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1 /*
2  * Copyright 2001-2006 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.time.base.BaseSingleFieldPeriod;
19 import org.joda.time.field.FieldUtils;
20 import org.joda.time.format.ISOPeriodFormat;
21 import org.joda.time.format.PeriodFormatter;
22
23 /**
24  * An immutable time period representing a number of weeks.
25  * <p>
26  * <code>Weeks</code> is an immutable period that can only store weeks.
27  * It does not store years, months or hours for example. As such it is a
28  * type-safe way of representing a number of weeks in an application.
29  * <p>
30  * The number of weeks is set in the constructor, and may be queried using
31  * <code>getWeeks()</code>. Basic mathematical operations are provided -
32  * <code>plus()</code>, <code>minus()</code>, <code>multipliedBy()</code> and
33  * <code>dividedBy()</code>.
34  * <p>
35  * <code>Weeks</code> is thread-safe and immutable.
36  *
37  * @author Stephen Colebourne
38  * @since 1.4
39  */
40 public final class Weeks extends BaseSingleFieldPeriod {
41
42     /** Constant representing zero weeks. */
43     public static final Weeks ZERO = new Weeks(0);
44     /** Constant representing one week. */
45     public static final Weeks ONE = new Weeks(1);
46     /** Constant representing two weeks. */
47     public static final Weeks TWO = new Weeks(2);
48     /** Constant representing three weeks. */
49     public static final Weeks THREE = new Weeks(3);
50     /** Constant representing the maximum nuber of weeks that can be stored in this object. */
51     public static final Weeks MAX_VALUE = new Weeks(Integer.MAX_VALUE);
52     /** Constant representing the minimum nuber of weeks that can be stored in this object. */
53     public static final Weeks MIN_VALUE = new Weeks(Integer.MIN_VALUE);
54
55     /** The paser to use for this class. */
56     private static final PeriodFormatter PARSER = ISOPeriodFormat.standard().withParseType(PeriodType.weeks());
57     /** Serialization version. */
58     private static final long serialVersionUID = 87525275727380866L;
59
60     //-----------------------------------------------------------------------
61 /**
62      * Obtains an instance of <code>Weeks</code> that may be cached.
63      * <code>Weeks</code> is immutable, so instances can be cached and shared.
64      * This factory method provides access to shared instances.
65      *
66      * @param weeks the number of weeks to obtain an instance for
67      * @return the instance of Weeks
68      */
69     public static Weeks weeks(int weeks) {
70         switch (weeks) {
71             case 0:
72                 return ZERO;
73             case 1:
74                 return ONE;
75             case 2:
76                 return TWO;
77             case 3:
78                 return THREE;
79             case Integer.MAX_VALUE:
80                 return MAX_VALUE;
81             case Integer.MIN_VALUE:
82                 return MIN_VALUE;
83             default:
84                 return new Weeks(weeks);
85         }
86     }
87
88     //-----------------------------------------------------------------------
89 /**
90      * Creates a <code>Weeks</code> representing the number of whole weeks
91      * between the two specified datetimes.
92      *
93      * @param start the start instant, must not be null
94      * @param end the end instant, must not be null
95      * @return the period in weeks
96      * @throws IllegalArgumentException if the instants are null or invalid
97      */
98     public static Weeks weeksBetween(ReadableInstant start, ReadableInstant end) {
99         int amount = BaseSingleFieldPeriod.between(start, end, DurationFieldType.weeks());
100         return Weeks.weeks(amount);
101     }
102
103     /**
104      * Creates a <code>Weeks</code> representing the number of whole weeks
105      * between the two specified partial datetimes.
106      * <p>
107      * The two partials must contain the same fields, for example you can specify
108      * two <code>LocalDate</code> objects.
109      *
110      * @param start the start partial date, must not be null
111      * @param end the end partial date, must not be null
112      * @return the period in weeks
113      * @throws IllegalArgumentException if the partials are null or invalid
114      */
115     public static Weeks weeksBetween(ReadablePartial start, ReadablePartial end) {
116         if (start instanceof LocalDate && end instanceof LocalDate) {
117             Chronology chrono = DateTimeUtils.getChronology(start.getChronology());
118             int weeks = chrono.weeks().getDifference(
119                     ((LocalDate) end).getLocalMillis(), ((LocalDate) start).getLocalMillis());
120             return Weeks.weeks(weeks);
121         }
122         int amount = BaseSingleFieldPeriod.between(start, end, ZERO);
123         return Weeks.weeks(amount);
124     }
125
126     /**
127      * Creates a <code>Weeks</code> representing the number of whole weeks
128      * in the specified interval.
129      *
130      * @param interval the interval to extract weeks from, null returns zero
131      * @return the period in weeks
132      * @throws IllegalArgumentException if the partials are null or invalid
133      */
134     public static Weeks weeksIn(ReadableInterval interval) {
135         if (interval == null) {
136             return Weeks.ZERO;
137         }
138         int amount = BaseSingleFieldPeriod.between(interval.getStart(), interval.getEnd(), DurationFieldType.weeks());
139         return Weeks.weeks(amount);
140     }
141
142     /**
143      * Creates a new <code>Weeks</code> representing the number of complete
144      * standard length weeks in the specified period.
145      * <p>
146      * This factory method converts all fields from the period to hours using standardised
147      * durations for each field. Only those fields which have a precise duration in
148      * the ISO UTC chronology can be converted.
149      * <ul>
150      * <li>One week consists of 7 days.
151      * <li>One day consists of 24 hours.
152      * <li>One hour consists of 60 minutes.
153      * <li>One minute consists of 60 weeks.
154      * <li>One second consists of 1000 milliseconds.
155      * </ul>
156      * Months and Years are imprecise and periods containing these values cannot be converted.
157      *
158      * @param period the period to get the number of hours from, null returns zero
159      * @return the period in weeks
160      * @throws IllegalArgumentException if the period contains imprecise duration values
161      */
162     public static Weeks standardWeeksIn(ReadablePeriod period) {
163         int amount = BaseSingleFieldPeriod.standardPeriodIn(period, DateTimeConstants.MILLIS_PER_WEEK);
164         return Weeks.weeks(amount);
165     }
166
167     /**
168      * Creates a new <code>Weeks</code> by parsing a string in the ISO8601 format 'PnW'.
169      * <p>
170      * The parse will accept the full ISO syntax of PnYnMnWnDTnHnMnS however only the
171      * weeks component may be non-zero. If any other component is non-zero, an exception
172      * will be thrown.
173      *
174      * @param periodStr the period string, null returns zero
175      * @return the period in weeks
176      * @throws IllegalArgumentException if the string format is invalid
177      */
178     public static Weeks parseWeeks(String JavaDoc periodStr) {
179         if (periodStr == null) {
180             return Weeks.ZERO;
181         }
182         Period p = PARSER.parsePeriod(periodStr);
183         return Weeks.weeks(p.getWeeks());
184     }
185
186     //-----------------------------------------------------------------------
187 /**
188      * Creates a new instance representing a number of weeks.
189      * You should consider using the factory method {@link #weeks(int)}
190      * instead of the constructor.
191      *
192      * @param weeks the number of weeks to represent
193      */
194     private Weeks(int weeks) {
195         super(weeks);
196     }
197
198     /**
199      * Resolves singletons.
200      *
201      * @return the singleton instance
202      */
203     private Object JavaDoc readResolve() {
204         return Weeks.weeks(getValue());
205     }
206
207     //-----------------------------------------------------------------------
208 /**
209      * Gets the duration field type, which is <code>weeks</code>.
210      *
211      * @return the period type
212      */
213     public DurationFieldType getFieldType() {
214         return DurationFieldType.weeks();
215     }
216
217     /**
218      * Gets the period type, which is <code>weeks</code>.
219      *
220      * @return the period type
221      */
222     public PeriodType getPeriodType() {
223         return PeriodType.weeks();
224     }
225
226     //-----------------------------------------------------------------------
227 /**
228      * Converts this period in weeks to a period in days assuming a
229      * 7 day week.
230      * <p>
231      * This method allows you to convert between different types of period.
232      * However to achieve this it makes the assumption that all weeks are
233      * 7 days long.
234      * This may not be true for some unusual chronologies. However, it is included
235      * as it is a useful operation for many applications and business rules.
236      *
237      * @return a period representing the number of days for this number of weeks
238      * @throws ArithmeticException if the number of days is too large to be represented
239      */
240     public Days toStandardDays() {
241         return Days.days(FieldUtils.safeMultiply(getValue(), DateTimeConstants.DAYS_PER_WEEK));
242     }
243
244     /**
245      * Converts this period in weeks to a period in hours assuming a
246      * 7 day week and 24 hour day.
247      * <p>
248      * This method allows you to convert between different types of period.
249      * However to achieve this it makes the assumption that all weeks are
250      * 7 days long and all days are 24 hours long.
251      * This is not true when daylight savings is considered and may also not
252      * be true for some unusual chronologies. However, it is included
253      * as it is a useful operation for many applications and business rules.
254      *
255      * @return a period representing the number of hours for this number of weeks
256      * @throws ArithmeticException if the number of hours is too large to be represented
257      */
258     public Hours toStandardHours() {
259         return Hours.hours(FieldUtils.safeMultiply(getValue(), DateTimeConstants.HOURS_PER_WEEK));
260     }
261
262     /**
263      * Converts this period in weeks to a period in minutes assuming a
264      * 7 day week, 24 hour day and 60 minute hour.
265      * <p>
266      * This method allows you to convert between different types of period.
267      * However to achieve this it makes the assumption that all weeks are
268      * 7 days long, all days are 24 hours long and all hours are 60 minutes long.
269      * This is not true when daylight savings is considered and may also not
270      * be true for some unusual chronologies. However, it is included
271      * as it is a useful operation for many applications and business rules.
272      *
273      * @return a period representing the number of minutes for this number of weeks
274      * @throws ArithmeticException if the number of minutes is too large to be represented
275      */
276     public Minutes toStandardMinutes() {
277         return Minutes.minutes(FieldUtils.safeMultiply(getValue(), DateTimeConstants.MINUTES_PER_WEEK));
278     }
279
280     /**
281      * Converts this period in weeks to a period in seconds assuming a
282      * 7 day week, 24 hour day, 60 minute hour and 60 second minute.
283      * <p>
284      * This method allows you to convert between different types of period.
285      * However to achieve this it makes the assumption that all weeks are
286      * 7 days long, all days are 24 hours long, all hours are 60 minutes long
287      * and all minutes are 60 seconds long.
288      * This is not true when daylight savings is considered and may also not
289      * 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 seconds for this number of weeks
293      * @throws ArithmeticException if the number of seconds is too large to be represented
294      */
295     public Seconds toStandardSeconds() {
296         return Seconds.seconds(FieldUtils.safeMultiply(getValue(), DateTimeConstants.SECONDS_PER_WEEK));
297     }
298
299     //-----------------------------------------------------------------------
300 /**
301      * Converts this period in weeks to a duration in milliweeks assuming a
302      * 7 day week, 24 hour day, 60 minute hour and 60 second minute.
303      * <p>
304      * This method allows you to convert from a period to a duration.
305      * However to achieve this it makes the assumption that all weeks are
306      * 7 days long, all days are 24 hours long, all hours are 60 minutes long
307      * and all minutes are 60 seconds long.
308      * This is not true when daylight savings time is considered, and may also
309      * not be true for some unusual chronologies. However, it is included as it
310      * is a useful operation for many applications and business rules.
311      *
312      * @return a period representing the number of hours for this number of weeks
313      */
314     public Duration toStandardDuration() {
315         long weeks = getValue(); // assign to a long
316 return new Duration(weeks * DateTimeConstants.MILLIS_PER_WEEK);
317     }
318
319     //-----------------------------------------------------------------------
320 /**
321      * Gets the number of weeks that this period represents.
322      *
323      * @return the number of weeks in the period
324      */
325     public int getWeeks() {
326         return getValue();
327     }
328
329     //-----------------------------------------------------------------------
330 /**
331      * Returns a new instance with the specified number of weeks added.
332      * <p>
333      * This instance is immutable and unaffected by this method call.
334      *
335      * @param weeks the amount of weeks to add, may be negative
336      * @return the new period plus the specified number of weeks
337      * @throws ArithmeticException if the result overflows an int
338      */
339     public Weeks plus(int weeks) {
340         if (weeks == 0) {
341             return this;
342         }
343         return Weeks.weeks(FieldUtils.safeAdd(getValue(), weeks));
344     }
345
346     /**
347      * Returns a new instance with the specified number of weeks added.
348      * <p>
349      * This instance is immutable and unaffected by this method call.
350      *
351      * @param weeks the amount of weeks to add, may be negative, null means zero
352      * @return the new period plus the specified number of weeks
353      * @throws ArithmeticException if the result overflows an int
354      */
355     public Weeks plus(Weeks weeks) {
356         if (weeks == null) {
357             return this;
358         }
359         return plus(weeks.getValue());
360     }
361
362     //-----------------------------------------------------------------------
363 /**
364      * Returns a new instance with the specified number of weeks taken away.
365      * <p>
366      * This instance is immutable and unaffected by this method call.
367      *
368      * @param weeks the amount of weeks to take away, may be negative
369      * @return the new period minus the specified number of weeks
370      * @throws ArithmeticException if the result overflows an int
371      */
372     public Weeks minus(int weeks) {
373         return plus(FieldUtils.safeNegate(weeks));
374     }
375
376     /**
377      * Returns a new instance with the specified number of weeks taken away.
378      * <p>
379      * This instance is immutable and unaffected by this method call.
380      *
381      * @param weeks the amount of weeks to take away, may be negative, null means zero
382      * @return the new period minus the specified number of weeks
383      * @throws ArithmeticException if the result overflows an int
384      */
385     public Weeks minus(Weeks weeks) {
386         if (weeks == null) {
387             return this;
388         }
389         return minus(weeks.getValue());
390     }
391
392     //-----------------------------------------------------------------------
393 /**
394      * Returns a new instance with the weeks multiplied by the specified scalar.
395      * <p>
396      * This instance is immutable and unaffected by this method call.
397      *
398      * @param scalar the amount to multiply by, may be negative
399      * @return the new period multiplied by the specified scalar
400      * @throws ArithmeticException if the result overflows an int
401      */
402     public Weeks multipliedBy(int scalar) {
403         return Weeks.weeks(FieldUtils.safeMultiply(getValue(), scalar));
404     }
405
406     /**
407      * Returns a new instance with the weeks divided by the specified divisor.
408      * The calculation uses integer division, thus 3 divided by 2 is 1.
409      * <p>
410      * This instance is immutable and unaffected by this method call.
411      *
412      * @param divisor the amount to divide by, may be negative
413      * @return the new period divided by the specified divisor
414      * @throws ArithmeticException if the divisor is zero
415      */
416     public Weeks dividedBy(int divisor) {
417         if (divisor == 1) {
418             return this;
419         }
420         return Weeks.weeks(getValue() / divisor);
421     }
422
423     //-----------------------------------------------------------------------
424 /**
425      * Returns a new instance with the weeks value negated.
426      *
427      * @return the new period with a negated value
428      * @throws ArithmeticException if the result overflows an int
429      */
430     public Weeks negated() {
431         return Weeks.weeks(FieldUtils.safeNegate(getValue()));
432     }
433
434     //-----------------------------------------------------------------------
435 /**
436      * Is this weeks instance greater than the specified number of weeks.
437      *
438      * @param other the other period, null means zero
439      * @return true if this weeks instance is greater than the specified one
440      */
441     public boolean isGreaterThan(Weeks other) {
442         if (other == null) {
443             return getValue() > 0;
444         }
445         return getValue() > other.getValue();
446     }
447
448     /**
449      * Is this weeks instance less than the specified number of weeks.
450      *
451      * @param other the other period, null means zero
452      * @return true if this weeks instance is less than the specified one
453      */
454     public boolean isLessThan(Weeks other) {
455         if (other == null) {
456             return getValue() < 0;
457         }
458         return getValue() < other.getValue();
459     }
460
461     //-----------------------------------------------------------------------
462 /**
463      * Gets this instance as a String in the ISO8601 duration format.
464      * <p>
465      * For example, "P4W" represents 4 weeks.
466      *
467      * @return the value as an ISO8601 string
468      */
469     public String JavaDoc toString() {
470         return "P" + String.valueOf(getValue()) + "W";
471     }
472
473 }
474
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