附录B org.jfree.date.SerialDate
代码清单B-1 SerialDate.Java
1 /* ========================================================================
2 * JCommon : a free general purpose class library for the Java(tm) platform
3 * ========================================================================
4 *
5 * (C) Copyright 2000-2005, by Object Refinery Limited and Contributors.
6 *
7 *
8 *
9 * This library is free software; you can redistribute it and/or modify it
10 * under the terms of the GNU Lesser General Public License as published by
11 * the Free Software Foundation; either version 2.1 of the License, or
12 * (at your option) any later version.
13 *
14 * This library is distributed in the hope that it will be useful, but
15 * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
16 * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
17 * License for more details.
18 *
19 * You should have received a copy of the GNU Lesser General Public
20 * License along with this library; if not, write to the Free Software
21 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
22 * USA.
23 *
24 * [Java is a trademark or registered trademark of Sun Microsystems, Inc.
25 * in the United States and other countries.]
26 *
27 * ---------------
28 * SerialDate.java
29 * ---------------
30 * (C) Copyright 2001-2005, by Object Refinery Limited.
31 *
32 * Original Author: David Gilbert (for Object Refinery Limited);
33 * Contributor(s): -;
34 *
35 * $Id: SerialDate.java,v 1.7 2005/11/03 09:25:17 mungady Exp $
36 *
37 * Changes (from 11-Oct-2001)
38 * --------------------------
39 * 11-Oct-2001 : Re-organised the class and moved it to new package
40 * com.jrefinery.date (DG);
41 * 05-Nov-2001 : Added a getDescription() method, and eliminated NotableDate
42 * class (DG);
43 * 12-Nov-2001 : IBD requires setDescription() method, now that NotableDate
44 * class is gone (DG); Changed getPreviousDayOfWeek(),
45 * getFollowingDayOfWeek() and getNearestDayOfWeek() to correct
46 * bugs (DG);
47 * 05-Dec-2001 : Fixed bug in SpreadsheetDate class (DG);
48 * 29-May-2002 : Moved the month constants into a separate interface
49 * (MonthConstants) (DG);
50 * 27-Aug-2002 : Fixed bug in addMonths() method, thanks to N???levka Petr (DG);
51 * 03-Oct-2002 : Fixed errors reported by Checkstyle (DG);
52 * 13-Mar-2003 : Implemented Serializable (DG);
53 * 29-May-2003 : Fixed bug in addMonths method (DG);
54 * 04-Sep-2003 : Implemented Comparable. Updated the isInRange javadocs (DG);
55 * 05-Jan-2005 : Fixed bug in addYears() method (1096282) (DG);
56 *
57 */
58
59 package org.jfree.date;
60
61 import java.io.Serializable;
62 import java.text.DateFormatSymbols;
63 import java.text.SimpleDateFormat;
64 import java.util.Calendar;
65 import java.util.GregorianCalendar;
66
67 /**
68 * An abstract class that defines our requirements for manipulating dates,
69 * without tying down a particular implementation.
70 * <P>
71 * Requirement 1 : match at least what Excel does for dates;
72 * Requirement 2 : class is immutable;
73 * <P>
74 * Why not just use java.util.Date? We will, when it makes sense. At times,
75 * java.util.Date can be *too* precise - it represents an instant in time,
76 * accurate to 1/1000th of a second (with the date itself depending on the
77 * time-zone). Sometimes we just want to represent a particular day (e.g. 21
78 * January 2015) without concerning ourselves about the time of day, or the
79 * time-zone, or anything else. That's what we've defined SerialDate for.
80 * <P>
81 * You can call getInstance() to get a concrete subclass of SerialDate,
82 * without worrying about the exact implementation.
83 *
84 * @author David Gilbert
85 */
86 public abstract class SerialDate implements Comparable,
87 Serializable,
88 MonthConstants {
89
90 /** For serialization. */
91 private static final long serialVersionUID = -293716040467423637L;
92
93 /** Date format symbols. */
94 public static final DateFormatSymbols
95 DATE_FORMAT_SYMBOLS = new SimpleDateFormat().getDateFormatSymbols();
96
97 /** The serial number for 1 January 1900. */
98 public static final int SERIAL_LOWER_BOUND = 2;
99
100 /** The serial number for 31 December 9999. */
101 public static final int SERIAL_UPPER_BOUND = 2958465;
102
103 /** The lowest year value supported by this date format. */
104 public static final int MINIMUM_YEAR_SUPPORTED = 1900;
105
106 /** The highest year value supported by this date format. */
107 public static final int MAXIMUM_YEAR_SUPPORTED = 9999;
108
109 /** Useful constant for Monday. Equivalent to java.util.Calendar.MONDAY. */
110 public static final int MONDAY = Calendar.MONDAY;
111
112 /**
113 * Useful constant for Tuesday. Equivalent to java.util.Calendar.TUESDAY.
114 */
115 public static final int TUESDAY = Calendar.TUESDAY;
116
117 /**
118 * Useful constant for Wednesday. Equivalent to
119 * java.util.Calendar.WEDNESDAY.
120 */
121 public static final int WEDNESDAY = Calendar.WEDNESDAY;
122
123 /**
124 * Useful constant for Thrusday. Equivalent to java.util.Calendar.THURSDAY.
125 */
126 public static final int THURSDAY = Calendar.THURSDAY;
127
128 /** Useful constant for Friday. Equivalent to java.util.Calendar.FRIDAY. */
129 public static final int FRIDAY = Calendar.FRIDAY;
130
131 /**
132 * Useful constant for Saturday. Equivalent to java.util.Calendar.SATURDAY.
133 */
134 public static final int SATURDAY = Calendar.SATURDAY;
135
136 /** Useful constant for Sunday. Equivalent to java.util.Calendar.SUNDAY. */
137 public static final int SUNDAY = Calendar.SUNDAY;
138
139 /** The number of days in each month in non leap years. */
140 static final int[] LAST_DAY_OF_MONTH =
141 {0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
142
143 /** The number of days in a (non-leap) year up to the end of each month. */
144 static final int[] AGGREGATE_DAYS_TO_END_OF_MONTH =
145 {0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334, 365};
146
147 /** The number of days in a year up to the end of the preceding month. */
148 static final int[] AGGREGATE_DAYS_TO_END_OF_PRECEDING_MONTH =
149 {0, 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334, 365};
150
151 /** The number of days in a leap year up to the end of each month. */
152 static final int[] LEAP_YEAR_AGGREGATE_DAYS_TO_END_OF_MONTH =
153 {0, 31, 60, 91, 121, 152, 182, 213, 244, 274, 305, 335, 366};
154
155 /**
156 * The number of days in a leap year up to the end of the preceding month.
157 */
158 static final int[]
159 LEAP_YEAR_AGGREGATE_DAYS_TO_END_OF_PRECEDING_MONTH =
160 {0, 0, 31, 60, 91, 121, 152, 182, 213, 244, 274, 305, 335, 366};
161
162 /** A useful constant for referring to the first week in a month. */
163 public static final int FIRST_WEEK_IN_MONTH = 1;
164
165 /** A useful constant for referring to the second week in a month. */
166 public static final int SECOND_WEEK_IN_MONTH = 2;
167
168 /** A useful constant for referring to the third week in a month. */
169 public static final int THIRD_WEEK_IN_MONTH = 3;
170
171 /** A useful constant for referring to the fourth week in a month. */
172 public static final int FOURTH_WEEK_IN_MONTH = 4;
173
174 /** A useful constant for referring to the last week in a month. */
175 public static final int LAST_WEEK_IN_MONTH = 0;
176
177 /** Useful range constant. */
178 public static final int INCLUDE_NONE = 0;
179
180 /** Useful range constant. */
181 public static final int INCLUDE_FIRST = 1;
182
183 /** Useful range constant. */
184 public static final int INCLUDE_SECOND = 2;
185
186 /** Useful range constant. */
187 public static final int INCLUDE_BOTH = 3;
188
189 /**
190 * Useful constant for specifying a day of the week relative to a fixed
191 * date.
192 */
193 public static final int PRECEDING = -1;
194
195 /**
196 * Useful constant for specifying a day of the week relative to a fixed
197 * date.
198 */
199 public static final int NEAREST = 0;
200
201 /**
202 * Useful constant for specifying a day of the week relative to a fixed
203 * date.
204 */
205 public static final int FOLLOWING = 1;
206
207 /** A description for the date. */
208 private String description;
209
210 /**
211 * Default constructor.
212 */
213 protected SerialDate() {
214 }
215
216 /**
217 * Returns <code>true</code> if the supplied integer code represents a
218 * valid day-of-the-week, and <code>false</code> otherwise.
219 *
220 * @param code the code being checked for validity.
221 *
222 * @return <code>true</code> if the supplied integer code represents a
223 * valid day-of-the-week, and <code>false</code> otherwise.
224 */
225 public static boolean isValidWeekdayCode(final int code) {
226
227 switch(code) {
228 case SUNDAY:
229 case MONDAY:
230 case TUESDAY:
231 case WEDNESDAY:
232 case THURSDAY:
233 case FRIDAY:
234 case SATURDAY:
235 return true;
236 default:
237 return false;
238 }
239
240 }
241
242 /**
243 * Converts the supplied string to a day of the week.
244 *
245 * @param s a string representing the day of the week.
246 *
247 * @return <code>-1</code> if the string is not convertable, the day of
248 * the week otherwise.
249 */
250 public static int stringToWeekdayCode(String s) {
251
252 final String[] shortWeekdayNames
253 = DATE_FORMAT_SYMBOLS.getShortWeekdays();
254 final String[] weekDayNames = DATE_FORMAT_SYMBOLS.getWeekdays();
255
256 int result = -1;
257 s = s.trim();
258 for (int i = 0; i < weekDayNames.length; i++) {
259 if (s.equals(shortWeekdayNames[i])) {
260 result = i;
261 break;
262 }
263 if (s.equals(weekDayNames[i])) {
264 result = i;
265 break;
266 }
267 }
268 return result;
269
270 }
271
272 /**
273 * Returns a string representing the supplied day-of-the-week.
274 * <P>
275 * Need to find a better approach.
276 *
277 * @param weekday the day of the week.
278 *
279 * @return a string representing the supplied day-of-the-week.
280 */
281 public static String weekdayCodeToString(final int weekday) {
282
283 final String[] weekdays = DATE_FORMAT_SYMBOLS.getWeekdays();
284 return weekdays[weekday];
285
286 }
287
288 /**
289 * Returns an array of month names.
290 *
291 * @return an array of month names.
292 */
293 public static String[] getMonths() {
294
295 return getMonths(false);
296
297 }
298
299 /**
300 * Returns an array of month names.
301 *
302 * @param shortened a flag indicating that shortened month names should
303 * be returned.
304 *
305 * @return an array of month names.
306 */
307 public static String[] getMonths(final boolean shortened) {
308
309 if (shortened) {
310 return DATE_FORMAT_SYMBOLS.getShortMonths();
311 }
312 else {
313 return DATE_FORMAT_SYMBOLS.getMonths();
314 }
315
316 }
317
318 /**
319 * Returns true if the supplied integer code represents a valid month.
320 *
321 * @param code the code being checked for validity.
322 *
323 * @return <code>true</code> if the supplied integer code represents a valid month.
324 *
325 */
326 public static boolean isValidMonthCode(final int code) {
327
328 switch(code) {
329 case JANUARY:
330 case FEBRUARY:
331 case MARCH:
332 case APRIL:
333 case MAY:
334 case JUNE:
335 case JULY:
336 case AUGUST:
337 case SEPTEMBER:
338 case OCTOBER:
339 case NOVEMBER:
340 case DECEMBER:
341 return true;
342 default:
343 return false;
344 }
345
346 }
347
348 /**
349 * Returns the quarter for the specified month.
350 *
351 * @param code the month code (1-12).
352 *
353 * @return the quarter that the month belongs to.
354 * @throws java.lang.IllegalArgumentException
355 */
356 public static int monthCodeToQuarter(final int code) {
357
358 switch(code) {
359 case JANUARY:
360 case FEBRUARY:
361 case MARCH: return 1;
362 case APRIL:
363 case MAY:
364 case JUNE: return 2;
365 case JULY:
366 case AUGUST:
367 case SEPTEMBER: return 3;
368 case OCTOBER:
369 case NOVEMBER:
370 case DECEMBER: return 4;
371 default: throw new IllegalArgumentException(
372 "SerialDate.monthCodeToQuarter: invalid month code.");
373 }
374
375 }
376
377 /**
378 * Returns a string representing the supplied month.
379 * <P>
380 * The string returned is the long form of the month name taken from the
381 * default locale.
382 *
383 * @param month the month.
384 *
385 * @return a string representing the supplied month.
386 */
387 public static String monthCodeToString(final int month) {
388
389 return monthCodeToString(month, false);
390
391 }
392
393 /**
394 * Returns a string representing the supplied month.
395 * <P>
396 * The string returned is the long or short form of the month name taken
397 * from the default locale.
398 *
399 * @param month the month.
400 * @param shortened if <code>true</code> return the abbreviation of the
401 * month.
402 *
403 * @return a string representing the supplied month.
404 * @throws java.lang.IllegalArgumentException
405 */
406 public static String monthCodeToString(final int month,
407 final boolean shortened) {
408
409 // check arguments...
410 if (!isValidMonthCode(month)) {
411 throw new IllegalArgumentException(
412 "SerialDate.monthCodeToString: month outside valid range.");
413 }
414
415 final String[] months;
416
417 if (shortened) {
418 months = DATE_FORMAT_SYMBOLS.getShortMonths();
419 }
420 else {
421 months = DATE_FORMAT_SYMBOLS.getMonths();
422 }
423
424 return months[month - 1];
425
426 }
427
428 /**
429 * Converts a string to a month code.
430 * <P>
431 * This method will return one of the constants JANUARY, FEBRUARY, ...,
432 * DECEMBER that corresponds to the string. If the string is not
433 * recognised, this method returns -1.
434 *
435 * @param s the string to parse.
436 *
437 * @return <code>-1</code> if the string is not parseable, the month of the
438 * year otherwise.
439 */
440 public static int stringToMonthCode(String s) {
441
442 final String[] shortMonthNames = DATE_FORMAT_SYMBOLS.getShortMonths();
443 final String[] monthNames = DATE_FORMAT_SYMBOLS.getMonths();
444
445 int result = -1;
446 s = s.trim();
447
448 // first try parsing the string as an integer (1-12)...
449 try {
450 result = Integer.parseInt(s);
451 }
452 catch (NumberFormatException e) {
453 // suppress
454 }
455
456 // now search through the month names...
457 if ((result < 1) || (result > 12)) {
458 for (int i = 0; i < monthNames.length; i++) {
459 if (s.equals(shortMonthNames[i])) {
460 result = i + 1;
461 break;
462 }
463 if (s.equals(monthNames[i])) {
464 result = i + 1;
465 break;
466 }
467 }
468 }
469
470 return result;
471
472 }
473
474 /**
475 * Returns true if the supplied integer code represents a valid
476 * week-in-the-month, and false otherwise.
477 *
478 * @param code the code being checked for validity.
479 * @return <code>true</code> if the supplied integer code represents a
480 * valid week-in-the-month.
481 */
482 public static boolean isValidWeekInMonthCode(final int code) {
483
484 switch(code) {
485 case FIRST_WEEK_IN_MONTH:
486 case SECOND_WEEK_IN_MONTH:
487 case THIRD_WEEK_IN_MONTH:
488 case FOURTH_WEEK_IN_MONTH:
489 case LAST_WEEK_IN_MONTH: return true;
490 default: return false;
491 }
492
493 }
494
495 /**
496 * Determines whether or not the specified year is a leap year.
497 *
498 * @param yyyy the year (in the range 1900 to 9999).
499 *
500 * @return <code>true</code> if the specified year is a leap year.
501 */
502 public static boolean isLeapYear(final int yyyy) {
503
504 if ((yyyy % 4) != 0) {
505 return false;
506 }
507 else if ((yyyy % 400) == 0) {
508 return true;
509 }
510 else if ((yyyy % 100) == 0) {
511 return false;
512 }
513 else {
514 return true;
515 }
516
517 }
518
519 /**
520 * Returns the number of leap years from 1900 to the specified year
521 * INCLUSIVE.
522 * <P>
523 * Note that 1900 is not a leap year.
524 *
525 * @param yyyy the year (in the range 1900 to 9999).
526 *
527 * @return the number of leap years from 1900 to the specified year.
528 */
529 public static int leapYearCount(final int yyyy) {
530
531 final int leap4 = (yyyy - 1896) / 4;
532 final int leap100 = (yyyy - 1800) / 100;
533 final int leap400 = (yyyy - 1600) / 400;
534 return leap4 - leap100 + leap400;
535
536 }
537
538 /**
539 * Returns the number of the last day of the month, taking into account
540 * leap years.
541 *
542 * @param month the month.
543 * @param yyyy the year (in the range 1900 to 9999).
544 *
545 * @return the number of the last day of the month.
546 */
547 public static int lastDayOfMonth(final int month, final int yyyy) {
548
549 final int result = LAST_DAY_OF_MONTH[month];
550 if (month != FEBRUARY) {
551 return result;
552 }
553 else if (isLeapYear(yyyy)) {
554 return result + 1;
555 }
556 else {
557 return result;
558 }
559
560 }
561
562 /**
563 * Creates a new date by adding the specified number of days to the base
564 * date.
565 *
566 * @param days the number of days to add (can be negative).
567 * @param base the base date.
568 *
569 * @return a new date.
570 */
571 public static SerialDate addDays(final int days, final SerialDate base) {
572
573 final int serialDayNumber = base.toSerial() + days;
574 return SerialDate.createInstance(serialDayNumber);
575
576 }
577
578 /**
579 * Creates a new date by adding the specified number of months to the base
580 * date.
581 * <P>
582 * If the base date is close to the end of the month, the day on the result
583 * may be adjusted slightly: 31 May + 1 month = 30 June.
584 *
585 * @param months the number of months to add (can be negative).
586 * @param base the base date.
587 *
588 * @return a new date.
589 */
590 public static SerialDate addMonths(final int months,
591 final SerialDate base) {
592
593 final int yy = (12 * base.getYYYY() + base.getMonth() + months - 1) / 12;
594
595 final int mm = (12 * base.getYYYY() + base.getMonth() + months - 1) % 12 + 1;
596
597 final int dd = Math.min(
598 base.getDayOfMonth(), SerialDate.lastDayOfMonth(mm, yy)
599 );
600 return SerialDate.createInstance(dd, mm, yy);
601
602 }
603
604 /**
605 * Creates a new date by adding the specified number of years to the base
606 * date.
607 *
608 * @param years the number of years to add (can be negative).
609 * @param base the base date.
610 *
611 * @return A new date.
612 */
613 public static SerialDate addYears(final int years, final SerialDate base) {
614
615 final int baseY = base.getYYYY();
616 final int baseM = base.getMonth();
617 final int baseD = base.getDayOfMonth();
618
619 final int targetY = baseY + years;
620 final int targetD = Math.min(
621 baseD, SerialDate.lastDayOfMonth(baseM, targetY)
622 );
623
624 return SerialDate.createInstance(targetD, baseM, targetY);
625
626 }
627
628 /**
629 * Returns the latest date that falls on the specified day-of-the-week and
630 * is BEFORE the base date.
631 *
632 * @param targetWeekday a code for the target day-of-the-week.
633 * @param base the base date.
634 *
635 * @return the latest date that falls on the specified day-of-the-week and
636 * is BEFORE the base date.
637 */
638 public static SerialDate getPreviousDayOfWeek(final int targetWeekday,
639 final SerialDate base) {
640
641 // check arguments...
642 if (!SerialDate.isValidWeekdayCode(targetWeekday)) {
643 throw new IllegalArgumentException(
644 "Invalid day-of-the-week code."
645 );
646 }
647
648 // find the date...
649 final int adjust;
650 final int baseDOW = base.getDayOfWeek();
651 if (baseDOW > targetWeekday) {
652 adjust = Math.min(0, targetWeekday - baseDOW);
653 }
654 else {
655 adjust = -7 + Math.max(0, targetWeekday - baseDOW);
656 }
657
658 return SerialDate.addDays(adjust, base);
659
660 }
661
662 /**
663 * Returns the earliest date that falls on the specified day-of-the-week
664 * and is AFTER the base date.
665 *
666 * @param targetWeekday a code for the target day-of-the-week.
667 * @param base the base date.
668 *
669 * @return the earliest date that falls on the specified day-of-the-week
670 * and is AFTER the base date.
671 */
672 public static SerialDate getFollowingDayOfWeek(final int targetWeekday,
673 final SerialDate base) {
674
675 // check arguments...
676 if (!SerialDate.isValidWeekdayCode(targetWeekday)) {
677 throw new IllegalArgumentException(
678 "Invalid day-of-the-week code."
679 );
680 }
681
682 // find the date...
683 final int adjust;
684 final int baseDOW = base.getDayOfWeek();
685 if (baseDOW > targetWeekday) {
686 adjust = 7 + Math.min(0, targetWeekday - baseDOW);
687 }
688 else {
689 adjust = Math.max(0, targetWeekday - baseDOW);
690 }
691
692 return SerialDate.addDays(adjust, base);
693 }
694
695 /**
696 * Returns the date that falls on the specified day-of-the-week and is
697 * CLOSEST to the base date.
698 *
699 * @param targetDOW a code for the target day-of-the-week.
700 * 
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