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1   /*
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3    * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4    *
5    * This code is free software; you can redistribute it and/or modify it
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7    * published by the Free Software Foundation.  Oracle designates this
8    * particular file as subject to the "Classpath" exception as provided
9    * by Oracle in the LICENSE file that accompanied this code.
10   *
11   * This code is distributed in the hope that it will be useful, but WITHOUT
12   * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13   * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
14   * version 2 for more details (a copy is included in the LICENSE file that
15   * accompanied this code).
16   *
17   * You should have received a copy of the GNU General Public License version
18   * 2 along with this work; if not, write to the Free Software Foundation,
19   * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20   *
21   * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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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         // the standalone and narrow styles are supported only through CalendarDataProviders.
2087         if (isStandaloneStyle(style) || isNarrowStyle(style)) {
2088             return CalendarDataUtility.retrieveFieldValueName(getCalendarType(),
2089                                                               field, get(field),
2090                                                               style, locale);
2091         }
2092 
2093         DateFormatSymbols symbols = DateFormatSymbols.getInstance(locale);
2094         String[] strings = getFieldStrings(field, style, symbols);
2095         if (strings != null) {
2096             int fieldValue = get(field);
2097             if (fieldValue < strings.length) {
2098                 return strings[fieldValue];
2099             }
2100         }
2101         return null;
2102     }
2103 
2104     /**
2105      * Returns a {@code Map} containing all names of the calendar
2106      * {@code field} in the given {@code style} and
2107      * {@code locale} and their corresponding field values. For
2108      * example, if this {@code Calendar} is a {@link
2109      * GregorianCalendar}, the returned map would contain "Jan" to
2110      * {@link #JANUARY}, "Feb" to {@link #FEBRUARY}, and so on, in the
2111      * {@linkplain #SHORT short} style in an English locale.
2112      *
2113      * <p>Narrow names may not be unique due to use of single characters,
2114      * such as "S" for Sunday and Saturday. In that case narrow names are not
2115      * included in the returned {@code Map}.
2116      *
2117      * <p>The values of other calendar fields may be taken into
2118      * account to determine a set of display names. For example, if
2119      * this {@code Calendar} is a lunisolar calendar system and
2120      * the year value given by the {@link #YEAR} field has a leap
2121      * month, this method would return month names containing the leap
2122      * month name, and month names are mapped to their values specific
2123      * for the year.
2124      *
2125      * <p>The default implementation supports display names contained in
2126      * a {@link DateFormatSymbols}. For example, if {@code field}
2127      * is {@link #MONTH} and {@code style} is {@link
2128      * #ALL_STYLES}, this method returns a {@code Map} containing
2129      * all strings returned by {@link DateFormatSymbols#getShortMonths()}
2130      * and {@link DateFormatSymbols#getMonths()}.
2131      *
2132      * @param field
2133      *        the calendar field for which the display names are returned
2134      * @param style
2135      *        the style applied to the string representation; one of {@link
2136      *        #SHORT_FORMAT} ({@link #SHORT}), {@link #SHORT_STANDALONE},
2137      *        {@link #LONG_FORMAT} ({@link #LONG}), {@link #LONG_STANDALONE},
2138      *        {@link #NARROW_FORMAT}, or {@link #NARROW_STANDALONE}
2139      * @param locale
2140      *        the locale for the display names
2141      * @return a {@code Map} containing all display names in
2142      *        {@code style} and {@code locale} and their
2143      *        field values, or {@code null} if no display names
2144      *        are defined for {@code field}
2145      * @exception IllegalArgumentException
2146      *        if {@code field} or {@code style} is invalid,
2147      *        or if this {@code Calendar} is non-lenient and any
2148      *        of the calendar fields have invalid values
2149      * @exception NullPointerException
2150      *        if {@code locale} is null
2151      * @since 1.6
2152      */
2153     public Map<String, Integer> getDisplayNames(int field, int style, Locale locale) {
2154         if (!checkDisplayNameParams(field, style, ALL_STYLES, NARROW_FORMAT, locale,
2155                                     ERA_MASK|MONTH_MASK|DAY_OF_WEEK_MASK|AM_PM_MASK)) {
2156             return null;
2157         }
2158         if (style == ALL_STYLES || isStandaloneStyle(style)) {
2159             return CalendarDataUtility.retrieveFieldValueNames(getCalendarType(), field, style, locale);
2160         }
2161         // SHORT, LONG, or NARROW
2162         return getDisplayNamesImpl(field, style, locale);
2163     }
2164 
2165     private Map<String,Integer> getDisplayNamesImpl(int field, int style, Locale locale) {
2166         DateFormatSymbols symbols = DateFormatSymbols.getInstance(locale);
2167         String[] strings = getFieldStrings(field, style, symbols);
2168         if (strings != null) {
2169             Map<String,Integer> names = new HashMap<>();
2170             for (int i = 0; i < strings.length; i++) {
2171                 if (strings[i].length() == 0) {
2172                     continue;
2173                 }
2174                 names.put(strings[i], i);
2175             }
2176             return names;
2177         }
2178         return null;
2179     }
2180 
2181     boolean checkDisplayNameParams(int field, int style, int minStyle, int maxStyle,
2182                                    Locale locale, int fieldMask) {
2183         int baseStyle = getBaseStyle(style); // Ignore the standalone mask
2184         if (field < 0 || field >= fields.length ||
2185             baseStyle < minStyle || baseStyle > maxStyle) {
2186             throw new IllegalArgumentException();
2187         }
2188         if (locale == null) {
2189             throw new NullPointerException();
2190         }
2191         return isFieldSet(fieldMask, field);
2192     }
2193 
2194     private String[] getFieldStrings(int field, int style, DateFormatSymbols symbols) {
2195         int baseStyle = getBaseStyle(style); // ignore the standalone mask
2196 
2197         // DateFormatSymbols doesn't support any narrow names.
2198         if (baseStyle == NARROW_FORMAT) {
2199             return null;
2200         }
2201 
2202         String[] strings = null;
2203         switch (field) {
2204         case ERA:
2205             strings = symbols.getEras();
2206             break;
2207 
2208         case MONTH:
2209             strings = (baseStyle == LONG) ? symbols.getMonths() : symbols.getShortMonths();
2210             break;
2211 
2212         case DAY_OF_WEEK:
2213             strings = (baseStyle == LONG) ? symbols.getWeekdays() : symbols.getShortWeekdays();
2214             break;
2215 
2216         case AM_PM:
2217             strings = symbols.getAmPmStrings();
2218             break;
2219         }
2220         return strings;
2221     }
2222 
2223     /**
2224      * Fills in any unset fields in the calendar fields. First, the {@link
2225      * #computeTime()} method is called if the time value (millisecond offset
2226      * from the <a href="#Epoch">Epoch</a>) has not been calculated from
2227      * calendar field values. Then, the {@link #computeFields()} method is
2228      * called to calculate all calendar field values.
2229      */
2230     protected void complete()
2231     {
2232         if (!isTimeSet) {
2233             updateTime();
2234         }
2235         if (!areFieldsSet || !areAllFieldsSet) {
2236             computeFields(); // fills in unset fields
2237             areAllFieldsSet = areFieldsSet = true;
2238         }
2239     }
2240 
2241     /**
2242      * Returns whether the value of the specified calendar field has been set
2243      * externally by calling one of the setter methods rather than by the
2244      * internal time calculation.
2245      *
2246      * @return <code>true</code> if the field has been set externally,
2247      * <code>false</code> otherwise.
2248      * @exception IndexOutOfBoundsException if the specified
2249      *                <code>field</code> is out of range
2250      *               (<code>field &lt; 0 || field &gt;= FIELD_COUNT</code>).
2251      * @see #selectFields()
2252      * @see #setFieldsComputed(int)
2253      */
2254     final boolean isExternallySet(int field) {
2255         return stamp[field] >= MINIMUM_USER_STAMP;
2256     }
2257 
2258     /**
2259      * Returns a field mask (bit mask) indicating all calendar fields that
2260      * have the state of externally or internally set.
2261      *
2262      * @return a bit mask indicating set state fields
2263      */
2264     final int getSetStateFields() {
2265         int mask = 0;
2266         for (int i = 0; i < fields.length; i++) {
2267             if (stamp[i] != UNSET) {
2268                 mask |= 1 << i;
2269             }
2270         }
2271         return mask;
2272     }
2273 
2274     /**
2275      * Sets the state of the specified calendar fields to
2276      * <em>computed</em>. This state means that the specified calendar fields
2277      * have valid values that have been set by internal time calculation
2278      * rather than by calling one of the setter methods.
2279      *
2280      * @param fieldMask the field to be marked as computed.
2281      * @exception IndexOutOfBoundsException if the specified
2282      *                <code>field</code> is out of range
2283      *               (<code>field &lt; 0 || field &gt;= FIELD_COUNT</code>).
2284      * @see #isExternallySet(int)
2285      * @see #selectFields()
2286      */
2287     final void setFieldsComputed(int fieldMask) {
2288         if (fieldMask == ALL_FIELDS) {
2289             for (int i = 0; i < fields.length; i++) {
2290                 stamp[i] = COMPUTED;
2291                 isSet[i] = true;
2292             }
2293             areFieldsSet = areAllFieldsSet = true;
2294         } else {
2295             for (int i = 0; i < fields.length; i++) {
2296                 if ((fieldMask & 1) == 1) {
2297                     stamp[i] = COMPUTED;
2298                     isSet[i] = true;
2299                 } else {
2300                     if (areAllFieldsSet && !isSet[i]) {
2301                         areAllFieldsSet = false;
2302                     }
2303                 }
2304                 fieldMask >>>= 1;
2305             }
2306         }
2307     }
2308 
2309     /**
2310      * Sets the state of the calendar fields that are <em>not</em> specified
2311      * by <code>fieldMask</code> to <em>unset</em>. If <code>fieldMask</code>
2312      * specifies all the calendar fields, then the state of this
2313      * <code>Calendar</code> becomes that all the calendar fields are in sync
2314      * with the time value (millisecond offset from the Epoch).
2315      *
2316      * @param fieldMask the field mask indicating which calendar fields are in
2317      * sync with the time value.
2318      * @exception IndexOutOfBoundsException if the specified
2319      *                <code>field</code> is out of range
2320      *               (<code>field &lt; 0 || field &gt;= FIELD_COUNT</code>).
2321      * @see #isExternallySet(int)
2322      * @see #selectFields()
2323      */
2324     final void setFieldsNormalized(int fieldMask) {
2325         if (fieldMask != ALL_FIELDS) {
2326             for (int i = 0; i < fields.length; i++) {
2327                 if ((fieldMask & 1) == 0) {
2328                     stamp[i] = fields[i] = 0; // UNSET == 0
2329                     isSet[i] = false;
2330                 }
2331                 fieldMask >>= 1;
2332             }
2333         }
2334 
2335         // Some or all of the fields are in sync with the
2336         // milliseconds, but the stamp values are not normalized yet.
2337         areFieldsSet = true;
2338         areAllFieldsSet = false;
2339     }
2340 
2341     /**
2342      * Returns whether the calendar fields are partially in sync with the time
2343      * value or fully in sync but not stamp values are not normalized yet.
2344      */
2345     final boolean isPartiallyNormalized() {
2346         return areFieldsSet && !areAllFieldsSet;
2347     }
2348 
2349     /**
2350      * Returns whether the calendar fields are fully in sync with the time
2351      * value.
2352      */
2353     final boolean isFullyNormalized() {
2354         return areFieldsSet && areAllFieldsSet;
2355     }
2356 
2357     /**
2358      * Marks this Calendar as not sync'd.
2359      */
2360     final void setUnnormalized() {
2361         areFieldsSet = areAllFieldsSet = false;
2362     }
2363 
2364     /**
2365      * Returns whether the specified <code>field</code> is on in the
2366      * <code>fieldMask</code>.
2367      */
2368     static boolean isFieldSet(int fieldMask, int field) {
2369         return (fieldMask & (1 << field)) != 0;
2370     }
2371 
2372     /**
2373      * Returns a field mask indicating which calendar field values
2374      * to be used to calculate the time value. The calendar fields are
2375      * returned as a bit mask, each bit of which corresponds to a field, i.e.,
2376      * the mask value of <code>field</code> is <code>(1 &lt;&lt;
2377      * field)</code>. For example, 0x26 represents the <code>YEAR</code>,
2378      * <code>MONTH</code>, and <code>DAY_OF_MONTH</code> fields (i.e., 0x26 is
2379      * equal to
2380      * <code>(1&lt;&lt;YEAR)|(1&lt;&lt;MONTH)|(1&lt;&lt;DAY_OF_MONTH))</code>.
2381      *
2382      * <p>This method supports the calendar fields resolution as described in
2383      * the class description. If the bit mask for a given field is on and its
2384      * field has not been set (i.e., <code>isSet(field)</code> is
2385      * <code>false</code>), then the default value of the field has to be
2386      * used, which case means that the field has been selected because the
2387      * selected combination involves the field.
2388      *
2389      * @return a bit mask of selected fields
2390      * @see #isExternallySet(int)
2391      */
2392     final int selectFields() {
2393         // This implementation has been taken from the GregorianCalendar class.
2394 
2395         // The YEAR field must always be used regardless of its SET
2396         // state because YEAR is a mandatory field to determine the date
2397         // and the default value (EPOCH_YEAR) may change through the
2398         // normalization process.
2399         int fieldMask = YEAR_MASK;
2400 
2401         if (stamp[ERA] != UNSET) {
2402             fieldMask |= ERA_MASK;
2403         }
2404         // Find the most recent group of fields specifying the day within
2405         // the year.  These may be any of the following combinations:
2406         //   MONTH + DAY_OF_MONTH
2407         //   MONTH + WEEK_OF_MONTH + DAY_OF_WEEK
2408         //   MONTH + DAY_OF_WEEK_IN_MONTH + DAY_OF_WEEK
2409         //   DAY_OF_YEAR
2410         //   WEEK_OF_YEAR + DAY_OF_WEEK
2411         // We look for the most recent of the fields in each group to determine
2412         // the age of the group.  For groups involving a week-related field such
2413         // as WEEK_OF_MONTH, DAY_OF_WEEK_IN_MONTH, or WEEK_OF_YEAR, both the
2414         // week-related field and the DAY_OF_WEEK must be set for the group as a
2415         // whole to be considered.  (See bug 4153860 - liu 7/24/98.)
2416         int dowStamp = stamp[DAY_OF_WEEK];
2417         int monthStamp = stamp[MONTH];
2418         int domStamp = stamp[DAY_OF_MONTH];
2419         int womStamp = aggregateStamp(stamp[WEEK_OF_MONTH], dowStamp);
2420         int dowimStamp = aggregateStamp(stamp[DAY_OF_WEEK_IN_MONTH], dowStamp);
2421         int doyStamp = stamp[DAY_OF_YEAR];
2422         int woyStamp = aggregateStamp(stamp[WEEK_OF_YEAR], dowStamp);
2423 
2424         int bestStamp = domStamp;
2425         if (womStamp > bestStamp) {
2426             bestStamp = womStamp;
2427         }
2428         if (dowimStamp > bestStamp) {
2429             bestStamp = dowimStamp;
2430         }
2431         if (doyStamp > bestStamp) {
2432             bestStamp = doyStamp;
2433         }
2434         if (woyStamp > bestStamp) {
2435             bestStamp = woyStamp;
2436         }
2437 
2438         /* No complete combination exists.  Look for WEEK_OF_MONTH,
2439          * DAY_OF_WEEK_IN_MONTH, or WEEK_OF_YEAR alone.  Treat DAY_OF_WEEK alone
2440          * as DAY_OF_WEEK_IN_MONTH.
2441          */
2442         if (bestStamp == UNSET) {
2443             womStamp = stamp[WEEK_OF_MONTH];
2444             dowimStamp = Math.max(stamp[DAY_OF_WEEK_IN_MONTH], dowStamp);
2445             woyStamp = stamp[WEEK_OF_YEAR];
2446             bestStamp = Math.max(Math.max(womStamp, dowimStamp), woyStamp);
2447 
2448             /* Treat MONTH alone or no fields at all as DAY_OF_MONTH.  This may
2449              * result in bestStamp = domStamp = UNSET if no fields are set,
2450              * which indicates DAY_OF_MONTH.
2451              */
2452             if (bestStamp == UNSET) {
2453                 bestStamp = domStamp = monthStamp;
2454             }
2455         }
2456 
2457         if (bestStamp == domStamp ||
2458            (bestStamp == womStamp && stamp[WEEK_OF_MONTH] >= stamp[WEEK_OF_YEAR]) ||
2459            (bestStamp == dowimStamp && stamp[DAY_OF_WEEK_IN_MONTH] >= stamp[WEEK_OF_YEAR])) {
2460             fieldMask |= MONTH_MASK;
2461             if (bestStamp == domStamp) {
2462                 fieldMask |= DAY_OF_MONTH_MASK;
2463             } else {
2464                 assert (bestStamp == womStamp || bestStamp == dowimStamp);
2465                 if (dowStamp != UNSET) {
2466                     fieldMask |= DAY_OF_WEEK_MASK;
2467                 }
2468                 if (womStamp == dowimStamp) {
2469                     // When they are equal, give the priority to
2470                     // WEEK_OF_MONTH for compatibility.
2471                     if (stamp[WEEK_OF_MONTH] >= stamp[DAY_OF_WEEK_IN_MONTH]) {
2472                         fieldMask |= WEEK_OF_MONTH_MASK;
2473                     } else {
2474                         fieldMask |= DAY_OF_WEEK_IN_MONTH_MASK;
2475                     }
2476                 } else {
2477                     if (bestStamp == womStamp) {
2478                         fieldMask |= WEEK_OF_MONTH_MASK;
2479                     } else {
2480                         assert (bestStamp == dowimStamp);
2481                         if (stamp[DAY_OF_WEEK_IN_MONTH] != UNSET) {
2482                             fieldMask |= DAY_OF_WEEK_IN_MONTH_MASK;
2483                         }
2484                     }
2485                 }
2486             }
2487         } else {
2488             assert (bestStamp == doyStamp || bestStamp == woyStamp ||
2489                     bestStamp == UNSET);
2490             if (bestStamp == doyStamp) {
2491                 fieldMask |= DAY_OF_YEAR_MASK;
2492             } else {
2493                 assert (bestStamp == woyStamp);
2494                 if (dowStamp != UNSET) {
2495                     fieldMask |= DAY_OF_WEEK_MASK;
2496                 }
2497                 fieldMask |= WEEK_OF_YEAR_MASK;
2498             }
2499         }
2500 
2501         // Find the best set of fields specifying the time of day.  There
2502         // are only two possibilities here; the HOUR_OF_DAY or the
2503         // AM_PM and the HOUR.
2504         int hourOfDayStamp = stamp[HOUR_OF_DAY];
2505         int hourStamp = aggregateStamp(stamp[HOUR], stamp[AM_PM]);
2506         bestStamp = (hourStamp > hourOfDayStamp) ? hourStamp : hourOfDayStamp;
2507 
2508         // if bestStamp is still UNSET, then take HOUR or AM_PM. (See 4846659)
2509         if (bestStamp == UNSET) {
2510             bestStamp = Math.max(stamp[HOUR], stamp[AM_PM]);
2511         }
2512 
2513         // Hours
2514         if (bestStamp != UNSET) {
2515             if (bestStamp == hourOfDayStamp) {
2516                 fieldMask |= HOUR_OF_DAY_MASK;
2517             } else {
2518                 fieldMask |= HOUR_MASK;
2519                 if (stamp[AM_PM] != UNSET) {
2520                     fieldMask |= AM_PM_MASK;
2521                 }
2522             }
2523         }
2524         if (stamp[MINUTE] != UNSET) {
2525             fieldMask |= MINUTE_MASK;
2526         }
2527         if (stamp[SECOND] != UNSET) {
2528             fieldMask |= SECOND_MASK;
2529         }
2530         if (stamp[MILLISECOND] != UNSET) {
2531             fieldMask |= MILLISECOND_MASK;
2532         }
2533         if (stamp[ZONE_OFFSET] >= MINIMUM_USER_STAMP) {
2534                 fieldMask |= ZONE_OFFSET_MASK;
2535         }
2536         if (stamp[DST_OFFSET] >= MINIMUM_USER_STAMP) {
2537             fieldMask |= DST_OFFSET_MASK;
2538         }
2539 
2540         return fieldMask;
2541     }
2542 
2543     int getBaseStyle(int style) {
2544         return style & ~STANDALONE_MASK;
2545     }
2546 
2547     boolean isStandaloneStyle(int style) {
2548         return (style & STANDALONE_MASK) != 0;
2549     }
2550 
2551     boolean isNarrowStyle(int style) {
2552         return style == NARROW_FORMAT || style == NARROW_STANDALONE;
2553     }
2554 
2555     /**
2556      * Returns the pseudo-time-stamp for two fields, given their
2557      * individual pseudo-time-stamps.  If either of the fields
2558      * is unset, then the aggregate is unset.  Otherwise, the
2559      * aggregate is the later of the two stamps.
2560      */
2561     private static int aggregateStamp(int stamp_a, int stamp_b) {
2562         if (stamp_a == UNSET || stamp_b == UNSET) {
2563             return UNSET;
2564         }
2565         return (stamp_a > stamp_b) ? stamp_a : stamp_b;
2566     }
2567 
2568     /**
2569      * Returns an unmodifiable {@code Set} containing all calendar types
2570      * supported by {@code Calendar} in the runtime environment. The available
2571      * calendar types can be used for the <a
2572      * href="Locale.html#def_locale_extension">Unicode locale extensions</a>.
2573      * The {@code Set} returned contains at least {@code "gregory"}. The
2574      * calendar types don't include aliases, such as {@code "gregorian"} for
2575      * {@code "gregory"}.
2576      *
2577      * @return an unmodifiable {@code Set} containing all available calendar types
2578      * @since 1.8
2579      * @see #getCalendarType()
2580      * @see Calendar.Builder#setCalendarType(String)
2581      * @see Locale#getUnicodeLocaleType(String)
2582      */
2583     public static Set<String> getAvailableCalendarTypes() {
2584         return AvailableCalendarTypes.SET;
2585     }
2586 
2587     private static class AvailableCalendarTypes {
2588         private static final Set<String> SET;
2589         static {
2590             Set<String> set = new HashSet<>(3);
2591             set.add("gregory");
2592             set.add("buddhist");
2593             set.add("japanese");
2594             SET = Collections.unmodifiableSet(set);
2595         }
2596         private AvailableCalendarTypes() {
2597         }
2598     }
2599 
2600     /**
2601      * Returns the calendar type of this {@code Calendar}. Calendar types are
2602      * defined by the <em>Unicode Locale Data Markup Language (LDML)</em>
2603      * specification.
2604      *
2605      * <p>The default implementation of this method returns the class name of
2606      * this {@code Calendar} instance. Any subclasses that implement
2607      * LDML-defined calendar systems should override this method to return
2608      * appropriate calendar types.
2609      *
2610      * @return the LDML-defined calendar type or the class name of this
2611      *         {@code Calendar} instance
2612      * @since 1.8
2613      * @see <a href="Locale.html#def_extensions">Locale extensions</a>
2614      * @see Locale.Builder#setLocale(Locale)
2615      * @see Locale.Builder#setUnicodeLocaleKeyword(String, String)
2616      */
2617     public String getCalendarType() {
2618         return this.getClass().getName();
2619     }
2620 
2621     /**
2622      * Compares this <code>Calendar</code> to the specified
2623      * <code>Object</code>.  The result is <code>true</code> if and only if
2624      * the argument is a <code>Calendar</code> object of the same calendar
2625      * system that represents the same time value (millisecond offset from the
2626      * <a href="#Epoch">Epoch</a>) under the same
2627      * <code>Calendar</code> parameters as this object.
2628      *
2629      * <p>The <code>Calendar</code> parameters are the values represented
2630      * by the <code>isLenient</code>, <code>getFirstDayOfWeek</code>,
2631      * <code>getMinimalDaysInFirstWeek</code> and <code>getTimeZone</code>
2632      * methods. If there is any difference in those parameters
2633      * between the two <code>Calendar</code>s, this method returns
2634      * <code>false</code>.
2635      *
2636      * <p>Use the {@link #compareTo(Calendar) compareTo} method to
2637      * compare only the time values.
2638      *
2639      * @param obj the object to compare with.
2640      * @return <code>true</code> if this object is equal to <code>obj</code>;
2641      * <code>false</code> otherwise.
2642      */
2643     @SuppressWarnings("EqualsWhichDoesntCheckParameterClass")
2644     @Override
2645     public boolean equals(Object obj) {
2646         if (this == obj) {
2647             return true;
2648         }
2649         try {
2650             Calendar that = (Calendar)obj;
2651             return compareTo(getMillisOf(that)) == 0 &&
2652                 lenient == that.lenient &&
2653                 firstDayOfWeek == that.firstDayOfWeek &&
2654                 minimalDaysInFirstWeek == that.minimalDaysInFirstWeek &&
2655                 zone.equals(that.zone);
2656         } catch (Exception e) {
2657             // Note: GregorianCalendar.computeTime throws
2658             // IllegalArgumentException if the ERA value is invalid
2659             // even it's in lenient mode.
2660         }
2661         return false;
2662     }
2663 
2664     /**
2665      * Returns a hash code for this calendar.
2666      *
2667      * @return a hash code value for this object.
2668      * @since 1.2
2669      */
2670     @Override
2671     public int hashCode() {
2672         // 'otheritems' represents the hash code for the previous versions.
2673         int otheritems = (lenient ? 1 : 0)
2674             | (firstDayOfWeek << 1)
2675             | (minimalDaysInFirstWeek << 4)
2676             | (zone.hashCode() << 7);
2677         long t = getMillisOf(this);
2678         return (int) t ^ (int)(t >> 32) ^ otheritems;
2679     }
2680 
2681     /**
2682      * Returns whether this <code>Calendar</code> represents a time
2683      * before the time represented by the specified
2684      * <code>Object</code>. This method is equivalent to:
2685      * <pre>{@code
2686      *         compareTo(when) < 0
2687      * }</pre>
2688      * if and only if <code>when</code> is a <code>Calendar</code>
2689      * instance. Otherwise, the method returns <code>false</code>.
2690      *
2691      * @param when the <code>Object</code> to be compared
2692      * @return <code>true</code> if the time of this
2693      * <code>Calendar</code> is before the time represented by
2694      * <code>when</code>; <code>false</code> otherwise.
2695      * @see     #compareTo(Calendar)
2696      */
2697     public boolean before(Object when) {
2698         return when instanceof Calendar
2699             && compareTo((Calendar)when) < 0;
2700     }
2701 
2702     /**
2703      * Returns whether this <code>Calendar</code> represents a time
2704      * after the time represented by the specified
2705      * <code>Object</code>. This method is equivalent to:
2706      * <pre>{@code
2707      *         compareTo(when) > 0
2708      * }</pre>
2709      * if and only if <code>when</code> is a <code>Calendar</code>
2710      * instance. Otherwise, the method returns <code>false</code>.
2711      *
2712      * @param when the <code>Object</code> to be compared
2713      * @return <code>true</code> if the time of this <code>Calendar</code> is
2714      * after the time represented by <code>when</code>; <code>false</code>
2715      * otherwise.
2716      * @see     #compareTo(Calendar)
2717      */
2718     public boolean after(Object when) {
2719         return when instanceof Calendar
2720             && compareTo((Calendar)when) > 0;
2721     }
2722 
2723     /**
2724      * Compares the time values (millisecond offsets from the <a
2725      * href="#Epoch">Epoch</a>) represented by two
2726      * <code>Calendar</code> objects.
2727      *
2728      * @param anotherCalendar the <code>Calendar</code> to be compared.
2729      * @return the value <code>0</code> if the time represented by the argument
2730      * is equal to the time represented by this <code>Calendar</code>; a value
2731      * less than <code>0</code> if the time of this <code>Calendar</code> is
2732      * before the time represented by the argument; and a value greater than
2733      * <code>0</code> if the time of this <code>Calendar</code> is after the
2734      * time represented by the argument.
2735      * @exception NullPointerException if the specified <code>Calendar</code> is
2736      *            <code>null</code>.
2737      * @exception IllegalArgumentException if the time value of the
2738      * specified <code>Calendar</code> object can't be obtained due to
2739      * any invalid calendar values.
2740      * @since   1.5
2741      */
2742     @Override
2743     public int compareTo(Calendar anotherCalendar) {
2744         return compareTo(getMillisOf(anotherCalendar));
2745     }
2746 
2747     /**
2748      * Adds or subtracts the specified amount of time to the given calendar field,
2749      * based on the calendar's rules. For example, to subtract 5 days from
2750      * the current time of the calendar, you can achieve it by calling:
2751      * <p><code>add(Calendar.DAY_OF_MONTH, -5)</code>.
2752      *
2753      * @param field the calendar field.
2754      * @param amount the amount of date or time to be added to the field.
2755      * @see #roll(int,int)
2756      * @see #set(int,int)
2757      */
2758     abstract public void add(int field, int amount);
2759 
2760     /**
2761      * Adds or subtracts (up/down) a single unit of time on the given time
2762      * field without changing larger fields. For example, to roll the current
2763      * date up by one day, you can achieve it by calling:
2764      * <p>roll(Calendar.DATE, true).
2765      * When rolling on the year or Calendar.YEAR field, it will roll the year
2766      * value in the range between 1 and the value returned by calling
2767      * <code>getMaximum(Calendar.YEAR)</code>.
2768      * When rolling on the month or Calendar.MONTH field, other fields like
2769      * date might conflict and, need to be changed. For instance,
2770      * rolling the month on the date 01/31/96 will result in 02/29/96.
2771      * When rolling on the hour-in-day or Calendar.HOUR_OF_DAY field, it will
2772      * roll the hour value in the range between 0 and 23, which is zero-based.
2773      *
2774      * @param field the time field.
2775      * @param up indicates if the value of the specified time field is to be
2776      * rolled up or rolled down. Use true if rolling up, false otherwise.
2777      * @see Calendar#add(int,int)
2778      * @see Calendar#set(int,int)
2779      */
2780     abstract public void roll(int field, boolean up);
2781 
2782     /**
2783      * Adds the specified (signed) amount to the specified calendar field
2784      * without changing larger fields.  A negative amount means to roll
2785      * down.
2786      *
2787      * <p>NOTE:  This default implementation on <code>Calendar</code> just repeatedly calls the
2788      * version of {@link #roll(int,boolean) roll()} that rolls by one unit.  This may not
2789      * always do the right thing.  For example, if the <code>DAY_OF_MONTH</code> field is 31,
2790      * rolling through February will leave it set to 28.  The <code>GregorianCalendar</code>
2791      * version of this function takes care of this problem.  Other subclasses
2792      * should also provide overrides of this function that do the right thing.
2793      *
2794      * @param field the calendar field.
2795      * @param amount the signed amount to add to the calendar <code>field</code>.
2796      * @since 1.2
2797      * @see #roll(int,boolean)
2798      * @see #add(int,int)
2799      * @see #set(int,int)
2800      */
2801     public void roll(int field, int amount)
2802     {
2803         while (amount > 0) {
2804             roll(field, true);
2805             amount--;
2806         }
2807         while (amount < 0) {
2808             roll(field, false);
2809             amount++;
2810         }
2811     }
2812 
2813     /**
2814      * Sets the time zone with the given time zone value.
2815      *
2816      * @param value the given time zone.
2817      */
2818     public void setTimeZone(TimeZone value)
2819     {
2820         zone = value;
2821         sharedZone = false;
2822         /* Recompute the fields from the time using the new zone.  This also
2823          * works if isTimeSet is false (after a call to set()).  In that case
2824          * the time will be computed from the fields using the new zone, then
2825          * the fields will get recomputed from that.  Consider the sequence of
2826          * calls: cal.setTimeZone(EST); cal.set(HOUR, 1); cal.setTimeZone(PST).
2827          * Is cal set to 1 o'clock EST or 1 o'clock PST?  Answer: PST.  More
2828          * generally, a call to setTimeZone() affects calls to set() BEFORE AND
2829          * AFTER it up to the next call to complete().
2830          */
2831         areAllFieldsSet = areFieldsSet = false;
2832     }
2833 
2834     /**
2835      * Gets the time zone.
2836      *
2837      * @return the time zone object associated with this calendar.
2838      */
2839     public TimeZone getTimeZone()
2840     {
2841         // If the TimeZone object is shared by other Calendar instances, then
2842         // create a clone.
2843         if (sharedZone) {
2844             zone = (TimeZone) zone.clone();
2845             sharedZone = false;
2846         }
2847         return zone;
2848     }
2849 
2850     /**
2851      * Returns the time zone (without cloning).
2852      */
2853     TimeZone getZone() {
2854         return zone;
2855     }
2856 
2857     /**
2858      * Sets the sharedZone flag to <code>shared</code>.
2859      */
2860     void setZoneShared(boolean shared) {
2861         sharedZone = shared;
2862     }
2863 
2864     /**
2865      * Specifies whether or not date/time interpretation is to be lenient.  With
2866      * lenient interpretation, a date such as "February 942, 1996" will be
2867      * treated as being equivalent to the 941st day after February 1, 1996.
2868      * With strict (non-lenient) interpretation, such dates will cause an exception to be
2869      * thrown. The default is lenient.
2870      *
2871      * @param lenient <code>true</code> if the lenient mode is to be turned
2872      * on; <code>false</code> if it is to be turned off.
2873      * @see #isLenient()
2874      * @see java.text.DateFormat#setLenient
2875      */
2876     public void setLenient(boolean lenient)
2877     {
2878         this.lenient = lenient;
2879     }
2880 
2881     /**
2882      * Tells whether date/time interpretation is to be lenient.
2883      *
2884      * @return <code>true</code> if the interpretation mode of this calendar is lenient;
2885      * <code>false</code> otherwise.
2886      * @see #setLenient(boolean)
2887      */
2888     public boolean isLenient()
2889     {
2890         return lenient;
2891     }
2892 
2893     /**
2894      * Sets what the first day of the week is; e.g., <code>SUNDAY</code> in the U.S.,
2895      * <code>MONDAY</code> in France.
2896      *
2897      * @param value the given first day of the week.
2898      * @see #getFirstDayOfWeek()
2899      * @see #getMinimalDaysInFirstWeek()
2900      */
2901     public void setFirstDayOfWeek(int value)
2902     {
2903         if (firstDayOfWeek == value) {
2904             return;
2905         }
2906         firstDayOfWeek = value;
2907         invalidateWeekFields();
2908     }
2909 
2910     /**
2911      * Gets what the first day of the week is; e.g., <code>SUNDAY</code> in the U.S.,
2912      * <code>MONDAY</code> in France.
2913      *
2914      * @return the first day of the week.
2915      * @see #setFirstDayOfWeek(int)
2916      * @see #getMinimalDaysInFirstWeek()
2917      */
2918     public int getFirstDayOfWeek()
2919     {
2920         return firstDayOfWeek;
2921     }
2922 
2923     /**
2924      * Sets what the minimal days required in the first week of the year are;
2925      * For example, if the first week is defined as one that contains the first
2926      * day of the first month of a year, call this method with value 1. If it
2927      * must be a full week, use value 7.
2928      *
2929      * @param value the given minimal days required in the first week
2930      * of the year.
2931      * @see #getMinimalDaysInFirstWeek()
2932      */
2933     public void setMinimalDaysInFirstWeek(int value)
2934     {
2935         if (minimalDaysInFirstWeek == value) {
2936             return;
2937         }
2938         minimalDaysInFirstWeek = value;
2939         invalidateWeekFields();
2940     }
2941 
2942     /**
2943      * Gets what the minimal days required in the first week of the year are;
2944      * e.g., if the first week is defined as one that contains the first day
2945      * of the first month of a year, this method returns 1. If
2946      * the minimal days required must be a full week, this method
2947      * returns 7.
2948      *
2949      * @return the minimal days required in the first week of the year.
2950      * @see #setMinimalDaysInFirstWeek(int)
2951      */
2952     public int getMinimalDaysInFirstWeek()
2953     {
2954         return minimalDaysInFirstWeek;
2955     }
2956 
2957     /**
2958      * Returns whether this {@code Calendar} supports week dates.
2959      *
2960      * <p>The default implementation of this method returns {@code false}.
2961      *
2962      * @return {@code true} if this {@code Calendar} supports week dates;
2963      *         {@code false} otherwise.
2964      * @see #getWeekYear()
2965      * @see #setWeekDate(int,int,int)
2966      * @see #getWeeksInWeekYear()
2967      * @since 1.7
2968      */
2969     public boolean isWeekDateSupported() {
2970         return false;
2971     }
2972 
2973     /**
2974      * Returns the week year represented by this {@code Calendar}. The
2975      * week year is in sync with the week cycle. The {@linkplain
2976      * #getFirstDayOfWeek() first day of the first week} is the first
2977      * day of the week year.
2978      *
2979      * <p>The default implementation of this method throws an
2980      * {@link UnsupportedOperationException}.
2981      *
2982      * @return the week year of this {@code Calendar}
2983      * @exception UnsupportedOperationException
2984      *            if any week year numbering isn't supported
2985      *            in this {@code Calendar}.
2986      * @see #isWeekDateSupported()
2987      * @see #getFirstDayOfWeek()
2988      * @see #getMinimalDaysInFirstWeek()
2989      * @since 1.7
2990      */
2991     public int getWeekYear() {
2992         throw new UnsupportedOperationException();
2993     }
2994 
2995     /**
2996      * Sets the date of this {@code Calendar} with the the given date
2997      * specifiers - week year, week of year, and day of week.
2998      *
2999      * <p>Unlike the {@code set} method, all of the calendar fields
3000      * and {@code time} values are calculated upon return.
3001      *
3002      * <p>If {@code weekOfYear} is out of the valid week-of-year range
3003      * in {@code weekYear}, the {@code weekYear} and {@code
3004      * weekOfYear} values are adjusted in lenient mode, or an {@code
3005      * IllegalArgumentException} is thrown in non-lenient mode.
3006      *
3007      * <p>The default implementation of this method throws an
3008      * {@code UnsupportedOperationException}.
3009      *
3010      * @param weekYear   the week year
3011      * @param weekOfYear the week number based on {@code weekYear}
3012      * @param dayOfWeek  the day of week value: one of the constants
3013      *                   for the {@link #DAY_OF_WEEK} field: {@link
3014      *                   #SUNDAY}, ..., {@link #SATURDAY}.
3015      * @exception IllegalArgumentException
3016      *            if any of the given date specifiers is invalid
3017      *            or any of the calendar fields are inconsistent
3018      *            with the given date specifiers in non-lenient mode
3019      * @exception UnsupportedOperationException
3020      *            if any week year numbering isn't supported in this
3021      *            {@code Calendar}.
3022      * @see #isWeekDateSupported()
3023      * @see #getFirstDayOfWeek()
3024      * @see #getMinimalDaysInFirstWeek()
3025      * @since 1.7
3026      */
3027     public void setWeekDate(int weekYear, int weekOfYear, int dayOfWeek) {
3028         throw new UnsupportedOperationException();
3029     }
3030 
3031     /**
3032      * Returns the number of weeks in the week year represented by this
3033      * {@code Calendar}.
3034      *
3035      * <p>The default implementation of this method throws an
3036      * {@code UnsupportedOperationException}.
3037      *
3038      * @return the number of weeks in the week year.
3039      * @exception UnsupportedOperationException
3040      *            if any week year numbering isn't supported in this
3041      *            {@code Calendar}.
3042      * @see #WEEK_OF_YEAR
3043      * @see #isWeekDateSupported()
3044      * @see #getWeekYear()
3045      * @see #getActualMaximum(int)
3046      * @since 1.7
3047      */
3048     public int getWeeksInWeekYear() {
3049         throw new UnsupportedOperationException();
3050     }
3051 
3052     /**
3053      * Returns the minimum value for the given calendar field of this
3054      * <code>Calendar</code> instance. The minimum value is defined as
3055      * the smallest value returned by the {@link #get(int) get} method
3056      * for any possible time value.  The minimum value depends on
3057      * calendar system specific parameters of the instance.
3058      *
3059      * @param field the calendar field.
3060      * @return the minimum value for the given calendar field.
3061      * @see #getMaximum(int)
3062      * @see #getGreatestMinimum(int)
3063      * @see #getLeastMaximum(int)
3064      * @see #getActualMinimum(int)
3065      * @see #getActualMaximum(int)
3066      */
3067     abstract public int getMinimum(int field);
3068 
3069     /**
3070      * Returns the maximum value for the given calendar field of this
3071      * <code>Calendar</code> instance. The maximum value is defined as
3072      * the largest value returned by the {@link #get(int) get} method
3073      * for any possible time value. The maximum value depends on
3074      * calendar system specific parameters of the instance.
3075      *
3076      * @param field the calendar field.
3077      * @return the maximum value for the given calendar field.
3078      * @see #getMinimum(int)
3079      * @see #getGreatestMinimum(int)
3080      * @see #getLeastMaximum(int)
3081      * @see #getActualMinimum(int)
3082      * @see #getActualMaximum(int)
3083      */
3084     abstract public int getMaximum(int field);
3085 
3086     /**
3087      * Returns the highest minimum value for the given calendar field
3088      * of this <code>Calendar</code> instance. The highest minimum
3089      * value is defined as the largest value returned by {@link
3090      * #getActualMinimum(int)} for any possible time value. The
3091      * greatest minimum value depends on calendar system specific
3092      * parameters of the instance.
3093      *
3094      * @param field the calendar field.
3095      * @return the highest minimum value for the given calendar field.
3096      * @see #getMinimum(int)
3097      * @see #getMaximum(int)
3098      * @see #getLeastMaximum(int)
3099      * @see #getActualMinimum(int)
3100      * @see #getActualMaximum(int)
3101      */
3102     abstract public int getGreatestMinimum(int field);
3103 
3104     /**
3105      * Returns the lowest maximum value for the given calendar field
3106      * of this <code>Calendar</code> instance. The lowest maximum
3107      * value is defined as the smallest value returned by {@link
3108      * #getActualMaximum(int)} for any possible time value. The least
3109      * maximum value depends on calendar system specific parameters of
3110      * the instance. For example, a <code>Calendar</code> for the
3111      * Gregorian calendar system returns 28 for the
3112      * <code>DAY_OF_MONTH</code> field, because the 28th is the last
3113      * day of the shortest month of this calendar, February in a
3114      * common year.
3115      *
3116      * @param field the calendar field.
3117      * @return the lowest maximum value for the given calendar field.
3118      * @see #getMinimum(int)
3119      * @see #getMaximum(int)
3120      * @see #getGreatestMinimum(int)
3121      * @see #getActualMinimum(int)
3122      * @see #getActualMaximum(int)
3123      */
3124     abstract public int getLeastMaximum(int field);
3125 
3126     /**
3127      * Returns the minimum value that the specified calendar field
3128      * could have, given the time value of this <code>Calendar</code>.
3129      *
3130      * <p>The default implementation of this method uses an iterative
3131      * algorithm to determine the actual minimum value for the
3132      * calendar field. Subclasses should, if possible, override this
3133      * with a more efficient implementation - in many cases, they can
3134      * simply return <code>getMinimum()</code>.
3135      *
3136      * @param field the calendar field
3137      * @return the minimum of the given calendar field for the time
3138      * value of this <code>Calendar</code>
3139      * @see #getMinimum(int)
3140      * @see #getMaximum(int)
3141      * @see #getGreatestMinimum(int)
3142      * @see #getLeastMaximum(int)
3143      * @see #getActualMaximum(int)
3144      * @since 1.2
3145      */
3146     public int getActualMinimum(int field) {
3147         int fieldValue = getGreatestMinimum(field);
3148         int endValue = getMinimum(field);
3149 
3150         // if we know that the minimum value is always the same, just return it
3151         if (fieldValue == endValue) {
3152             return fieldValue;
3153         }
3154 
3155         // clone the calendar so we don't mess with the real one, and set it to
3156         // accept anything for the field values
3157         Calendar work = (Calendar)this.clone();
3158         work.setLenient(true);
3159 
3160         // now try each value from getLeastMaximum() to getMaximum() one by one until
3161         // we get a value that normalizes to another value.  The last value that
3162         // normalizes to itself is the actual minimum for the current date
3163         int result = fieldValue;
3164 
3165         do {
3166             work.set(field, fieldValue);
3167             if (work.get(field) != fieldValue) {
3168                 break;
3169             } else {
3170                 result = fieldValue;
3171                 fieldValue--;
3172             }
3173         } while (fieldValue >= endValue);
3174 
3175         return result;
3176     }
3177 
3178     /**
3179      * Returns the maximum value that the specified calendar field
3180      * could have, given the time value of this
3181      * <code>Calendar</code>. For example, the actual maximum value of
3182      * the <code>MONTH</code> field is 12 in some years, and 13 in
3183      * other years in the Hebrew calendar system.
3184      *
3185      * <p>The default implementation of this method uses an iterative
3186      * algorithm to determine the actual maximum value for the
3187      * calendar field. Subclasses should, if possible, override this
3188      * with a more efficient implementation.
3189      *
3190      * @param field the calendar field
3191      * @return the maximum of the given calendar field for the time
3192      * value of this <code>Calendar</code>
3193      * @see #getMinimum(int)
3194      * @see #getMaximum(int)
3195      * @see #getGreatestMinimum(int)
3196      * @see #getLeastMaximum(int)
3197      * @see #getActualMinimum(int)
3198      * @since 1.2
3199      */
3200     public int getActualMaximum(int field) {
3201         int fieldValue = getLeastMaximum(field);
3202         int endValue = getMaximum(field);
3203 
3204         // if we know that the maximum value is always the same, just return it.
3205         if (fieldValue == endValue) {
3206             return fieldValue;
3207         }
3208 
3209         // clone the calendar so we don't mess with the real one, and set it to
3210         // accept anything for the field values.
3211         Calendar work = (Calendar)this.clone();
3212         work.setLenient(true);
3213 
3214         // if we're counting weeks, set the day of the week to Sunday.  We know the
3215         // last week of a month or year will contain the first day of the week.
3216         if (field == WEEK_OF_YEAR || field == WEEK_OF_MONTH) {
3217             work.set(DAY_OF_WEEK, firstDayOfWeek);
3218         }
3219 
3220         // now try each value from getLeastMaximum() to getMaximum() one by one until
3221         // we get a value that normalizes to another value.  The last value that
3222         // normalizes to itself is the actual maximum for the current date
3223         int result = fieldValue;
3224 
3225         do {
3226             work.set(field, fieldValue);
3227             if (work.get(field) != fieldValue) {
3228                 break;
3229             } else {
3230                 result = fieldValue;
3231                 fieldValue++;
3232             }
3233         } while (fieldValue <= endValue);
3234 
3235         return result;
3236     }
3237 
3238     /**
3239      * Creates and returns a copy of this object.
3240      *
3241      * @return a copy of this object.
3242      */
3243     @Override
3244     public Object clone()
3245     {
3246         try {
3247             Calendar other = (Calendar) super.clone();
3248 
3249             other.fields = new int[FIELD_COUNT];
3250             other.isSet = new boolean[FIELD_COUNT];
3251             other.stamp = new int[FIELD_COUNT];
3252             for (int i = 0; i < FIELD_COUNT; i++) {
3253                 other.fields[i] = fields[i];
3254                 other.stamp[i] = stamp[i];
3255                 other.isSet[i] = isSet[i];
3256             }
3257             other.zone = (TimeZone) zone.clone();
3258             return other;
3259         }
3260         catch (CloneNotSupportedException e) {
3261             // this shouldn't happen, since we are Cloneable
3262             throw new InternalError(e);
3263         }
3264     }
3265 
3266     private static final String[] FIELD_NAME = {
3267         "ERA", "YEAR", "MONTH", "WEEK_OF_YEAR", "WEEK_OF_MONTH", "DAY_OF_MONTH",
3268         "DAY_OF_YEAR", "DAY_OF_WEEK", "DAY_OF_WEEK_IN_MONTH", "AM_PM", "HOUR",
3269         "HOUR_OF_DAY", "MINUTE", "SECOND", "MILLISECOND", "ZONE_OFFSET",
3270         "DST_OFFSET"
3271     };
3272 
3273     /**
3274      * Returns the name of the specified calendar field.
3275      *
3276      * @param field the calendar field
3277      * @return the calendar field name
3278      * @exception IndexOutOfBoundsException if <code>field</code> is negative,
3279      * equal to or greater then <code>FIELD_COUNT</code>.
3280      */
3281     static String getFieldName(int field) {
3282         return FIELD_NAME[field];
3283     }
3284 
3285     /**
3286      * Return a string representation of this calendar. This method
3287      * is intended to be used only for debugging purposes, and the
3288      * format of the returned string may vary between implementations.
3289      * The returned string may be empty but may not be <code>null</code>.
3290      *
3291      * @return  a string representation of this calendar.
3292      */
3293     @Override
3294     public String toString() {
3295         // NOTE: BuddhistCalendar.toString() interprets the string
3296         // produced by this method so that the Gregorian year number
3297         // is substituted by its B.E. year value. It relies on
3298         // "...,YEAR=<year>,..." or "...,YEAR=?,...".
3299         StringBuilder buffer = new StringBuilder(800);
3300         buffer.append(getClass().getName()).append('[');
3301         appendValue(buffer, "time", isTimeSet, time);
3302         buffer.append(",areFieldsSet=").append(areFieldsSet);
3303         buffer.append(",areAllFieldsSet=").append(areAllFieldsSet);
3304         buffer.append(",lenient=").append(lenient);
3305         buffer.append(",zone=").append(zone);
3306         appendValue(buffer, ",firstDayOfWeek", true, (long) firstDayOfWeek);
3307         appendValue(buffer, ",minimalDaysInFirstWeek", true, (long) minimalDaysInFirstWeek);
3308         for (int i = 0; i < FIELD_COUNT; ++i) {
3309             buffer.append(',');
3310             appendValue(buffer, FIELD_NAME[i], isSet(i), (long) fields[i]);
3311         }
3312         buffer.append(']');
3313         return buffer.toString();
3314     }
3315 
3316     // =======================privates===============================
3317 
3318     private static void appendValue(StringBuilder sb, String item, boolean valid, long value) {
3319         sb.append(item).append('=');
3320         if (valid) {
3321             sb.append(value);
3322         } else {
3323             sb.append('?');
3324         }
3325     }
3326 
3327     /**
3328      * Both firstDayOfWeek and minimalDaysInFirstWeek are locale-dependent.
3329      * They are used to figure out the week count for a specific date for
3330      * a given locale. These must be set when a Calendar is constructed.
3331      * @param desiredLocale the given locale.
3332      */
3333     private void setWeekCountData(Locale desiredLocale)
3334     {
3335         /* try to get the Locale data from the cache */
3336         int[] data = cachedLocaleData.get(desiredLocale);
3337         if (data == null) {  /* cache miss */
3338             data = new int[2];
3339             data[0] = CalendarDataUtility.retrieveFirstDayOfWeek(desiredLocale);
3340             data[1] = CalendarDataUtility.retrieveMinimalDaysInFirstWeek(desiredLocale);
3341             cachedLocaleData.putIfAbsent(desiredLocale, data);
3342         }
3343         firstDayOfWeek = data[0];
3344         minimalDaysInFirstWeek = data[1];
3345     }
3346 
3347     /**
3348      * Recomputes the time and updates the status fields isTimeSet
3349      * and areFieldsSet.  Callers should check isTimeSet and only
3350      * call this method if isTimeSet is false.
3351      */
3352     private void updateTime() {
3353         computeTime();
3354         // The areFieldsSet and areAllFieldsSet values are no longer
3355         // controlled here (as of 1.5).
3356         isTimeSet = true;
3357     }
3358 
3359     private int compareTo(long t) {
3360         long thisTime = getMillisOf(this);
3361         return (thisTime > t) ? 1 : (thisTime == t) ? 0 : -1;
3362     }
3363 
3364     private static long getMillisOf(Calendar calendar) {
3365         if (calendar.isTimeSet) {
3366             return calendar.time;
3367         }
3368         Calendar cal = (Calendar) calendar.clone();
3369         cal.setLenient(true);
3370         return cal.getTimeInMillis();
3371     }
3372 
3373     /**
3374      * Adjusts the stamp[] values before nextStamp overflow. nextStamp
3375      * is set to the next stamp value upon the return.
3376      */
3377     private void adjustStamp() {
3378         int max = MINIMUM_USER_STAMP;
3379         int newStamp = MINIMUM_USER_STAMP;
3380 
3381         for (;;) {
3382             int min = Integer.MAX_VALUE;
3383             for (int i = 0; i < stamp.length; i++) {
3384                 int v = stamp[i];
3385                 if (v >= newStamp && min > v) {
3386                     min = v;
3387                 }
3388                 if (max < v) {
3389                     max = v;
3390                 }
3391             }
3392             if (max != min && min == Integer.MAX_VALUE) {
3393                 break;
3394             }
3395             for (int i = 0; i < stamp.length; i++) {
3396                 if (stamp[i] == min) {
3397                     stamp[i] = newStamp;
3398                 }
3399             }
3400             newStamp++;
3401             if (min == max) {
3402                 break;
3403             }
3404         }
3405         nextStamp = newStamp;
3406     }
3407 
3408     /**
3409      * Sets the WEEK_OF_MONTH and WEEK_OF_YEAR fields to new values with the
3410      * new parameter value if they have been calculated internally.
3411      */
3412     private void invalidateWeekFields()
3413     {
3414         if (stamp[WEEK_OF_MONTH] != COMPUTED &&
3415             stamp[WEEK_OF_YEAR] != COMPUTED) {
3416             return;
3417         }
3418 
3419         // We have to check the new values of these fields after changing
3420         // firstDayOfWeek and/or minimalDaysInFirstWeek. If the field values
3421         // have been changed, then set the new values. (4822110)
3422         Calendar cal = (Calendar) clone();
3423         cal.setLenient(true);
3424         cal.clear(WEEK_OF_MONTH);
3425         cal.clear(WEEK_OF_YEAR);
3426 
3427         if (stamp[WEEK_OF_MONTH] == COMPUTED) {
3428             int weekOfMonth = cal.get(WEEK_OF_MONTH);
3429             if (fields[WEEK_OF_MONTH] != weekOfMonth) {
3430                 fields[WEEK_OF_MONTH] = weekOfMonth;
3431             }
3432         }
3433 
3434         if (stamp[WEEK_OF_YEAR] == COMPUTED) {
3435             int weekOfYear = cal.get(WEEK_OF_YEAR);
3436             if (fields[WEEK_OF_YEAR] != weekOfYear) {
3437                 fields[WEEK_OF_YEAR] = weekOfYear;
3438             }
3439         }
3440     }
3441 
3442     /**
3443      * Save the state of this object to a stream (i.e., serialize it).
3444      *
3445      * Ideally, <code>Calendar</code> would only write out its state data and
3446      * the current time, and not write any field data out, such as
3447      * <code>fields[]</code>, <code>isTimeSet</code>, <code>areFieldsSet</code>,
3448      * and <code>isSet[]</code>.  <code>nextStamp</code> also should not be part
3449      * of the persistent state. Unfortunately, this didn't happen before JDK 1.1
3450      * shipped. To be compatible with JDK 1.1, we will always have to write out
3451      * the field values and state flags.  However, <code>nextStamp</code> can be
3452      * removed from the serialization stream; this will probably happen in the
3453      * near future.
3454      */
3455     private synchronized void writeObject(ObjectOutputStream stream)
3456          throws IOException
3457     {
3458         // Try to compute the time correctly, for the future (stream
3459         // version 2) in which we don't write out fields[] or isSet[].
3460         if (!isTimeSet) {
3461             try {
3462                 updateTime();
3463             }
3464             catch (IllegalArgumentException e) {}
3465         }
3466 
3467         // If this Calendar has a ZoneInfo, save it and set a
3468         // SimpleTimeZone equivalent (as a single DST schedule) for
3469         // backward compatibility.
3470         TimeZone savedZone = null;
3471         if (zone instanceof ZoneInfo) {
3472             SimpleTimeZone stz = ((ZoneInfo)zone).getLastRuleInstance();
3473             if (stz == null) {
3474                 stz = new SimpleTimeZone(zone.getRawOffset(), zone.getID());
3475             }
3476             savedZone = zone;
3477             zone = stz;
3478         }
3479 
3480         // Write out the 1.1 FCS object.
3481         stream.defaultWriteObject();
3482 
3483         // Write out the ZoneInfo object
3484         // 4802409: we write out even if it is null, a temporary workaround
3485         // the real fix for bug 4844924 in corba-iiop
3486         stream.writeObject(savedZone);
3487         if (savedZone != null) {
3488             zone = savedZone;
3489         }
3490     }
3491 
3492     private static class CalendarAccessControlContext {
3493         private static final AccessControlContext INSTANCE;
3494         static {
3495             RuntimePermission perm = new RuntimePermission("accessClassInPackage.sun.util.calendar");
3496             PermissionCollection perms = perm.newPermissionCollection();
3497             perms.add(perm);
3498             INSTANCE = new AccessControlContext(new ProtectionDomain[] {
3499                                                     new ProtectionDomain(null, perms)
3500                                                 });
3501         }
3502         private CalendarAccessControlContext() {
3503         }
3504     }
3505 
3506     /**
3507      * Reconstitutes this object from a stream (i.e., deserialize it).
3508      */
3509     private void readObject(ObjectInputStream stream)
3510          throws IOException, ClassNotFoundException
3511     {
3512         final ObjectInputStream input = stream;
3513         input.defaultReadObject();
3514 
3515         stamp = new int[FIELD_COUNT];
3516 
3517         // Starting with version 2 (not implemented yet), we expect that
3518         // fields[], isSet[], isTimeSet, and areFieldsSet may not be
3519         // streamed out anymore.  We expect 'time' to be correct.
3520         if (serialVersionOnStream >= 2)
3521         {
3522             isTimeSet = true;
3523             if (fields == null) {
3524                 fields = new int[FIELD_COUNT];
3525             }
3526             if (isSet == null) {
3527                 isSet = new boolean[FIELD_COUNT];
3528             }
3529         }
3530         else if (serialVersionOnStream >= 0)
3531         {
3532             for (int i=0; i<FIELD_COUNT; ++i) {
3533                 stamp[i] = isSet[i] ? COMPUTED : UNSET;
3534             }
3535         }
3536 
3537         serialVersionOnStream = currentSerialVersion;
3538 
3539         // If there's a ZoneInfo object, use it for zone.
3540         ZoneInfo zi = null;
3541         try {
3542             zi = AccessController.doPrivileged(
3543                     new PrivilegedExceptionAction<ZoneInfo>() {
3544                         @Override
3545                         public ZoneInfo run() throws Exception {
3546                             return (ZoneInfo) input.readObject();
3547                         }
3548                     },
3549                     CalendarAccessControlContext.INSTANCE);
3550         } catch (PrivilegedActionException pae) {
3551             Exception e = pae.getException();
3552             if (!(e instanceof OptionalDataException)) {
3553                 if (e instanceof RuntimeException) {
3554                     throw (RuntimeException) e;
3555                 } else if (e instanceof IOException) {
3556                     throw (IOException) e;
3557                 } else if (e instanceof ClassNotFoundException) {
3558                     throw (ClassNotFoundException) e;
3559                 }
3560                 throw new RuntimeException(e);
3561             }
3562         }
3563         if (zi != null) {
3564             zone = zi;
3565         }
3566 
3567         // If the deserialized object has a SimpleTimeZone, try to
3568         // replace it with a ZoneInfo equivalent (as of 1.4) in order
3569         // to be compatible with the SimpleTimeZone-based
3570         // implementation as much as possible.
3571         if (zone instanceof SimpleTimeZone) {
3572             String id = zone.getID();
3573             TimeZone tz = TimeZone.getTimeZone(id);
3574             if (tz != null && tz.hasSameRules(zone) && tz.getID().equals(id)) {
3575                 zone = tz;
3576             }
3577         }
3578     }
3579 
3580     /**
3581      * Converts this object to an {@link Instant}.
3582      * <p>
3583      * The conversion creates an {@code Instant} that represents the
3584      * same point on the time-line as this {@code Calendar}.
3585      *
3586      * @return the instant representing the same point on the time-line
3587      * @since 1.8
3588      */
3589     public final Instant toInstant() {
3590         return Instant.ofEpochMilli(getTimeInMillis());
3591     }
3592 }