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 hours.
27 * <p>
28 * <code>Hours</code> is an immutable period that can only store hours.
29 * It does not store years, months or minutes for example. As such it is a
30 * type-safe way of representing a number of hours in an application.
31 * <p>
32 * The number of hours is set in the constructor, and may be queried using
33 * <code>getHours()</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>Hours</code> is thread-safe and immutable.
38 *
39 * @author Stephen Colebourne
40 * @since 1.4
41 */
42 public final class Hours extends BaseSingleFieldPeriod {
43
44 /** Constant representing zero hours. */
45 public static final Hours ZERO = new Hours(0);
46 /** Constant representing one hour. */
47 public static final Hours ONE = new Hours(1);
48 /** Constant representing two hours. */
49 public static final Hours TWO = new Hours(2);
50 /** Constant representing three hours. */
51 public static final Hours THREE = new Hours(3);
52 /** Constant representing four hours. */
53 public static final Hours FOUR = new Hours(4);
54 /** Constant representing five hours. */
55 public static final Hours FIVE = new Hours(5);
56 /** Constant representing six hours. */
57 public static final Hours SIX = new Hours(6);
58 /** Constant representing seven hours. */
59 public static final Hours SEVEN = new Hours(7);
60 /** Constant representing eight hours. */
61 public static final Hours EIGHT = new Hours(8);
62 /** Constant representing the maximum number of hours that can be stored in this object. */
63 public static final Hours MAX_VALUE = new Hours(Integer.MAX_VALUE);
64 /** Constant representing the minimum number of hours that can be stored in this object. */
65 public static final Hours MIN_VALUE = new Hours(Integer.MIN_VALUE);
66
67 /** The paser to use for this class. */
68 private static final PeriodFormatter PARSER = ISOPeriodFormat.standard().withParseType(PeriodType.hours());
69 /** Serialization version. */
70 private static final long serialVersionUID = 87525275727380864L;
71
72 //-----------------------------------------------------------------------
73 /**
74 * Obtains an instance of <code>Hours</code> that may be cached.
75 * <code>Hours</code> is immutable, so instances can be cached and shared.
76 * This factory method provides access to shared instances.
77 *
78 * @param hours the number of hours to obtain an instance for
79 * @return the instance of Hours
80 */
81 public static Hours hours(int hours) {
82 switch (hours) {
83 case 0:
84 return ZERO;
85 case 1:
86 return ONE;
87 case 2:
88 return TWO;
89 case 3:
90 return THREE;
91 case 4:
92 return FOUR;
93 case 5:
94 return FIVE;
95 case 6:
96 return SIX;
97 case 7:
98 return SEVEN;
99 case 8:
100 return EIGHT;
101 case Integer.MAX_VALUE:
102 return MAX_VALUE;
103 case Integer.MIN_VALUE:
104 return MIN_VALUE;
105 default:
106 return new Hours(hours);
107 }
108 }
109
110 //-----------------------------------------------------------------------
111 /**
112 * Creates a <code>Hours</code> representing the number of whole hours
113 * between the two specified datetimes.
114 *
115 * @param start the start instant, must not be null
116 * @param end the end instant, must not be null
117 * @return the period in hours
118 * @throws IllegalArgumentException if the instants are null or invalid
119 */
120 public static Hours hoursBetween(ReadableInstant start, ReadableInstant end) {
121 int amount = BaseSingleFieldPeriod.between(start, end, DurationFieldType.hours());
122 return Hours.hours(amount);
123 }
124
125 /**
126 * Creates a <code>Hours</code> representing the number of whole hours
127 * between the two specified partial datetimes.
128 * <p>
129 * The two partials must contain the same fields, for example you can specify
130 * two <code>LocalTime</code> objects.
131 *
132 * @param start the start partial date, must not be null
133 * @param end the end partial date, must not be null
134 * @return the period in hours
135 * @throws IllegalArgumentException if the partials are null or invalid
136 */
137 public static Hours hoursBetween(ReadablePartial start, ReadablePartial end) {
138 if (start instanceof LocalTime && end instanceof LocalTime) {
139 Chronology chrono = DateTimeUtils.getChronology(start.getChronology());
140 int hours = chrono.hours().getDifference(
141 ((LocalTime) end).getLocalMillis(), ((LocalTime) start).getLocalMillis());
142 return Hours.hours(hours);
143 }
144 int amount = BaseSingleFieldPeriod.between(start, end, ZERO);
145 return Hours.hours(amount);
146 }
147
148 /**
149 * Creates a <code>Hours</code> representing the number of whole hours
150 * in the specified interval.
151 *
152 * @param interval the interval to extract hours from, null returns zero
153 * @return the period in hours
154 * @throws IllegalArgumentException if the partials are null or invalid
155 */
156 public static Hours hoursIn(ReadableInterval interval) {
157 if (interval == null) {
158 return Hours.ZERO;
159 }
160 int amount = BaseSingleFieldPeriod.between(interval.getStart(), interval.getEnd(), DurationFieldType.hours());
161 return Hours.hours(amount);
162 }
163
164 /**
165 * Creates a new <code>Hours</code> representing the number of complete
166 * standard length hours in the specified period.
167 * <p>
168 * This factory method converts all fields from the period to hours using standardised
169 * durations for each field. Only those fields which have a precise duration in
170 * the ISO UTC chronology can be converted.
171 * <ul>
172 * <li>One week consists of 7 days.
173 * <li>One day consists of 24 hours.
174 * <li>One hour consists of 60 minutes.
175 * <li>One minute consists of 60 seconds.
176 * <li>One second consists of 1000 milliseconds.
177 * </ul>
178 * Months and Years are imprecise and periods containing these values cannot be converted.
179 *
180 * @param period the period to get the number of hours from, null returns zero
181 * @return the period in hours
182 * @throws IllegalArgumentException if the period contains imprecise duration values
183 */
184 public static Hours standardHoursIn(ReadablePeriod period) {
185 int amount = BaseSingleFieldPeriod.standardPeriodIn(period, DateTimeConstants.MILLIS_PER_HOUR);
186 return Hours.hours(amount);
187 }
188
189 /**
190 * Creates a new <code>Hours</code> by parsing a string in the ISO8601 format 'PTnH'.
191 * <p>
192 * The parse will accept the full ISO syntax of PnYnMnWnDTnHnMnS however only the
193 * hours component may be non-zero. If any other component is non-zero, an exception
194 * will be thrown.
195 *
196 * @param periodStr the period string, null returns zero
197 * @return the period in hours
198 * @throws IllegalArgumentException if the string format is invalid
199 */
200 @FromString
201 public static Hours parseHours(String periodStr) {
202 if (periodStr == null) {
203 return Hours.ZERO;
204 }
205 Period p = PARSER.parsePeriod(periodStr);
206 return Hours.hours(p.getHours());
207 }
208
209 //-----------------------------------------------------------------------
210 /**
211 * Creates a new instance representing a number of hours.
212 * You should consider using the factory method {@link #hours(int)}
213 * instead of the constructor.
214 *
215 * @param hours the number of hours to represent
216 */
217 private Hours(int hours) {
218 super(hours);
219 }
220
221 /**
222 * Resolves singletons.
223 *
224 * @return the singleton instance
225 */
226 private Object readResolve() {
227 return Hours.hours(getValue());
228 }
229
230 //-----------------------------------------------------------------------
231 /**
232 * Gets the duration field type, which is <code>hours</code>.
233 *
234 * @return the period type
235 */
236 public DurationFieldType getFieldType() {
237 return DurationFieldType.hours();
238 }
239
240 /**
241 * Gets the period type, which is <code>hours</code>.
242 *
243 * @return the period type
244 */
245 public PeriodType getPeriodType() {
246 return PeriodType.hours();
247 }
248
249 //-----------------------------------------------------------------------
250 /**
251 * Converts this period in hours to a period in weeks assuming a
252 * 7 day week and 24 hour day.
253 * <p>
254 * This method allows you to convert between different types of period.
255 * However to achieve this it makes the assumption that all weeks are 7 days
256 * long and all days are 24 hours long.
257 * This is not true when daylight savings time is considered, and may also
258 * not be true for some unusual chronologies. However, it is included as it
259 * is a useful operation for many applications and business rules.
260 *
261 * @return a period representing the number of whole weeks for this number of hours
262 */
263 public Weeks toStandardWeeks() {
264 return Weeks.weeks(getValue() / DateTimeConstants.HOURS_PER_WEEK);
265 }
266
267 /**
268 * Converts this period in hours to a period in days assuming a
269 * 24 hour day.
270 * <p>
271 * This method allows you to convert between different types of period.
272 * However to achieve this it makes the assumption that all days are 24 hours long.
273 * This is not true when daylight savings time is considered, and may also
274 * not be true for some unusual chronologies. However, it is included as it
275 * is a useful operation for many applications and business rules.
276 *
277 * @return a period representing the number of whole days for this number of hours
278 */
279 public Days toStandardDays() {
280 return Days.days(getValue() / DateTimeConstants.HOURS_PER_DAY);
281 }
282
283 /**
284 * Converts this period in hours to a period in minutes assuming a
285 * 60 minute hour.
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 hours are 60 minutes long.
289 * This may not be true for some unusual chronologies. However, it is included
290 * as it is a useful operation for many applications and business rules.
291 *
292 * @return a period representing the number of minutes for this number of hours
293 * @throws ArithmeticException if the number of minutes is too large to be represented
294 */
295 public Minutes toStandardMinutes() {
296 return Minutes.minutes(FieldUtils.safeMultiply(getValue(), DateTimeConstants.MINUTES_PER_HOUR));
297 }
298
299 /**
300 * Converts this period in hours to a period in seconds assuming a
301 * 60 minute hour and 60 second minute.
302 * <p>
303 * This method allows you to convert between different types of period.
304 * However to achieve this it makes the assumption that all hours are
305 * 60 minutes long and all minutes are 60 seconds long.
306 * This may not be true for some unusual chronologies. However, it is included
307 * as it is a useful operation for many applications and business rules.
308 *
309 * @return a period representing the number of seconds for this number of hours
310 * @throws ArithmeticException if the number of seconds is too large to be represented
311 */
312 public Seconds toStandardSeconds() {
313 return Seconds.seconds(FieldUtils.safeMultiply(getValue(), DateTimeConstants.SECONDS_PER_HOUR));
314 }
315
316 //-----------------------------------------------------------------------
317 /**
318 * Converts this period in hours to a duration in milliseconds assuming a
319 * 60 minute hour and 60 second minute.
320 * <p>
321 * This method allows you to convert from a period to a duration.
322 * However to achieve this it makes the assumption that all hours are
323 * 60 minutes and all minutes are 60 seconds. This might not be true for an
324 * unusual chronology, for example one that takes leap seconds into account.
325 * However, the method is included as it is a useful operation for many
326 * applications and business rules.
327 *
328 * @return a duration equivalent to this number of hours
329 */
330 public Duration toStandardDuration() {
331 long hours = getValue(); // assign to a long
332 return new Duration(hours * DateTimeConstants.MILLIS_PER_HOUR);
333 }
334
335 //-----------------------------------------------------------------------
336 /**
337 * Gets the number of hours that this period represents.
338 *
339 * @return the number of hours in the period
340 */
341 public int getHours() {
342 return getValue();
343 }
344
345 //-----------------------------------------------------------------------
346 /**
347 * Returns a new instance with the specified number of hours added.
348 * <p>
349 * This instance is immutable and unaffected by this method call.
350 *
351 * @param hours the amount of hours to add, may be negative
352 * @return the new period plus the specified number of hours
353 * @throws ArithmeticException if the result overflows an int
354 */
355 public Hours plus(int hours) {
356 if (hours == 0) {
357 return this;
358 }
359 return Hours.hours(FieldUtils.safeAdd(getValue(), hours));
360 }
361
362 /**
363 * Returns a new instance with the specified number of hours added.
364 * <p>
365 * This instance is immutable and unaffected by this method call.
366 *
367 * @param hours the amount of hours to add, may be negative, null means zero
368 * @return the new period plus the specified number of hours
369 * @throws ArithmeticException if the result overflows an int
370 */
371 public Hours plus(Hours hours) {
372 if (hours == null) {
373 return this;
374 }
375 return plus(hours.getValue());
376 }
377
378 //-----------------------------------------------------------------------
379 /**
380 * Returns a new instance with the specified number of hours taken away.
381 * <p>
382 * This instance is immutable and unaffected by this method call.
383 *
384 * @param hours the amount of hours to take away, may be negative
385 * @return the new period minus the specified number of hours
386 * @throws ArithmeticException if the result overflows an int
387 */
388 public Hours minus(int hours) {
389 return plus(FieldUtils.safeNegate(hours));
390 }
391
392 /**
393 * Returns a new instance with the specified number of hours taken away.
394 * <p>
395 * This instance is immutable and unaffected by this method call.
396 *
397 * @param hours the amount of hours to take away, may be negative, null means zero
398 * @return the new period minus the specified number of hours
399 * @throws ArithmeticException if the result overflows an int
400 */
401 public Hours minus(Hours hours) {
402 if (hours == null) {
403 return this;
404 }
405 return minus(hours.getValue());
406 }
407
408 //-----------------------------------------------------------------------
409 /**
410 * Returns a new instance with the hours multiplied by the specified scalar.
411 * <p>
412 * This instance is immutable and unaffected by this method call.
413 *
414 * @param scalar the amount to multiply by, may be negative
415 * @return the new period multiplied by the specified scalar
416 * @throws ArithmeticException if the result overflows an int
417 */
418 public Hours multipliedBy(int scalar) {
419 return Hours.hours(FieldUtils.safeMultiply(getValue(), scalar));
420 }
421
422 /**
423 * Returns a new instance with the hours divided by the specified divisor.
424 * The calculation uses integer division, thus 3 divided by 2 is 1.
425 * <p>
426 * This instance is immutable and unaffected by this method call.
427 *
428 * @param divisor the amount to divide by, may be negative
429 * @return the new period divided by the specified divisor
430 * @throws ArithmeticException if the divisor is zero
431 */
432 public Hours dividedBy(int divisor) {
433 if (divisor == 1) {
434 return this;
435 }
436 return Hours.hours(getValue() / divisor);
437 }
438
439 //-----------------------------------------------------------------------
440 /**
441 * Returns a new instance with the hours value negated.
442 *
443 * @return the new period with a negated value
444 * @throws ArithmeticException if the result overflows an int
445 */
446 public Hours negated() {
447 return Hours.hours(FieldUtils.safeNegate(getValue()));
448 }
449
450 //-----------------------------------------------------------------------
451 /**
452 * Is this hours instance greater than the specified number of hours.
453 *
454 * @param other the other period, null means zero
455 * @return true if this hours instance is greater than the specified one
456 */
457 public boolean isGreaterThan(Hours other) {
458 if (other == null) {
459 return getValue() > 0;
460 }
461 return getValue() > other.getValue();
462 }
463
464 /**
465 * Is this hours instance less than the specified number of hours.
466 *
467 * @param other the other period, null means zero
468 * @return true if this hours instance is less than the specified one
469 */
470 public boolean isLessThan(Hours other) {
471 if (other == null) {
472 return getValue() < 0;
473 }
474 return getValue() < other.getValue();
475 }
476
477 //-----------------------------------------------------------------------
478 /**
479 * Gets this instance as a String in the ISO8601 duration format.
480 * <p>
481 * For example, "PT4H" represents 4 hours.
482 *
483 * @return the value as an ISO8601 string
484 */
485 @ToString
486 public String toString() {
487 return "PT" + String.valueOf(getValue()) + "H";
488 }
489
490 }