1/* GENERATED SOURCE. DO NOT MODIFY. */ 2// © 2016 and later: Unicode, Inc. and others. 3// License & terms of use: http://www.unicode.org/copyright.html#License 4/* 5 * Copyright (C) 1996-2016, International Business Machines 6 * Corporation and others. All Rights Reserved. 7 */ 8 9package android.icu.util; 10 11import java.util.Date; 12import java.util.Locale; 13 14import android.icu.util.ULocale.Category; 15 16/** 17 * <strong>[icu enhancement]</strong> ICU's replacement for {@link java.util.GregorianCalendar}. Methods, fields, and other functionality specific to ICU are labeled '<strong>[icu]</strong>'. 18 * 19 * <p><code>GregorianCalendar</code> is a concrete subclass of 20 * {@link Calendar} 21 * and provides the standard calendar used by most of the world. 22 * 23 * <p>The standard (Gregorian) calendar has 2 eras, BC and AD. 24 * 25 * <p>This implementation handles a single discontinuity, which corresponds by 26 * default to the date the Gregorian calendar was instituted (October 15, 1582 27 * in some countries, later in others). The cutover date may be changed by the 28 * caller by calling <code>setGregorianChange()</code>. 29 * 30 * <p>Historically, in those countries which adopted the Gregorian calendar first, 31 * October 4, 1582 was thus followed by October 15, 1582. This calendar models 32 * this correctly. Before the Gregorian cutover, <code>GregorianCalendar</code> 33 * implements the Julian calendar. The only difference between the Gregorian 34 * and the Julian calendar is the leap year rule. The Julian calendar specifies 35 * leap years every four years, whereas the Gregorian calendar omits century 36 * years which are not divisible by 400. 37 * 38 * <p><code>GregorianCalendar</code> implements <em>proleptic</em> Gregorian and 39 * Julian calendars. That is, dates are computed by extrapolating the current 40 * rules indefinitely far backward and forward in time. As a result, 41 * <code>GregorianCalendar</code> may be used for all years to generate 42 * meaningful and consistent results. However, dates obtained using 43 * <code>GregorianCalendar</code> are historically accurate only from March 1, 4 44 * AD onward, when modern Julian calendar rules were adopted. Before this date, 45 * leap year rules were applied irregularly, and before 45 BC the Julian 46 * calendar did not even exist. 47 * 48 * <p>Prior to the institution of the Gregorian calendar, New Year's Day was 49 * March 25. To avoid confusion, this calendar always uses January 1. A manual 50 * adjustment may be made if desired for dates that are prior to the Gregorian 51 * changeover and which fall between January 1 and March 24. 52 * 53 * <p>Values calculated for the <code>WEEK_OF_YEAR</code> field range from 1 to 54 * 53. Week 1 for a year is the earliest seven day period starting on 55 * <code>getFirstDayOfWeek()</code> that contains at least 56 * <code>getMinimalDaysInFirstWeek()</code> days from that year. It thus 57 * depends on the values of <code>getMinimalDaysInFirstWeek()</code>, 58 * <code>getFirstDayOfWeek()</code>, and the day of the week of January 1. 59 * Weeks between week 1 of one year and week 1 of the following year are 60 * numbered sequentially from 2 to 52 or 53 (as needed). 61 62 * <p>For example, January 1, 1998 was a Thursday. If 63 * <code>getFirstDayOfWeek()</code> is <code>MONDAY</code> and 64 * <code>getMinimalDaysInFirstWeek()</code> is 4 (these are the values 65 * reflecting ISO 8601 and many national standards), then week 1 of 1998 starts 66 * on December 29, 1997, and ends on January 4, 1998. If, however, 67 * <code>getFirstDayOfWeek()</code> is <code>SUNDAY</code>, then week 1 of 1998 68 * starts on January 4, 1998, and ends on January 10, 1998; the first three days 69 * of 1998 then are part of week 53 of 1997. 70 * 71 * <p>Values calculated for the <code>WEEK_OF_MONTH</code> field range from 0 or 72 * 1 to 4 or 5. Week 1 of a month (the days with <code>WEEK_OF_MONTH = 73 * 1</code>) is the earliest set of at least 74 * <code>getMinimalDaysInFirstWeek()</code> contiguous days in that month, 75 * ending on the day before <code>getFirstDayOfWeek()</code>. Unlike 76 * week 1 of a year, week 1 of a month may be shorter than 7 days, need 77 * not start on <code>getFirstDayOfWeek()</code>, and will not include days of 78 * the previous month. Days of a month before week 1 have a 79 * <code>WEEK_OF_MONTH</code> of 0. 80 * 81 * <p>For example, if <code>getFirstDayOfWeek()</code> is <code>SUNDAY</code> 82 * and <code>getMinimalDaysInFirstWeek()</code> is 4, then the first week of 83 * January 1998 is Sunday, January 4 through Saturday, January 10. These days 84 * have a <code>WEEK_OF_MONTH</code> of 1. Thursday, January 1 through 85 * Saturday, January 3 have a <code>WEEK_OF_MONTH</code> of 0. If 86 * <code>getMinimalDaysInFirstWeek()</code> is changed to 3, then January 1 87 * through January 3 have a <code>WEEK_OF_MONTH</code> of 1. 88 * 89 * <p> 90 * <strong>Example:</strong> 91 * <blockquote> 92 * <pre> 93 * // get the supported ids for GMT-08:00 (Pacific Standard Time) 94 * String[] ids = TimeZone.getAvailableIDs(-8 * 60 * 60 * 1000); 95 * // if no ids were returned, something is wrong. get out. 96 * if (ids.length == 0) 97 * System.exit(0); 98 * 99 * // begin output 100 * System.out.println("Current Time"); 101 * 102 * // create a Pacific Standard Time time zone 103 * SimpleTimeZone pdt = new SimpleTimeZone(-8 * 60 * 60 * 1000, ids[0]); 104 * 105 * // set up rules for daylight savings time 106 * pdt.setStartRule(Calendar.MARCH, 2, Calendar.SUNDAY, 2 * 60 * 60 * 1000); 107 * pdt.setEndRule(Calendar.NOVEMBER, 1, Calendar.SUNDAY, 2 * 60 * 60 * 1000); 108 * 109 * // create a GregorianCalendar with the Pacific Daylight time zone 110 * // and the current date and time 111 * Calendar calendar = new GregorianCalendar(pdt); 112 * Date trialTime = new Date(); 113 * calendar.setTime(trialTime); 114 * 115 * // print out a bunch of interesting things 116 * System.out.println("ERA: " + calendar.get(Calendar.ERA)); 117 * System.out.println("YEAR: " + calendar.get(Calendar.YEAR)); 118 * System.out.println("MONTH: " + calendar.get(Calendar.MONTH)); 119 * System.out.println("WEEK_OF_YEAR: " + calendar.get(Calendar.WEEK_OF_YEAR)); 120 * System.out.println("WEEK_OF_MONTH: " + calendar.get(Calendar.WEEK_OF_MONTH)); 121 * System.out.println("DATE: " + calendar.get(Calendar.DATE)); 122 * System.out.println("DAY_OF_MONTH: " + calendar.get(Calendar.DAY_OF_MONTH)); 123 * System.out.println("DAY_OF_YEAR: " + calendar.get(Calendar.DAY_OF_YEAR)); 124 * System.out.println("DAY_OF_WEEK: " + calendar.get(Calendar.DAY_OF_WEEK)); 125 * System.out.println("DAY_OF_WEEK_IN_MONTH: " 126 * + calendar.get(Calendar.DAY_OF_WEEK_IN_MONTH)); 127 * System.out.println("AM_PM: " + calendar.get(Calendar.AM_PM)); 128 * System.out.println("HOUR: " + calendar.get(Calendar.HOUR)); 129 * System.out.println("HOUR_OF_DAY: " + calendar.get(Calendar.HOUR_OF_DAY)); 130 * System.out.println("MINUTE: " + calendar.get(Calendar.MINUTE)); 131 * System.out.println("SECOND: " + calendar.get(Calendar.SECOND)); 132 * System.out.println("MILLISECOND: " + calendar.get(Calendar.MILLISECOND)); 133 * System.out.println("ZONE_OFFSET: " 134 * + (calendar.get(Calendar.ZONE_OFFSET)/(60*60*1000))); 135 * System.out.println("DST_OFFSET: " 136 * + (calendar.get(Calendar.DST_OFFSET)/(60*60*1000))); 137 138 * System.out.println("Current Time, with hour reset to 3"); 139 * calendar.clear(Calendar.HOUR_OF_DAY); // so doesn't override 140 * calendar.set(Calendar.HOUR, 3); 141 * System.out.println("ERA: " + calendar.get(Calendar.ERA)); 142 * System.out.println("YEAR: " + calendar.get(Calendar.YEAR)); 143 * System.out.println("MONTH: " + calendar.get(Calendar.MONTH)); 144 * System.out.println("WEEK_OF_YEAR: " + calendar.get(Calendar.WEEK_OF_YEAR)); 145 * System.out.println("WEEK_OF_MONTH: " + calendar.get(Calendar.WEEK_OF_MONTH)); 146 * System.out.println("DATE: " + calendar.get(Calendar.DATE)); 147 * System.out.println("DAY_OF_MONTH: " + calendar.get(Calendar.DAY_OF_MONTH)); 148 * System.out.println("DAY_OF_YEAR: " + calendar.get(Calendar.DAY_OF_YEAR)); 149 * System.out.println("DAY_OF_WEEK: " + calendar.get(Calendar.DAY_OF_WEEK)); 150 * System.out.println("DAY_OF_WEEK_IN_MONTH: " 151 * + calendar.get(Calendar.DAY_OF_WEEK_IN_MONTH)); 152 * System.out.println("AM_PM: " + calendar.get(Calendar.AM_PM)); 153 * System.out.println("HOUR: " + calendar.get(Calendar.HOUR)); 154 * System.out.println("HOUR_OF_DAY: " + calendar.get(Calendar.HOUR_OF_DAY)); 155 * System.out.println("MINUTE: " + calendar.get(Calendar.MINUTE)); 156 * System.out.println("SECOND: " + calendar.get(Calendar.SECOND)); 157 * System.out.println("MILLISECOND: " + calendar.get(Calendar.MILLISECOND)); 158 * System.out.println("ZONE_OFFSET: " 159 * + (calendar.get(Calendar.ZONE_OFFSET)/(60*60*1000))); // in hours 160 * System.out.println("DST_OFFSET: " 161 * + (calendar.get(Calendar.DST_OFFSET)/(60*60*1000))); // in hours</pre> 162 * </blockquote> 163 * <p> 164 * GregorianCalendar usually should be instantiated using 165 * {@link android.icu.util.Calendar#getInstance(ULocale)} passing in a <code>ULocale</code> 166 * with the tag <code>"@calendar=gregorian"</code>.</p> 167 168 * @see Calendar 169 * @see TimeZone 170 * @author Deborah Goldsmith, Mark Davis, Chen-Lieh Huang, Alan Liu 171 */ 172public class GregorianCalendar extends Calendar { 173 // jdk1.4.2 serialver 174 private static final long serialVersionUID = 9199388694351062137L; 175 176 /* 177 * Implementation Notes 178 * 179 * The Julian day number, as used here, is a modified number which has its 180 * onset at midnight, rather than noon. 181 * 182 * The epoch is the number of days or milliseconds from some defined 183 * starting point. The epoch for java.util.Date is used here; that is, 184 * milliseconds from January 1, 1970 (Gregorian), midnight UTC. Other 185 * epochs which are used are January 1, year 1 (Gregorian), which is day 1 186 * of the Gregorian calendar, and December 30, year 0 (Gregorian), which is 187 * day 1 of the Julian calendar. 188 * 189 * We implement the proleptic Julian and Gregorian calendars. This means we 190 * implement the modern definition of the calendar even though the 191 * historical usage differs. For example, if the Gregorian change is set 192 * to new Date(Long.MIN_VALUE), we have a pure Gregorian calendar which 193 * labels dates preceding the invention of the Gregorian calendar in 1582 as 194 * if the calendar existed then. 195 * 196 * Likewise, with the Julian calendar, we assume a consistent 4-year leap 197 * rule, even though the historical pattern of leap years is irregular, 198 * being every 3 years from 45 BC through 9 BC, then every 4 years from 8 AD 199 * onwards, with no leap years in-between. Thus date computations and 200 * functions such as isLeapYear() are not intended to be historically 201 * accurate. 202 * 203 * Given that milliseconds are a long, day numbers such as Julian day 204 * numbers, Gregorian or Julian calendar days, or epoch days, are also 205 * longs. Years can fit into an int. 206 */ 207 208////////////////// 209// Class Variables 210////////////////// 211 212 /** 213 * Value of the <code>ERA</code> field indicating 214 * the period before the common era (before Christ), also known as BCE. 215 * The sequence of years at the transition from <code>BC</code> to <code>AD</code> is 216 * ..., 2 BC, 1 BC, 1 AD, 2 AD,... 217 * @see Calendar#ERA 218 */ 219 public static final int BC = 0; 220 221 /** 222 * Value of the <code>ERA</code> field indicating 223 * the common era (Anno Domini), also known as CE. 224 * The sequence of years at the transition from <code>BC</code> to <code>AD</code> is 225 * ..., 2 BC, 1 BC, 1 AD, 2 AD,... 226 * @see Calendar#ERA 227 */ 228 public static final int AD = 1; 229 230 private static final int EPOCH_YEAR = 1970; 231 232 private static final int[][] MONTH_COUNT = { 233 //len len2 st st2 234 { 31, 31, 0, 0 }, // Jan 235 { 28, 29, 31, 31 }, // Feb 236 { 31, 31, 59, 60 }, // Mar 237 { 30, 30, 90, 91 }, // Apr 238 { 31, 31, 120, 121 }, // May 239 { 30, 30, 151, 152 }, // Jun 240 { 31, 31, 181, 182 }, // Jul 241 { 31, 31, 212, 213 }, // Aug 242 { 30, 30, 243, 244 }, // Sep 243 { 31, 31, 273, 274 }, // Oct 244 { 30, 30, 304, 305 }, // Nov 245 { 31, 31, 334, 335 } // Dec 246 // len length of month 247 // len2 length of month in a leap year 248 // st days in year before start of month 249 // st2 days in year before month in leap year 250 }; 251 252 /** 253 * Old year limits were least max 292269054, max 292278994. 254 */ 255 private static final int LIMITS[][] = { 256 // Minimum Greatest Least Maximum 257 // Minimum Maximum 258 { 0, 0, 1, 1 }, // ERA 259 { 1, 1, 5828963, 5838270 }, // YEAR 260 { 0, 0, 11, 11 }, // MONTH 261 { 1, 1, 52, 53 }, // WEEK_OF_YEAR 262 {/* */}, // WEEK_OF_MONTH 263 { 1, 1, 28, 31 }, // DAY_OF_MONTH 264 { 1, 1, 365, 366 }, // DAY_OF_YEAR 265 {/* */}, // DAY_OF_WEEK 266 { -1, -1, 4, 5 }, // DAY_OF_WEEK_IN_MONTH 267 {/* */}, // AM_PM 268 {/* */}, // HOUR 269 {/* */}, // HOUR_OF_DAY 270 {/* */}, // MINUTE 271 {/* */}, // SECOND 272 {/* */}, // MILLISECOND 273 {/* */}, // ZONE_OFFSET 274 {/* */}, // DST_OFFSET 275 { -5838270, -5838270, 5828964, 5838271 }, // YEAR_WOY 276 {/* */}, // DOW_LOCAL 277 { -5838269, -5838269, 5828963, 5838270 }, // EXTENDED_YEAR 278 {/* */}, // JULIAN_DAY 279 {/* */}, // MILLISECONDS_IN_DAY 280 {/* */}, // IS_LEAP_MONTH 281 }; 282 283 /** 284 */ 285 protected int handleGetLimit(int field, int limitType) { 286 return LIMITS[field][limitType]; 287 } 288 289///////////////////// 290// Instance Variables 291///////////////////// 292 293 /** 294 * The point at which the Gregorian calendar rules are used, measured in 295 * milliseconds from the standard epoch. Default is October 15, 1582 296 * (Gregorian) 00:00:00 UTC or -12219292800000L. For this value, October 4, 297 * 1582 (Julian) is followed by October 15, 1582 (Gregorian). This 298 * corresponds to Julian day number 2299161. 299 * @serial 300 */ 301 private long gregorianCutover = -12219292800000L; 302 303 /** 304 * Julian day number of the Gregorian cutover. 305 */ 306 private transient int cutoverJulianDay = 2299161; 307 308 /** 309 * The year of the gregorianCutover, with 0 representing 310 * 1 BC, -1 representing 2 BC, etc. 311 */ 312 private transient int gregorianCutoverYear = 1582; 313 314 /** 315 * Used by handleComputeJulianDay() and handleComputeMonthStart(). 316 */ 317 transient protected boolean isGregorian; 318 319 /** 320 * Used by handleComputeJulianDay() and handleComputeMonthStart(). 321 */ 322 transient protected boolean invertGregorian; 323 324/////////////// 325// Constructors 326/////////////// 327 328 /** 329 * Constructs a default GregorianCalendar using the current time 330 * in the default time zone with the default <code>FORMAT</code> locale. 331 * @see Category#FORMAT 332 */ 333 public GregorianCalendar() { 334 this(TimeZone.getDefault(), ULocale.getDefault(Category.FORMAT)); 335 } 336 337 /** 338 * Constructs a GregorianCalendar based on the current time 339 * in the given time zone with the default <code>FORMAT</code> locale. 340 * @param zone the given time zone. 341 * @see Category#FORMAT 342 */ 343 public GregorianCalendar(TimeZone zone) { 344 this(zone, ULocale.getDefault(Category.FORMAT)); 345 } 346 347 /** 348 * Constructs a GregorianCalendar based on the current time 349 * in the default time zone with the given locale. 350 * @param aLocale the given locale. 351 */ 352 public GregorianCalendar(Locale aLocale) { 353 this(TimeZone.getDefault(), aLocale); 354 } 355 356 /** 357 * <strong>[icu]</strong> Constructs a GregorianCalendar based on the current time 358 * in the default time zone with the given locale. 359 * @param locale the given ulocale. 360 */ 361 public GregorianCalendar(ULocale locale) { 362 this(TimeZone.getDefault(), locale); 363 } 364 365 /** 366 * <strong>[icu]</strong> Constructs a GregorianCalendar based on the current time 367 * in the given time zone with the given locale. 368 * @param zone the given time zone. 369 * @param aLocale the given locale. 370 */ 371 public GregorianCalendar(TimeZone zone, Locale aLocale) { 372 super(zone, aLocale); 373 setTimeInMillis(System.currentTimeMillis()); 374 } 375 376 /** 377 * Constructs a GregorianCalendar based on the current time 378 * in the given time zone with the given locale. 379 * @param zone the given time zone. 380 * @param locale the given ulocale. 381 */ 382 public GregorianCalendar(TimeZone zone, ULocale locale) { 383 super(zone, locale); 384 setTimeInMillis(System.currentTimeMillis()); 385 } 386 387 /** 388 * Constructs a GregorianCalendar with the given date set 389 * in the default time zone with the default <code>FORMAT</code> locale. 390 * @param year the value used to set the YEAR time field in the calendar. 391 * @param month the value used to set the MONTH time field in the calendar. 392 * Month value is 0-based. e.g., 0 for January. 393 * @param date the value used to set the DATE time field in the calendar. 394 * @see Category#FORMAT 395 */ 396 public GregorianCalendar(int year, int month, int date) { 397 super(TimeZone.getDefault(), ULocale.getDefault(Category.FORMAT)); 398 set(ERA, AD); 399 set(YEAR, year); 400 set(MONTH, month); 401 set(DATE, date); 402 } 403 404 /** 405 * Constructs a GregorianCalendar with the given date 406 * and time set for the default time zone with the default <code>FORMAT</code> locale. 407 * @param year the value used to set the YEAR time field in the calendar. 408 * @param month the value used to set the MONTH time field in the calendar. 409 * Month value is 0-based. e.g., 0 for January. 410 * @param date the value used to set the DATE time field in the calendar. 411 * @param hour the value used to set the HOUR_OF_DAY time field 412 * in the calendar. 413 * @param minute the value used to set the MINUTE time field 414 * in the calendar. 415 * @see Category#FORMAT 416 */ 417 public GregorianCalendar(int year, int month, int date, int hour, 418 int minute) { 419 super(TimeZone.getDefault(), ULocale.getDefault(Category.FORMAT)); 420 set(ERA, AD); 421 set(YEAR, year); 422 set(MONTH, month); 423 set(DATE, date); 424 set(HOUR_OF_DAY, hour); 425 set(MINUTE, minute); 426 } 427 428 /** 429 * Constructs a GregorianCalendar with the given date 430 * and time set for the default time zone with the default <code>FORMAT</code> locale. 431 * @param year the value used to set the YEAR time field in the calendar. 432 * @param month the value used to set the MONTH time field in the calendar. 433 * Month value is 0-based. e.g., 0 for January. 434 * @param date the value used to set the DATE time field in the calendar. 435 * @param hour the value used to set the HOUR_OF_DAY time field 436 * in the calendar. 437 * @param minute the value used to set the MINUTE time field 438 * in the calendar. 439 * @param second the value used to set the SECOND time field 440 * in the calendar. 441 * @see Category#FORMAT 442 */ 443 public GregorianCalendar(int year, int month, int date, int hour, 444 int minute, int second) { 445 super(TimeZone.getDefault(), ULocale.getDefault(Category.FORMAT)); 446 set(ERA, AD); 447 set(YEAR, year); 448 set(MONTH, month); 449 set(DATE, date); 450 set(HOUR_OF_DAY, hour); 451 set(MINUTE, minute); 452 set(SECOND, second); 453 } 454 455///////////////// 456// Public methods 457///////////////// 458 459 /** 460 * Sets the GregorianCalendar change date. This is the point when the switch 461 * from Julian dates to Gregorian dates occurred. Default is October 15, 462 * 1582. Previous to this, dates will be in the Julian calendar. 463 * <p> 464 * To obtain a pure Julian calendar, set the change date to 465 * <code>Date(Long.MAX_VALUE)</code>. To obtain a pure Gregorian calendar, 466 * set the change date to <code>Date(Long.MIN_VALUE)</code>. 467 * 468 * @param date the given Gregorian cutover date. 469 */ 470 public void setGregorianChange(Date date) { 471 gregorianCutover = date.getTime(); 472 473 // If the cutover has an extreme value, then create a pure 474 // Gregorian or pure Julian calendar by giving the cutover year and 475 // JD extreme values. 476 if (gregorianCutover <= MIN_MILLIS) { 477 gregorianCutoverYear = cutoverJulianDay = Integer.MIN_VALUE; 478 } else if (gregorianCutover >= MAX_MILLIS) { 479 gregorianCutoverYear = cutoverJulianDay = Integer.MAX_VALUE; 480 } else { 481 // Precompute two internal variables which we use to do the actual 482 // cutover computations. These are the Julian day of the cutover 483 // and the cutover year. 484 cutoverJulianDay = (int) floorDivide(gregorianCutover, ONE_DAY); 485 486 // Convert cutover millis to extended year 487 GregorianCalendar cal = new GregorianCalendar(getTimeZone()); 488 cal.setTime(date); 489 gregorianCutoverYear = cal.get(EXTENDED_YEAR); 490 } 491 } 492 493 /** 494 * Gets the Gregorian Calendar change date. This is the point when the 495 * switch from Julian dates to Gregorian dates occurred. Default is 496 * October 15, 1582. Previous to this, dates will be in the Julian 497 * calendar. 498 * @return the Gregorian cutover date for this calendar. 499 */ 500 public final Date getGregorianChange() { 501 return new Date(gregorianCutover); 502 } 503 504 /** 505 * Determines if the given year is a leap year. Returns true if the 506 * given year is a leap year. 507 * @param year the given year. 508 * @return true if the given year is a leap year; false otherwise. 509 */ 510 public boolean isLeapYear(int year) { 511 return year >= gregorianCutoverYear ? 512 ((year%4 == 0) && ((year%100 != 0) || (year%400 == 0))) : // Gregorian 513 (year%4 == 0); // Julian 514 } 515 516 /** 517 * Returns true if the given Calendar object is equivalent to this 518 * one. Calendar override. 519 * 520 * @param other the Calendar to be compared with this Calendar 521 */ 522 public boolean isEquivalentTo(Calendar other) { 523 return super.isEquivalentTo(other) && 524 gregorianCutover == ((GregorianCalendar)other).gregorianCutover; 525 } 526 527 /** 528 * Override hashCode. 529 * Generates the hash code for the GregorianCalendar object 530 */ 531 public int hashCode() { 532 return super.hashCode() ^ (int)gregorianCutover; 533 } 534 535 /** 536 * Roll a field by a signed amount. 537 */ 538 public void roll(int field, int amount) { 539 540 switch (field) { 541 case WEEK_OF_YEAR: 542 { 543 // Unlike WEEK_OF_MONTH, WEEK_OF_YEAR never shifts the day of the 544 // week. Also, rolling the week of the year can have seemingly 545 // strange effects simply because the year of the week of year 546 // may be different from the calendar year. For example, the 547 // date Dec 28, 1997 is the first day of week 1 of 1998 (if 548 // weeks start on Sunday and the minimal days in first week is 549 // <= 3). 550 int woy = get(WEEK_OF_YEAR); 551 // Get the ISO year, which matches the week of year. This 552 // may be one year before or after the calendar year. 553 int isoYear = get(YEAR_WOY); 554 int isoDoy = internalGet(DAY_OF_YEAR); 555 if (internalGet(MONTH) == Calendar.JANUARY) { 556 if (woy >= 52) { 557 isoDoy += handleGetYearLength(isoYear); 558 } 559 } else { 560 if (woy == 1) { 561 isoDoy -= handleGetYearLength(isoYear - 1); 562 } 563 } 564 woy += amount; 565 // Do fast checks to avoid unnecessary computation: 566 if (woy < 1 || woy > 52) { 567 // Determine the last week of the ISO year. 568 // We do this using the standard formula we use 569 // everywhere in this file. If we can see that the 570 // days at the end of the year are going to fall into 571 // week 1 of the next year, we drop the last week by 572 // subtracting 7 from the last day of the year. 573 int lastDoy = handleGetYearLength(isoYear); 574 int lastRelDow = (lastDoy - isoDoy + internalGet(DAY_OF_WEEK) - 575 getFirstDayOfWeek()) % 7; 576 if (lastRelDow < 0) lastRelDow += 7; 577 if ((6 - lastRelDow) >= getMinimalDaysInFirstWeek()) lastDoy -= 7; 578 int lastWoy = weekNumber(lastDoy, lastRelDow + 1); 579 woy = ((woy + lastWoy - 1) % lastWoy) + 1; 580 } 581 set(WEEK_OF_YEAR, woy); 582 set(YEAR, isoYear); // Why not YEAR_WOY? - Alan 11/6/00 583 return; 584 } 585 586 default: 587 super.roll(field, amount); 588 return; 589 } 590 } 591 592 /** 593 * Return the minimum value that this field could have, given the current date. 594 * For the Gregorian calendar, this is the same as getMinimum() and getGreatestMinimum(). 595 */ 596 public int getActualMinimum(int field) { 597 return getMinimum(field); 598 } 599 600 /** 601 * Return the maximum value that this field could have, given the current date. 602 * For example, with the date "Feb 3, 1997" and the DAY_OF_MONTH field, the actual 603 * maximum would be 28; for "Feb 3, 1996" it s 29. Similarly for a Hebrew calendar, 604 * for some years the actual maximum for MONTH is 12, and for others 13. 605 */ 606 public int getActualMaximum(int field) { 607 /* It is a known limitation that the code here (and in getActualMinimum) 608 * won't behave properly at the extreme limits of GregorianCalendar's 609 * representable range (except for the code that handles the YEAR 610 * field). That's because the ends of the representable range are at 611 * odd spots in the year. For calendars with the default Gregorian 612 * cutover, these limits are Sun Dec 02 16:47:04 GMT 292269055 BC to Sun 613 * Aug 17 07:12:55 GMT 292278994 AD, somewhat different for non-GMT 614 * zones. As a result, if the calendar is set to Aug 1 292278994 AD, 615 * the actual maximum of DAY_OF_MONTH is 17, not 30. If the date is Mar 616 * 31 in that year, the actual maximum month might be Jul, whereas is 617 * the date is Mar 15, the actual maximum might be Aug -- depending on 618 * the precise semantics that are desired. Similar considerations 619 * affect all fields. Nonetheless, this effect is sufficiently arcane 620 * that we permit it, rather than complicating the code to handle such 621 * intricacies. - liu 8/20/98 622 623 * UPDATE: No longer true, since we have pulled in the limit values on 624 * the year. - Liu 11/6/00 */ 625 626 switch (field) { 627 628 case YEAR: 629 /* The year computation is no different, in principle, from the 630 * others, however, the range of possible maxima is large. In 631 * addition, the way we know we've exceeded the range is different. 632 * For these reasons, we use the special case code below to handle 633 * this field. 634 * 635 * The actual maxima for YEAR depend on the type of calendar: 636 * 637 * Gregorian = May 17, 292275056 BC - Aug 17, 292278994 AD 638 * Julian = Dec 2, 292269055 BC - Jan 3, 292272993 AD 639 * Hybrid = Dec 2, 292269055 BC - Aug 17, 292278994 AD 640 * 641 * We know we've exceeded the maximum when either the month, date, 642 * time, or era changes in response to setting the year. We don't 643 * check for month, date, and time here because the year and era are 644 * sufficient to detect an invalid year setting. NOTE: If code is 645 * added to check the month and date in the future for some reason, 646 * Feb 29 must be allowed to shift to Mar 1 when setting the year. 647 */ 648 { 649 Calendar cal = (Calendar) clone(); 650 cal.setLenient(true); 651 652 int era = cal.get(ERA); 653 Date d = cal.getTime(); 654 655 /* Perform a binary search, with the invariant that lowGood is a 656 * valid year, and highBad is an out of range year. 657 */ 658 int lowGood = LIMITS[YEAR][1]; 659 int highBad = LIMITS[YEAR][2]+1; 660 while ((lowGood + 1) < highBad) { 661 int y = (lowGood + highBad) / 2; 662 cal.set(YEAR, y); 663 if (cal.get(YEAR) == y && cal.get(ERA) == era) { 664 lowGood = y; 665 } else { 666 highBad = y; 667 cal.setTime(d); // Restore original fields 668 } 669 } 670 671 return lowGood; 672 } 673 674 default: 675 return super.getActualMaximum(field); 676 } 677 } 678 679////////////////////// 680// Proposed public API 681////////////////////// 682 683 /** 684 * Return true if the current time for this Calendar is in Daylignt 685 * Savings Time. 686 */ 687 boolean inDaylightTime() { 688 if (!getTimeZone().useDaylightTime()) return false; 689 complete(); // Force update of DST_OFFSET field 690 return internalGet(DST_OFFSET) != 0; 691 } 692 693 694///////////////////// 695// Calendar framework 696///////////////////// 697 698 /** 699 */ 700 protected int handleGetMonthLength(int extendedYear, int month) { 701 // If the month is out of range, adjust it into range, and 702 // modify the extended year value accordingly. 703 if (month < 0 || month > 11) { 704 int[] rem = new int[1]; 705 extendedYear += floorDivide(month, 12, rem); 706 month = rem[0]; 707 } 708 709 return MONTH_COUNT[month][isLeapYear(extendedYear)?1:0]; 710 } 711 712 /** 713 */ 714 protected int handleGetYearLength(int eyear) { 715 return isLeapYear(eyear) ? 366 : 365; 716 } 717 718///////////////////////////// 719// Time => Fields computation 720///////////////////////////// 721 722 /** 723 * Override Calendar to compute several fields specific to the hybrid 724 * Gregorian-Julian calendar system. These are: 725 * 726 * <ul><li>ERA 727 * <li>YEAR 728 * <li>MONTH 729 * <li>DAY_OF_MONTH 730 * <li>DAY_OF_YEAR 731 * <li>EXTENDED_YEAR</ul> 732 */ 733 protected void handleComputeFields(int julianDay) { 734 int eyear, month, dayOfMonth, dayOfYear; 735 736 if (julianDay >= cutoverJulianDay) { 737 month = getGregorianMonth(); 738 dayOfMonth = getGregorianDayOfMonth(); 739 dayOfYear = getGregorianDayOfYear(); 740 eyear = getGregorianYear(); 741 } else { 742 // The Julian epoch day (not the same as Julian Day) 743 // is zero on Saturday December 30, 0 (Gregorian). 744 long julianEpochDay = julianDay - (JAN_1_1_JULIAN_DAY - 2); 745 eyear = (int) floorDivide(4*julianEpochDay + 1464, 1461); 746 747 // Compute the Julian calendar day number for January 1, eyear 748 long january1 = 365L*(eyear-1L) + floorDivide(eyear-1L, 4L); 749 dayOfYear = (int)(julianEpochDay - january1); // 0-based 750 751 // Julian leap years occurred historically every 4 years starting 752 // with 8 AD. Before 8 AD the spacing is irregular; every 3 years 753 // from 45 BC to 9 BC, and then none until 8 AD. However, we don't 754 // implement this historical detail; instead, we implement the 755 // computatinally cleaner proleptic calendar, which assumes 756 // consistent 4-year cycles throughout time. 757 boolean isLeap = ((eyear&0x3) == 0); // equiv. to (eyear%4 == 0) 758 759 // Common Julian/Gregorian calculation 760 int correction = 0; 761 int march1 = isLeap ? 60 : 59; // zero-based DOY for March 1 762 if (dayOfYear >= march1) { 763 correction = isLeap ? 1 : 2; 764 } 765 month = (12 * (dayOfYear + correction) + 6) / 367; // zero-based month 766 dayOfMonth = dayOfYear - MONTH_COUNT[month][isLeap?3:2] + 1; // one-based DOM 767 ++dayOfYear; 768 } 769 internalSet(MONTH, month); 770 internalSet(DAY_OF_MONTH, dayOfMonth); 771 internalSet(DAY_OF_YEAR, dayOfYear); 772 internalSet(EXTENDED_YEAR, eyear); 773 int era = AD; 774 if (eyear < 1) { 775 era = BC; 776 eyear = 1 - eyear; 777 } 778 internalSet(ERA, era); 779 internalSet(YEAR, eyear); 780 } 781 782///////////////////////////// 783// Fields => Time computation 784///////////////////////////// 785 786 /** 787 */ 788 protected int handleGetExtendedYear() { 789 int year; 790 if (newerField(EXTENDED_YEAR, YEAR) == EXTENDED_YEAR) { 791 year = internalGet(EXTENDED_YEAR, EPOCH_YEAR); 792 } else { 793 // The year defaults to the epoch start, the era to AD 794 int era = internalGet(ERA, AD); 795 if (era == BC) { 796 year = 1 - internalGet(YEAR, 1); // Convert to extended year 797 } else { 798 year = internalGet(YEAR, EPOCH_YEAR); 799 } 800 } 801 return year; 802 } 803 804 /** 805 */ 806 protected int handleComputeJulianDay(int bestField) { 807 808 invertGregorian = false; 809 810 int jd = super.handleComputeJulianDay(bestField); 811 812 // The following check handles portions of the cutover year BEFORE the 813 // cutover itself happens. 814 if (isGregorian != (jd >= cutoverJulianDay)) { 815 invertGregorian = true; 816 jd = super.handleComputeJulianDay(bestField); 817 } 818 819 return jd; 820 } 821 822 /** 823 * Return JD of start of given month/year 824 */ 825 protected int handleComputeMonthStart(int eyear, int month, boolean useMonth) { 826 827 // If the month is out of range, adjust it into range, and 828 // modify the extended year value accordingly. 829 if (month < 0 || month > 11) { 830 int[] rem = new int[1]; 831 eyear += floorDivide(month, 12, rem); 832 month = rem[0]; 833 } 834 835 boolean isLeap = eyear%4 == 0; 836 int y = eyear - 1; 837 int julianDay = 365*y + floorDivide(y, 4) + (JAN_1_1_JULIAN_DAY - 3); 838 839 isGregorian = (eyear >= gregorianCutoverYear); 840 if (invertGregorian) { 841 isGregorian = !isGregorian; 842 } 843 if (isGregorian) { 844 isLeap = isLeap && ((eyear%100 != 0) || (eyear%400 == 0)); 845 // Add 2 because Gregorian calendar starts 2 days after 846 // Julian calendar 847 julianDay += floorDivide(y, 400) - floorDivide(y, 100) + 2; 848 } 849 850 // At this point julianDay indicates the day BEFORE the first 851 // day of January 1, <eyear> of either the Julian or Gregorian 852 // calendar. 853 854 if (month != 0) { 855 julianDay += MONTH_COUNT[month][isLeap?3:2]; 856 } 857 858 return julianDay; 859 } 860 861 /** 862 * {@inheritDoc} 863 */ 864 public String getType() { 865 return "gregorian"; 866 } 867 868 /* 869 private static CalendarFactory factory; 870 public static CalendarFactory factory() { 871 if (factory == null) { 872 factory = new CalendarFactory() { 873 public Calendar create(TimeZone tz, ULocale loc) { 874 return new GregorianCalendar(tz, loc); 875 } 876 877 public String factoryName() { 878 return "Gregorian"; 879 } 880 }; 881 } 882 return factory; 883 } 884 */ 885} 886