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
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7 * published by the Free Software Foundation. Oracle designates this
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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).
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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
66 /**
67 * Framework-level interface defining read-write access to a temporal object,
68 * such as a date, time, offset or some combination of these.
69 * <p>
70 * This is the base interface type for date, time and offset objects that
71 * are complete enough to be manipulated using plus and minus.
72 * It is implemented by those classes that can provide and manipulate information
73 * as {@linkplain TemporalField fields} or {@linkplain TemporalQuery queries}.
74 * See {@link TemporalAccessor} for the read-only version of this interface.
75 * <p>
76 * Most date and time information can be represented as a number.
77 * These are modeled using {@code TemporalField} with the number held using
78 * a {@code long} to handle large values. Year, month and day-of-month are
79 * simple examples of fields, but they also include instant and offsets.
80 * See {@link ChronoField} for the standard set of fields.
81 * <p>
82 * Two pieces of date/time information cannot be represented by numbers,
83 * the {@linkplain java.time.chrono.Chronology chronology} and the
84 * {@linkplain java.time.ZoneId time-zone}.
85 * These can be accessed via {@link #query(TemporalQuery) queries} using
86 * the static methods defined on {@link TemporalQuery}.
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 * @implSpec
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 * Checks if the specified unit is supported.
133 * <p>
134 * This checks if the specified unit can be added to, or subtracted from, this date-time.
135 * If false, then calling the {@link #plus(long, TemporalUnit)} and
136 * {@link #minus(long, TemporalUnit) minus} methods will throw an exception.
137 *
138 * @implSpec
139 * Implementations must check and handle all units defined in {@link ChronoUnit}.
140 * If the unit is supported, then true must be returned, otherwise false must be returned.
141 * <p>
142 * If the field is not a {@code ChronoUnit}, then the result of this method
143 * is obtained by invoking {@code TemporalUnit.isSupportedBy(Temporal)}
144 * passing {@code this} as the argument.
145 * <p>
146 * Implementations must ensure that no observable state is altered when this
147 * read-only method is invoked.
148 *
149 * @param unit the unit to check, null returns false
150 * @return true if the unit can be added/subtracted, false if not
151 */
152 boolean isSupported(TemporalUnit unit);
153
154 /**
155 * Returns an adjusted object of the same type as this object with the adjustment made.
156 * <p>
157 * This adjusts this date-time according to the rules of the specified adjuster.
158 * A simple adjuster might simply set the one of the fields, such as the year field.
159 * A more complex adjuster might set the date to the last day of the month.
160 * A selection of common adjustments is provided in {@link TemporalAdjuster}.
161 * These include finding the "last day of the month" and "next Wednesday".
162 * The adjuster is responsible for handling special cases, such as the varying
163 * lengths of month and leap years.
164 * <p>
165 * Some example code indicating how and why this method is used:
166 * <pre>
167 * date = date.with(Month.JULY); // most key classes implement TemporalAdjuster
168 * date = date.with(lastDayOfMonth()); // static import from Adjusters
169 * date = date.with(next(WEDNESDAY)); // static import from Adjusters and DayOfWeek
170 * </pre>
171 *
172 * @implSpec
173 * Implementations must not alter either this object.
174 * Instead, an adjusted copy of the original must be returned.
175 * This provides equivalent, safe behavior for immutable and mutable implementations.
176 * <p>
177 * The default implementation must behave equivalent to this code:
178 * <pre>
179 * return adjuster.adjustInto(this);
180 * </pre>
181 *
182 * @param adjuster the adjuster to use, not null
183 * @return an object of the same type with the specified adjustment made, not null
184 * @throws DateTimeException if unable to make the adjustment
185 * @throws ArithmeticException if numeric overflow occurs
186 */
187 default Temporal with(TemporalAdjuster adjuster) {
188 return adjuster.adjustInto(this);
189 }
190
191 /**
192 * Returns an object of the same type as this object with the specified field altered.
193 * <p>
194 * This returns a new object based on this one with the value for the specified field changed.
195 * For example, on a {@code LocalDate}, this could be used to set the year, month or day-of-month.
196 * The returned object will have the same observable type as this object.
197 * <p>
198 * In some cases, changing a field is not fully defined. For example, if the target object is
199 * a date representing the 31st January, then changing the month to February would be unclear.
200 * In cases like this, the field is responsible for resolving the result. Typically it will choose
201 * the previous valid date, which would be the last valid day of February in this example.
202 *
203 * @implSpec
204 * Implementations must check and handle all fields defined in {@link ChronoField}.
205 * If the field is supported, then the adjustment must be performed.
206 * If unsupported, then an {@code UnsupportedTemporalTypeException} must be thrown.
207 * <p>
208 * If the field is not a {@code ChronoField}, then the result of this method
209 * is obtained by invoking {@code TemporalField.adjustInto(Temporal, long)}
210 * passing {@code this} as the first argument.
211 * <p>
212 * Implementations must not alter either this object or the specified temporal object.
213 * Instead, an adjusted copy of the original must be returned.
214 * This provides equivalent, safe behavior for immutable and mutable implementations.
215 *
216 * @param field the field to set in the result, not null
217 * @param newValue the new value of the field in the result
218 * @return an object of the same type with the specified field set, not null
219 * @throws DateTimeException if the field cannot be set
220 * @throws UnsupportedTemporalTypeException if the field is not supported
221 * @throws ArithmeticException if numeric overflow occurs
222 */
223 Temporal with(TemporalField field, long newValue);
224
225 //-----------------------------------------------------------------------
226 /**
227 * Returns an object of the same type as this object with an amount added.
228 * <p>
229 * This adjusts this temporal, adding according to the rules of the specified amount.
230 * The amount is typically a {@link java.time.Period} but may be any other type implementing
231 * the {@link TemporalAmount} interface, such as {@link java.time.Duration}.
232 * <p>
233 * Some example code indicating how and why this method is used:
234 * <pre>
235 * date = date.plus(period); // add a Period instance
236 * date = date.plus(duration); // add a Duration instance
237 * date = date.plus(workingDays(6)); // example user-written workingDays method
238 * </pre>
239 * <p>
240 * Note that calling {@code plus} followed by {@code minus} is not guaranteed to
241 * return the same date-time.
242 *
243 * @implSpec
244 * Implementations must not alter either this object.
245 * Instead, an adjusted copy of the original must be returned.
246 * This provides equivalent, safe behavior for immutable and mutable implementations.
247 * <p>
248 * The default implementation must behave equivalent to this code:
249 * <pre>
250 * return amount.addTo(this);
251 * </pre>
252 *
253 * @param amount the amount to add, not null
254 * @return an object of the same type with the specified adjustment made, not null
255 * @throws DateTimeException if the addition cannot be made
256 * @throws ArithmeticException if numeric overflow occurs
257 */
258 default Temporal plus(TemporalAmount amount) {
259 return amount.addTo(this);
260 }
261
262 /**
263 * Returns an object of the same type as this object with the specified period added.
264 * <p>
265 * This method returns a new object based on this one with the specified period added.
266 * For example, on a {@code LocalDate}, this could be used to add a number of years, months or days.
267 * The returned object will have the same observable type as this object.
268 * <p>
269 * In some cases, changing a field is not fully defined. For example, if the target object is
270 * a date representing the 31st January, then adding one month would be unclear.
271 * In cases like this, the field is responsible for resolving the result. Typically it will choose
272 * the previous valid date, which would be the last valid day of February in this example.
273 *
274 * @implSpec
275 * Implementations must check and handle all units defined in {@link ChronoUnit}.
276 * If the unit is supported, then the addition must be performed.
277 * If unsupported, then an {@code UnsupportedTemporalTypeException} must be thrown.
278 * <p>
279 * If the unit is not a {@code ChronoUnit}, then the result of this method
280 * is obtained by invoking {@code TemporalUnit.addTo(Temporal, long)}
281 * passing {@code this} as the first argument.
282 * <p>
283 * Implementations must not alter either this object or the specified temporal object.
284 * Instead, an adjusted copy of the original must be returned.
285 * This provides equivalent, safe behavior for immutable and mutable implementations.
286 *
287 * @param amountToAdd the amount of the specified unit to add, may be negative
288 * @param unit the unit of the period to add, not null
289 * @return an object of the same type with the specified period added, not null
290 * @throws DateTimeException if the unit cannot be added
291 * @throws UnsupportedTemporalTypeException if the unit is not supported
292 * @throws ArithmeticException if numeric overflow occurs
293 */
294 Temporal plus(long amountToAdd, TemporalUnit unit);
295
296 //-----------------------------------------------------------------------
297 /**
298 * Returns an object of the same type as this object with an amount subtracted.
299 * <p>
300 * This adjusts this temporal, subtracting according to the rules of the specified amount.
301 * The amount is typically a {@link java.time.Period} but may be any other type implementing
302 * the {@link TemporalAmount} interface, such as {@link java.time.Duration}.
303 * <p>
304 * Some example code indicating how and why this method is used:
305 * <pre>
306 * date = date.minus(period); // subtract a Period instance
307 * date = date.minus(duration); // subtract a Duration instance
308 * date = date.minus(workingDays(6)); // example user-written workingDays method
309 * </pre>
310 * <p>
311 * Note that calling {@code plus} followed by {@code minus} is not guaranteed to
312 * return the same date-time.
313 *
314 * @implSpec
315 * Implementations must not alter either this object.
316 * Instead, an adjusted copy of the original must be returned.
317 * This provides equivalent, safe behavior for immutable and mutable implementations.
318 * <p>
319 * The default implementation must behave equivalent to this code:
320 * <pre>
321 * return amount.subtractFrom(this);
322 * </pre>
323 *
324 * @param amount the amount to subtract, not null
325 * @return an object of the same type with the specified adjustment made, not null
326 * @throws DateTimeException if the subtraction cannot be made
327 * @throws ArithmeticException if numeric overflow occurs
328 */
329 default Temporal minus(TemporalAmount amount) {
330 return amount.subtractFrom(this);
331 }
332
333 /**
334 * Returns an object of the same type as this object with the specified period subtracted.
335 * <p>
336 * This method returns a new object based on this one with the specified period subtracted.
337 * For example, on a {@code LocalDate}, this could be used to subtract a number of years, months or days.
338 * The returned object will have the same observable type as this object.
339 * <p>
340 * In some cases, changing a field is not fully defined. For example, if the target object is
341 * a date representing the 31st March, then subtracting one month would be unclear.
342 * In cases like this, the field is responsible for resolving the result. Typically it will choose
343 * the previous valid date, which would be the last valid day of February in this example.
344 *
345 * @implSpec
346 * Implementations must behave in a manor equivalent to the default method behavior.
347 * <p>
348 * Implementations must not alter either this object or the specified temporal object.
349 * Instead, an adjusted copy of the original must be returned.
350 * This provides equivalent, safe behavior for immutable and mutable implementations.
351 * <p>
352 * The default implementation must behave equivalent to this code:
353 * <pre>
354 * return (amountToSubtract == Long.MIN_VALUE ?
355 * plus(Long.MAX_VALUE, unit).plus(1, unit) : plus(-amountToSubtract, unit));
356 * </pre>
357 *
358 * @param amountToSubtract the amount of the specified unit to subtract, may be negative
359 * @param unit the unit of the period to subtract, not null
360 * @return an object of the same type with the specified period subtracted, not null
361 * @throws DateTimeException if the unit cannot be subtracted
362 * @throws UnsupportedTemporalTypeException if the unit is not supported
363 * @throws ArithmeticException if numeric overflow occurs
364 */
365 default Temporal minus(long amountToSubtract, TemporalUnit unit) {
366 return (amountToSubtract == Long.MIN_VALUE ? plus(Long.MAX_VALUE, unit).plus(1, unit) : plus(-amountToSubtract, unit));
367 }
368
369 //-----------------------------------------------------------------------
370 /**
371 * Calculates the amount of time until another temporal in terms of the specified unit.
372 * <p>
373 * This calculates the amount of time between two temporal objects
374 * of the same type in terms of a single {@code TemporalUnit}.
375 * The start and end points are {@code this} and the specified temporal.
376 * The result will be negative if the end is before the start.
377 * For example, the period in hours between two temporal objects can be
378 * calculated using {@code startTime.until(endTime, HOURS)}.
379 * <p>
380 * The calculation returns a whole number, representing the number of
381 * complete units between the two temporals.
382 * For example, the period in hours between the times 11:30 and 13:29
383 * will only be one hour as it is one minute short of two hours.
384 * <p>
385 * There are two equivalent ways of using this method.
386 * The first is to invoke this method directly.
387 * The second is to use {@link TemporalUnit#between(Temporal, Temporal)}:
388 * <pre>
389 * // these two lines are equivalent
390 * temporal = start.until(end, unit);
391 * temporal = unit.between(start, end);
392 * </pre>
393 * The choice should be made based on which makes the code more readable.
394 * <p>
395 * For example, this method allows the number of days between two dates to
396 * be calculated:
397 * <pre>
398 * long daysBetween = start.until(end, DAYS);
399 * // or alternatively
400 * long daysBetween = DAYS.between(start, end);
401 * </pre>
402 *
403 * @implSpec
404 * Implementations must begin by checking to ensure that the input temporal
405 * object is of the same observable type as the implementation.
406 * They must then perform the calculation for all instances of {@link ChronoUnit}.
407 * An {@code UnsupportedTemporalTypeException} must be thrown for {@code ChronoUnit}
408 * instances that are unsupported.
409 * <p>
410 * If the unit is not a {@code ChronoUnit}, then the result of this method
411 * is obtained by invoking {@code TemporalUnit.between(Temporal, Temporal)}
412 * passing {@code this} as the first argument and the input temporal as
413 * the second argument.
414 * <p>
415 * In summary, implementations must behave in a manner equivalent to this code:
416 * <pre>
417 * // check input temporal is the same type as this class
418 * if (unit instanceof ChronoUnit) {
419 * // if unit is supported, then calculate and return result
420 * // else throw UnsupportedTemporalTypeException for unsupported units
421 * }
422 * return unit.between(this, endTemporal);
423 * </pre>
424 * <p>
425 * Implementations must ensure that no observable state is altered when this
426 * read-only method is invoked.
427 *
428 * @param endTemporal the end temporal, of the same type as this object, not null
429 * @param unit the unit to measure the amount in, not null
430 * @return the amount of time between this temporal object and the specified one
431 * in terms of the unit; positive if the specified object is later than this one,
432 * negative if it is earlier than this one
433 * @throws DateTimeException if the amount cannot be calculated
434 * @throws UnsupportedTemporalTypeException if the unit is not supported
435 * @throws ArithmeticException if numeric overflow occurs
436 */
437 long until(Temporal endTemporal, TemporalUnit unit);
438
439 }