</code> indicating the
 383      * month. This is a calendar-specific value. The first month of
 384      * the year in the Gregorian and Julian calendars is
 385      * <code>JANUARY</code> which is 0; the last depends on the number
 386      * of months in a year.
 387      *
 388      * @see #JANUARY
 389      * @see #FEBRUARY
 390      * @see #MARCH
 391      * @see #APRIL
 392      * @see #MAY
 393      * @see #JUNE
 394      * @see #JULY
 395      * @see #AUGUST
 396      * @see #SEPTEMBER
 397      * @see #OCTOBER
 398      * @see #NOVEMBER
 399      * @see #DECEMBER
 400      * @see #UNDECIMBER
 401      */
 402     public final static int MONTH = 2;
 403 
 404     /**
 405      * Field number for <code>get</code> and <code>set</code> indicating the
 406      * week number within the current year.  The first week of the year, as
 407      * defined by <code>getFirstDayOfWeek()</code> and
 408      * <code>getMinimalDaysInFirstWeek()</code>, has value 1.  Subclasses define
 409      * the value of <code>WEEK_OF_YEAR</code> for days before the first week of
 410      * the year.
 411      *
 412      * @see #getFirstDayOfWeek
 413      * @see #getMinimalDaysInFirstWeek
 414      */
 415     public final static int WEEK_OF_YEAR = 3;
 416 
 417     /**
 418      * Field number for <code>get</code> and <code>set</code> indicating the
 419      * week number within the current month.  The first week of the month, as
 420      * defined by <code>getFirstDayOfWeek()</code> and
 421      * <code>getMinimalDaysInFirstWeek()</code>, has value 1.  Subclasses define
 422      * the value of <code>WEEK_OF_MONTH</code> for days before the first week of
 423      * the month.
 424      *
 425      * @see #getFirstDayOfWeek
 426      * @see #getMinimalDaysInFirstWeek
 427      */
 428     public final static int WEEK_OF_MONTH = 4;
 429 
 430     /**
 431      * Field number for <code>get</code> and <code>set</code> indicating the
 432      * day of the month. This is a synonym for <code>DAY_OF_MONTH</code>.
 433      * The first day of the month has value 1.
 434      *
 435      * @see #DAY_OF_MONTH
 436      */
 437     public final static int DATE = 5;
 438 
 439     /**
 440      * Field number for <code>get</code> and <code>set</code> indicating the
 441      * day of the month. This is a synonym for <code>DATE</code>.
 442      * The first day of the month has value 1.
 443      *
 444      * @see #DATE
 445      */
 446     public final static int DAY_OF_MONTH = 5;
 447 
 448     /**
 449      * Field number for <code>get</code> and <code>set</code> indicating the day
 450      * number within the current year.  The first day of the year has value 1.
 451      */
 452     public final static int DAY_OF_YEAR = 6;
 453 
 454     /**
 455      * Field number for <code>get</code> and <code>set</code> indicating the day
 456      * of the week.  This field takes values <code>SUNDAY</code>,
 457      * <code>MONDAY</code>, <code>TUESDAY</code>, <code>WEDNESDAY</code>,
 458      * <code>THURSDAY</code>, <code>FRIDAY</code>, and <code>SATURDAY</code>.
 459      *
 460      * @see #SUNDAY
 461      * @see #MONDAY
 462      * @see #TUESDAY
 463      * @see #WEDNESDAY
 464      * @see #THURSDAY
 465      * @see #FRIDAY
 466      * @see #SATURDAY
 467      */
 468     public final static int DAY_OF_WEEK = 7;
 469 
 470     /**
 471      * Field number for <code>get</code> and <code>set</code> indicating the
 472      * ordinal number of the day of the week within the current month. Together
 473      * with the <code>DAY_OF_WEEK</code> field, this uniquely specifies a day
 474      * within a month.  Unlike <code>WEEK_OF_MONTH</code> and
 475      * <code>WEEK_OF_YEAR</code>, this field's value does <em>not</em> depend on
 476      * <code>getFirstDayOfWeek()</code> or
 477      * <code>getMinimalDaysInFirstWeek()</code>.  <code>DAY_OF_MONTH 1</code>
 478      * through <code>7</code> always correspond to <code>DAY_OF_WEEK_IN_MONTH
 479      * 1</code>; <code>8</code> through <code>14</code> correspond to
 480      * <code>DAY_OF_WEEK_IN_MONTH 2</code>, and so on.
 481      * <code>DAY_OF_WEEK_IN_MONTH 0</code> indicates the week before
 482      * <code>DAY_OF_WEEK_IN_MONTH 1</code>.  Negative values count back from the
 483      * end of the month, so the last Sunday of a month is specified as
 484      * <code>DAY_OF_WEEK = SUNDAY, DAY_OF_WEEK_IN_MONTH = -1</code>.  Because
 485      * negative values count backward they will usually be aligned differently
 486      * within the month than positive values.  For example, if a month has 31
 487      * days, <code>DAY_OF_WEEK_IN_MONTH -1</code> will overlap
 488      * <code>DAY_OF_WEEK_IN_MONTH 5</code> and the end of <code>4</code>.
 489      *
 490      * @see #DAY_OF_WEEK
 491      * @see #WEEK_OF_MONTH
 492      */
 493     public final static int DAY_OF_WEEK_IN_MONTH = 8;
 494 
 495     /**
 496      * Field number for <code>get</code> and <code>set</code> indicating
 497      * whether the <code>HOUR</code> is before or after noon.
 498      * E.g., at 10:04:15.250 PM the <code>AM_PM</code> is <code>PM</code>.
 499      *
 500      * @see #AM
 501      * @see #PM
 502      * @see #HOUR
 503      */
 504     public final static int AM_PM = 9;
 505 
 506     /**
 507      * Field number for <code>get</code> and <code>set</code> indicating the
 508      * hour of the morning or afternoon. <code>HOUR</code> is used for the
 509      * 12-hour clock (0 - 11). Noon and midnight are represented by 0, not by 12.
 510      * E.g., at 10:04:15.250 PM the <code>HOUR</code> is 10.
 511      *
 512      * @see #AM_PM
 513      * @see #HOUR_OF_DAY
 514      */
 515     public final static int HOUR = 10;
 516 
 517     /**
 518      * Field number for <code>get</code> and <code>set</code> indicating the
 519      * hour of the day. <code>HOUR_OF_DAY</code> is used for the 24-hour clock.
 520      * E.g., at 10:04:15.250 PM the <code>HOUR_OF_DAY</code> is 22.
 521      *
 522      * @see #HOUR
 523      */
 524     public final static int HOUR_OF_DAY = 11;
 525 
 526     /**
 527      * Field number for <code>get</code> and <code>set</code> indicating the
 528      * minute within the hour.
 529      * E.g., at 10:04:15.250 PM the <code>MINUTE</code> is 4.
 530      */
 531     public final static int MINUTE = 12;
 532 
 533     /**
 534      * Field number for <code>get</code> and <code>set</code> indicating the
 535      * second within the minute.
 536      * E.g., at 10:04:15.250 PM the <code>SECOND</code> is 15.
 537      */
 538     public final static int SECOND = 13;
 539 
 540     /**
 541      * Field number for <code>get</code> and <code>set</code> indicating the
 542      * millisecond within the second.
 543      * E.g., at 10:04:15.250 PM the <code>MILLISECOND</code> is 250.
 544      */
 545     public final static int MILLISECOND = 14;
 546 
 547     /**
 548      * Field number for <code>get</code> and <code>set</code>
 549      * indicating the raw offset from GMT in milliseconds.
 550      * <p>
 551      * This field reflects the correct GMT offset value of the time
 552      * zone of this <code>Calendar</code> if the
 553      * <code>TimeZone</code> implementation subclass supports
 554      * historical GMT offset changes.
 555      */
 556     public final static int ZONE_OFFSET = 15;
 557 
 558     /**
 559      * Field number for <code>get</code> and <code>set</code> indicating the
 560      * daylight saving offset in milliseconds.
 561      * <p>
 562      * This field reflects the correct daylight saving offset value of
 563      * the time zone of this <code>Calendar</code> if the
 564      * <code>TimeZone</code> implementation subclass supports
 565      * historical Daylight Saving Time schedule changes.
 566      */
 567     public final static int DST_OFFSET = 16;
 568 
 569     /**
 570      * The number of distinct fields recognized by <code>get</code> and <code>set</code>.
 571      * Field numbers range from <code>0..FIELD_COUNT-1</code>.
 572      */
 573     public final static int FIELD_COUNT = 17;
 574 
 575     /**
 576      * Value of the {@link #DAY_OF_WEEK} field indicating
 577      * Sunday.
 578      */
 579     public final static int SUNDAY = 1;
 580 
 581     /**
 582      * Value of the {@link #DAY_OF_WEEK} field indicating
 583      * Monday.
 584      */
 585     public final static int MONDAY = 2;
 586 
 587     /**
 588      * Value of the {@link #DAY_OF_WEEK} field indicating
 589      * Tuesday.
 590      */
 591     public final static int TUESDAY = 3;
 592 
 593     /**
 594      * Value of the {@link #DAY_OF_WEEK} field indicating
 595      * Wednesday.
 596      */
 597     public final static int WEDNESDAY = 4;
 598 
 599     /**
 600      * Value of the {@link #DAY_OF_WEEK} field indicating
 601      * Thursday.
 602      */
 603     public final static int THURSDAY = 5;
 604 
 605     /**
 606      * Value of the {@link #DAY_OF_WEEK} field indicating
 607      * Friday.
 608      */
 609     public final static int FRIDAY = 6;
 610 
 611     /**
 612      * Value of the {@link #DAY_OF_WEEK} field indicating
 613      * Saturday.
 614      */
 615     public final static int SATURDAY = 7;
 616 
 617     /**
 618      * Value of the {@link #MONTH} field indicating the
 619      * first month of the year in the Gregorian and Julian calendars.
 620      */
 621     public final static int JANUARY = 0;
 622 
 623     /**
 624      * Value of the {@link #MONTH} field indicating the
 625      * second month of the year in the Gregorian and Julian calendars.
 626      */
 627     public final static int FEBRUARY = 1;
 628 
 629     /**
 630      * Value of the {@link #MONTH} field indicating the
 631      * third month of the year in the Gregorian and Julian calendars.
 632      */
 633     public final static int MARCH = 2;
 634 
 635     /**
 636      * Value of the {@link #MONTH} field indicating the
 637      * fourth month of the year in the Gregorian and Julian calendars.
 638      */
 639     public final static int APRIL = 3;
 640 
 641     /**
 642      * Value of the {@link #MONTH} field indicating the
 643      * fifth month of the year in the Gregorian and Julian calendars.
 644      */
 645     public final static int MAY = 4;
 646 
 647     /**
 648      * Value of the {@link #MONTH} field indicating the
 649      * sixth month of the year in the Gregorian and Julian calendars.
 650      */
 651     public final static int JUNE = 5;
 652 
 653     /**
 654      * Value of the {@link #MONTH} field indicating the
 655      * seventh month of the year in the Gregorian and Julian calendars.
 656      */
 657     public final static int JULY = 6;
 658 
 659     /**
 660      * Value of the {@link #MONTH} field indicating the
 661      * eighth month of the year in the Gregorian and Julian calendars.
 662      */
 663     public final static int AUGUST = 7;
 664 
 665     /**
 666      * Value of the {@link #MONTH} field indicating the
 667      * ninth month of the year in the Gregorian and Julian calendars.
 668      */
 669     public final static int SEPTEMBER = 8;
 670 
 671     /**
 672      * Value of the {@link #MONTH} field indicating the
 673      * tenth month of the year in the Gregorian and Julian calendars.
 674      */
 675     public final static int OCTOBER = 9;
 676 
 677     /**
 678      * Value of the {@link #MONTH} field indicating the
 679      * eleventh month of the year in the Gregorian and Julian calendars.
 680      */
 681     public final static int NOVEMBER = 10;
 682 
 683     /**
 684      * Value of the {@link #MONTH} field indicating the
 685      * twelfth month of the year in the Gregorian and Julian calendars.
 686      */
 687     public final static int DECEMBER = 11;
 688 
 689     /**
 690      * Value of the {@link #MONTH} field indicating the
 691      * thirteenth month of the year. Although <code>GregorianCalendar</code>
 692      * does not use this value, lunar calendars do.
 693      */
 694     public final static int UNDECIMBER = 12;
 695 
 696     /**
 697      * Value of the {@link #AM_PM} field indicating the
 698      * period of the day from midnight to just before noon.
 699      */
 700     public final static int AM = 0;
 701 
 702     /**
 703      * Value of the {@link #AM_PM} field indicating the
 704      * period of the day from noon to just before midnight.
 705      */
 706     public final static int PM = 1;
 707 
 708     /**
 709      * A style specifier for {@link #getDisplayNames(int, int, Locale)
 710      * getDisplayNames} indicating names in all styles, such as
 711      * "January" and "Jan".
 712      *
 713      * @see #SHORT_FORMAT
 714      * @see #LONG_FORMAT
 715      * @see #SHORT_STANDALONE
 716      * @see #LONG_STANDALONE
 717      * @see #SHORT
 718      * @see #LONG
 719      * @since 1.6
 720      */
 721     public static final int ALL_STYLES = 0;
 722 
 723     static final int STANDALONE_MASK = 0x8000;
 724 
 725     /**
 726      * A style specifier for {@link #getDisplayName(int, int, Locale)
 727      * getDisplayName} and {@link #getDisplayNames(int, int, Locale)
 728      * getDisplayNames} equivalent to {@link #SHORT_FORMAT}.
 729      *
 730      * @see #SHORT_STANDALONE
 731      * @see #LONG
 732      * @since 1.6
 733      */
 734     public static final int SHORT = 1;
 735 
 736     /**
 737      * A style specifier for {@link #getDisplayName(int, int, Locale)
 738      * getDisplayName} and {@link #getDisplayNames(int, int, Locale)
 739      * getDisplayNames} equivalent to {@link #LONG_FORMAT}.
 740      *
 741      * @see #LONG_STANDALONE
 742      * @see #SHORT
 743      * @since 1.6
 744      */
 745     public static final int LONG = 2;
 746 
 747     /**
 748      * A style specifier for {@link #getDisplayName(int, int, Locale)
 749      * getDisplayName} and {@link #getDisplayNames(int, int, Locale)
 750      * getDisplayNames} indicating a narrow name used for format. Narrow names
 751      * are typically single character strings, such as "M" for Monday.
 752      *
 753      * @see #NARROW_STANDALONE
 754      * @see #SHORT_FORMAT
 755      * @see #LONG_FORMAT
 756      * @since 1.8
 757      */
 758     public static final int NARROW_FORMAT = 4;
 759 
 760     /**
 761      * A style specifier for {@link #getDisplayName(int, int, Locale)
 762      * getDisplayName} and {@link #getDisplayNames(int, int, Locale)
 763      * getDisplayNames} indicating a narrow name independently. Narrow names
 764      * are typically single character strings, such as "M" for Monday.
 765      *
 766      * @see #NARROW_FORMAT
 767      * @see #SHORT_STANDALONE
 768      * @see #LONG_STANDALONE
 769      * @since 1.8
 770      */
 771     public static final int NARROW_STANDALONE = NARROW_FORMAT | STANDALONE_MASK;
 772 
 773     /**
 774      * A style specifier for {@link #getDisplayName(int, int, Locale)
 775      * getDisplayName} and {@link #getDisplayNames(int, int, Locale)
 776      * getDisplayNames} indicating a short name used for format.
 777      *
 778      * @see #SHORT_STANDALONE
 779      * @see #LONG_FORMAT
 780      * @see #LONG_STANDALONE
 781      * @since 1.8
 782      */
 783     public static final int SHORT_FORMAT = 1;
 784 
 785     /**
 786      * A style specifier for {@link #getDisplayName(int, int, Locale)
 787      * getDisplayName} and {@link #getDisplayNames(int, int, Locale)
 788      * getDisplayNames} indicating a long name used for format.
 789      *
 790      * @see #LONG_STANDALONE
 791      * @see #SHORT_FORMAT
 792      * @see #SHORT_STANDALONE
 793      * @since 1.8
 794      */
 795     public static final int LONG_FORMAT = 2;
 796 
 797     /**
 798      * A style specifier for {@link #getDisplayName(int, int, Locale)
 799      * getDisplayName} and {@link #getDisplayNames(int, int, Locale)
 800      * getDisplayNames} indicating a short name used independently,
 801      * such as a month abbreviation as calendar headers.
 802      *
 803      * @see #SHORT_FORMAT
 804      * @see #LONG_FORMAT
 805      * @see #LONG_STANDALONE
 806      * @since 1.8
 807      */
 808     public static final int SHORT_STANDALONE = SHORT | STANDALONE_MASK;
 809 
 810     /**
 811      * A style specifier for {@link #getDisplayName(int, int, Locale)
 812      * getDisplayName} and {@link #getDisplayNames(int, int, Locale)
 813      * getDisplayNames} indicating a long name used independently,
 814      * such as a month name as calendar headers.
 815      *
 816      * @see #LONG_FORMAT
 817      * @see #SHORT_FORMAT
 818      * @see #SHORT_STANDALONE
 819      * @since 1.8
 820      */
 821     public static final int LONG_STANDALONE = LONG | STANDALONE_MASK;
 822 
 823     // Internal notes:
 824     // Calendar contains two kinds of time representations: current "time" in
 825     // milliseconds, and a set of calendar "fields" representing the current time.
 826     // The two representations are usually in sync, but can get out of sync
 827     // as follows.
 828     // 1. Initially, no fields are set, and the time is invalid.
 829     // 2. If the time is set, all fields are computed and in sync.
 830     // 3. If a single field is set, the time is invalid.
 831     // Recomputation of the time and fields happens when the object needs
 832     // to return a result to the user, or use a result for a computation.
 833 
 834     /**
 835      * The calendar field values for the currently set time for this calendar.
 836      * This is an array of <code>FIELD_COUNT</code> integers, with index values
 837      * <code>ERA</code> through <code>DST_OFFSET</code>.
 838      * @serial
 839      */
 840     @SuppressWarnings("ProtectedField")
 841     protected int           fields[];
 842 
 843     /**
 844      * The flags which tell if a specified calendar field for the calendar is set.
 845      * A new object has no fields set.  After the first call to a method
 846      * which generates the fields, they all remain set after that.
 847      * This is an array of <code>FIELD_COUNT</code> booleans, with index values
 848      * <code>ERA</code> through <code>DST_OFFSET</code>.
 849      * @serial
 850      */
 851     @SuppressWarnings("ProtectedField")
 852     protected boolean       isSet[];
 853 
 854     /**
 855      * Pseudo-time-stamps which specify when each field was set. There
 856      * are two special values, UNSET and COMPUTED. Values from
 857      * MINIMUM_USER_SET to Integer.MAX_VALUE are legal user set values.
 858      */
 859     transient private int   stamp[];
 860 
 861     /**
 862      * The currently set time for this calendar, expressed in milliseconds after
 863      * January 1, 1970, 0:00:00 GMT.
 864      * @see #isTimeSet
 865      * @serial
 866      */
 867     @SuppressWarnings("ProtectedField")
 868     protected long          time;
 869 
 870     /**
 871      * True if then the value of <code>time</code> is valid.
 872      * The time is made invalid by a change to an item of <code>field[]</code>.
 873      * @see #time
 874      * @serial
 875      */
 876     @SuppressWarnings("ProtectedField")
 877     protected boolean       isTimeSet;
 878 
 879     /**
 880      * True if <code>fields[]</code> are in sync with the currently set time.
 881      * If false, then the next attempt to get the value of a field will
 882      * force a recomputation of all fields from the current value of
 883      * <code>time</code>.
 884      * @serial
 885      */
 886     @SuppressWarnings("ProtectedField")
 887     protected boolean       areFieldsSet;
 888 
 889     /**
 890      * True if all fields have been set.
 891      * @serial
 892      */
 893     transient boolean       areAllFieldsSet;
 894 
 895     /**
 896      * <code>True</code> if this calendar allows out-of-range field values during computation
 897      * of <code>time</code> from <code>fields[]</code>.
 898      * @see #setLenient
 899      * @see #isLenient
 900      * @serial
 901      */
 902     private boolean         lenient = true;
 903 
 904     /**
 905      * The <code>TimeZone</code> used by this calendar. <code>Calendar</code>
 906      * uses the time zone data to translate between locale and GMT time.
 907      * @serial
 908      */
 909     private TimeZone        zone;
 910 
 911     /**
 912      * <code>True</code> if zone references to a shared TimeZone object.
 913      */
 914     transient private boolean sharedZone = false;
 915 
 916     /**
 917      * The first day of the week, with possible values <code>SUNDAY</code>,
 918      * <code>MONDAY</code>, etc.  This is a locale-dependent value.
 919      * @serial
 920      */
 921     private int             firstDayOfWeek;
 922 
 923     /**
 924      * The number of days required for the first week in a month or year,
 925      * with possible values from 1 to 7.  This is a locale-dependent value.
 926      * @serial
 927      */
 928     private int             minimalDaysInFirstWeek;
 929 
 930     /**
 931      * Cache to hold the firstDayOfWeek and minimalDaysInFirstWeek
 932      * of a Locale.
 933      */
 934     private static final ConcurrentMap<Locale, int[]> cachedLocaleData
 935         = new ConcurrentHashMap<>(3);
 936 
 937     // Special values of stamp[]
 938     /**
 939      * The corresponding fields[] has no value.
 940      */
 941     private static final int        UNSET = 0;
 942 
 943     /**
 944      * The value of the corresponding fields[] has been calculated internally.
 945      */
 946     private static final int        COMPUTED = 1;
 947 
 948     /**
 949      * The value of the corresponding fields[] has been set externally. Stamp
 950      * values which are greater than 1 represents the (pseudo) time when the
 951      * corresponding fields[] value was set.
 952      */
 953     private static final int        MINIMUM_USER_STAMP = 2;
 954 
 955     /**
 956      * The mask value that represents all of the fields.
 957      */
 958     static final int ALL_FIELDS = (1 << FIELD_COUNT) - 1;
 959 
 960     /**
 961      * The next available value for <code>stamp[]</code>, an internal array.
 962      * This actually should not be written out to the stream, and will probably
 963      * be removed from the stream in the near future.  In the meantime,
 964      * a value of <code>MINIMUM_USER_STAMP</code> should be used.
 965      * @serial
 966      */
 967     private int             nextStamp = MINIMUM_USER_STAMP;
 968 
 969     // the internal serial version which says which version was written
 970     // - 0 (default) for version up to JDK 1.1.5
 971     // - 1 for version from JDK 1.1.6, which writes a correct 'time' value
 972     //     as well as compatible values for other fields.  This is a
 973     //     transitional format.
 974     // - 2 (not implemented yet) a future version, in which fields[],
 975     //     areFieldsSet, and isTimeSet become transient, and isSet[] is
 976     //     removed. In JDK 1.1.6 we write a format compatible with version 2.
 977     static final int        currentSerialVersion = 1;
 978 
 979     /**
 980      * The version of the serialized data on the stream.  Possible values:
 981      * <dl>
 982      * <dt><b>0</b> or not present on stream</dt>
 983      * <dd>
 984      * JDK 1.1.5 or earlier.
 985      * </dd>
 986      * <dt><b>1</b></dt>
 987      * <dd>
 988      * JDK 1.1.6 or later.  Writes a correct 'time' value
 989      * as well as compatible values for other fields.  This is a
 990      * transitional format.
 991      * </dd>
 992      * </dl>
 993      * When streaming out this class, the most recent format
 994      * and the highest allowable <code>serialVersionOnStream</code>
 995      * is written.
 996      * @serial
 997      * @since JDK1.1.6
 998      */
 999     private int             serialVersionOnStream = currentSerialVersion;
1000 
1001     // Proclaim serialization compatibility with JDK 1.1
1002     static final long       serialVersionUID = -1807547505821590642L;
1003 
1004     // Mask values for calendar fields
1005     @SuppressWarnings("PointlessBitwiseExpression")
1006     final static int ERA_MASK           = (1 << ERA);
1007     final static int YEAR_MASK          = (1 << YEAR);
1008     final static int MONTH_MASK         = (1 << MONTH);
1009     final static int WEEK_OF_YEAR_MASK  = (1 << WEEK_OF_YEAR);
1010     final static int WEEK_OF_MONTH_MASK = (1 << WEEK_OF_MONTH);
1011     final static int DAY_OF_MONTH_MASK  = (1 << DAY_OF_MONTH);
1012     final static int DATE_MASK          = DAY_OF_MONTH_MASK;
1013     final static int DAY_OF_YEAR_MASK   = (1 << DAY_OF_YEAR);
1014     final static int DAY_OF_WEEK_MASK   = (1 << DAY_OF_WEEK);
1015     final static int DAY_OF_WEEK_IN_MONTH_MASK  = (1 << DAY_OF_WEEK_IN_MONTH);
1016     final static int AM_PM_MASK         = (1 << AM_PM);
1017     final static int HOUR_MASK          = (1 << HOUR);
1018     final static int HOUR_OF_DAY_MASK   = (1 << HOUR_OF_DAY);
1019     final static int MINUTE_MASK        = (1 << MINUTE);
1020     final static int SECOND_MASK        = (1 << SECOND);
1021     final static int MILLISECOND_MASK   = (1 << MILLISECOND);
1022     final static int ZONE_OFFSET_MASK   = (1 << ZONE_OFFSET);
1023     final static int DST_OFFSET_MASK    = (1 << DST_OFFSET);
1024 
1025     /**
1026      * {@code Calendar.Builder} is used for creating a {@code Calendar} from
1027      * various date-time parameters.
1028      *
1029      * <p>There are two ways to set a {@code Calendar} to a date-time value. One
1030      * is to set the instant parameter to a millisecond offset from the <a
1031      * href="Calendar.html#Epoch">Epoch</a>. The other is to set individual
1032      * field parameters, such as {@link Calendar#YEAR YEAR}, to their desired
1033      * values. These two ways can't be mixed. Trying to set both the instant and
1034      * individual fields will cause an {@link IllegalStateException} to be
1035      * thrown. However, it is permitted to override previous values of the
1036      * instant or field parameters.
1037      *
1038      * <p>If no enough field parameters are given for determining date and/or
1039      * time, calendar specific default values are used when building a
1040      * {@code Calendar}. For example, if the {@link Calendar#YEAR YEAR} value
1041      * isn't given for the Gregorian calendar, 1970 will be used. If there are
1042      * any conflicts among field parameters, the <a
1043      * href="Calendar.html#resolution"> resolution rules</a> are applied.
1044      * Therefore, the order of field setting matters.
1045      *
1046      * <p>In addition to the date-time parameters,
1047      * the {@linkplain #setLocale(Locale) locale},
1048      * {@linkplain #setTimeZone(TimeZone) time zone},
1049      * {@linkplain #setWeekDefinition(int, int) week definition}, and
1050      * {@linkplain #setLenient(boolean) leniency mode} parameters can be set.
1051      *
1052      * <p><b>Examples</b>
1053      * <p>The following are sample usages. Sample code assumes that the
1054      * {@code Calendar} constants are statically imported.
1055      *
1056      * <p>The following code produces a {@code Calendar} with date 2012-12-31
1057      * (Gregorian) because Monday is the first day of a week with the <a
1058      * href="GregorianCalendar.html#iso8601_compatible_setting"> ISO 8601
1059      * compatible week parameters</a>.
1060      * <pre>
1061      *   Calendar cal = new Calendar.Builder().setCalendarType("iso8601")
1062      *                        .setWeekDate(2013, 1, MONDAY).build();</pre>
1063      * <p>The following code produces a Japanese {@code Calendar} with date
1064      * 1989-01-08 (Gregorian), assuming that the default {@link Calendar#ERA ERA}
1065      * is <em>Heisei</em> that started on that day.
1066      * <pre>
1067      *   Calendar cal = new Calendar.Builder().setCalendarType("japanese")
1068      *                        .setFields(YEAR, 1, DAY_OF_YEAR, 1).build();</pre>
1069      *
1070      * @since 1.8
1071      * @see Calendar#getInstance(TimeZone, Locale)
1072      * @see Calendar#fields
1073      */
1074     public static class Builder {
1075         private static final int NFIELDS = FIELD_COUNT + 1; // +1 for WEEK_YEAR
1076         private static final int WEEK_YEAR = FIELD_COUNT;
1077 
1078         private long instant;
1079         // Calendar.stamp[] (lower half) and Calendar.fields[] (upper half) combined
1080         private int[] fields;
1081         // Pseudo timestamp starting from MINIMUM_USER_STAMP.
1082         // (COMPUTED is used to indicate that the instant has been set.)
1083         private int nextStamp;
1084         // maxFieldIndex keeps the max index of fields which have been set.
1085         // (WEEK_YEAR is never included.)
1086         private int maxFieldIndex;
1087         private String type;
1088         private TimeZone zone;
1089         private boolean lenient = true;
1090         private Locale locale;
1091         private int firstDayOfWeek, minimalDaysInFirstWeek;
1092 
1093         /**
1094          * Constructs a {@code Calendar.Builder}.
1095          */
1096         public Builder() {
1097         }
1098 
1099         /**
1100          * Sets the instant parameter to the given {@code instant} value that is
1101          * a millisecond offset from <a href="Calendar.html#Epoch">the
1102          * Epoch</a>.
1103          *
1104          * @param instant a millisecond offset from the Epoch
1105          * @return this {@code Calendar.Builder}
1106          * @throws IllegalStateException if any of the field parameters have
1107          *                               already been set
1108          * @see Calendar#setTime(Date)
1109          * @see Calendar#setTimeInMillis(long)
1110          * @see Calendar#time
1111          */
1112         public Builder setInstant(long instant) {
1113             if (fields != null) {
1114                 throw new IllegalStateException();
1115             }
1116             this.instant = instant;
1117             nextStamp = COMPUTED;
1118             return this;
1119         }
1120 
1121         /**
1122          * Sets the instant parameter to the {@code instant} value given by a
1123          * {@link Date}. This method is equivalent to a call to
1124          * {@link #setInstant(long) setInstant(instant.getTime())}.
1125          *
1126          * @param instant a {@code Date} representing a millisecond offset from
1127          *                the Epoch
1128          * @return this {@code Calendar.Builder}
1129          * @throws NullPointerException  if {@code instant} is {@code null}
1130          * @throws IllegalStateException if any of the field parameters have
1131          *                               already been set
1132          * @see Calendar#setTime(Date)
1133          * @see Calendar#setTimeInMillis(long)
1134          * @see Calendar#time
1135          */
1136         public Builder setInstant(Date instant) {
1137             return setInstant(instant.getTime()); // NPE if instant == null
1138         }
1139 
1140         /**
1141          * Sets the {@code field} parameter to the given {@code value}.
1142          * {@code field} is an index to the {@link Calendar#fields}, such as
1143          * {@link Calendar#DAY_OF_MONTH DAY_OF_MONTH}. Field value validation is
1144          * not performed in this method. Any out of range values are either
1145          * normalized in lenient mode or detected as an invalid value in
1146          * non-lenient mode when building a {@code Calendar}.
1147          *
1148          * @param field an index to the {@code Calendar} fields
1149          * @param value the field value
1150          * @return this {@code Calendar.Builder}
1151          * @throws IllegalArgumentException if {@code field} is invalid
1152          * @throws IllegalStateException if the instant value has already been set,
1153          *                      or if fields have been set too many
1154          *                      (approximately {@link Integer#MAX_VALUE}) times.
1155          * @see Calendar#set(int, int)
1156          */
1157         public Builder set(int field, int value) {
1158             // Note: WEEK_YEAR can't be set with this method.
1159             if (field < 0 || field >= FIELD_COUNT) {
1160                 throw new IllegalArgumentException("field is invalid");
1161             }
1162             if (isInstantSet()) {
1163                 throw new IllegalStateException("instant has been set");
1164             }
1165             allocateFields();
1166             internalSet(field, value);
1167             return this;
1168         }
1169 
1170         /**
1171          * Sets field parameters to their values given by
1172          * {@code fieldValuePairs} that are pairs of a field and its value.
1173          * For example,
1174          * <pre>
1175          *   setFeilds(Calendar.YEAR, 2013,
1176          *             Calendar.MONTH, Calendar.DECEMBER,
1177          *             Calendar.DAY_OF_MONTH, 23);</pre>
1178          * is equivalent to the sequence of the following
1179          * {@link #set(int, int) set} calls:
1180          * <pre>
1181          *   set(Calendar.YEAR, 2013)
1182          *   .set(Calendar.MONTH, Calendar.DECEMBER)
1183          *   .set(Calendar.DAY_OF_MONTH, 23);</pre>
1184          *
1185          * @param fieldValuePairs field-value pairs
1186          * @return this {@code Calendar.Builder}
1187          * @throws NullPointerException if {@code fieldValuePairs} is {@code null}
1188          * @throws IllegalArgumentException if any of fields are invalid,
1189          *             or if {@code fieldValuePairs.length} is an odd number.
1190          * @throws IllegalStateException    if the instant value has been set,
1191          *             or if fields have been set too many (approximately
1192          *             {@link Integer#MAX_VALUE}) times.
1193          */
1194         public Builder setFields(int... fieldValuePairs) {
1195             int len = fieldValuePairs.length;
1196             if ((len % 2) != 0) {
1197                 throw new IllegalArgumentException();
1198             }
1199             if (isInstantSet()) {
1200                 throw new IllegalStateException("instant has been set");
1201             }
1202             if ((nextStamp + len / 2) < 0) {
1203                 throw new IllegalStateException("stamp counter overflow");
1204             }
1205             allocateFields();
1206             for (int i = 0; i < len; ) {
1207                 int field = fieldValuePairs[i++];
1208                 // Note: WEEK_YEAR can't be set with this method.
1209                 if (field < 0 || field >= FIELD_COUNT) {
1210                     throw new IllegalArgumentException("field is invalid");
1211                 }
1212                 internalSet(field, fieldValuePairs[i++]);
1213             }
1214             return this;
1215         }
1216 
1217         /**
1218          * Sets the date field parameters to the values given by {@code year},
1219          * {@code month}, and {@code dayOfMonth}. This method is equivalent to
1220          * a call to:
1221          * <pre>
1222          *   setFields(Calendar.YEAR, year,
1223          *             Calendar.MONTH, month,
1224          *             Calendar.DAY_OF_MONTH, dayOfMonth);</pre>
1225          *
1226          * @param year       the {@link Calendar#YEAR YEAR} value
1227          * @param month      the {@link Calendar#MONTH MONTH} value
1228          *                   (the month numbering is <em>0-based</em>).
1229          * @param dayOfMonth the {@link Calendar#DAY_OF_MONTH DAY_OF_MONTH} value
1230          * @return this {@code Calendar.Builder}
1231          */
1232         public Builder setDate(int year, int month, int dayOfMonth) {
1233             return setFields(YEAR, year, MONTH, month, DAY_OF_MONTH, dayOfMonth);
1234         }
1235 
1236         /**
1237          * Sets the time of day field parameters to the values given by
1238          * {@code hourOfDay}, {@code minute}, and {@code second}. This method is
1239          * equivalent to a call to:
1240          * <pre>
1241          *   setTimeOfDay(hourOfDay, minute, second, 0);</pre>
1242          *
1243          * @param hourOfDay the {@link Calendar#HOUR_OF_DAY HOUR_OF_DAY} value
1244          *                  (24-hour clock)
1245          * @param minute    the {@link Calendar#MINUTE MINUTE} value
1246          * @param second    the {@link Calendar#SECOND SECOND} value
1247          * @return this {@code Calendar.Builder}
1248          */
1249         public Builder setTimeOfDay(int hourOfDay, int minute, int second) {
1250             return setTimeOfDay(hourOfDay, minute, second, 0);
1251         }
1252 
1253         /**
1254          * Sets the time of day field parameters to the values given by
1255          * {@code hourOfDay}, {@code minute}, {@code second}, and
1256          * {@code millis}. This method is equivalent to a call to:
1257          * <pre>
1258          *   setFields(Calendar.HOUR_OF_DAY, hourOfDay,
1259          *             Calendar.MINUTE, minute,
1260          *             Calendar.SECOND, second,
1261          *             Calendar.MILLISECOND, millis);</pre>
1262          *
1263          * @param hourOfDay the {@link Calendar#HOUR_OF_DAY HOUR_OF_DAY} value
1264          *                  (24-hour clock)
1265          * @param minute    the {@link Calendar#MINUTE MINUTE} value
1266          * @param second    the {@link Calendar#SECOND SECOND} value
1267          * @param millis    the {@link Calendar#MILLISECOND MILLISECOND} value
1268          * @return this {@code Calendar.Builder}
1269          */
1270         public Builder setTimeOfDay(int hourOfDay, int minute, int second, int millis) {
1271             return setFields(HOUR_OF_DAY, hourOfDay, MINUTE, minute,
1272                              SECOND, second, MILLISECOND, millis);
1273         }
1274 
1275         /**
1276          * Sets the week-based date parameters to the values with the given
1277          * date specifiers - week year, week of year, and day of week.
1278          *
1279          * <p>If the specified calendar doesn't support week dates, the
1280          * {@link #build() build} method will throw an {@link IllegalArgumentException}.
1281          *
1282          * @param weekYear   the week year
1283          * @param weekOfYear the week number based on {@code weekYear}
1284          * @param dayOfWeek  the day of week value: one of the constants
1285          *     for the {@link Calendar#DAY_OF_WEEK DAY_OF_WEEK} field:
1286          *     {@link Calendar#SUNDAY SUNDAY}, ..., {@link Calendar#SATURDAY SATURDAY}.
1287          * @return this {@code Calendar.Builder}
1288          * @see Calendar#setWeekDate(int, int, int)
1289          * @see Calendar#isWeekDateSupported()
1290          */
1291         public Builder setWeekDate(int weekYear, int weekOfYear, int dayOfWeek) {
1292             allocateFields();
1293             internalSet(WEEK_YEAR, weekYear);
1294             internalSet(WEEK_OF_YEAR, weekOfYear);
1295             internalSet(DAY_OF_WEEK, dayOfWeek);
1296             return this;
1297         }
1298 
1299         /**
1300          * Sets the time zone parameter to the given {@code zone}. If no time
1301          * zone parameter is given to this {@code Caledar.Builder}, the
1302          * {@linkplain TimeZone#getDefault() default
1303          * <code>TimeZone</code>} will be used in the {@link #build() build}
1304          * method.
1305          *
1306          * @param zone the {@link TimeZone}
1307          * @return this {@code Calendar.Builder}
1308          * @throws NullPointerException if {@code zone} is {@code null}
1309          * @see Calendar#setTimeZone(TimeZone)
1310          */
1311         public Builder setTimeZone(TimeZone zone) {
1312             if (zone == null) {
1313                 throw new NullPointerException();
1314             }
1315             this.zone = zone;
1316             return this;
1317         }
1318 
1319         /**
1320          * Sets the lenient mode parameter to the value given by {@code lenient}.
1321          * If no lenient parameter is given to this {@code Calendar.Builder},
1322          * lenient mode will be used in the {@link #build() build} method.
1323          *
1324          * @param lenient {@code true} for lenient mode;
1325          *                {@code false} for non-lenient mode
1326          * @return this {@code Calendar.Builder}
1327          * @see Calendar#setLenient(boolean)
1328          */
1329         public Builder setLenient(boolean lenient) {
1330             this.lenient = lenient;
1331             return this;
1332         }
1333 
1334         /**
1335          * Sets the calendar type parameter to the given {@code type}. The
1336          * calendar type given by this method has precedence over any explicit
1337          * or implicit calendar type given by the
1338          * {@linkplain #setLocale(Locale) locale}.
1339          *
1340          * <p>In addition to the available calendar types returned by the
1341          * {@link Calendar#getAvailableCalendarTypes() Calendar.getAvailableCalendarTypes}
1342          * method, {@code "gregorian"} and {@code "iso8601"} as aliases of
1343          * {@code "gregory"} can be used with this method.
1344          *
1345          * @param type the calendar type
1346          * @return this {@code Calendar.Builder}
1347          * @throws NullPointerException if {@code type} is {@code null}
1348          * @throws IllegalArgumentException if {@code type} is unknown
1349          * @throws IllegalStateException if another calendar type has already been set
1350          * @see Calendar#getCalendarType()
1351          * @see Calendar#getAvailableCalendarTypes()
1352          */
1353         public Builder setCalendarType(String type) {
1354             if (type.equals("gregorian")) { // NPE if type == null
1355                 type = "gregory";
1356             }
1357             if (!Calendar.getAvailableCalendarTypes().contains(type)
1358                     && !type.equals("iso8601")) {
1359                 throw new IllegalArgumentException("unknown calendar type: " + type);
1360             }
1361             if (this.type == null) {
1362                 this.type = type;
1363             } else {
1364                 if (!this.type.equals(type)) {
1365                     throw new IllegalStateException("calendar type override");
1366                 }
1367             }
1368             return this;
1369         }
1370 
1371         /**
1372          * Sets the locale parameter to the given {@code locale}. If no locale
1373          * is given to this {@code Calendar.Builder}, the {@linkplain
1374          * Locale#getDefault(Locale.Category) default <code>Locale</code>}
1375          * for {@link Locale.Category#FORMAT} will be used.
1376          *
1377          * <p>If no calendar type is explicitly given by a call to the
1378          * {@link #setCalendarType(String) setCalendarType} method,
1379          * the {@code Locale} value is used to determine what type of
1380          * {@code Calendar} to be built.
1381          *
1382          * <p>If no week definition parameters are explicitly given by a call to
1383          * the {@link #setWeekDefinition(int,int) setWeekDefinition} method, the
1384          * {@code Locale}'s default values are used.
1385          *
1386          * @param locale the {@link Locale}
1387          * @throws NullPointerException if {@code locale} is {@code null}
1388          * @return this {@code Calendar.Builder}
1389          * @see Calendar#getInstance(Locale)
1390          */
1391         public Builder setLocale(Locale locale) {
1392             if (locale == null) {
1393                 throw new NullPointerException();
1394             }
1395             this.locale = locale;
1396             return this;
1397         }
1398 
1399         /**
1400          * Sets the week definition parameters to the values given by
1401          * {@code firstDayOfWeek} and {@code minimalDaysInFirstWeek} that are
1402          * used to determine the <a href="Calendar.html#First_Week">first
1403          * week</a> of a year. The parameters given by this method have
1404          * precedence over the default values given by the
1405          * {@linkplain #setLocale(Locale) locale}.
1406          *
1407          * @param firstDayOfWeek the first day of a week; one of
1408          *                       {@link Calendar#SUNDAY} to {@link Calendar#SATURDAY}
1409          * @param minimalDaysInFirstWeek the minimal number of days in the first
1410          *                               week (1..7)
1411          * @return this {@code Calendar.Builder}
1412          * @throws IllegalArgumentException if {@code firstDayOfWeek} or
1413          *                                  {@code minimalDaysInFirstWeek} is invalid
1414          * @see Calendar#getFirstDayOfWeek()
1415          * @see Calendar#getMinimalDaysInFirstWeek()
1416          */
1417         public Builder setWeekDefinition(int firstDayOfWeek, int minimalDaysInFirstWeek) {
1418             if (!isValidWeekParameter(firstDayOfWeek)
1419                     || !isValidWeekParameter(minimalDaysInFirstWeek)) {
1420                 throw new IllegalArgumentException();
1421             }
1422             this.firstDayOfWeek = firstDayOfWeek;
1423             this.minimalDaysInFirstWeek = minimalDaysInFirstWeek;
1424             return this;
1425         }
1426 
1427         /**
1428          * Returns a {@code Calendar} built from the parameters set by the
1429          * setter methods. The calendar type given by the {@link #setCalendarType(String)
1430          * setCalendarType} method or the {@linkplain #setLocale(Locale) locale} is
1431          * used to determine what {@code Calendar} to be created. If no explicit
1432          * calendar type is given, the locale's default calendar is created.
1433          *
1434          * <p>If the calendar type is {@code "iso8601"}, the
1435          * {@linkplain GregorianCalendar#setGregorianChange(Date) Gregorian change date}
1436          * of a {@link GregorianCalendar} is set to {@code Date(Long.MIN_VALUE)}
1437          * to be the <em>proleptic</em> Gregorian calendar. Its week definition
1438          * parameters are also set to be <a
1439          * href="GregorianCalendar.html#iso8601_compatible_setting">compatible
1440          * with the ISO 8601 standard</a>. Note that the
1441          * {@link GregorianCalendar#getCalendarType() getCalendarType} method of
1442          * a {@code GregorianCalendar} created with {@code "iso8601"} returns
1443          * {@code "gregory"}.
1444          *
1445          * <p>The default values are used for locale and time zone if these
1446          * parameters haven't been given explicitly.
1447          *
1448          * <p>Any out of range field values are either normalized in lenient
1449          * mode or detected as an invalid value in non-lenient mode.
1450          *
1451          * @return a {@code Calendar} built with parameters of this {@code
1452          *         Calendar.Builder}
1453          * @throws IllegalArgumentException if the calendar type is unknown, or
1454          *             if any invalid field values are given in non-lenient mode, or
1455          *             if a week date is given for the calendar type that doesn't
1456          *             support week dates.
1457          * @see Calendar#getInstance(TimeZone, Locale)
1458          * @see Locale#getDefault(Locale.Category)
1459          * @see TimeZone#getDefault()
1460          */
1461         public Calendar build() {
1462             if (locale == null) {
1463                 locale = Locale.getDefault();
1464             }
1465             if (zone == null) {
1466                 zone = TimeZone.getDefault();
1467             }
1468             Calendar cal;
1469             if (type == null) {
1470                 type = locale.getUnicodeLocaleType("ca");
1471             }
1472             if (type == null) {
1473                 if (locale.getCountry() == "TH"
1474                     && locale.getLanguage() == "th") {
1475                     type = "buddhist";
1476                 } else {
1477                     type = "gregory";
1478                 }
1479             }
1480             switch (type) {
1481             case "gregory":
1482                 cal = new GregorianCalendar(zone, locale, true);
1483                 break;
1484             case "iso8601":
1485                 GregorianCalendar gcal = new GregorianCalendar(zone, locale, true);
1486                 // make gcal a proleptic Gregorian
1487                 gcal.setGregorianChange(new Date(Long.MIN_VALUE));
1488                 // and week definition to be compatible with ISO 8601
1489                 setWeekDefinition(MONDAY, 4);
1490                 cal = gcal;
1491                 break;
1492             case "buddhist":
1493                 cal = new BuddhistCalendar(zone, locale);
1494                 cal.clear();
1495                 break;
1496             case "japanese":
1497                 cal = new JapaneseImperialCalendar(zone, locale, true);
1498                 break;
1499             default:
1500                 throw new IllegalArgumentException("unknown calendar type: " + type);
1501             }
1502             cal.setLenient(lenient);
1503             if (firstDayOfWeek != 0) {
1504                 cal.setFirstDayOfWeek(firstDayOfWeek);
1505                 cal.setMinimalDaysInFirstWeek(minimalDaysInFirstWeek);
1506             }
1507             if (isInstantSet()) {
1508                 cal.setTimeInMillis(instant);
1509                 cal.complete();
1510                 return cal;
1511             }
1512 
1513             if (fields != null) {
1514                 boolean weekDate = isSet(WEEK_YEAR)
1515                                        && fields[WEEK_YEAR] > fields[YEAR];
1516                 if (weekDate && !cal.isWeekDateSupported()) {
1517                     throw new IllegalArgumentException("week date is unsupported by " + type);
1518                 }
1519 
1520                 // Set the fields from the min stamp to the max stamp so that
1521                 // the fields resolution works in the Calendar.
1522                 for (int stamp = MINIMUM_USER_STAMP; stamp < nextStamp; stamp++) {
1523                     for (int index = 0; index <= maxFieldIndex; index++) {
1524                         if (fields[index] == stamp) {
1525                             cal.set(index, fields[NFIELDS + index]);
1526                             break;
1527                         }
1528                     }
1529                 }
1530 
1531                 if (weekDate) {
1532                     int weekOfYear = isSet(WEEK_OF_YEAR) ? fields[NFIELDS + WEEK_OF_YEAR] : 1;
1533                     int dayOfWeek = isSet(DAY_OF_WEEK)
1534                                     ? fields[NFIELDS + DAY_OF_WEEK] : cal.getFirstDayOfWeek();
1535                     cal.setWeekDate(fields[NFIELDS + WEEK_YEAR], weekOfYear, dayOfWeek);
1536                 }
1537                 cal.complete();
1538             }
1539 
1540             return cal;
1541         }
1542 
1543         private void allocateFields() {
1544             if (fields == null) {
1545                 fields = new int[NFIELDS * 2];
1546                 nextStamp = MINIMUM_USER_STAMP;
1547                 maxFieldIndex = -1;
1548             }
1549         }
1550 
1551         private void internalSet(int field, int value) {
1552             fields[field] = nextStamp++;
1553             if (nextStamp < 0) {
1554                 throw new IllegalStateException("stamp counter overflow");
1555             }
1556             fields[NFIELDS + field] = value;
1557             if (field > maxFieldIndex && field < WEEK_YEAR) {
1558                 maxFieldIndex = field;
1559             }
1560         }
1561 
1562         private boolean isInstantSet() {
1563             return nextStamp == COMPUTED;
1564         }
1565 
1566         private boolean isSet(int index) {
1567             return fields != null && fields[index] > UNSET;
1568         }
1569 
1570         private boolean isValidWeekParameter(int value) {
1571             return value > 0 && value <= 7;
1572         }
1573     }
1574 
1575     /**
1576      * Constructs a Calendar with the default time zone
1577      * and the default {@link java.util.Locale.Category#FORMAT FORMAT}
1578      * locale.
1579      * @see     TimeZone#getDefault
1580      */
1581     protected Calendar()
1582     {
1583         this(TimeZone.getDefaultRef(), Locale.getDefault(Locale.Category.FORMAT));
1584         sharedZone = true;
1585     }
1586 
1587     /**
1588      * Constructs a calendar with the specified time zone and locale.
1589      *
1590      * @param zone the time zone to use
1591      * @param aLocale the locale for the week data
1592      */
1593     protected Calendar(TimeZone zone, Locale aLocale)
1594     {
1595         fields = new int[FIELD_COUNT];
1596         isSet = new boolean[FIELD_COUNT];
1597         stamp = new int[FIELD_COUNT];
1598 
1599         this.zone = zone;
1600         setWeekCountData(aLocale);
1601     }
1602 
1603     /**
1604      * Gets a calendar using the default time zone and locale. The
1605      * <code>Calendar</code> returned is based on the current time
1606      * in the default time zone with the default
1607      * {@link Locale.Category#FORMAT FORMAT} locale.
1608      *
1609      * @return a Calendar.
1610      */
1611     public static Calendar getInstance()
1612     {
1613         return createCalendar(TimeZone.getDefault(), Locale.getDefault(Locale.Category.FORMAT));
1614     }
1615 
1616     /**
1617      * Gets a calendar using the specified time zone and default locale.
1618      * The <code>Calendar</code> returned is based on the current time
1619      * in the given time zone with the default
1620      * {@link Locale.Category#FORMAT FORMAT} locale.
1621      *
1622      * @param zone the time zone to use
1623      * @return a Calendar.
1624      */
1625     public static Calendar getInstance(TimeZone zone)
1626     {
1627         return createCalendar(zone, Locale.getDefault(Locale.Category.FORMAT));
1628     }
1629 
1630     /**
1631      * Gets a calendar using the default time zone and specified locale.
1632      * The <code>Calendar</code> returned is based on the current time
1633      * in the default time zone with the given locale.
1634      *
1635      * @param aLocale the locale for the week data
1636      * @return a Calendar.
1637      */
1638     public static Calendar getInstance(Locale aLocale)
1639     {
1640         return createCalendar(TimeZone.getDefault(), aLocale);
1641     }
1642 
1643     /**
1644      * Gets a calendar with the specified time zone and locale.
1645      * The <code>Calendar</code> returned is based on the current time
1646      * in the given time zone with the given locale.
1647      *
1648      * @param zone the time zone to use
1649      * @param aLocale the locale for the week data
1650      * @return a Calendar.
1651      */
1652     public static Calendar getInstance(TimeZone zone,
1653                                        Locale aLocale)
1654     {
1655         return createCalendar(zone, aLocale);
1656     }
1657 
1658     private static Calendar createCalendar(TimeZone zone,
1659                                            Locale aLocale)
1660     {
1661         CalendarProvider provider =
1662             LocaleProviderAdapter.getAdapter(CalendarProvider.class, aLocale)
1663                                  .getCalendarProvider();
1664         if (provider != null) {
1665             try {
1666                 return provider.getInstance(zone, aLocale);
1667             } catch (IllegalArgumentException iae) {
1668                 // fall back to the default instantiation
1669             }
1670         }
1671 
1672         Calendar cal = null;
1673 
1674         if (aLocale.hasExtensions()) {
1675             String caltype = aLocale.getUnicodeLocaleType("ca");
1676             if (caltype != null) {
1677                 switch (caltype) {
1678                 case "buddhist":
1679                 cal = new BuddhistCalendar(zone, aLocale);
1680                     break;
1681                 case "japanese":
1682                     cal = new JapaneseImperialCalendar(zone, aLocale);
1683                     break;
1684                 case "gregory":
1685                     cal = new GregorianCalendar(zone, aLocale);
1686                     break;
1687                 }
1688             }
1689         }
1690         if (cal == null) {
1691             // If no known calendar type is explicitly specified,
1692             // perform the traditional way to create a Calendar:
1693             // create a BuddhistCalendar for th_TH locale,
1694             // a JapaneseImperialCalendar for ja_JP_JP locale, or
1695             // a GregorianCalendar for any other locales.
1696             // NOTE: The language, country and variant strings are interned.
1697             if (aLocale.getLanguage() == "th" && aLocale.getCountry() == "TH") {
1698                 cal = new BuddhistCalendar(zone, aLocale);
1699             } else if (aLocale.getVariant() == "JP" && aLocale.getLanguage() == "ja"
1700                        && aLocale.getCountry() == "JP") {
1701                 cal = new JapaneseImperialCalendar(zone, aLocale);
1702             } else {
1703                 cal = new GregorianCalendar(zone, aLocale);
1704             }
1705         }
1706         return cal;
1707     }
1708 
1709     /**
1710      * Returns an array of all locales for which the <code>getInstance</code>
1711      * methods of this class can return localized instances.
1712      * The array returned must contain at least a <code>Locale</code>
1713      * instance equal to {@link java.util.Locale#US Locale.US}.
1714      *
1715      * @return An array of locales for which localized
1716      *         <code>Calendar</code> instances are available.
1717      */
1718     public static synchronized Locale[] getAvailableLocales()
1719     {
1720         return DateFormat.getAvailableLocales();
1721     }
1722 
1723     /**
1724      * Converts the current calendar field values in {@link #fields fields[]}
1725      * to the millisecond time value
1726      * {@link #time}.
1727      *
1728      * @see #complete()
1729      * @see #computeFields()
1730      */
1731     protected abstract void computeTime();
1732 
1733     /**
1734      * Converts the current millisecond time value {@link #time}
1735      * to calendar field values in {@link #fields fields[]}.
1736      * This allows you to sync up the calendar field values with
1737      * a new time that is set for the calendar.  The time is <em>not</em>
1738      * recomputed first; to recompute the time, then the fields, call the
1739      * {@link #complete()} method.
1740      *
1741      * @see #computeTime()
1742      */
1743     protected abstract void computeFields();
1744 
1745     /**
1746      * Returns a <code>Date</code> object representing this
1747      * <code>Calendar</code>'s time value (millisecond offset from the <a
1748      * href="#Epoch">Epoch</a>").
1749      *
1750      * @return a <code>Date</code> representing the time value.
1751      * @see #setTime(Date)
1752      * @see #getTimeInMillis()
1753      */
1754     public final Date getTime() {
1755         return new Date(getTimeInMillis());
1756     }
1757 
1758     /**
1759      * Sets this Calendar's time with the given <code>Date</code>.
1760      * <p>
1761      * Note: Calling <code>setTime()</code> with
1762      * <code>Date(Long.MAX_VALUE)</code> or <code>Date(Long.MIN_VALUE)</code>
1763      * may yield incorrect field values from <code>get()</code>.
1764      *
1765      * @param date the given Date.
1766      * @see #getTime()
1767      * @see #setTimeInMillis(long)
1768      */
1769     public final void setTime(Date date) {
1770         setTimeInMillis(date.getTime());
1771     }
1772 
1773     /**
1774      * Returns this Calendar's time value in milliseconds.
1775      *
1776      * @return the current time as UTC milliseconds from the epoch.
1777      * @see #getTime()
1778      * @see #setTimeInMillis(long)
1779      */
1780     public long getTimeInMillis() {
1781         if (!isTimeSet) {
1782             updateTime();
1783         }
1784         return time;
1785     }
1786 
1787     /**
1788      * Sets this Calendar's current time from the given long value.
1789      *
1790      * @param millis the new time in UTC milliseconds from the epoch.
1791      * @see #setTime(Date)
1792      * @see #getTimeInMillis()
1793      */
1794     public void setTimeInMillis(long millis) {
1795         // If we don't need to recalculate the calendar field values,
1796         // do nothing.
1797         if (time == millis && isTimeSet && areFieldsSet && areAllFieldsSet
1798             && (zone instanceof ZoneInfo) && !((ZoneInfo)zone).isDirty()) {
1799             return;
1800         }
1801         time = millis;
1802         isTimeSet = true;
1803         areFieldsSet = false;
1804         computeFields();
1805         areAllFieldsSet = areFieldsSet = true;
1806     }
1807 
1808     /**
1809      * Returns the value of the given calendar field. In lenient mode,
1810      * all calendar fields are normalized. In non-lenient mode, all
1811      * calendar fields are validated and this method throws an
1812      * exception if any calendar fields have out-of-range values. The
1813      * normalization and validation are handled by the
1814      * {@link #complete()} method, which process is calendar
1815      * system dependent.
1816      *
1817      * @param field the given calendar field.
1818      * @return the value for the given calendar field.
1819      * @throws ArrayIndexOutOfBoundsException if the specified field is out of range
1820      *             (<code>field &lt; 0 || field &gt;= FIELD_COUNT</code>).
1821      * @see #set(int,int)
1822      * @see #complete()
1823      */
1824     public int get(int field)
1825     {
1826         complete();
1827         return internalGet(field);
1828     }
1829 
1830     /**
1831      * Returns the value of the given calendar field. This method does
1832      * not involve normalization or validation of the field value.
1833      *
1834      * @param field the given calendar field.
1835      * @return the value for the given calendar field.
1836      * @see #get(int)
1837      */
1838     protected final int internalGet(int field)
1839     {
1840         return fields[field];
1841     }
1842 
1843     /**
1844      * Sets the value of the given calendar field. This method does
1845      * not affect any setting state of the field in this
1846      * <code>Calendar</code> instance.
1847      *
1848      * @throws IndexOutOfBoundsException if the specified field is out of range
1849      *             (<code>field &lt; 0 || field &gt;= FIELD_COUNT</code>).
1850      * @see #areFieldsSet
1851      * @see #isTimeSet
1852      * @see #areAllFieldsSet
1853      * @see #set(int,int)
1854      */
1855     final void internalSet(int field, int value)
1856     {
1857         fields[field] = value;
1858     }
1859 
1860     /**
1861      * Sets the given calendar field to the given value. The value is not
1862      * interpreted by this method regardless of the leniency mode.
1863      *
1864      * @param field the given calendar field.
1865      * @param value the value to be set for the given calendar field.
1866      * @throws ArrayIndexOutOfBoundsException if the specified field is out of range
1867      *             (<code>field &lt; 0 || field &gt;= FIELD_COUNT</code>).
1868      * in non-lenient mode.
1869      * @see #set(int,int,int)
1870      * @see #set(int,int,int,int,int)
1871      * @see #set(int,int,int,int,int,int)
1872      * @see #get(int)
1873      */
1874     public void set(int field, int value)
1875     {
1876         // If the fields are partially normalized, calculate all the
1877         // fields before changing any fields.
1878         if (areFieldsSet && !areAllFieldsSet) {
1879             computeFields();
1880         }
1881         internalSet(field, value);
1882         isTimeSet = false;
1883         areFieldsSet = false;
1884         isSet[field] = true;
1885         stamp[field] = nextStamp++;
1886         if (nextStamp == Integer.MAX_VALUE) {
1887             adjustStamp();
1888         }
1889     }
1890 
1891     /**
1892      * Sets the values for the calendar fields <code>YEAR</code>,
1893      * <code>MONTH</code>, and <code>DAY_OF_MONTH</code>.
1894      * Previous values of other calendar fields are retained.  If this is not desired,
1895      * call {@link #clear()} first.
1896      *
1897      * @param year the value used to set the <code>YEAR</code> calendar field.
1898      * @param month the value used to set the <code>MONTH</code> calendar field.
1899      * Month value is 0-based. e.g., 0 for January.
1900      * @param date the value used to set the <code>DAY_OF_MONTH</code> calendar field.
1901      * @see #set(int,int)
1902      * @see #set(int,int,int,int,int)
1903      * @see #set(int,int,int,int,int,int)
1904      */
1905     public final void set(int year, int month, int date)
1906     {
1907         set(YEAR, year);
1908         set(MONTH, month);
1909         set(DATE, date);
1910     }
1911 
1912     /**
1913      * Sets the values for the calendar fields <code>YEAR</code>,
1914      * <code>MONTH</code>, <code>DAY_OF_MONTH</code>,
1915      * <code>HOUR_OF_DAY</code>, and <code>MINUTE</code>.
1916      * Previous values of other fields are retained.  If this is not desired,
1917      * call {@link #clear()} first.
1918      *
1919      * @param year the value used to set the <code>YEAR</code> calendar field.
1920      * @param month the value used to set the <code>MONTH</code> calendar field.
1921      * Month value is 0-based. e.g., 0 for January.
1922      * @param date the value used to set the <code>DAY_OF_MONTH</code> calendar field.
1923      * @param hourOfDay the value used to set the <code>HOUR_OF_DAY</code> calendar field.
1924      * @param minute the value used to set the <code>MINUTE</code> calendar field.
1925      * @see #set(int,int)
1926      * @see #set(int,int,int)
1927      * @see #set(int,int,int,int,int,int)
1928      */
1929     public final void set(int year, int month, int date, int hourOfDay, int minute)
1930     {
1931         set(YEAR, year);
1932         set(MONTH, month);
1933         set(DATE, date);
1934         set(HOUR_OF_DAY, hourOfDay);
1935         set(MINUTE, minute);
1936     }
1937 
1938     /**
1939      * Sets the values for the fields <code>YEAR</code>, <code>MONTH</code>,
1940      * <code>DAY_OF_MONTH</code>, <code>HOUR_OF_DAY</code>, <code>MINUTE</code>, and
1941      * <code>SECOND</code>.
1942      * Previous values of other fields are retained.  If this is not desired,
1943      * call {@link #clear()} first.
1944      *
1945      * @param year the value used to set the <code>YEAR</code> calendar field.
1946      * @param month the value used to set the <code>MONTH</code> calendar field.
1947      * Month value is 0-based. e.g., 0 for January.
1948      * @param date the value used to set the <code>DAY_OF_MONTH</code> calendar field.
1949      * @param hourOfDay the value used to set the <code>HOUR_OF_DAY</code> calendar field.
1950      * @param minute the value used to set the <code>MINUTE</code> calendar field.
1951      * @param second the value used to set the <code>SECOND</code> calendar field.
1952      * @see #set(int,int)
1953      * @see #set(int,int,int)
1954      * @see #set(int,int,int,int,int)
1955      */
1956     public final void set(int year, int month, int date, int hourOfDay, int minute,
1957                           int second)
1958     {
1959         set(YEAR, year);
1960         set(MONTH, month);
1961         set(DATE, date);
1962         set(HOUR_OF_DAY, hourOfDay);
1963         set(MINUTE, minute);
1964         set(SECOND, second);
1965     }
1966 
1967     /**
1968      * Sets all the calendar field values and the time value
1969      * (millisecond offset from the <a href="#Epoch">Epoch</a>) of
1970      * this <code>Calendar</code> undefined. This means that {@link
1971      * #isSet(int) isSet()} will return <code>false</code> for all the
1972      * calendar fields, and the date and time calculations will treat
1973      * the fields as if they had never been set. A
1974      * <code>Calendar</code> implementation class may use its specific
1975      * default field values for date/time calculations. For example,
1976      * <code>GregorianCalendar</code> uses 1970 if the
1977      * <code>YEAR</code> field value is undefined.
1978      *
1979      * @see #clear(int)
1980      */
1981     public final void clear()
1982     {
1983         for (int i = 0; i < fields.length; ) {
1984             stamp[i] = fields[i] = 0; // UNSET == 0
1985             isSet[i++] = false;
1986         }
1987         areAllFieldsSet = areFieldsSet = false;
1988         isTimeSet = false;
1989     }
1990 
1991     /**
1992      * Sets the given calendar field value and the time value
1993      * (millisecond offset from the <a href="#Epoch">Epoch</a>) of
1994      * this <code>Calendar</code> undefined. This means that {@link
1995      * #isSet(int) isSet(field)} will return <code>false</code>, and
1996      * the date and time calculations will treat the field as if it
1997      * had never been set. A <code>Calendar</code> implementation
1998      * class may use the field's specific default value for date and
1999      * time calculations.
2000      *
2001      * <p>The {@link #HOUR_OF_DAY}, {@link #HOUR} and {@link #AM_PM}
2002      * fields are handled independently and the <a
2003      * href="#time_resolution">the resolution rule for the time of
2004      * day</a> is applied. Clearing one of the fields doesn't reset
2005      * the hour of day value of this <code>Calendar</code>. Use {@link
2006      * #set(int,int) set(Calendar.HOUR_OF_DAY, 0)} to reset the hour
2007      * value.
2008      *
2009      * @param field the calendar field to be cleared.
2010      * @see #clear()
2011      */
2012     public final void clear(int field)
2013     {
2014         fields[field] = 0;
2015         stamp[field] = UNSET;
2016         isSet[field] = false;
2017 
2018         areAllFieldsSet = areFieldsSet = false;
2019         isTimeSet = false;
2020     }
2021 
2022     /**
2023      * Determines if the given calendar field has a value set,
2024      * including cases that the value has been set by internal fields
2025      * calculations triggered by a <code>get</code> method call.
2026      *
2027      * @param field the calendar field to test
2028      * @return <code>true</code> if the given calendar field has a value set;
2029      * <code>false</code> otherwise.
2030      */
2031     public final boolean isSet(int field)
2032     {
2033         return stamp[field] != UNSET;
2034     }
2035 
2036     /**
2037      * Returns the string representation of the calendar
2038      * <code>field</code> value in the given <code>style</code> and
2039      * <code>locale</code>.  If no string representation is
2040      * applicable, <code>null</code> is returned. This method calls
2041      * {@link Calendar#get(int) get(field)} to get the calendar
2042      * <code>field</code> value if the string representation is
2043      * applicable to the given calendar <code>field</code>.
2044      *
2045      * <p>For example, if this <code>Calendar</code> is a
2046      * <code>GregorianCalendar</code> and its date is 2005-01-01, then
2047      * the string representation of the {@link #MONTH} field would be
2048      * "January" in the long style in an English locale or "Jan" in
2049      * the short style. However, no string representation would be
2050      * available for the {@link #DAY_OF_MONTH} field, and this method
2051      * would return <code>null</code>.
2052      *
2053      * <p>The default implementation supports the calendar fields for
2054      * which a {@link DateFormatSymbols} has names in the given
2055      * <code>locale</code>.
2056      *
2057      * @param field
2058      *        the calendar field for which the string representation
2059      *        is returned
2060      * @param style
2061      *        the style applied to the string representation; one of {@link
2062      *        #SHORT_FORMAT} ({@link #SHORT}), {@link #SHORT_STANDALONE},
2063      *        {@link #LONG_FORMAT} ({@link #LONG}), {@link #LONG_STANDALONE},
2064      *        {@link #NARROW_FORMAT}, or {@link #NARROW_STANDALONE}.
2065      * @param locale
2066      *        the locale for the string representation
2067      *        (any calendar types specified by {@code locale} are ignored)
2068      * @return the string representation of the given
2069      *        {@code field} in the given {@code style}, or
2070      *        {@code null} if no string representation is
2071      *        applicable.
2072      * @exception IllegalArgumentException
2073      *        if {@code field} or {@code style} is invalid,
2074      *        or if this {@code Calendar} is non-lenient and any
2075      *        of the calendar fields have invalid values
2076      * @exception NullPointerException
2077      *        if {@code locale} is null
2078      * @since 1.6
2079      */
2080     public String getDisplayName(int field, int style, Locale locale) {
2081         if (!checkDisplayNameParams(field, style, SHORT, NARROW_FORMAT, locale,
2082                             ERA_MASK|MONTH_MASK|DAY_OF_WEEK_MASK|AM_PM_MASK)) {
2083             return null;
2084         }
2085 
2086         String calendarType = getCalendarType();
2087         int fieldValue = get(field);
2088         // the standalone and narrow styles are supported only through CalendarDataProviders.
2089         if (isStandaloneStyle(style) || isNarrowFormatStyle(style)) {
2090             String val = CalendarDataUtility.retrieveFieldValueName(calendarType,
2091                                                                     field, fieldValue,
2092                                                                     style, locale);
2093             // Perform fallback here to follow the CLDR rules
2094             if (val == null) {
2095                 if (isNarrowFormatStyle(style)) {
2096                     val = CalendarDataUtility.retrieveFieldValueName(calendarType,
2097                                                                      field, fieldValue,
2098                                                                      toStandaloneStyle(style),
2099                                                                      locale);
2100                 } else if (isStandaloneStyle(style)) {
2101                     val = CalendarDataUtility.retrieveFieldValueName(calendarType,
2102                                                                      field, fieldValue,
2103                                                                      getBaseStyle(style),
2104                                                                      locale);
2105                 }
2106             }
2107             return val;
2108         }
2109 
2110         DateFormatSymbols symbols = DateFormatSymbols.getInstance(locale);
2111         String[] strings = getFieldStrings(field, style, symbols);
2112         if (strings != null) {
2113             if (fieldValue < strings.length) {
2114                 return strings[fieldValue];
2115             }
2116         }
2117         return null;
2118     }
2119 
2120     /**
2121      * Returns a {@code Map} containing all names of the calendar
2122      * {@code field} in the given {@code style} and
2123      * {@code locale} and their corresponding field values. For
2124      * example, if this {@code Calendar} is a {@link
2125      * GregorianCalendar}, the returned map would contain "Jan" to
2126      * {@link #JANUARY}, "Feb" to {@link #FEBRUARY}, and so on, in the
2127      * {@linkplain #SHORT short} style in an English locale.
2128      *
2129      * <p>Narrow names may not be unique due to use of single characters,
2130      * such as "S" for Sunday and Saturday. In that case narrow names are not
2131      * included in the returned {@code Map}.
2132      *
2133      * <p>The values of other calendar fields may be taken into
2134      * account to determine a set of display names. For example, if
2135      * this {@code Calendar} is a lunisolar calendar system and
2136      * the year value given by the {@link #YEAR} field has a leap
2137      * month, this method would return month names containing the leap
2138      * month name, and month names are mapped to their values specific
2139      * for the year.
2140      *
2141      * <p>The default implementation supports display names contained in
2142      * a {@link DateFormatSymbols}. For example, if {@code field}
2143      * is {@link #MONTH} and {@code style} is {@link
2144      * #ALL_STYLES}, this method returns a {@code Map} containing
2145      * all strings returned by {@link DateFormatSymbols#getShortMonths()}
2146      * and {@link DateFormatSymbols#getMonths()}.
2147      *
2148      * @param field
2149      *        the calendar field for which the display names are returned
2150      * @param style
2151      *        the style applied to the string representation; one of {@link
2152      *        #SHORT_FORMAT} ({@link #SHORT}), {@link #SHORT_STANDALONE},
2153      *        {@link #LONG_FORMAT} ({@link #LONG}), {@link #LONG_STANDALONE},
2154      *        {@link #NARROW_FORMAT}, or {@link #NARROW_STANDALONE}
2155      * @param locale
2156      *        the locale for the display names
2157      * @return a {@code Map} containing all display names in
2158      *        {@code style} and {@code locale} and their
2159      *        field values, or {@code null} if no display names
2160      *        are defined for {@code field}
2161      * @exception IllegalArgumentException
2162      *        if {@code field} or {@code style} is invalid,
2163      *        or if this {@code Calendar} is non-lenient and any
2164      *        of the calendar fields have invalid values
2165      * @exception NullPointerException
2166      *        if {@code locale} is null
2167      * @since 1.6
2168      */
2169     public Map<String, Integer> getDisplayNames(int field, int style, Locale locale) {
2170         if (!checkDisplayNameParams(field, style, ALL_STYLES, NARROW_FORMAT, locale,
2171                                     ERA_MASK|MONTH_MASK|DAY_OF_WEEK_MASK|AM_PM_MASK)) {
2172             return null;
2173         }
2174 
2175         String calendarType = getCalendarType();
2176         if (style == ALL_STYLES || isStandaloneStyle(style) || isNarrowFormatStyle(style)) {
2177             Map<String, Integer> map;
2178             map = CalendarDataUtility.retrieveFieldValueNames(calendarType, field, style, locale);
2179 
2180             // Perform fallback here to follow the CLDR rules
2181             if (map == null) {
2182                 if (isNarrowFormatStyle(style)) {
2183                     map = CalendarDataUtility.retrieveFieldValueNames(calendarType, field,
2184                                                                       toStandaloneStyle(style), locale);
2185                 } else if (style != ALL_STYLES) {
2186                     map = CalendarDataUtility.retrieveFieldValueNames(calendarType, field,
2187                                                                       getBaseStyle(style), locale);
2188                 }
2189             }
2190             return map;
2191         }
2192 
2193         // SHORT or LONG
2194         return getDisplayNamesImpl(field, style, locale);
2195     }
2196 
2197     private Map<String,Integer> getDisplayNamesImpl(int field, int style, Locale locale) {
2198         DateFormatSymbols symbols = DateFormatSymbols.getInstance(locale);
2199         String[] strings = getFieldStrings(field, style, symbols);
2200         if (strings != null) {
2201             Map<String,Integer> names = new HashMap<>();
2202             for (int i = 0; i < strings.length; i++) {
2203                 if (strings[i].length() == 0) {
2204                     continue;
2205                 }
2206                 names.put(strings[i], i);
2207             }
2208             return names;
2209         }
2210         return null;
2211     }
2212 
2213     boolean checkDisplayNameParams(int field, int style, int minStyle, int maxStyle,
2214                                    Locale locale, int fieldMask) {
2215         int baseStyle = getBaseStyle(style); // Ignore the standalone mask
2216         if (field < 0 || field >= fields.length ||
2217             baseStyle < minStyle || baseStyle > maxStyle) {
2218             throw new IllegalArgumentException();
2219         }
2220         if (locale == null) {
2221             throw new NullPointerException();
2222         }
2223         return isFieldSet(fieldMask, field);
2224     }
2225 
2226     private String[] getFieldStrings(int field, int style, DateFormatSymbols symbols) {
2227         int baseStyle = getBaseStyle(style); // ignore the standalone mask
2228 
2229         // DateFormatSymbols doesn't support any narrow names.
2230         if (baseStyle == NARROW_FORMAT) {
2231             return null;
2232         }
2233 
2234         String[] strings = null;
2235         switch (field) {
2236         case ERA:
2237             strings = symbols.getEras();
2238             break;
2239 
2240         case MONTH:
2241             strings = (baseStyle == LONG) ? symbols.getMonths() : symbols.getShortMonths();
2242             break;
2243 
2244         case DAY_OF_WEEK:
2245             strings = (baseStyle == LONG) ? symbols.getWeekdays() : symbols.getShortWeekdays();
2246             break;
2247 
2248         case AM_PM:
2249             strings = symbols.getAmPmStrings();
2250             break;
2251         }
2252         return strings;
2253     }
2254 
2255     /**
2256      * Fills in any unset fields in the calendar fields. First, the {@link
2257      * #computeTime()} method is called if the time value (millisecond offset
2258      * from the <a href="#Epoch">Epoch</a>) has not been calculated from
2259      * calendar field values. Then, the {@link #computeFields()} method is
2260      * called to calculate all calendar field values.
2261      */
2262     protected void complete()
2263     {
2264         if (!isTimeSet) {
2265             updateTime();
2266         }
2267         if (!areFieldsSet || !areAllFieldsSet) {
2268             computeFields(); // fills in unset fields
2269             areAllFieldsSet = areFieldsSet = true;
2270         }
2271     }
2272 
2273     /**
2274      * Returns whether the value of the specified calendar field has been set
2275      * externally by calling one of the setter methods rather than by the
2276      * internal time calculation.
2277      *
2278      * @return <code>true</code> if the field has been set externally,
2279      * <code>false</code> otherwise.
2280      * @exception IndexOutOfBoundsException if the specified
2281      *                <code>field</code> is out of range
2282      *               (<code>field &lt; 0 || field &gt;= FIELD_COUNT</code>).
2283      * @see #selectFields()
2284      * @see #setFieldsComputed(int)
2285      */
2286     final boolean isExternallySet(int field) {
2287         return stamp[field] >= MINIMUM_USER_STAMP;
2288     }
2289 
2290     /**
2291      * Returns a field mask (bit mask) indicating all calendar fields that
2292      * have the state of externally or internally set.
2293      *
2294      * @return a bit mask indicating set state fields
2295      */
2296     final int getSetStateFields() {
2297         int mask = 0;
2298         for (int i = 0; i < fields.length; i++) {
2299             if (stamp[i] != UNSET) {
2300                 mask |= 1 << i;
2301             }
2302         }
2303         return mask;
2304     }
2305 
2306     /**
2307      * Sets the state of the specified calendar fields to
2308      * <em>computed</em>. This state means that the specified calendar fields
2309      * have valid values that have been set by internal time calculation
2310      * rather than by calling one of the setter methods.
2311      *
2312      * @param fieldMask the field to be marked as computed.
2313      * @exception IndexOutOfBoundsException if the specified
2314      *                <code>field</code> is out of range
2315      *               (<code>field &lt; 0 || field &gt;= FIELD_COUNT</code>).
2316      * @see #isExternallySet(int)
2317      * @see #selectFields()
2318      */
2319     final void setFieldsComputed(int fieldMask) {
2320         if (fieldMask == ALL_FIELDS) {
2321             for (int i = 0; i < fields.length; i++) {
2322                 stamp[i] = COMPUTED;
2323                 isSet[i] = true;
2324             }
2325             areFieldsSet = areAllFieldsSet = true;
2326         } else {
2327             for (int i = 0; i < fields.length; i++) {
2328                 if ((fieldMask & 1) == 1) {
2329                     stamp[i] = COMPUTED;
2330                     isSet[i] = true;
2331                 } else {
2332                     if (areAllFieldsSet && !isSet[i]) {
2333                         areAllFieldsSet = false;
2334                     }
2335                 }
2336                 fieldMask >>>= 1;
2337             }
2338         }
2339     }
2340 
2341     /**
2342      * Sets the state of the calendar fields that are <em>not</em> specified
2343      * by <code>fieldMask</code> to <em>unset</em>. If <code>fieldMask</code>
2344      * specifies all the calendar fields, then the state of this
2345      * <code>Calendar</code> becomes that all the calendar fields are in sync
2346      * with the time value (millisecond offset from the Epoch).
2347      *
2348      * @param fieldMask the field mask indicating which calendar fields are in
2349      * sync with the time value.
2350      * @exception IndexOutOfBoundsException if the specified
2351      *                <code>field</code> is out of range
2352      *               (<code>field &lt; 0 || field &gt;= FIELD_COUNT</code>).
2353      * @see #isExternallySet(int)
2354      * @see #selectFields()
2355      */
2356     final void setFieldsNormalized(int fieldMask) {
2357         if (fieldMask != ALL_FIELDS) {
2358             for (int i = 0; i < fields.length; i++) {
2359                 if ((fieldMask & 1) == 0) {
2360                     stamp[i] = fields[i] = 0; // UNSET == 0
2361                     isSet[i] = false;
2362                 }
2363                 fieldMask >>= 1;
2364             }
2365         }
2366 
2367         // Some or all of the fields are in sync with the
2368         // milliseconds, but the stamp values are not normalized yet.
2369         areFieldsSet = true;
2370         areAllFieldsSet = false;
2371     }
2372 
2373     /**
2374      * Returns whether the calendar fields are partially in sync with the time
2375      * value or fully in sync but not stamp values are not normalized yet.
2376      */
2377     final boolean isPartiallyNormalized() {
2378         return areFieldsSet && !areAllFieldsSet;
2379     }
2380 
2381     /**
2382      * Returns whether the calendar fields are fully in sync with the time
2383      * value.
2384      */
2385     final boolean isFullyNormalized() {
2386         return areFieldsSet && areAllFieldsSet;
2387     }
2388 
2389     /**
2390      * Marks this Calendar as not sync'd.
2391      */
2392     final void setUnnormalized() {
2393         areFieldsSet = areAllFieldsSet = false;
2394     }
2395 
2396     /**
2397      * Returns whether the specified <code>field</code> is on in the
2398      * <code>fieldMask</code>.
2399      */
2400     static boolean isFieldSet(int fieldMask, int field) {
2401         return (fieldMask & (1 << field)) != 0;
2402     }
2403 
2404     /**
2405      * Returns a field mask indicating which calendar field values
2406      * to be used to calculate the time value. The calendar fields are
2407      * returned as a bit mask, each bit of which corresponds to a field, i.e.,
2408      * the mask value of <code>field</code> is <code>(1 &lt;&lt;
2409      * field)</code>. For example, 0x26 represents the <code>YEAR</code>,
2410      * <code>MONTH</code>, and <code>DAY_OF_MONTH</code> fields (i.e., 0x26 is
2411      * equal to
2412      * <code>(1&lt;&lt;YEAR)|(1&lt;&lt;MONTH)|(1&lt;&lt;DAY_OF_MONTH))</code>.
2413      *
2414      * <p>This method supports the calendar fields resolution as described in
2415      * the class description. If the bit mask for a given field is on and its
2416      * field has not been set (i.e., <code>isSet(field)</code> is
2417      * <code>false</code>), then the default value of the field has to be
2418      * used, which case means that the field has been selected because the
2419      * selected combination involves the field.
2420      *
2421      * @return a bit mask of selected fields
2422      * @see #isExternallySet(int)
2423      */
2424     final int selectFields() {
2425         // This implementation has been taken from the GregorianCalendar class.
2426 
2427         // The YEAR field must always be used regardless of its SET
2428         // state because YEAR is a mandatory field to determine the date
2429         // and the default value (EPOCH_YEAR) may change through the
2430         // normalization process.
2431         int fieldMask = YEAR_MASK;
2432 
2433         if (stamp[ERA] != UNSET) {
2434             fieldMask |= ERA_MASK;
2435         }
2436         // Find the most recent group of fields specifying the day within
2437         // the year.  These may be any of the following combinations:
2438         //   MONTH + DAY_OF_MONTH
2439         //   MONTH + WEEK_OF_MONTH + DAY_OF_WEEK
2440         //   MONTH + DAY_OF_WEEK_IN_MONTH + DAY_OF_WEEK
2441         //   DAY_OF_YEAR
2442         //   WEEK_OF_YEAR + DAY_OF_WEEK
2443         // We look for the most recent of the fields in each group to determine
2444         // the age of the group.  For groups involving a week-related field such
2445         // as WEEK_OF_MONTH, DAY_OF_WEEK_IN_MONTH, or WEEK_OF_YEAR, both the
2446         // week-related field and the DAY_OF_WEEK must be set for the group as a
2447         // whole to be considered.  (See bug 4153860 - liu 7/24/98.)
2448         int dowStamp = stamp[DAY_OF_WEEK];
2449         int monthStamp = stamp[MONTH];
2450         int domStamp = stamp[DAY_OF_MONTH];
2451         int womStamp = aggregateStamp(stamp[WEEK_OF_MONTH], dowStamp);
2452         int dowimStamp = aggregateStamp(stamp[DAY_OF_WEEK_IN_MONTH], dowStamp);
2453         int doyStamp = stamp[DAY_OF_YEAR];
2454         int woyStamp = aggregateStamp(stamp[WEEK_OF_YEAR], dowStamp);
2455 
2456         int bestStamp = domStamp;
2457         if (womStamp > bestStamp) {
2458             bestStamp = womStamp;
2459         }
2460         if (dowimStamp > bestStamp) {
2461             bestStamp = dowimStamp;
2462         }
2463         if (doyStamp > bestStamp) {
2464             bestStamp = doyStamp;
2465         }
2466         if (woyStamp > bestStamp) {
2467             bestStamp = woyStamp;
2468         }
2469 
2470         /* No complete combination exists.  Look for WEEK_OF_MONTH,
2471          * DAY_OF_WEEK_IN_MONTH, or WEEK_OF_YEAR alone.  Treat DAY_OF_WEEK alone
2472          * as DAY_OF_WEEK_IN_MONTH.
2473          */
2474         if (bestStamp == UNSET) {
2475             womStamp = stamp[WEEK_OF_MONTH];
2476             dowimStamp = Math.max(stamp[DAY_OF_WEEK_IN_MONTH], dowStamp);
2477             woyStamp = stamp[WEEK_OF_YEAR];
2478             bestStamp = Math.max(Math.max(womStamp, dowimStamp), woyStamp);
2479 
2480             /* Treat MONTH alone or no fields at all as DAY_OF_MONTH.  This may
2481              * result in bestStamp = domStamp = UNSET if no fields are set,
2482              * which indicates DAY_OF_MONTH.
2483              */
2484             if (bestStamp == UNSET) {
2485                 bestStamp = domStamp = monthStamp;
2486             }
2487         }
2488 
2489         if (bestStamp == domStamp ||
2490            (bestStamp == womStamp && stamp[WEEK_OF_MONTH] >= stamp[WEEK_OF_YEAR]) ||
2491            (bestStamp == dowimStamp && stamp[DAY_OF_WEEK_IN_MONTH] >= stamp[WEEK_OF_YEAR])) {
2492             fieldMask |= MONTH_MASK;
2493             if (bestStamp == domStamp) {
2494                 fieldMask |= DAY_OF_MONTH_MASK;
2495             } else {
2496                 assert (bestStamp == womStamp || bestStamp == dowimStamp);
2497                 if (dowStamp != UNSET) {
2498                     fieldMask |= DAY_OF_WEEK_MASK;
2499                 }
2500                 if (womStamp == dowimStamp) {
2501                     // When they are equal, give the priority to
2502                     // WEEK_OF_MONTH for compatibility.
2503                     if (stamp[WEEK_OF_MONTH] >= stamp[DAY_OF_WEEK_IN_MONTH]) {
2504                         fieldMask |= WEEK_OF_MONTH_MASK;
2505                     } else {
2506                         fieldMask |= DAY_OF_WEEK_IN_MONTH_MASK;
2507                     }
2508                 } else {
2509                     if (bestStamp == womStamp) {
2510                         fieldMask |= WEEK_OF_MONTH_MASK;
2511                     } else {
2512                         assert (bestStamp == dowimStamp);
2513                         if (stamp[DAY_OF_WEEK_IN_MONTH] != UNSET) {
2514                             fieldMask |= DAY_OF_WEEK_IN_MONTH_MASK;
2515                         }
2516                     }
2517                 }
2518             }
2519         } else {
2520             assert (bestStamp == doyStamp || bestStamp == woyStamp ||
2521                     bestStamp == UNSET);
2522             if (bestStamp == doyStamp) {
2523                 fieldMask |= DAY_OF_YEAR_MASK;
2524             } else {
2525                 assert (bestStamp == woyStamp);
2526                 if (dowStamp != UNSET) {
2527                     fieldMask |= DAY_OF_WEEK_MASK;
2528                 }
2529                 fieldMask |= WEEK_OF_YEAR_MASK;
2530             }
2531         }
2532 
2533         // Find the best set of fields specifying the time of day.  There
2534         // are only two possibilities here; the HOUR_OF_DAY or the
2535         // AM_PM and the HOUR.
2536         int hourOfDayStamp = stamp[HOUR_OF_DAY];
2537         int hourStamp = aggregateStamp(stamp[HOUR], stamp[AM_PM]);
2538         bestStamp = (hourStamp > hourOfDayStamp) ? hourStamp : hourOfDayStamp;
2539 
2540         // if bestStamp is still UNSET, then take HOUR or AM_PM. (See 4846659)
2541         if (bestStamp == UNSET) {
2542             bestStamp = Math.max(stamp[HOUR], stamp[AM_PM]);
2543         }
2544 
2545         // Hours
2546         if (bestStamp != UNSET) {
2547             if (bestStamp == hourOfDayStamp) {
2548                 fieldMask |= HOUR_OF_DAY_MASK;
2549             } else {
2550                 fieldMask |= HOUR_MASK;
2551                 if (stamp[AM_PM] != UNSET) {
2552                     fieldMask |= AM_PM_MASK;
2553                 }
2554             }
2555         }
2556         if (stamp[MINUTE] != UNSET) {
2557             fieldMask |= MINUTE_MASK;
2558         }
2559         if (stamp[SECOND] != UNSET) {
2560             fieldMask |= SECOND_MASK;
2561         }
2562         if (stamp[MILLISECOND] != UNSET) {
2563             fieldMask |= MILLISECOND_MASK;
2564         }
2565         if (stamp[ZONE_OFFSET] >= MINIMUM_USER_STAMP) {
2566                 fieldMask |= ZONE_OFFSET_MASK;
2567         }
2568         if (stamp[DST_OFFSET] >= MINIMUM_USER_STAMP) {
2569             fieldMask |= DST_OFFSET_MASK;
2570         }
2571 
2572         return fieldMask;
2573     }
2574 
2575     int getBaseStyle(int style) {
2576         return style & ~STANDALONE_MASK;
2577     }
2578 
2579     private int toStandaloneStyle(int style) {
2580         return style | STANDALONE_MASK;
2581     }
2582 
2583     private boolean isStandaloneStyle(int style) {
2584         return (style & STANDALONE_MASK) != 0;
2585     }
2586 
2587     private boolean isNarrowStyle(int style) {
2588         return style == NARROW_FORMAT || style == NARROW_STANDALONE;
2589     }
2590 
2591     private boolean isNarrowFormatStyle(int style) {
2592         return style == NARROW_FORMAT;
2593     }
2594 
2595     /**
2596      * Returns the pseudo-time-stamp for two fields, given their
2597      * individual pseudo-time-stamps.  If either of the fields
2598      * is unset, then the aggregate is unset.  Otherwise, the
2599      * aggregate is the later of the two stamps.
2600      */
2601     private static int aggregateStamp(int stamp_a, int stamp_b) {
2602         if (stamp_a == UNSET || stamp_b == UNSET) {
2603             return UNSET;
2604         }
2605         return (stamp_a > stamp_b) ? stamp_a : stamp_b;
2606     }
2607 
2608     /**
2609      * Returns an unmodifiable {@code Set} containing all calendar types
2610      * supported by {@code Calendar} in the runtime environment. The available
2611      * calendar types can be used for the <a
2612      * href="Locale.html#def_locale_extension">Unicode locale extensions</a>.
2613      * The {@code Set} returned contains at least {@code "gregory"}. The
2614      * calendar types don't include aliases, such as {@code "gregorian"} for
2615      * {@code "gregory"}.
2616      *
2617      * @return an unmodifiable {@code Set} containing all available calendar types
2618      * @since 1.8
2619      * @see #getCalendarType()
2620      * @see Calendar.Builder#setCalendarType(String)
2621      * @see Locale#getUnicodeLocaleType(String)
2622      */
2623     public static Set<String> getAvailableCalendarTypes() {
2624         return AvailableCalendarTypes.SET;
2625     }
2626 
2627     private static class AvailableCalendarTypes {
2628         private static final Set<String> SET;
2629         static {
2630             Set<String> set = new HashSet<>(3);
2631             set.add("gregory");
2632             set.add("buddhist");
2633             set.add("japanese");
2634             SET = Collections.unmodifiableSet(set);
2635         }
2636         private AvailableCalendarTypes() {
2637         }
2638     }
2639 
2640     /**
2641      * Returns the calendar type of this {@code Calendar}. Calendar types are
2642      * defined by the <em>Unicode Locale Data Markup Language (LDML)</em>
2643      * specification.
2644      *
2645      * <p>The default implementation of this method returns the class name of
2646      * this {@code Calendar} instance. Any subclasses that implement
2647      * LDML-defined calendar systems should override this method to return
2648      * appropriate calendar types.
2649      *
2650      * @return the LDML-defined calendar type or the class name of this
2651      *         {@code Calendar} instance
2652      * @since 1.8
2653      * @see <a href="Locale.html#def_extensions">Locale extensions</a>
2654      * @see Locale.Builder#setLocale(Locale)
2655      * @see Locale.Builder#setUnicodeLocaleKeyword(String, String)
2656      */
2657     public String getCalendarType() {
2658         return this.getClass().getName();
2659     }
2660 
2661     /**
2662      * Compares this <code>Calendar</code> to the specified
2663      * <code>Object</code>.  The result is <code>true</code> if and only if
2664      * the argument is a <code>Calendar</code> object of the same calendar
2665      * system that represents the same time value (millisecond offset from the
2666      * <a href="#Epoch">Epoch</a>) under the same
2667      * <code>Calendar</code> parameters as this object.
2668      *
2669      * <p>The <code>Calendar</code> parameters are the values represented
2670      * by the <code>isLenient</code>, <code>getFirstDayOfWeek</code>,
2671      * <code>getMinimalDaysInFirstWeek</code> and <code>getTimeZone</code>
2672      * methods. If there is any difference in those parameters
2673      * between the two <code>Calendar</code>s, this method returns
2674      * <code>false</code>.
2675      *
2676      * <p>Use the {@link #compareTo(Calendar) compareTo} method to
2677      * compare only the time values.
2678      *
2679      * @param obj the object to compare with.
2680      * @return <code>true</code> if this object is equal to <code>obj</code>;
2681      * <code>false</code> otherwise.
2682      */
2683     @SuppressWarnings("EqualsWhichDoesntCheckParameterClass")
2684     @Override
2685     public boolean equals(Object obj) {
2686         if (this == obj) {
2687             return true;
2688         }
2689         try {
2690             Calendar that = (Calendar)obj;
2691             return compareTo(getMillisOf(that)) == 0 &&
2692                 lenient == that.lenient &&
2693                 firstDayOfWeek == that.firstDayOfWeek &&
2694                 minimalDaysInFirstWeek == that.minimalDaysInFirstWeek &&
2695                 zone.equals(that.zone);
2696         } catch (Exception e) {
2697             // Note: GregorianCalendar.computeTime throws
2698             // IllegalArgumentException if the ERA value is invalid
2699             // even it's in lenient mode.
2700         }
2701         return false;
2702     }
2703 
2704     /**
2705      * Returns a hash code for this calendar.
2706      *
2707      * @return a hash code value for this object.
2708      * @since 1.2
2709      */
2710     @Override
2711     public int hashCode() {
2712         // 'otheritems' represents the hash code for the previous versions.
2713         int otheritems = (lenient ? 1 : 0)
2714             | (firstDayOfWeek << 1)
2715             | (minimalDaysInFirstWeek << 4)
2716             | (zone.hashCode() << 7);
2717         long t = getMillisOf(this);
2718         return (int) t ^ (int)(t >> 32) ^ otheritems;
2719     }
2720 
2721     /**
2722      * Returns whether this <code>Calendar</code> represents a time
2723      * before the time represented by the specified
2724      * <code>Object</code>. This method is equivalent to:
2725      * <pre>{@code
2726      *         compareTo(when) < 0
2727      * }</pre>
2728      * if and only if <code>when</code> is a <code>Calendar</code>
2729      * instance. Otherwise, the method returns <code>false</code>.
2730      *
2731      * @param when the <code>Object</code> to be compared
2732      * @return <code>true</code> if the time of this
2733      * <code>Calendar</code> is before the time represented by
2734      * <code>when</code>; <code>false</code> otherwise.
2735      * @see     #compareTo(Calendar)
2736      */
2737     public boolean before(Object when) {
2738         return when instanceof Calendar
2739             && compareTo((Calendar)when) < 0;
2740     }
2741 
2742     /**
2743      * Returns whether this <code>Calendar</code> represents a time
2744      * after the time represented by the specified
2745      * <code>Object</code>. This method is equivalent to:
2746      * <pre>{@code
2747      *         compareTo(when) > 0
2748      * }</pre>
2749      * if and only if <code>when</code> is a <code>Calendar</code>
2750      * instance. Otherwise, the method returns <code>false</code>.
2751      *
2752      * @param when the <code>Object</code> to be compared
2753      * @return <code>true</code> if the time of this <code>Calendar</code> is
2754      * after the time represented by <code>when</code>; <code>false</code>
2755      * otherwise.
2756      * @see     #compareTo(Calendar)
2757      */
2758     public boolean after(Object when) {
2759         return when instanceof Calendar
2760             && compareTo((Calendar)when) > 0;
2761     }
2762 
2763     /**
2764      * Compares the time values (millisecond offsets from the <a
2765      * href="#Epoch">Epoch</a>) represented by two
2766      * <code>Calendar</code> objects.
2767      *
2768      * @param anotherCalendar the <code>Calendar</code> to be compared.
2769      * @return the value <code>0</code> if the time represented by the argument
2770      * is equal to the time represented by this <code>Calendar</code>; a value
2771      * less than <code>0</code> if the time of this <code>Calendar</code> is
2772      * before the time represented by the argument; and a value greater than
2773      * <code>0</code> if the time of this <code>Calendar</code> is after the
2774      * time represented by the argument.
2775      * @exception NullPointerException if the specified <code>Calendar</code> is
2776      *            <code>null</code>.
2777      * @exception IllegalArgumentException if the time value of the
2778      * specified <code>Calendar</code> object can't be obtained due to
2779      * any invalid calendar values.
2780      * @since   1.5
2781      */
2782     @Override
2783     public int compareTo(Calendar anotherCalendar) {
2784         return compareTo(getMillisOf(anotherCalendar));
2785     }
2786 
2787     /**
2788      * Adds or subtracts the specified amount of time to the given calendar field,
2789      * based on the calendar's rules. For example, to subtract 5 days from
2790      * the current time of the calendar, you can achieve it by calling:
2791      * <p><code>add(Calendar.DAY_OF_MONTH, -5)</code>.
2792      *
2793      * @param field the calendar field.
2794      * @param amount the amount of date or time to be added to the field.
2795      * @see #roll(int,int)
2796      * @see #set(int,int)
2797      */
2798     abstract public void add(int field, int amount);
2799 
2800     /**
2801      * Adds or subtracts (up/down) a single unit of time on the given time
2802      * field without changing larger fields. For example, to roll the current
2803      * date up by one day, you can achieve it by calling:
2804      * <p>roll(Calendar.DATE, true).
2805      * When rolling on the year or Calendar.YEAR field, it will roll the year
2806      * value in the range between 1 and the value returned by calling
2807      * <code>getMaximum(Calendar.YEAR)</code>.
2808      * When rolling on the month or Calendar.MONTH field, other fields like
2809      * date might conflict and, need to be changed. For instance,
2810      * rolling the month on the date 01/31/96 will result in 02/29/96.
2811      * When rolling on the hour-in-day or Calendar.HOUR_OF_DAY field, it will
2812      * roll the hour value in the range between 0 and 23, which is zero-based.
2813      *
2814      * @param field the time field.
2815      * @param up indicates if the value of the specified time field is to be
2816      * rolled up or rolled down. Use true if rolling up, false otherwise.
2817      * @see Calendar#add(int,int)
2818      * @see Calendar#set(int,int)
2819      */
2820     abstract public void roll(int field, boolean up);
2821 
2822     /**
2823      * Adds the specified (signed) amount to the specified calendar field
2824      * without changing larger fields.  A negative amount means to roll
2825      * down.
2826      *
2827      * <p>NOTE:  This default implementation on <code>Calendar</code> just repeatedly calls the
2828      * version of {@link #roll(int,boolean) roll()} that rolls by one unit.  This may not
2829      * always do the right thing.  For example, if the <code>DAY_OF_MONTH</code> field is 31,
2830      * rolling through February will leave it set to 28.  The <code>GregorianCalendar</code>
2831      * version of this function takes care of this problem.  Other subclasses
2832      * should also provide overrides of this function that do the right thing.
2833      *
2834      * @param field the calendar field.
2835      * @param amount the signed amount to add to the calendar <code>field</code>.
2836      * @since 1.2
2837      * @see #roll(int,boolean)
2838      * @see #add(int,int)
2839      * @see #set(int,int)
2840      */
2841     public void roll(int field, int amount)
2842     {
2843         while (amount > 0) {
2844             roll(field, true);
2845             amount--;
2846         }
2847         while (amount < 0) {
2848             roll(field, false);
2849             amount++;
2850         }
2851     }
2852 
2853     /**
2854      * Sets the time zone with the given time zone value.
2855      *
2856      * @param value the given time zone.
2857      */
2858     public void setTimeZone(TimeZone value)
2859     {
2860         zone = value;
2861         sharedZone = false;
2862         /* Recompute the fields from the time using the new zone.  This also
2863          * works if isTimeSet is false (after a call to set()).  In that case
2864          * the time will be computed from the fields using the new zone, then
2865          * the fields will get recomputed from that.  Consider the sequence of
2866          * calls: cal.setTimeZone(EST); cal.set(HOUR, 1); cal.setTimeZone(PST).
2867          * Is cal set to 1 o'clock EST or 1 o'clock PST?  Answer: PST.  More
2868          * generally, a call to setTimeZone() affects calls to set() BEFORE AND
2869          * AFTER it up to the next call to complete().
2870          */
2871         areAllFieldsSet = areFieldsSet = false;
2872     }
2873 
2874     /**
2875      * Gets the time zone.
2876      *
2877      * @return the time zone object associated with this calendar.
2878      */
2879     public TimeZone getTimeZone()
2880     {
2881         // If the TimeZone object is shared by other Calendar instances, then
2882         // create a clone.
2883         if (sharedZone) {
2884             zone = (TimeZone) zone.clone();
2885             sharedZone = false;
2886         }
2887         return zone;
2888     }
2889 
2890     /**
2891      * Returns the time zone (without cloning).
2892      */
2893     TimeZone getZone() {
2894         return zone;
2895     }
2896 
2897     /**
2898      * Sets the sharedZone flag to <code>shared</code>.
2899      */
2900     void setZoneShared(boolean shared) {
2901         sharedZone = shared;
2902     }
2903 
2904     /**
2905      * Specifies whether or not date/time interpretation is to be lenient.  With
2906      * lenient interpretation, a date such as "February 942, 1996" will be
2907      * treated as being equivalent to the 941st day after February 1, 1996.
2908      * With strict (non-lenient) interpretation, such dates will cause an exception to be
2909      * thrown. The default is lenient.
2910      *
2911      * @param lenient <code>true</code> if the lenient mode is to be turned
2912      * on; <code>false</code> if it is to be turned off.
2913      * @see #isLenient()
2914      * @see java.text.DateFormat#setLenient
2915      */
2916     public void setLenient(boolean lenient)
2917     {
2918         this.lenient = lenient;
2919     }
2920 
2921     /**
2922      * Tells whether date/time interpretation is to be lenient.
2923      *
2924      * @return <code>true</code> if the interpretation mode of this calendar is lenient;
2925      * <code>false</code> otherwise.
2926      * @see #setLenient(boolean)
2927      */
2928     public boolean isLenient()
2929     {
2930         return lenient;
2931     }
2932 
2933     /**
2934      * Sets what the first day of the week is; e.g., <code>SUNDAY</code> in the U.S.,
2935      * <code>MONDAY</code> in France.
2936      *
2937      * @param value the given first day of the week.
2938      * @see #getFirstDayOfWeek()
2939      * @see #getMinimalDaysInFirstWeek()
2940      */
2941     public void setFirstDayOfWeek(int value)
2942     {
2943         if (firstDayOfWeek == value) {
2944             return;
2945         }
2946         firstDayOfWeek = value;
2947         invalidateWeekFields();
2948     }
2949 
2950     /**
2951      * Gets what the first day of the week is; e.g., <code>SUNDAY</code> in the U.S.,
2952      * <code>MONDAY</code> in France.
2953      *
2954      * @return the first day of the week.
2955      * @see #setFirstDayOfWeek(int)
2956      * @see #getMinimalDaysInFirstWeek()
2957      */
2958     public int getFirstDayOfWeek()
2959     {
2960         return firstDayOfWeek;
2961     }
2962 
2963     /**
2964      * Sets what the minimal days required in the first week of the year are;
2965      * For example, if the first week is defined as one that contains the first
2966      * day of the first month of a year, call this method with value 1. If it
2967      * must be a full week, use value 7.
2968      *
2969      * @param value the given minimal days required in the first week
2970      * of the year.
2971      * @see #getMinimalDaysInFirstWeek()
2972      */
2973     public void setMinimalDaysInFirstWeek(int value)
2974     {
2975         if (minimalDaysInFirstWeek == value) {
2976             return;
2977         }
2978         minimalDaysInFirstWeek = value;
2979         invalidateWeekFields();
2980     }
2981 
2982     /**
2983      * Gets what the minimal days required in the first week of the year are;
2984      * e.g., if the first week is defined as one that contains the first day
2985      * of the first month of a year, this method returns 1. If
2986      * the minimal days required must be a full week, this method
2987      * returns 7.
2988      *
2989      * @return the minimal days required in the first week of the year.
2990      * @see #setMinimalDaysInFirstWeek(int)
2991      */
2992     public int getMinimalDaysInFirstWeek()
2993     {
2994         return minimalDaysInFirstWeek;
2995     }
2996 
2997     /**
2998      * Returns whether this {@code Calendar} supports week dates.
2999      *
3000      * <p>The default implementation of this method returns {@code false}.
3001      *
3002      * @return {@code true} if this {@code Calendar} supports week dates;
3003      *         {@code false} otherwise.
3004      * @see #getWeekYear()
3005      * @see #setWeekDate(int,int,int)
3006      * @see #getWeeksInWeekYear()
3007      * @since 1.7
3008      */
3009     public boolean isWeekDateSupported() {
3010         return false;
3011     }
3012 
3013     /**
3014      * Returns the week year represented by this {@code Calendar}. The
3015      * week year is in sync with the week cycle. The {@linkplain
3016      * #getFirstDayOfWeek() first day of the first week} is the first
3017      * day of the week year.
3018      *
3019      * <p>The default implementation of this method throws an
3020      * {@link UnsupportedOperationException}.
3021      *
3022      * @return the week year of this {@code Calendar}
3023      * @exception UnsupportedOperationException
3024      *            if any week year numbering isn't supported
3025      *            in this {@code Calendar}.
3026      * @see #isWeekDateSupported()
3027      * @see #getFirstDayOfWeek()
3028      * @see #getMinimalDaysInFirstWeek()
3029      * @since 1.7
3030      */
3031     public int getWeekYear() {
3032         throw new UnsupportedOperationException();
3033     }
3034 
3035     /**
3036      * Sets the date of this {@code Calendar} with the the given date
3037      * specifiers - week year, week of year, and day of week.
3038      *
3039      * <p>Unlike the {@code set} method, all of the calendar fields
3040      * and {@code time} values are calculated upon return.
3041      *
3042      * <p>If {@code weekOfYear} is out of the valid week-of-year range
3043      * in {@code weekYear}, the {@code weekYear} and {@code
3044      * weekOfYear} values are adjusted in lenient mode, or an {@code
3045      * IllegalArgumentException} is thrown in non-lenient mode.
3046      *
3047      * <p>The default implementation of this method throws an
3048      * {@code UnsupportedOperationException}.
3049      *
3050      * @param weekYear   the week year
3051      * @param weekOfYear the week number based on {@code weekYear}
3052      * @param dayOfWeek  the day of week value: one of the constants
3053      *                   for the {@link #DAY_OF_WEEK} field: {@link
3054      *                   #SUNDAY}, ..., {@link #SATURDAY}.
3055      * @exception IllegalArgumentException
3056      *            if any of the given date specifiers is invalid
3057      *            or any of the calendar fields are inconsistent
3058      *            with the given date specifiers in non-lenient mode
3059      * @exception UnsupportedOperationException
3060      *            if any week year numbering isn't supported in this
3061      *            {@code Calendar}.
3062      * @see #isWeekDateSupported()
3063      * @see #getFirstDayOfWeek()
3064      * @see #getMinimalDaysInFirstWeek()
3065      * @since 1.7
3066      */
3067     public void setWeekDate(int weekYear, int weekOfYear, int dayOfWeek) {
3068         throw new UnsupportedOperationException();
3069     }
3070 
3071     /**
3072      * Returns the number of weeks in the week year represented by this
3073      * {@code Calendar}.
3074      *
3075      * <p>The default implementation of this method throws an
3076      * {@code UnsupportedOperationException}.
3077      *
3078      * @return the number of weeks in the week year.
3079      * @exception UnsupportedOperationException
3080      *            if any week year numbering isn't supported in this
3081      *            {@code Calendar}.
3082      * @see #WEEK_OF_YEAR
3083      * @see #isWeekDateSupported()
3084      * @see #getWeekYear()
3085      * @see #getActualMaximum(int)
3086      * @since 1.7
3087      */
3088     public int getWeeksInWeekYear() {
3089         throw new UnsupportedOperationException();
3090     }
3091 
3092     /**
3093      * Returns the minimum value for the given calendar field of this
3094      * <code>Calendar</code> instance. The minimum value is defined as
3095      * the smallest value returned by the {@link #get(int) get} method
3096      * for any possible time value.  The minimum value depends on
3097      * calendar system specific parameters of the instance.
3098      *
3099      * @param field the calendar field.
3100      * @return the minimum value for the given calendar field.
3101      * @see #getMaximum(int)
3102      * @see #getGreatestMinimum(int)
3103      * @see #getLeastMaximum(int)
3104      * @see #getActualMinimum(int)
3105      * @see #getActualMaximum(int)
3106      */
3107     abstract public int getMinimum(int field);
3108 
3109     /**
3110      * Returns the maximum value for the given calendar field of this
3111      * <code>Calendar</code> instance. The maximum value is defined as
3112      * the largest value returned by the {@link #get(int) get} method
3113      * for any possible time value. The maximum value depends on
3114      * calendar system specific parameters of the instance.
3115      *
3116      * @param field the calendar field.
3117      * @return the maximum value for the given calendar field.
3118      * @see #getMinimum(int)
3119      * @see #getGreatestMinimum(int)
3120      * @see #getLeastMaximum(int)
3121      * @see #getActualMinimum(int)
3122      * @see #getActualMaximum(int)
3123      */
3124     abstract public int getMaximum(int field);
3125 
3126     /**
3127      * Returns the highest minimum value for the given calendar field
3128      * of this <code>Calendar</code> instance. The highest minimum
3129      * value is defined as the largest value returned by {@link
3130      * #getActualMinimum(int)} for any possible time value. The
3131      * greatest minimum value depends on calendar system specific
3132      * parameters of the instance.
3133      *
3134      * @param field the calendar field.
3135      * @return the highest minimum value for the given calendar field.
3136      * @see #getMinimum(int)
3137      * @see #getMaximum(int)
3138      * @see #getLeastMaximum(int)
3139      * @see #getActualMinimum(int)
3140      * @see #getActualMaximum(int)
3141      */
3142     abstract public int getGreatestMinimum(int field);
3143 
3144     /**
3145      * Returns the lowest maximum value for the given calendar field
3146      * of this <code>Calendar</code> instance. The lowest maximum
3147      * value is defined as the smallest value returned by {@link
3148      * #getActualMaximum(int)} for any possible time value. The least
3149      * maximum value depends on calendar system specific parameters of
3150      * the instance. For example, a <code>Calendar</code> for the
3151      * Gregorian calendar system returns 28 for the
3152      * <code>DAY_OF_MONTH</code> field, because the 28th is the last
3153      * day of the shortest month of this calendar, February in a
3154      * common year.
3155      *
3156      * @param field the calendar field.
3157      * @return the lowest maximum value for the given calendar field.
3158      * @see #getMinimum(int)
3159      * @see #getMaximum(int)
3160      * @see #getGreatestMinimum(int)
3161      * @see #getActualMinimum(int)
3162      * @see #getActualMaximum(int)
3163      */
3164     abstract public int getLeastMaximum(int field);
3165 
3166     /**
3167      * Returns the minimum value that the specified calendar field
3168      * could have, given the time value of this <code>Calendar</code>.
3169      *
3170      * <p>The default implementation of this method uses an iterative
3171      * algorithm to determine the actual minimum value for the
3172      * calendar field. Subclasses should, if possible, override this
3173      * with a more efficient implementation - in many cases, they can
3174      * simply return <code>getMinimum()</code>.
3175      *
3176      * @param field the calendar field
3177      * @return the minimum of the given calendar field for the time
3178      * value of this <code>Calendar</code>
3179      * @see #getMinimum(int)
3180      * @see #getMaximum(int)
3181      * @see #getGreatestMinimum(int)
3182      * @see #getLeastMaximum(int)
3183      * @see #getActualMaximum(int)
3184      * @since 1.2
3185      */
3186     public int getActualMinimum(int field) {
3187         int fieldValue = getGreatestMinimum(field);
3188         int endValue = getMinimum(field);
3189 
3190         // if we know that the minimum value is always the same, just return it
3191         if (fieldValue == endValue) {
3192             return fieldValue;
3193         }
3194 
3195         // clone the calendar so we don't mess with the real one, and set it to
3196         // accept anything for the field values
3197         Calendar work = (Calendar)this.clone();
3198         work.setLenient(true);
3199 
3200         // now try each value from getLeastMaximum() to getMaximum() one by one until
3201         // we get a value that normalizes to another value.  The last value that
3202         // normalizes to itself is the actual minimum for the current date
3203         int result = fieldValue;
3204 
3205         do {
3206             work.set(field, fieldValue);
3207             if (work.get(field) != fieldValue) {
3208                 break;
3209             } else {
3210                 result = fieldValue;
3211                 fieldValue--;
3212             }
3213         } while (fieldValue >= endValue);
3214 
3215         return result;
3216     }
3217 
3218     /**
3219      * Returns the maximum value that the specified calendar field
3220      * could have, given the time value of this
3221      * <code>Calendar</code>. For example, the actual maximum value of
3222      * the <code>MONTH</code> field is 12 in some years, and 13 in
3223      * other years in the Hebrew calendar system.
3224      *
3225      * <p>The default implementation of this method uses an iterative
3226      * algorithm to determine the actual maximum value for the
3227      * calendar field. Subclasses should, if possible, override this
3228      * with a more efficient implementation.
3229      *
3230      * @param field the calendar field
3231      * @return the maximum of the given calendar field for the time
3232      * value of this <code>Calendar</code>
3233      * @see #getMinimum(int)
3234      * @see #getMaximum(int)
3235      * @see #getGreatestMinimum(int)
3236      * @see #getLeastMaximum(int)
3237      * @see #getActualMinimum(int)
3238      * @since 1.2
3239      */
3240     public int getActualMaximum(int field) {
3241         int fieldValue = getLeastMaximum(field);
3242         int endValue = getMaximum(field);
3243 
3244         // if we know that the maximum value is always the same, just return it.
3245         if (fieldValue == endValue) {
3246             return fieldValue;
3247         }
3248 
3249         // clone the calendar so we don't mess with the real one, and set it to
3250         // accept anything for the field values.
3251         Calendar work = (Calendar)this.clone();
3252         work.setLenient(true);
3253 
3254         // if we're counting weeks, set the day of the week to Sunday.  We know the
3255         // last week of a month or year will contain the first day of the week.
3256         if (field == WEEK_OF_YEAR || field == WEEK_OF_MONTH) {
3257             work.set(DAY_OF_WEEK, firstDayOfWeek);
3258         }
3259 
3260         // now try each value from getLeastMaximum() to getMaximum() one by one until
3261         // we get a value that normalizes to another value.  The last value that
3262         // normalizes to itself is the actual maximum for the current date
3263         int result = fieldValue;
3264 
3265         do {
3266             work.set(field, fieldValue);
3267             if (work.get(field) != fieldValue) {
3268                 break;
3269             } else {
3270                 result = fieldValue;
3271                 fieldValue++;
3272             }
3273         } while (fieldValue <= endValue);
3274 
3275         return result;
3276     }
3277 
3278     /**
3279      * Creates and returns a copy of this object.
3280      *
3281      * @return a copy of this object.
3282      */
3283     @Override
3284     public Object clone()
3285     {
3286         try {
3287             Calendar other = (Calendar) super.clone();
3288 
3289             other.fields = new int[FIELD_COUNT];
3290             other.isSet = new boolean[FIELD_COUNT];
3291             other.stamp = new int[FIELD_COUNT];
3292             for (int i = 0; i < FIELD_COUNT; i++) {
3293                 other.fields[i] = fields[i];
3294                 other.stamp[i] = stamp[i];
3295                 other.isSet[i] = isSet[i];
3296             }
3297             other.zone = (TimeZone) zone.clone();
3298             return other;
3299         }
3300         catch (CloneNotSupportedException e) {
3301             // this shouldn't happen, since we are Cloneable
3302             throw new InternalError(e);
3303         }
3304     }
3305 
3306     private static final String[] FIELD_NAME = {
3307         "ERA", "YEAR", "MONTH", "WEEK_OF_YEAR", "WEEK_OF_MONTH", "DAY_OF_MONTH",
3308         "DAY_OF_YEAR", "DAY_OF_WEEK", "DAY_OF_WEEK_IN_MONTH", "AM_PM", "HOUR",
3309         "HOUR_OF_DAY", "MINUTE", "SECOND", "MILLISECOND", "ZONE_OFFSET",
3310         "DST_OFFSET"
3311     };
3312 
3313     /**
3314      * Returns the name of the specified calendar field.
3315      *
3316      * @param field the calendar field
3317      * @return the calendar field name
3318      * @exception IndexOutOfBoundsException if <code>field</code> is negative,
3319      * equal to or greater then <code>FIELD_COUNT</code>.
3320      */
3321     static String getFieldName(int field) {
3322         return FIELD_NAME[field];
3323     }
3324 
3325     /**
3326      * Return a string representation of this calendar. This method
3327      * is intended to be used only for debugging purposes, and the
3328      * format of the returned string may vary between implementations.
3329      * The returned string may be empty but may not be <code>null</code>.
3330      *
3331      * @return  a string representation of this calendar.
3332      */
3333     @Override
3334     public String toString() {
3335         // NOTE: BuddhistCalendar.toString() interprets the string
3336         // produced by this method so that the Gregorian year number
3337         // is substituted by its B.E. year value. It relies on
3338         // "...,YEAR=<year>,..." or "...,YEAR=?,...".
3339         StringBuilder buffer = new StringBuilder(800);
3340         buffer.append(getClass().getName()).append('[');
3341         appendValue(buffer, "time", isTimeSet, time);
3342         buffer.append(",areFieldsSet=").append(areFieldsSet);
3343         buffer.append(",areAllFieldsSet=").append(areAllFieldsSet);
3344         buffer.append(",lenient=").append(lenient);
3345         buffer.append(",zone=").append(zone);
3346         appendValue(buffer, ",firstDayOfWeek", true, (long) firstDayOfWeek);
3347         appendValue(buffer, ",minimalDaysInFirstWeek", true, (long) minimalDaysInFirstWeek);
3348         for (int i = 0; i < FIELD_COUNT; ++i) {
3349             buffer.append(',');
3350             appendValue(buffer, FIELD_NAME[i], isSet(i), (long) fields[i]);
3351         }
3352         buffer.append(']');
3353         return buffer.toString();
3354     }
3355 
3356     // =======================privates===============================
3357 
3358     private static void appendValue(StringBuilder sb, String item, boolean valid, long value) {
3359         sb.append(item).append('=');
3360         if (valid) {
3361             sb.append(value);
3362         } else {
3363             sb.append('?');
3364         }
3365     }
3366 
3367     /**
3368      * Both firstDayOfWeek and minimalDaysInFirstWeek are locale-dependent.
3369      * They are used to figure out the week count for a specific date for
3370      * a given locale. These must be set when a Calendar is constructed.
3371      * @param desiredLocale the given locale.
3372      */
3373     private void setWeekCountData(Locale desiredLocale)
3374     {
3375         /* try to get the Locale data from the cache */
3376         int[] data = cachedLocaleData.get(desiredLocale);
3377         if (data == null) {  /* cache miss */
3378             data = new int[2];
3379             data[0] = CalendarDataUtility.retrieveFirstDayOfWeek(desiredLocale);
3380             data[1] = CalendarDataUtility.retrieveMinimalDaysInFirstWeek(desiredLocale);
3381             cachedLocaleData.putIfAbsent(desiredLocale, data);
3382         }
3383         firstDayOfWeek = data[0];
3384         minimalDaysInFirstWeek = data[1];
3385     }
3386 
3387     /**
3388      * Recomputes the time and updates the status fields isTimeSet
3389      * and areFieldsSet.  Callers should check isTimeSet and only
3390      * call this method if isTimeSet is false.
3391      */
3392     private void updateTime() {
3393         computeTime();
3394         // The areFieldsSet and areAllFieldsSet values are no longer
3395         // controlled here (as of 1.5).
3396         isTimeSet = true;
3397     }
3398 
3399     private int compareTo(long t) {
3400         long thisTime = getMillisOf(this);
3401         return (thisTime > t) ? 1 : (thisTime == t) ? 0 : -1;
3402     }
3403 
3404     private static long getMillisOf(Calendar calendar) {
3405         if (calendar.isTimeSet) {
3406             return calendar.time;
3407         }
3408         Calendar cal = (Calendar) calendar.clone();
3409         cal.setLenient(true);
3410         return cal.getTimeInMillis();
3411     }
3412 
3413     /**
3414      * Adjusts the stamp[] values before nextStamp overflow. nextStamp
3415      * is set to the next stamp value upon the return.
3416      */
3417     private void adjustStamp() {
3418         int max = MINIMUM_USER_STAMP;
3419         int newStamp = MINIMUM_USER_STAMP;
3420 
3421         for (;;) {
3422             int min = Integer.MAX_VALUE;
3423             for (int i = 0; i < stamp.length; i++) {
3424                 int v = stamp[i];
3425                 if (v >= newStamp && min > v) {
3426                     min = v;
3427                 }
3428                 if (max < v) {
3429                     max = v;
3430                 }
3431             }
3432             if (max != min && min == Integer.MAX_VALUE) {
3433                 break;
3434             }
3435             for (int i = 0; i < stamp.length; i++) {
3436                 if (stamp[i] == min) {
3437                     stamp[i] = newStamp;
3438                 }
3439             }
3440             newStamp++;
3441             if (min == max) {
3442                 break;
3443             }
3444         }
3445         nextStamp = newStamp;
3446     }
3447 
3448     /**
3449      * Sets the WEEK_OF_MONTH and WEEK_OF_YEAR fields to new values with the
3450      * new parameter value if they have been calculated internally.
3451      */
3452     private void invalidateWeekFields()
3453     {
3454         if (stamp[WEEK_OF_MONTH] != COMPUTED &&
3455             stamp[WEEK_OF_YEAR] != COMPUTED) {
3456             return;
3457         }
3458 
3459         // We have to check the new values of these fields after changing
3460         // firstDayOfWeek and/or minimalDaysInFirstWeek. If the field values
3461         // have been changed, then set the new values. (4822110)
3462         Calendar cal = (Calendar) clone();
3463         cal.setLenient(true);
3464         cal.clear(WEEK_OF_MONTH);
3465         cal.clear(WEEK_OF_YEAR);
3466 
3467         if (stamp[WEEK_OF_MONTH] == COMPUTED) {
3468             int weekOfMonth = cal.get(WEEK_OF_MONTH);
3469             if (fields[WEEK_OF_MONTH] != weekOfMonth) {
3470                 fields[WEEK_OF_MONTH] = weekOfMonth;
3471             }
3472         }
3473 
3474         if (stamp[WEEK_OF_YEAR] == COMPUTED) {
3475             int weekOfYear = cal.get(WEEK_OF_YEAR);
3476             if (fields[WEEK_OF_YEAR] != weekOfYear) {
3477                 fields[WEEK_OF_YEAR] = weekOfYear;
3478             }
3479         }
3480     }
3481 
3482     /**
3483      * Save the state of this object to a stream (i.e., serialize it).
3484      *
3485      * Ideally, <code>Calendar</code> would only write out its state data and
3486      * the current time, and not write any field data out, such as
3487      * <code>fields[]</code>, <code>isTimeSet</code>, <code>areFieldsSet</code>,
3488      * and <code>isSet[]</code>.  <code>nextStamp</code> also should not be part
3489      * of the persistent state. Unfortunately, this didn't happen before JDK 1.1
3490      * shipped. To be compatible with JDK 1.1, we will always have to write out
3491      * the field values and state flags.  However, <code>nextStamp</code> can be
3492      * removed from the serialization stream; this will probably happen in the
3493      * near future.
3494      */
3495     private synchronized void writeObject(ObjectOutputStream stream)
3496          throws IOException
3497     {
3498         // Try to compute the time correctly, for the future (stream
3499         // version 2) in which we don't write out fields[] or isSet[].
3500         if (!isTimeSet) {
3501             try {
3502                 updateTime();
3503             }
3504             catch (IllegalArgumentException e) {}
3505         }
3506 
3507         // If this Calendar has a ZoneInfo, save it and set a
3508         // SimpleTimeZone equivalent (as a single DST schedule) for
3509         // backward compatibility.
3510         TimeZone savedZone = null;
3511         if (zone instanceof ZoneInfo) {
3512             SimpleTimeZone stz = ((ZoneInfo)zone).getLastRuleInstance();
3513             if (stz == null) {
3514                 stz = new SimpleTimeZone(zone.getRawOffset(), zone.getID());
3515             }
3516             savedZone = zone;
3517             zone = stz;
3518         }
3519 
3520         // Write out the 1.1 FCS object.
3521         stream.defaultWriteObject();
3522 
3523         // Write out the ZoneInfo object
3524         // 4802409: we write out even if it is null, a temporary workaround
3525         // the real fix for bug 4844924 in corba-iiop
3526         stream.writeObject(savedZone);
3527         if (savedZone != null) {
3528             zone = savedZone;
3529         }
3530     }
3531 
3532     private static class CalendarAccessControlContext {
3533         private static final AccessControlContext INSTANCE;
3534         static {
3535             RuntimePermission perm = new RuntimePermission("accessClassInPackage.sun.util.calendar");
3536             PermissionCollection perms = perm.newPermissionCollection();
3537             perms.add(perm);
3538             INSTANCE = new AccessControlContext(new ProtectionDomain[] {
3539                                                     new ProtectionDomain(null, perms)
3540                                                 });
3541         }
3542         private CalendarAccessControlContext() {
3543         }
3544     }
3545 
3546     /**
3547      * Reconstitutes this object from a stream (i.e., deserialize it).
3548      */
3549     private void readObject(ObjectInputStream stream)
3550          throws IOException, ClassNotFoundException
3551     {
3552         final ObjectInputStream input = stream;
3553         input.defaultReadObject();
3554 
3555         stamp = new int[FIELD_COUNT];
3556 
3557         // Starting with version 2 (not implemented yet), we expect that
3558         // fields[], isSet[], isTimeSet, and areFieldsSet may not be
3559         // streamed out anymore.  We expect 'time' to be correct.
3560         if (serialVersionOnStream >= 2)
3561         {
3562             isTimeSet = true;
3563             if (fields == null) {
3564                 fields = new int[FIELD_COUNT];
3565             }
3566             if (isSet == null) {
3567                 isSet = new boolean[FIELD_COUNT];
3568             }
3569         }
3570         else if (serialVersionOnStream >= 0)
3571         {
3572             for (int i=0; i<FIELD_COUNT; ++i) {
3573                 stamp[i] = isSet[i] ? COMPUTED : UNSET;
3574             }
3575         }
3576 
3577         serialVersionOnStream = currentSerialVersion;
3578 
3579         // If there's a ZoneInfo object, use it for zone.
3580         ZoneInfo zi = null;
3581         try {
3582             zi = AccessController.doPrivileged(
3583                     new PrivilegedExceptionAction<ZoneInfo>() {
3584                         @Override
3585                         public ZoneInfo run() throws Exception {
3586                             return (ZoneInfo) input.readObject();
3587                         }
3588                     },
3589                     CalendarAccessControlContext.INSTANCE);
3590         } catch (PrivilegedActionException pae) {
3591             Exception e = pae.getException();
3592             if (!(e instanceof OptionalDataException)) {
3593                 if (e instanceof RuntimeException) {
3594                     throw (RuntimeException) e;
3595                 } else if (e instanceof IOException) {
3596                     throw (IOException) e;
3597                 } else if (e instanceof ClassNotFoundException) {
3598                     throw (ClassNotFoundException) e;
3599                 }
3600                 throw new RuntimeException(e);
3601             }
3602         }
3603         if (zi != null) {
3604             zone = zi;
3605         }
3606 
3607         // If the deserialized object has a SimpleTimeZone, try to
3608         // replace it with a ZoneInfo equivalent (as of 1.4) in order
3609         // to be compatible with the SimpleTimeZone-based
3610         // implementation as much as possible.
3611         if (zone instanceof SimpleTimeZone) {
3612             String id = zone.getID();
3613             TimeZone tz = TimeZone.getTimeZone(id);
3614             if (tz != null && tz.hasSameRules(zone) && tz.getID().equals(id)) {
3615                 zone = tz;
3616             }
3617         }
3618     }
3619 
3620     /**
3621      * Converts this object to an {@link Instant}.
3622      * <p>
3623      * The conversion creates an {@code Instant} that represents the
3624      * same point on the time-line as this {@code Calendar}.
3625      *
3626      * @return the instant representing the same point on the time-line
3627      * @since 1.8
3628      */
3629     public final Instant toInstant() {
3630         return Instant.ofEpochMilli(getTimeInMillis());
3631     }
3632 }