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, 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 java.time.DateTimeException; 65 import java.time.ZoneId; 66 67 /** 68 * Framework-level interface defining read-write access to a temporal object, 69 * such as a date, time, offset or some combination of these. 70 * <p> 71 * This is the base interface type for date, time and offset objects that 72 * are complete enough to be manipulated using plus and minus. 73 * It is implemented by those classes that can provide and manipulate information 74 * as {@linkplain TemporalField fields} or {@linkplain TemporalQuery queries}. 75 * See {@link TemporalAccessor} for the read-only version of this interface. 76 * <p> 77 * Most date and time information can be represented as a number. 78 * These are modeled using {@code TemporalField} with the number held using 79 * a {@code long} to handle large values. Year, month and day-of-month are 80 * simple examples of fields, but they also include instant and offsets. 81 * See {@link ChronoField} for the standard set of fields. 82 * <p> 83 * Two pieces of date/time information cannot be represented by numbers, 84 * the {@linkplain java.time.chrono.Chronology chronology} and the {@linkplain ZoneId time-zone}. 85 * These can be accessed via {@link #query(TemporalQuery) queries} using 86 * the static methods defined on {@link Queries}. 87 * <p> 88 * This interface is a framework-level interface that should not be widely 89 * used in application code. Instead, applications should create and pass 90 * around instances of concrete types, such as {@code LocalDate}. 91 * There are many reasons for this, part of which is that implementations 92 * of this interface may be in calendar systems other than ISO. 93 * See {@link java.time.chrono.ChronoLocalDate} for a fuller discussion of the issues. 94 * 95 * <h3>When to implement</h3> 96 * <p> 97 * A class should implement this interface if it meets three criteria: 98 * <p><ul> 99 * <li>it provides access to date/time/offset information, as per {@code TemporalAccessor} 100 * <li>the set of fields are contiguous from the largest to the smallest 101 * <li>the set of fields are complete, such that no other field is needed to define the 102 * valid range of values for the fields that are represented 103 * </ul><p> 104 * <p> 105 * Four examples make this clear: 106 * <p><ul> 107 * <li>{@code LocalDate} implements this interface as it represents a set of fields 108 * that are contiguous from days to forever and require no external information to determine 109 * the validity of each date. It is therefore able to implement plus/minus correctly. 110 * <li>{@code LocalTime} implements this interface as it represents a set of fields 111 * that are contiguous from nanos to within days and require no external information to determine 112 * validity. It is able to implement plus/minus correctly, by wrapping around the day. 113 * <li>{@code MonthDay}, the combination of month-of-year and day-of-month, does not implement 114 * this interface. While the combination is contiguous, from days to months within years, 115 * the combination does not have sufficient information to define the valid range of values 116 * for day-of-month. As such, it is unable to implement plus/minus correctly. 117 * <li>The combination day-of-week and day-of-month ("Friday the 13th") should not implement 118 * this interface. It does not represent a contiguous set of fields, as days to weeks overlaps 119 * days to months. 120 * </ul><p> 121 * 122 * <h3>Specification for implementors</h3> 123 * This interface places no restrictions on the mutability of implementations, 124 * however immutability is strongly recommended. 125 * All implementations must be {@link Comparable}. 126 * 127 * @since 1.8 128 */ 129 public interface Temporal extends TemporalAccessor { 130 131 /** 132 * Returns an adjusted object of the same type as this object with the adjustment made. 133 * <p> 134 * This adjusts this date-time according to the rules of the specified adjuster. 135 * A simple adjuster might simply set the one of the fields, such as the year field. 136 * A more complex adjuster might set the date to the last day of the month. 137 * A selection of common adjustments is provided in {@link Adjusters}. 138 * These include finding the "last day of the month" and "next Wednesday". 139 * The adjuster is responsible for handling special cases, such as the varying 140 * lengths of month and leap years. 141 * <p> 142 * Some example code indicating how and why this method is used: 143 * <pre> 144 * date = date.with(Month.JULY); // most key classes implement TemporalAdjuster 145 * date = date.with(lastDayOfMonth()); // static import from Adjusters 146 * date = date.with(next(WEDNESDAY)); // static import from Adjusters and DayOfWeek 147 * </pre> 148 * 149 * <h3>Specification for implementors</h3> 150 * Implementations must not alter either this object. 151 * Instead, an adjusted copy of the original must be returned. 152 * This provides equivalent, safe behavior for immutable and mutable implementations. 153 * <p> 154 * The default implementation must behave equivalent to this code: 155 * <pre> 156 * return adjuster.adjustInto(this); 157 * </pre> 158 * 159 * @param adjuster the adjuster to use, not null 160 * @return an object of the same type with the specified adjustment made, not null 161 * @throws DateTimeException if unable to make the adjustment 162 * @throws ArithmeticException if numeric overflow occurs 163 */ 164 public default Temporal with(TemporalAdjuster adjuster) { 165 return adjuster.adjustInto(this); 166 } 167 168 /** 169 * Returns an object of the same type as this object with the specified field altered. 170 * <p> 171 * This returns a new object based on this one with the value for the specified field changed. 172 * For example, on a {@code LocalDate}, this could be used to set the year, month or day-of-month. 173 * The returned object will have the same observable type as this object. 174 * <p> 175 * In some cases, changing a field is not fully defined. For example, if the target object is 176 * a date representing the 31st January, then changing the month to February would be unclear. 177 * In cases like this, the field is responsible for resolving the result. Typically it will choose 178 * the previous valid date, which would be the last valid day of February in this example. 179 * 180 * <h3>Specification for implementors</h3> 181 * Implementations must check and handle all fields defined in {@link ChronoField}. 182 * If the field is supported, then the adjustment must be performed. 183 * If unsupported, then a {@code DateTimeException} must be thrown. 184 * <p> 185 * If the field is not a {@code ChronoField}, then the result of this method 186 * is obtained by invoking {@code TemporalField.adjustInto(Temporal, long)} 187 * passing {@code this} as the first argument. 188 * <p> 189 * Implementations must not alter either this object or the specified temporal object. 190 * Instead, an adjusted copy of the original must be returned. 191 * This provides equivalent, safe behavior for immutable and mutable implementations. 192 * 193 * @param field the field to set in the result, not null 194 * @param newValue the new value of the field in the result 195 * @return an object of the same type with the specified field set, not null 196 * @throws DateTimeException if the field cannot be set 197 * @throws ArithmeticException if numeric overflow occurs 198 */ 199 Temporal with(TemporalField field, long newValue); 200 201 //----------------------------------------------------------------------- 202 /** 203 * Returns an object of the same type as this object with an amount added. 204 * <p> 205 * This adjusts this temporal, adding according to the rules of the specified amount. 206 * The amount is typically a {@link java.time.Period} but may be any other type implementing 207 * the {@link TemporalAmount} interface, such as {@link java.time.Duration}. 208 * <p> 209 * Some example code indicating how and why this method is used: 210 * <pre> 211 * date = date.plus(period); // add a Period instance 212 * date = date.plus(duration); // add a Duration instance 213 * date = date.plus(MONTHS.between(start, end)); // static import of MONTHS field 214 * date = date.plus(workingDays(6)); // example user-written workingDays method 215 * </pre> 216 * <p> 217 * Note that calling {@code plus} followed by {@code minus} is not guaranteed to 218 * return the same date-time. 219 * 220 * <h3>Specification for implementors</h3> 221 * Implementations must not alter either this object. 222 * Instead, an adjusted copy of the original must be returned. 223 * This provides equivalent, safe behavior for immutable and mutable implementations. 224 * <p> 225 * The default implementation must behave equivalent to this code: 226 * <pre> 227 * return amount.addTo(this); 228 * </pre> 229 * 230 * @param amount the amount to add, not null 231 * @return an object of the same type with the specified adjustment made, not null 232 * @throws DateTimeException if the addition cannot be made 233 * @throws ArithmeticException if numeric overflow occurs 234 */ 235 public default Temporal plus(TemporalAmount amount) { 236 return amount.addTo(this); 237 } 238 239 /** 240 * Returns an object of the same type as this object with the specified period added. 241 * <p> 242 * This method returns a new object based on this one with the specified period added. 243 * For example, on a {@code LocalDate}, this could be used to add a number of years, months or days. 244 * The returned object will have the same observable type as this object. 245 * <p> 246 * In some cases, changing a field is not fully defined. For example, if the target object is 247 * a date representing the 31st January, then adding one month would be unclear. 248 * In cases like this, the field is responsible for resolving the result. Typically it will choose 249 * the previous valid date, which would be the last valid day of February in this example. 250 * <p> 251 * If the implementation represents a date-time that has boundaries, such as {@code LocalTime}, 252 * then the permitted units must include the boundary unit, but no multiples of the boundary unit. 253 * For example, {@code LocalTime} must accept {@code DAYS} but not {@code WEEKS} or {@code MONTHS}. 254 * 255 * <h3>Specification for implementors</h3> 256 * Implementations must check and handle all units defined in {@link ChronoUnit}. 257 * If the unit is supported, then the addition must be performed. 258 * If unsupported, then a {@code DateTimeException} must be thrown. 259 * <p> 260 * If the unit is not a {@code ChronoUnit}, then the result of this method 261 * is obtained by invoking {@code TemporalUnit.addTo(Temporal, long)} 262 * passing {@code this} as the first argument. 263 * <p> 264 * Implementations must not alter either this object or the specified temporal object. 265 * Instead, an adjusted copy of the original must be returned. 266 * This provides equivalent, safe behavior for immutable and mutable implementations. 267 * 268 * @param amountToAdd the amount of the specified unit to add, may be negative 269 * @param unit the unit of the period to add, not null 270 * @return an object of the same type with the specified period added, not null 271 * @throws DateTimeException if the unit cannot be added 272 * @throws ArithmeticException if numeric overflow occurs 273 */ 274 Temporal plus(long amountToAdd, TemporalUnit unit); 275 276 //----------------------------------------------------------------------- 277 /** 278 * Returns an object of the same type as this object with an amount subtracted. 279 * <p> 280 * This adjusts this temporal, subtracting according to the rules of the specified amount. 281 * The amount is typically a {@link java.time.Period} but may be any other type implementing 282 * the {@link TemporalAmount} interface, such as {@link java.time.Duration}. 283 * <p> 284 * Some example code indicating how and why this method is used: 285 * <pre> 286 * date = date.minus(period); // subtract a Period instance 287 * date = date.minus(duration); // subtract a Duration instance 288 * date = date.minus(MONTHS.between(start, end)); // static import of MONTHS field 289 * date = date.minus(workingDays(6)); // example user-written workingDays method 290 * </pre> 291 * <p> 292 * Note that calling {@code plus} followed by {@code minus} is not guaranteed to 293 * return the same date-time. 294 * 295 * <h3>Specification for implementors</h3> 296 * Implementations must not alter either this object. 297 * Instead, an adjusted copy of the original must be returned. 298 * This provides equivalent, safe behavior for immutable and mutable implementations. 299 * <p> 300 * The default implementation must behave equivalent to this code: 301 * <pre> 302 * return amount.subtractFrom(this); 303 * </pre> 304 * 305 * @param amount the amount to subtract, not null 306 * @return an object of the same type with the specified adjustment made, not null 307 * @throws DateTimeException if the subtraction cannot be made 308 * @throws ArithmeticException if numeric overflow occurs 309 */ 310 public default Temporal minus(TemporalAmount amount) { 311 return amount.subtractFrom(this); 312 } 313 314 /** 315 * Returns an object of the same type as this object with the specified period subtracted. 316 * <p> 317 * This method returns a new object based on this one with the specified period subtracted. 318 * For example, on a {@code LocalDate}, this could be used to subtract a number of years, months or days. 319 * The returned object will have the same observable type as this object. 320 * <p> 321 * In some cases, changing a field is not fully defined. For example, if the target object is 322 * a date representing the 31st March, then subtracting one month would be unclear. 323 * In cases like this, the field is responsible for resolving the result. Typically it will choose 324 * the previous valid date, which would be the last valid day of February in this example. 325 * <p> 326 * If the implementation represents a date-time that has boundaries, such as {@code LocalTime}, 327 * then the permitted units must include the boundary unit, but no multiples of the boundary unit. 328 * For example, {@code LocalTime} must accept {@code DAYS} but not {@code WEEKS} or {@code MONTHS}. 329 * 330 * <h3>Specification for implementors</h3> 331 * Implementations must behave in a manor equivalent to the default method behavior. 332 * <p> 333 * Implementations must not alter either this object or the specified temporal object. 334 * Instead, an adjusted copy of the original must be returned. 335 * This provides equivalent, safe behavior for immutable and mutable implementations. 336 * <p> 337 * The default implementation must behave equivalent to this code: 338 * <pre> 339 * return (amountToSubtract == Long.MIN_VALUE ? 340 * plus(Long.MAX_VALUE, unit).plus(1, unit) : plus(-amountToSubtract, unit)); 341 * </pre> 342 * 343 * @param amountToSubtract the amount of the specified unit to subtract, may be negative 344 * @param unit the unit of the period to subtract, not null 345 * @return an object of the same type with the specified period subtracted, not null 346 * @throws DateTimeException if the unit cannot be subtracted 347 * @throws ArithmeticException if numeric overflow occurs 348 */ 349 public default Temporal minus(long amountToSubtract, TemporalUnit unit) { 350 return (amountToSubtract == Long.MIN_VALUE ? plus(Long.MAX_VALUE, unit).plus(1, unit) : plus(-amountToSubtract, unit)); 351 } 352 353 //----------------------------------------------------------------------- 354 /** 355 * Calculates the period between this temporal and another temporal in 356 * terms of the specified unit. 357 * <p> 358 * This calculates the period between two temporals in terms of a single unit. 359 * The start and end points are {@code this} and the specified temporal. 360 * The result will be negative if the end is before the start. 361 * For example, the period in hours between two temporal objects can be 362 * calculated using {@code startTime.periodUntil(endTime, HOURS)}. 363 * <p> 364 * The calculation returns a whole number, representing the number of 365 * complete units between the two temporals. 366 * For example, the period in hours between the times 11:30 and 13:29 367 * will only be one hour as it is one minute short of two hours. 368 * <p> 369 * There are two equivalent ways of using this method. 370 * The first is to invoke this method directly. 371 * The second is to use {@link TemporalUnit#between(Temporal, Temporal)}: 372 * <pre> 373 * // these two lines are equivalent 374 * temporal = start.periodUntil(end, unit); 375 * temporal = unit.between(start, end); 376 * </pre> 377 * The choice should be made based on which makes the code more readable. 378 * <p> 379 * For example, this method allows the number of days between two dates to 380 * be calculated: 381 * <pre> 382 * long daysBetween = start.periodUntil(end, DAYS); 383 * // or alternatively 384 * long daysBetween = DAYS.between(start, end); 385 * </pre> 386 * 387 * <h3>Specification for implementors</h3> 388 * Implementations must begin by checking to ensure that the input temporal 389 * object is of the same observable type as the implementation. 390 * They must then perform the calculation for all instances of {@link ChronoUnit}. 391 * A {@code DateTimeException} must be thrown for {@code ChronoUnit} 392 * instances that are unsupported. 393 * <p> 394 * If the unit is not a {@code ChronoUnit}, then the result of this method 395 * is obtained by invoking {@code TemporalUnit.between(Temporal, Temporal)} 396 * passing {@code this} as the first argument and the input temporal as 397 * the second argument. 398 * <p> 399 * In summary, implementations must behave in a manner equivalent to this code: 400 * <pre> 401 * // check input temporal is the same type as this class 402 * if (unit instanceof ChronoUnit) { 403 * // if unit is supported, then calculate and return result 404 * // else throw DateTimeException for unsupported units 405 * } 406 * return unit.between(this, endTemporal); 407 * </pre> 408 * <p> 409 * Neither this object, nor the specified temporal, may be altered. 410 * 411 * @param endTemporal the end temporal, of the same type as this object, not null 412 * @param unit the unit to measure the period in, not null 413 * @return the period between this temporal object and the specified one in terms of 414 * the unit; positive if the specified object is later than this one, negative if 415 * it is earlier than this one 416 * @throws DateTimeException if the period cannot be calculated 417 * @throws ArithmeticException if numeric overflow occurs 418 */ 419 long periodUntil(Temporal endTemporal, TemporalUnit unit); 420 421 }