1 /*
2 * Copyright 2001-2010 Stephen Colebourne
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16 package org.joda.time;
17
18 import org.joda.convert.FromString;
19 import org.joda.convert.ToString;
20 import org.joda.time.base.BaseSingleFieldPeriod;
21 import org.joda.time.field.FieldUtils;
22 import org.joda.time.format.ISOPeriodFormat;
23 import org.joda.time.format.PeriodFormatter;
24
25 /**
26 * An immutable time period representing a number of weeks.
27 * <p>
28 * <code>Weeks</code> is an immutable period that can only store weeks.
29 * It does not store years, months or hours for example. As such it is a
30 * type-safe way of representing a number of weeks in an application.
31 * <p>
32 * The number of weeks is set in the constructor, and may be queried using
33 * <code>getWeeks()</code>. Basic mathematical operations are provided -
34 * <code>plus()</code>, <code>minus()</code>, <code>multipliedBy()</code> and
35 * <code>dividedBy()</code>.
36 * <p>
37 * <code>Weeks</code> is thread-safe and immutable.
38 *
39 * @author Stephen Colebourne
40 * @since 1.4
41 */
42 public final class Weeks extends BaseSingleFieldPeriod {
43
44 /** Constant representing zero weeks. */
45 public static final Weeks ZERO = new Weeks(0);
46 /** Constant representing one week. */
47 public static final Weeks ONE = new Weeks(1);
48 /** Constant representing two weeks. */
49 public static final Weeks TWO = new Weeks(2);
50 /** Constant representing three weeks. */
51 public static final Weeks THREE = new Weeks(3);
52 /** Constant representing the maximum number of weeks that can be stored in this object. */
53 public static final Weeks MAX_VALUE = new Weeks(Integer.MAX_VALUE);
54 /** Constant representing the minimum number of weeks that can be stored in this object. */
55 public static final Weeks MIN_VALUE = new Weeks(Integer.MIN_VALUE);
56
57 /** The paser to use for this class. */
58 private static final PeriodFormatter PARSER = ISOPeriodFormat.standard().withParseType(PeriodType.weeks());
59 /** Serialization version. */
60 private static final long serialVersionUID = 87525275727380866L;
61
62 //-----------------------------------------------------------------------
63 /**
64 * Obtains an instance of <code>Weeks</code> that may be cached.
65 * <code>Weeks</code> is immutable, so instances can be cached and shared.
66 * This factory method provides access to shared instances.
67 *
68 * @param weeks the number of weeks to obtain an instance for
69 * @return the instance of Weeks
70 */
71 public static Weeks weeks(int weeks) {
72 switch (weeks) {
73 case 0:
74 return ZERO;
75 case 1:
76 return ONE;
77 case 2:
78 return TWO;
79 case 3:
80 return THREE;
81 case Integer.MAX_VALUE:
82 return MAX_VALUE;
83 case Integer.MIN_VALUE:
84 return MIN_VALUE;
85 default:
86 return new Weeks(weeks);
87 }
88 }
89
90 //-----------------------------------------------------------------------
91 /**
92 * Creates a <code>Weeks</code> representing the number of whole weeks
93 * between the two specified datetimes.
94 *
95 * @param start the start instant, must not be null
96 * @param end the end instant, must not be null
97 * @return the period in weeks
98 * @throws IllegalArgumentException if the instants are null or invalid
99 */
100 public static Weeks weeksBetween(ReadableInstant start, ReadableInstant end) {
101 int amount = BaseSingleFieldPeriod.between(start, end, DurationFieldType.weeks());
102 return Weeks.weeks(amount);
103 }
104
105 /**
106 * Creates a <code>Weeks</code> representing the number of whole weeks
107 * between the two specified partial datetimes.
108 * <p>
109 * The two partials must contain the same fields, for example you can specify
110 * two <code>LocalDate</code> objects.
111 *
112 * @param start the start partial date, must not be null
113 * @param end the end partial date, must not be null
114 * @return the period in weeks
115 * @throws IllegalArgumentException if the partials are null or invalid
116 */
117 public static Weeks weeksBetween(ReadablePartial start, ReadablePartial end) {
118 if (start instanceof LocalDate && end instanceof LocalDate) {
119 Chronology chrono = DateTimeUtils.getChronology(start.getChronology());
120 int weeks = chrono.weeks().getDifference(
121 ((LocalDate) end).getLocalMillis(), ((LocalDate) start).getLocalMillis());
122 return Weeks.weeks(weeks);
123 }
124 int amount = BaseSingleFieldPeriod.between(start, end, ZERO);
125 return Weeks.weeks(amount);
126 }
127
128 /**
129 * Creates a <code>Weeks</code> representing the number of whole weeks
130 * in the specified interval.
131 *
132 * @param interval the interval to extract weeks from, null returns zero
133 * @return the period in weeks
134 * @throws IllegalArgumentException if the partials are null or invalid
135 */
136 public static Weeks weeksIn(ReadableInterval interval) {
137 if (interval == null) {
138 return Weeks.ZERO;
139 }
140 int amount = BaseSingleFieldPeriod.between(interval.getStart(), interval.getEnd(), DurationFieldType.weeks());
141 return Weeks.weeks(amount);
142 }
143
144 /**
145 * Creates a new <code>Weeks</code> representing the number of complete
146 * standard length weeks in the specified period.
147 * <p>
148 * This factory method converts all fields from the period to hours using standardised
149 * durations for each field. Only those fields which have a precise duration in
150 * the ISO UTC chronology can be converted.
151 * <ul>
152 * <li>One week consists of 7 days.
153 * <li>One day consists of 24 hours.
154 * <li>One hour consists of 60 minutes.
155 * <li>One minute consists of 60 weeks.
156 * <li>One second consists of 1000 milliseconds.
157 * </ul>
158 * Months and Years are imprecise and periods containing these values cannot be converted.
159 *
160 * @param period the period to get the number of hours from, null returns zero
161 * @return the period in weeks
162 * @throws IllegalArgumentException if the period contains imprecise duration values
163 */
164 public static Weeks standardWeeksIn(ReadablePeriod period) {
165 int amount = BaseSingleFieldPeriod.standardPeriodIn(period, DateTimeConstants.MILLIS_PER_WEEK);
166 return Weeks.weeks(amount);
167 }
168
169 /**
170 * Creates a new <code>Weeks</code> by parsing a string in the ISO8601 format 'PnW'.
171 * <p>
172 * The parse will accept the full ISO syntax of PnYnMnWnDTnHnMnS however only the
173 * weeks component may be non-zero. If any other component is non-zero, an exception
174 * will be thrown.
175 *
176 * @param periodStr the period string, null returns zero
177 * @return the period in weeks
178 * @throws IllegalArgumentException if the string format is invalid
179 */
180 @FromString
181 public static Weeks parseWeeks(String periodStr) {
182 if (periodStr == null) {
183 return Weeks.ZERO;
184 }
185 Period p = PARSER.parsePeriod(periodStr);
186 return Weeks.weeks(p.getWeeks());
187 }
188
189 //-----------------------------------------------------------------------
190 /**
191 * Creates a new instance representing a number of weeks.
192 * You should consider using the factory method {@link #weeks(int)}
193 * instead of the constructor.
194 *
195 * @param weeks the number of weeks to represent
196 */
197 private Weeks(int weeks) {
198 super(weeks);
199 }
200
201 /**
202 * Resolves singletons.
203 *
204 * @return the singleton instance
205 */
206 private Object readResolve() {
207 return Weeks.weeks(getValue());
208 }
209
210 //-----------------------------------------------------------------------
211 /**
212 * Gets the duration field type, which is <code>weeks</code>.
213 *
214 * @return the period type
215 */
216 public DurationFieldType getFieldType() {
217 return DurationFieldType.weeks();
218 }
219
220 /**
221 * Gets the period type, which is <code>weeks</code>.
222 *
223 * @return the period type
224 */
225 public PeriodType getPeriodType() {
226 return PeriodType.weeks();
227 }
228
229 //-----------------------------------------------------------------------
230 /**
231 * Converts this period in weeks to a period in days assuming a
232 * 7 day week.
233 * <p>
234 * This method allows you to convert between different types of period.
235 * However to achieve this it makes the assumption that all weeks are
236 * 7 days long.
237 * This may not be true for some unusual chronologies. However, it is included
238 * as it is a useful operation for many applications and business rules.
239 *
240 * @return a period representing the number of days for this number of weeks
241 * @throws ArithmeticException if the number of days is too large to be represented
242 */
243 public Days toStandardDays() {
244 return Days.days(FieldUtils.safeMultiply(getValue(), DateTimeConstants.DAYS_PER_WEEK));
245 }
246
247 /**
248 * Converts this period in weeks to a period in hours assuming a
249 * 7 day week and 24 hour day.
250 * <p>
251 * This method allows you to convert between different types of period.
252 * However to achieve this it makes the assumption that all weeks are
253 * 7 days long and all days are 24 hours long.
254 * This is not true when daylight savings is considered and may also not
255 * be true for some unusual chronologies. However, it is included
256 * as it is a useful operation for many applications and business rules.
257 *
258 * @return a period representing the number of hours for this number of weeks
259 * @throws ArithmeticException if the number of hours is too large to be represented
260 */
261 public Hours toStandardHours() {
262 return Hours.hours(FieldUtils.safeMultiply(getValue(), DateTimeConstants.HOURS_PER_WEEK));
263 }
264
265 /**
266 * Converts this period in weeks to a period in minutes assuming a
267 * 7 day week, 24 hour day and 60 minute hour.
268 * <p>
269 * This method allows you to convert between different types of period.
270 * However to achieve this it makes the assumption that all weeks are
271 * 7 days long, all days are 24 hours long and all hours are 60 minutes long.
272 * This is not true when daylight savings is considered and may also not
273 * be true for some unusual chronologies. However, it is included
274 * as it is a useful operation for many applications and business rules.
275 *
276 * @return a period representing the number of minutes for this number of weeks
277 * @throws ArithmeticException if the number of minutes is too large to be represented
278 */
279 public Minutes toStandardMinutes() {
280 return Minutes.minutes(FieldUtils.safeMultiply(getValue(), DateTimeConstants.MINUTES_PER_WEEK));
281 }
282
283 /**
284 * Converts this period in weeks to a period in seconds assuming a
285 * 7 day week, 24 hour day, 60 minute hour and 60 second minute.
286 * <p>
287 * This method allows you to convert between different types of period.
288 * However to achieve this it makes the assumption that all weeks are
289 * 7 days long, all days are 24 hours long, all hours are 60 minutes long
290 * and all minutes are 60 seconds long.
291 * This is not true when daylight savings is considered and may also not
292 * be true for some unusual chronologies. However, it is included
293 * as it is a useful operation for many applications and business rules.
294 *
295 * @return a period representing the number of seconds for this number of weeks
296 * @throws ArithmeticException if the number of seconds is too large to be represented
297 */
298 public Seconds toStandardSeconds() {
299 return Seconds.seconds(FieldUtils.safeMultiply(getValue(), DateTimeConstants.SECONDS_PER_WEEK));
300 }
301
302 //-----------------------------------------------------------------------
303 /**
304 * Converts this period in weeks to a duration in milliweeks assuming a
305 * 7 day week, 24 hour day, 60 minute hour and 60 second minute.
306 * <p>
307 * This method allows you to convert from a period to a duration.
308 * However to achieve this it makes the assumption that all weeks are
309 * 7 days long, all days are 24 hours long, all hours are 60 minutes long
310 * and all minutes are 60 seconds long.
311 * This is not true when daylight savings time is considered, and may also
312 * not be true for some unusual chronologies. However, it is included as it
313 * is a useful operation for many applications and business rules.
314 *
315 * @return a duration equivalent to this number of weeks
316 */
317 public Duration toStandardDuration() {
318 long weeks = getValue(); // assign to a long
319 return new Duration(weeks * DateTimeConstants.MILLIS_PER_WEEK);
320 }
321
322 //-----------------------------------------------------------------------
323 /**
324 * Gets the number of weeks that this period represents.
325 *
326 * @return the number of weeks in the period
327 */
328 public int getWeeks() {
329 return getValue();
330 }
331
332 //-----------------------------------------------------------------------
333 /**
334 * Returns a new instance with the specified number of weeks added.
335 * <p>
336 * This instance is immutable and unaffected by this method call.
337 *
338 * @param weeks the amount of weeks to add, may be negative
339 * @return the new period plus the specified number of weeks
340 * @throws ArithmeticException if the result overflows an int
341 */
342 public Weeks plus(int weeks) {
343 if (weeks == 0) {
344 return this;
345 }
346 return Weeks.weeks(FieldUtils.safeAdd(getValue(), weeks));
347 }
348
349 /**
350 * Returns a new instance with the specified number of weeks added.
351 * <p>
352 * This instance is immutable and unaffected by this method call.
353 *
354 * @param weeks the amount of weeks to add, may be negative, null means zero
355 * @return the new period plus the specified number of weeks
356 * @throws ArithmeticException if the result overflows an int
357 */
358 public Weeks plus(Weeks weeks) {
359 if (weeks == null) {
360 return this;
361 }
362 return plus(weeks.getValue());
363 }
364
365 //-----------------------------------------------------------------------
366 /**
367 * Returns a new instance with the specified number of weeks taken away.
368 * <p>
369 * This instance is immutable and unaffected by this method call.
370 *
371 * @param weeks the amount of weeks to take away, may be negative
372 * @return the new period minus the specified number of weeks
373 * @throws ArithmeticException if the result overflows an int
374 */
375 public Weeks minus(int weeks) {
376 return plus(FieldUtils.safeNegate(weeks));
377 }
378
379 /**
380 * Returns a new instance with the specified number of weeks taken away.
381 * <p>
382 * This instance is immutable and unaffected by this method call.
383 *
384 * @param weeks the amount of weeks to take away, may be negative, null means zero
385 * @return the new period minus the specified number of weeks
386 * @throws ArithmeticException if the result overflows an int
387 */
388 public Weeks minus(Weeks weeks) {
389 if (weeks == null) {
390 return this;
391 }
392 return minus(weeks.getValue());
393 }
394
395 //-----------------------------------------------------------------------
396 /**
397 * Returns a new instance with the weeks multiplied by the specified scalar.
398 * <p>
399 * This instance is immutable and unaffected by this method call.
400 *
401 * @param scalar the amount to multiply by, may be negative
402 * @return the new period multiplied by the specified scalar
403 * @throws ArithmeticException if the result overflows an int
404 */
405 public Weeks multipliedBy(int scalar) {
406 return Weeks.weeks(FieldUtils.safeMultiply(getValue(), scalar));
407 }
408
409 /**
410 * Returns a new instance with the weeks divided by the specified divisor.
411 * The calculation uses integer division, thus 3 divided by 2 is 1.
412 * <p>
413 * This instance is immutable and unaffected by this method call.
414 *
415 * @param divisor the amount to divide by, may be negative
416 * @return the new period divided by the specified divisor
417 * @throws ArithmeticException if the divisor is zero
418 */
419 public Weeks dividedBy(int divisor) {
420 if (divisor == 1) {
421 return this;
422 }
423 return Weeks.weeks(getValue() / divisor);
424 }
425
426 //-----------------------------------------------------------------------
427 /**
428 * Returns a new instance with the weeks value negated.
429 *
430 * @return the new period with a negated value
431 * @throws ArithmeticException if the result overflows an int
432 */
433 public Weeks negated() {
434 return Weeks.weeks(FieldUtils.safeNegate(getValue()));
435 }
436
437 //-----------------------------------------------------------------------
438 /**
439 * Is this weeks instance greater than the specified number of weeks.
440 *
441 * @param other the other period, null means zero
442 * @return true if this weeks instance is greater than the specified one
443 */
444 public boolean isGreaterThan(Weeks other) {
445 if (other == null) {
446 return getValue() > 0;
447 }
448 return getValue() > other.getValue();
449 }
450
451 /**
452 * Is this weeks instance less than the specified number of weeks.
453 *
454 * @param other the other period, null means zero
455 * @return true if this weeks instance is less than the specified one
456 */
457 public boolean isLessThan(Weeks other) {
458 if (other == null) {
459 return getValue() < 0;
460 }
461 return getValue() < other.getValue();
462 }
463
464 //-----------------------------------------------------------------------
465 /**
466 * Gets this instance as a String in the ISO8601 duration format.
467 * <p>
468 * For example, "P4W" represents 4 weeks.
469 *
470 * @return the value as an ISO8601 string
471 */
472 @ToString
473 public String toString() {
474 return "P" + String.valueOf(getValue()) + "W";
475 }
476
477 }