1 /* 2 * Copyright (c) 2012, 2013, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. Oracle designates this 8 * particular file as subject to the "Classpath" exception as provided 9 * by Oracle in the LICENSE file that accompanied this code. 10 * 11 * This code is distributed in the hope that it will be useful, but WITHOUT 12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 14 * version 2 for more details (a copy is included in the LICENSE file that 15 * accompanied this code). 16 * 17 * You should have received a copy of the GNU General Public License version 18 * 2 along with this work; if not, write to the Free Software Foundation, 19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 20 * 21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 22 * or visit www.oracle.com if you need additional information or have any 23 * questions. 24 */ 25 26 /* 27 * This file is available under and governed by the GNU General Public 28 * License version 2 only, as published by the Free Software Foundation. 29 * However, the following notice accompanied the original version of this 30 * file: 31 * 32 * Copyright (c) 2012-2013, Stephen Colebourne & Michael Nascimento Santos 33 * 34 * All rights reserved. 35 * 36 * Redistribution and use in source and binary forms, with or without 37 * modification, are permitted provided that the following conditions are met: 38 * 39 * * Redistributions of source code must retain the above copyright notice, 40 * this list of conditions and the following disclaimer. 41 * 42 * * Redistributions in binary form must reproduce the above copyright notice, 43 * this list of conditions and the following disclaimer in the documentation 44 * and/or other materials provided with the distribution. 45 * 46 * * Neither the name of JSR-310 nor the names of its contributors 47 * may be used to endorse or promote products derived from this software 48 * without specific prior written permission. 49 * 50 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 51 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 52 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 53 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR 54 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, 55 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, 56 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR 57 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF 58 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING 59 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS 60 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 61 */ 62 package java.time.temporal; 63 64 import static java.time.temporal.ChronoField.DAY_OF_MONTH; 65 import static java.time.temporal.ChronoField.DAY_OF_WEEK; 66 import static java.time.temporal.ChronoField.DAY_OF_YEAR; 67 import static java.time.temporal.ChronoUnit.DAYS; 68 import static java.time.temporal.ChronoUnit.MONTHS; 69 import static java.time.temporal.ChronoUnit.YEARS; 70 71 import java.time.DayOfWeek; 72 import java.time.LocalDate; 73 import java.util.Objects; 74 import java.util.function.UnaryOperator; 75 76 /** 77 * Common and useful TemporalAdjusters. 78 * <p> 79 * Adjusters are a key tool for modifying temporal objects. 80 * They exist to externalize the process of adjustment, permitting different 81 * approaches, as per the strategy design pattern. 82 * Examples might be an adjuster that sets the date avoiding weekends, or one that 83 * sets the date to the last day of the month. 84 * <p> 85 * There are two equivalent ways of using a {@code TemporalAdjuster}. 86 * The first is to invoke the method on the interface directly. 87 * The second is to use {@link Temporal#with(TemporalAdjuster)}: 88 * <pre> 89 * // these two lines are equivalent, but the second approach is recommended 90 * temporal = thisAdjuster.adjustInto(temporal); 91 * temporal = temporal.with(thisAdjuster); 92 * </pre> 93 * It is recommended to use the second approach, {@code with(TemporalAdjuster)}, 94 * as it is a lot clearer to read in code. 95 * <p> 96 * This class contains a standard set of adjusters, available as static methods. 97 * These include: 98 * <ul> 99 * <li>finding the first or last day of the month 100 * <li>finding the first day of next month 101 * <li>finding the first or last day of the year 102 * <li>finding the first day of next year 103 * <li>finding the first or last day-of-week within a month, such as "first Wednesday in June" 104 * <li>finding the next or previous day-of-week, such as "next Thursday" 105 * </ul> 106 * 107 * @implSpec 108 * All the implementations supplied by the static methods are immutable. 109 * 110 * @see TemporalAdjuster 111 * @since 1.8 112 */ 113 public final class TemporalAdjusters { 114 115 /** 116 * Private constructor since this is a utility class. 117 */ TemporalAdjusters()118 private TemporalAdjusters() { 119 } 120 121 //----------------------------------------------------------------------- 122 /** 123 * Obtains a {@code TemporalAdjuster} that wraps a date adjuster. 124 * <p> 125 * The {@code TemporalAdjuster} is based on the low level {@code Temporal} interface. 126 * This method allows an adjustment from {@code LocalDate} to {@code LocalDate} 127 * to be wrapped to match the temporal-based interface. 128 * This is provided for convenience to make user-written adjusters simpler. 129 * <p> 130 * In general, user-written adjusters should be static constants: 131 * <pre>{@code 132 * static TemporalAdjuster TWO_DAYS_LATER = 133 * TemporalAdjusters.ofDateAdjuster(date -> date.plusDays(2)); 134 * }</pre> 135 * 136 * @param dateBasedAdjuster the date-based adjuster, not null 137 * @return the temporal adjuster wrapping on the date adjuster, not null 138 */ ofDateAdjuster(UnaryOperator<LocalDate> dateBasedAdjuster)139 public static TemporalAdjuster ofDateAdjuster(UnaryOperator<LocalDate> dateBasedAdjuster) { 140 Objects.requireNonNull(dateBasedAdjuster, "dateBasedAdjuster"); 141 return (temporal) -> { 142 LocalDate input = LocalDate.from(temporal); 143 LocalDate output = dateBasedAdjuster.apply(input); 144 return temporal.with(output); 145 }; 146 } 147 148 //----------------------------------------------------------------------- 149 /** 150 * Returns the "first day of month" adjuster, which returns a new date set to 151 * the first day of the current month. 152 * <p> 153 * The ISO calendar system behaves as follows:<br> 154 * The input 2011-01-15 will return 2011-01-01.<br> 155 * The input 2011-02-15 will return 2011-02-01. 156 * <p> 157 * The behavior is suitable for use with most calendar systems. 158 * It is equivalent to: 159 * <pre> 160 * temporal.with(DAY_OF_MONTH, 1); 161 * </pre> 162 * 163 * @return the first day-of-month adjuster, not null 164 */ firstDayOfMonth()165 public static TemporalAdjuster firstDayOfMonth() { 166 return (temporal) -> temporal.with(DAY_OF_MONTH, 1); 167 } 168 169 /** 170 * Returns the "last day of month" adjuster, which returns a new date set to 171 * the last day of the current month. 172 * <p> 173 * The ISO calendar system behaves as follows:<br> 174 * The input 2011-01-15 will return 2011-01-31.<br> 175 * The input 2011-02-15 will return 2011-02-28.<br> 176 * The input 2012-02-15 will return 2012-02-29 (leap year).<br> 177 * The input 2011-04-15 will return 2011-04-30. 178 * <p> 179 * The behavior is suitable for use with most calendar systems. 180 * It is equivalent to: 181 * <pre> 182 * long lastDay = temporal.range(DAY_OF_MONTH).getMaximum(); 183 * temporal.with(DAY_OF_MONTH, lastDay); 184 * </pre> 185 * 186 * @return the last day-of-month adjuster, not null 187 */ lastDayOfMonth()188 public static TemporalAdjuster lastDayOfMonth() { 189 return (temporal) -> temporal.with(DAY_OF_MONTH, temporal.range(DAY_OF_MONTH).getMaximum()); 190 } 191 192 /** 193 * Returns the "first day of next month" adjuster, which returns a new date set to 194 * the first day of the next month. 195 * <p> 196 * The ISO calendar system behaves as follows:<br> 197 * The input 2011-01-15 will return 2011-02-01.<br> 198 * The input 2011-02-15 will return 2011-03-01. 199 * <p> 200 * The behavior is suitable for use with most calendar systems. 201 * It is equivalent to: 202 * <pre> 203 * temporal.with(DAY_OF_MONTH, 1).plus(1, MONTHS); 204 * </pre> 205 * 206 * @return the first day of next month adjuster, not null 207 */ firstDayOfNextMonth()208 public static TemporalAdjuster firstDayOfNextMonth() { 209 return (temporal) -> temporal.with(DAY_OF_MONTH, 1).plus(1, MONTHS); 210 } 211 212 //----------------------------------------------------------------------- 213 /** 214 * Returns the "first day of year" adjuster, which returns a new date set to 215 * the first day of the current year. 216 * <p> 217 * The ISO calendar system behaves as follows:<br> 218 * The input 2011-01-15 will return 2011-01-01.<br> 219 * The input 2011-02-15 will return 2011-01-01.<br> 220 * <p> 221 * The behavior is suitable for use with most calendar systems. 222 * It is equivalent to: 223 * <pre> 224 * temporal.with(DAY_OF_YEAR, 1); 225 * </pre> 226 * 227 * @return the first day-of-year adjuster, not null 228 */ firstDayOfYear()229 public static TemporalAdjuster firstDayOfYear() { 230 return (temporal) -> temporal.with(DAY_OF_YEAR, 1); 231 } 232 233 /** 234 * Returns the "last day of year" adjuster, which returns a new date set to 235 * the last day of the current year. 236 * <p> 237 * The ISO calendar system behaves as follows:<br> 238 * The input 2011-01-15 will return 2011-12-31.<br> 239 * The input 2011-02-15 will return 2011-12-31.<br> 240 * <p> 241 * The behavior is suitable for use with most calendar systems. 242 * It is equivalent to: 243 * <pre> 244 * long lastDay = temporal.range(DAY_OF_YEAR).getMaximum(); 245 * temporal.with(DAY_OF_YEAR, lastDay); 246 * </pre> 247 * 248 * @return the last day-of-year adjuster, not null 249 */ lastDayOfYear()250 public static TemporalAdjuster lastDayOfYear() { 251 return (temporal) -> temporal.with(DAY_OF_YEAR, temporal.range(DAY_OF_YEAR).getMaximum()); 252 } 253 254 /** 255 * Returns the "first day of next year" adjuster, which returns a new date set to 256 * the first day of the next year. 257 * <p> 258 * The ISO calendar system behaves as follows:<br> 259 * The input 2011-01-15 will return 2012-01-01. 260 * <p> 261 * The behavior is suitable for use with most calendar systems. 262 * It is equivalent to: 263 * <pre> 264 * temporal.with(DAY_OF_YEAR, 1).plus(1, YEARS); 265 * </pre> 266 * 267 * @return the first day of next month adjuster, not null 268 */ firstDayOfNextYear()269 public static TemporalAdjuster firstDayOfNextYear() { 270 return (temporal) -> temporal.with(DAY_OF_YEAR, 1).plus(1, YEARS); 271 } 272 273 //----------------------------------------------------------------------- 274 /** 275 * Returns the first in month adjuster, which returns a new date 276 * in the same month with the first matching day-of-week. 277 * This is used for expressions like 'first Tuesday in March'. 278 * <p> 279 * The ISO calendar system behaves as follows:<br> 280 * The input 2011-12-15 for (MONDAY) will return 2011-12-05.<br> 281 * The input 2011-12-15 for (FRIDAY) will return 2011-12-02.<br> 282 * <p> 283 * The behavior is suitable for use with most calendar systems. 284 * It uses the {@code DAY_OF_WEEK} and {@code DAY_OF_MONTH} fields 285 * and the {@code DAYS} unit, and assumes a seven day week. 286 * 287 * @param dayOfWeek the day-of-week, not null 288 * @return the first in month adjuster, not null 289 */ firstInMonth(DayOfWeek dayOfWeek)290 public static TemporalAdjuster firstInMonth(DayOfWeek dayOfWeek) { 291 return TemporalAdjusters.dayOfWeekInMonth(1, dayOfWeek); 292 } 293 294 /** 295 * Returns the last in month adjuster, which returns a new date 296 * in the same month with the last matching day-of-week. 297 * This is used for expressions like 'last Tuesday in March'. 298 * <p> 299 * The ISO calendar system behaves as follows:<br> 300 * The input 2011-12-15 for (MONDAY) will return 2011-12-26.<br> 301 * The input 2011-12-15 for (FRIDAY) will return 2011-12-30.<br> 302 * <p> 303 * The behavior is suitable for use with most calendar systems. 304 * It uses the {@code DAY_OF_WEEK} and {@code DAY_OF_MONTH} fields 305 * and the {@code DAYS} unit, and assumes a seven day week. 306 * 307 * @param dayOfWeek the day-of-week, not null 308 * @return the first in month adjuster, not null 309 */ lastInMonth(DayOfWeek dayOfWeek)310 public static TemporalAdjuster lastInMonth(DayOfWeek dayOfWeek) { 311 return TemporalAdjusters.dayOfWeekInMonth(-1, dayOfWeek); 312 } 313 314 /** 315 * Returns the day-of-week in month adjuster, which returns a new date 316 * in the same month with the ordinal day-of-week. 317 * This is used for expressions like the 'second Tuesday in March'. 318 * <p> 319 * The ISO calendar system behaves as follows:<br> 320 * The input 2011-12-15 for (1,TUESDAY) will return 2011-12-06.<br> 321 * The input 2011-12-15 for (2,TUESDAY) will return 2011-12-13.<br> 322 * The input 2011-12-15 for (3,TUESDAY) will return 2011-12-20.<br> 323 * The input 2011-12-15 for (4,TUESDAY) will return 2011-12-27.<br> 324 * The input 2011-12-15 for (5,TUESDAY) will return 2012-01-03.<br> 325 * The input 2011-12-15 for (-1,TUESDAY) will return 2011-12-27 (last in month).<br> 326 * The input 2011-12-15 for (-4,TUESDAY) will return 2011-12-06 (3 weeks before last in month).<br> 327 * The input 2011-12-15 for (-5,TUESDAY) will return 2011-11-29 (4 weeks before last in month).<br> 328 * The input 2011-12-15 for (0,TUESDAY) will return 2011-11-29 (last in previous month).<br> 329 * <p> 330 * For a positive or zero ordinal, the algorithm is equivalent to finding the first 331 * day-of-week that matches within the month and then adding a number of weeks to it. 332 * For a negative ordinal, the algorithm is equivalent to finding the last 333 * day-of-week that matches within the month and then subtracting a number of weeks to it. 334 * The ordinal number of weeks is not validated and is interpreted leniently 335 * according to this algorithm. This definition means that an ordinal of zero finds 336 * the last matching day-of-week in the previous month. 337 * <p> 338 * The behavior is suitable for use with most calendar systems. 339 * It uses the {@code DAY_OF_WEEK} and {@code DAY_OF_MONTH} fields 340 * and the {@code DAYS} unit, and assumes a seven day week. 341 * 342 * @param ordinal the week within the month, unbounded but typically from -5 to 5 343 * @param dayOfWeek the day-of-week, not null 344 * @return the day-of-week in month adjuster, not null 345 */ dayOfWeekInMonth(int ordinal, DayOfWeek dayOfWeek)346 public static TemporalAdjuster dayOfWeekInMonth(int ordinal, DayOfWeek dayOfWeek) { 347 Objects.requireNonNull(dayOfWeek, "dayOfWeek"); 348 int dowValue = dayOfWeek.getValue(); 349 if (ordinal >= 0) { 350 return (temporal) -> { 351 Temporal temp = temporal.with(DAY_OF_MONTH, 1); 352 int curDow = temp.get(DAY_OF_WEEK); 353 int dowDiff = (dowValue - curDow + 7) % 7; 354 dowDiff += (ordinal - 1L) * 7L; // safe from overflow 355 return temp.plus(dowDiff, DAYS); 356 }; 357 } else { 358 return (temporal) -> { 359 Temporal temp = temporal.with(DAY_OF_MONTH, temporal.range(DAY_OF_MONTH).getMaximum()); 360 int curDow = temp.get(DAY_OF_WEEK); 361 int daysDiff = dowValue - curDow; 362 daysDiff = (daysDiff == 0 ? 0 : (daysDiff > 0 ? daysDiff - 7 : daysDiff)); 363 daysDiff -= (-ordinal - 1L) * 7L; // safe from overflow 364 return temp.plus(daysDiff, DAYS); 365 }; 366 } 367 } 368 369 //----------------------------------------------------------------------- 370 /** 371 * Returns the next day-of-week adjuster, which adjusts the date to the 372 * first occurrence of the specified day-of-week after the date being adjusted. 373 * <p> 374 * The ISO calendar system behaves as follows:<br> 375 * The input 2011-01-15 (a Saturday) for parameter (MONDAY) will return 2011-01-17 (two days later).<br> 376 * The input 2011-01-15 (a Saturday) for parameter (WEDNESDAY) will return 2011-01-19 (four days later).<br> 377 * The input 2011-01-15 (a Saturday) for parameter (SATURDAY) will return 2011-01-22 (seven days later). 378 * <p> 379 * The behavior is suitable for use with most calendar systems. 380 * It uses the {@code DAY_OF_WEEK} field and the {@code DAYS} unit, 381 * and assumes a seven day week. 382 * 383 * @param dayOfWeek the day-of-week to move the date to, not null 384 * @return the next day-of-week adjuster, not null 385 */ 386 public static TemporalAdjuster next(DayOfWeek dayOfWeek) { 387 int dowValue = dayOfWeek.getValue(); 388 return (temporal) -> { 389 int calDow = temporal.get(DAY_OF_WEEK); 390 int daysDiff = calDow - dowValue; 391 return temporal.plus(daysDiff >= 0 ? 7 - daysDiff : -daysDiff, DAYS); 392 }; 393 } 394 395 /** 396 * Returns the next-or-same day-of-week adjuster, which adjusts the date to the 397 * first occurrence of the specified day-of-week after the date being adjusted 398 * unless it is already on that day in which case the same object is returned. 399 * <p> 400 * The ISO calendar system behaves as follows:<br> 401 * The input 2011-01-15 (a Saturday) for parameter (MONDAY) will return 2011-01-17 (two days later).<br> 402 * The input 2011-01-15 (a Saturday) for parameter (WEDNESDAY) will return 2011-01-19 (four days later).<br> 403 * The input 2011-01-15 (a Saturday) for parameter (SATURDAY) will return 2011-01-15 (same as input). 404 * <p> 405 * The behavior is suitable for use with most calendar systems. 406 * It uses the {@code DAY_OF_WEEK} field and the {@code DAYS} unit, 407 * and assumes a seven day week. 408 * 409 * @param dayOfWeek the day-of-week to check for or move the date to, not null 410 * @return the next-or-same day-of-week adjuster, not null 411 */ 412 public static TemporalAdjuster nextOrSame(DayOfWeek dayOfWeek) { 413 int dowValue = dayOfWeek.getValue(); 414 return (temporal) -> { 415 int calDow = temporal.get(DAY_OF_WEEK); 416 if (calDow == dowValue) { 417 return temporal; 418 } 419 int daysDiff = calDow - dowValue; 420 return temporal.plus(daysDiff >= 0 ? 7 - daysDiff : -daysDiff, DAYS); 421 }; 422 } 423 424 /** 425 * Returns the previous day-of-week adjuster, which adjusts the date to the 426 * first occurrence of the specified day-of-week before the date being adjusted. 427 * <p> 428 * The ISO calendar system behaves as follows:<br> 429 * The input 2011-01-15 (a Saturday) for parameter (MONDAY) will return 2011-01-10 (five days earlier).<br> 430 * The input 2011-01-15 (a Saturday) for parameter (WEDNESDAY) will return 2011-01-12 (three days earlier).<br> 431 * The input 2011-01-15 (a Saturday) for parameter (SATURDAY) will return 2011-01-08 (seven days earlier). 432 * <p> 433 * The behavior is suitable for use with most calendar systems. 434 * It uses the {@code DAY_OF_WEEK} field and the {@code DAYS} unit, 435 * and assumes a seven day week. 436 * 437 * @param dayOfWeek the day-of-week to move the date to, not null 438 * @return the previous day-of-week adjuster, not null 439 */ 440 public static TemporalAdjuster previous(DayOfWeek dayOfWeek) { 441 int dowValue = dayOfWeek.getValue(); 442 return (temporal) -> { 443 int calDow = temporal.get(DAY_OF_WEEK); 444 int daysDiff = dowValue - calDow; 445 return temporal.minus(daysDiff >= 0 ? 7 - daysDiff : -daysDiff, DAYS); 446 }; 447 } 448 449 /** 450 * Returns the previous-or-same day-of-week adjuster, which adjusts the date to the 451 * first occurrence of the specified day-of-week before the date being adjusted 452 * unless it is already on that day in which case the same object is returned. 453 * <p> 454 * The ISO calendar system behaves as follows:<br> 455 * The input 2011-01-15 (a Saturday) for parameter (MONDAY) will return 2011-01-10 (five days earlier).<br> 456 * The input 2011-01-15 (a Saturday) for parameter (WEDNESDAY) will return 2011-01-12 (three days earlier).<br> 457 * The input 2011-01-15 (a Saturday) for parameter (SATURDAY) will return 2011-01-15 (same as input). 458 * <p> 459 * The behavior is suitable for use with most calendar systems. 460 * It uses the {@code DAY_OF_WEEK} field and the {@code DAYS} unit, 461 * and assumes a seven day week. 462 * 463 * @param dayOfWeek the day-of-week to check for or move the date to, not null 464 * @return the previous-or-same day-of-week adjuster, not null 465 */ 466 public static TemporalAdjuster previousOrSame(DayOfWeek dayOfWeek) { 467 int dowValue = dayOfWeek.getValue(); 468 return (temporal) -> { 469 int calDow = temporal.get(DAY_OF_WEEK); 470 if (calDow == dowValue) { 471 return temporal; 472 } 473 int daysDiff = dowValue - calDow; 474 return temporal.minus(daysDiff >= 0 ? 7 - daysDiff : -daysDiff, DAYS); 475 }; 476 } 477 478 } 479