001 /* ===========================================================
002 * JFreeChart : a free chart library for the Java(tm) platform
003 * ===========================================================
004 *
005 * (C) Copyright 2000-2008, by Object Refinery Limited and Contributors.
006 *
007 * Project Info: http://www.jfree.org/jfreechart/index.html
008 *
009 * This library is free software; you can redistribute it and/or modify it
010 * under the terms of the GNU Lesser General Public License as published by
011 * the Free Software Foundation; either version 2.1 of the License, or
012 * (at your option) any later version.
013 *
014 * This library is distributed in the hope that it will be useful, but
015 * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
016 * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
017 * License for more details.
018 *
019 * You should have received a copy of the GNU Lesser General Public
020 * License along with this library; if not, write to the Free Software
021 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
022 * USA.
023 *
024 * [Java is a trademark or registered trademark of Sun Microsystems, Inc.
025 * in the United States and other countries.]
026 *
027 * ----------
028 * Month.java
029 * ----------
030 * (C) Copyright 2001-2008, by Object Refinery Limited and Contributors.
031 *
032 * Original Author: David Gilbert (for Object Refinery Limited);
033 * Contributor(s): Chris Boek;
034 *
035 * Changes
036 * -------
037 * 11-Oct-2001 : Version 1 (DG);
038 * 14-Nov-2001 : Added method to get year as primitive (DG);
039 * Override for toString() method (DG);
040 * 18-Dec-2001 : Changed order of parameters in constructor (DG);
041 * 19-Dec-2001 : Added a new constructor as suggested by Paul English (DG);
042 * 29-Jan-2002 : Worked on the parseMonth() method (DG);
043 * 14-Feb-2002 : Fixed bugs in the Month constructors (DG);
044 * 26-Feb-2002 : Changed getStart(), getMiddle() and getEnd() methods to
045 * evaluate with reference to a particular time zone (DG);
046 * 19-Mar-2002 : Changed API for TimePeriod classes (DG);
047 * 10-Sep-2002 : Added getSerialIndex() method (DG);
048 * 04-Oct-2002 : Fixed errors reported by Checkstyle (DG);
049 * 10-Jan-2003 : Changed base class and method names (DG);
050 * 13-Mar-2003 : Moved to com.jrefinery.data.time package, and implemented
051 * Serializable (DG);
052 * 21-Oct-2003 : Added hashCode() method (DG);
053 * 01-Nov-2005 : Fixed bug 1345383 (argument check in constructor) (DG);
054 * ------------- JFREECHART 1.0.x ---------------------------------------------
055 * 05-Oct-2006 : Updated API docs (DG);
056 * 06-Oct-2006 : Refactored to cache first and last millisecond values (DG);
057 * 04-Apr-2007 : Fixed bug in Month(Date, TimeZone) constructor (CB);
058 * 01-Sep-2008 : Added clarification for previous() and next() methods (DG);
059 * 16-Sep-2008 : Deprecated DEFAULT_TIME_ZONE, and updated parsing to handle
060 * extended range in Year (DG);
061 *
062 */
063
064 package org.jfree.data.time;
065
066 import java.io.Serializable;
067 import java.util.Calendar;
068 import java.util.Date;
069 import java.util.TimeZone;
070
071 import org.jfree.date.MonthConstants;
072 import org.jfree.date.SerialDate;
073
074 /**
075 * Represents a single month. This class is immutable, which is a requirement
076 * for all {@link RegularTimePeriod} subclasses.
077 */
078 public class Month extends RegularTimePeriod implements Serializable {
079
080 /** For serialization. */
081 private static final long serialVersionUID = -5090216912548722570L;
082
083 /** The month (1-12). */
084 private int month;
085
086 /** The year in which the month falls. */
087 private int year;
088
089 /** The first millisecond. */
090 private long firstMillisecond;
091
092 /** The last millisecond. */
093 private long lastMillisecond;
094
095 /**
096 * Constructs a new Month, based on the current system time.
097 */
098 public Month() {
099 this(new Date());
100 }
101
102 /**
103 * Constructs a new month instance.
104 *
105 * @param month the month (in the range 1 to 12).
106 * @param year the year.
107 */
108 public Month(int month, int year) {
109 if ((month < 1) || (month > 12)) {
110 throw new IllegalArgumentException("Month outside valid range.");
111 }
112 this.month = month;
113 this.year = year;
114 peg(Calendar.getInstance());
115 }
116
117 /**
118 * Constructs a new month instance.
119 *
120 * @param month the month (in the range 1 to 12).
121 * @param year the year.
122 */
123 public Month(int month, Year year) {
124 if ((month < 1) || (month > 12)) {
125 throw new IllegalArgumentException("Month outside valid range.");
126 }
127 this.month = month;
128 this.year = year.getYear();
129 peg(Calendar.getInstance());
130 }
131
132 /**
133 * Constructs a new <code>Month</code> instance, based on a date/time and
134 * the default time zone.
135 *
136 * @param time the date/time (<code>null</code> not permitted).
137 *
138 * @see #Month(Date, TimeZone)
139 */
140 public Month(Date time) {
141 this(time, TimeZone.getDefault());
142 }
143
144 /**
145 * Constructs a new <code>Month</code> instance, based on a date/time and
146 * a time zone. The first and last millisecond values are initially
147 * pegged to the given time zone also.
148 *
149 * @param time the date/time.
150 * @param zone the time zone (<code>null</code> not permitted).
151 */
152 public Month(Date time, TimeZone zone) {
153 // FIXME: need a locale as well as a timezone
154 Calendar calendar = Calendar.getInstance(zone);
155 calendar.setTime(time);
156 this.month = calendar.get(Calendar.MONTH) + 1;
157 this.year = calendar.get(Calendar.YEAR);
158 peg(calendar);
159 }
160
161 /**
162 * Returns the year in which the month falls.
163 *
164 * @return The year in which the month falls (as a Year object).
165 */
166 public Year getYear() {
167 return new Year(this.year);
168 }
169
170 /**
171 * Returns the year in which the month falls.
172 *
173 * @return The year in which the month falls (as an int).
174 */
175 public int getYearValue() {
176 return this.year;
177 }
178
179 /**
180 * Returns the month. Note that 1=JAN, 2=FEB, ...
181 *
182 * @return The month.
183 */
184 public int getMonth() {
185 return this.month;
186 }
187
188 /**
189 * Returns the first millisecond of the month. This will be determined
190 * relative to the time zone specified in the constructor, or in the
191 * calendar instance passed in the most recent call to the
192 * {@link #peg(Calendar)} method.
193 *
194 * @return The first millisecond of the month.
195 *
196 * @see #getLastMillisecond()
197 */
198 public long getFirstMillisecond() {
199 return this.firstMillisecond;
200 }
201
202 /**
203 * Returns the last millisecond of the month. This will be
204 * determined relative to the time zone specified in the constructor, or
205 * in the calendar instance passed in the most recent call to the
206 * {@link #peg(Calendar)} method.
207 *
208 * @return The last millisecond of the month.
209 *
210 * @see #getFirstMillisecond()
211 */
212 public long getLastMillisecond() {
213 return this.lastMillisecond;
214 }
215
216 /**
217 * Recalculates the start date/time and end date/time for this time period
218 * relative to the supplied calendar (which incorporates a time zone).
219 *
220 * @param calendar the calendar (<code>null</code> not permitted).
221 *
222 * @since 1.0.3
223 */
224 public void peg(Calendar calendar) {
225 this.firstMillisecond = getFirstMillisecond(calendar);
226 this.lastMillisecond = getLastMillisecond(calendar);
227 }
228
229 /**
230 * Returns the month preceding this one. Note that the returned
231 * {@link Month} is "pegged" using the default time-zone, irrespective of
232 * the time-zone used to peg of the current month (which is not recorded
233 * anywhere). See the {@link #peg(Calendar)} method.
234 *
235 * @return The month preceding this one.
236 */
237 public RegularTimePeriod previous() {
238 Month result;
239 if (this.month != MonthConstants.JANUARY) {
240 result = new Month(this.month - 1, this.year);
241 }
242 else {
243 if (this.year > 1900) {
244 result = new Month(MonthConstants.DECEMBER, this.year - 1);
245 }
246 else {
247 result = null;
248 }
249 }
250 return result;
251 }
252
253 /**
254 * Returns the month following this one. Note that the returned
255 * {@link Month} is "pegged" using the default time-zone, irrespective of
256 * the time-zone used to peg of the current month (which is not recorded
257 * anywhere). See the {@link #peg(Calendar)} method.
258 *
259 * @return The month following this one.
260 */
261 public RegularTimePeriod next() {
262 Month result;
263 if (this.month != MonthConstants.DECEMBER) {
264 result = new Month(this.month + 1, this.year);
265 }
266 else {
267 if (this.year < 9999) {
268 result = new Month(MonthConstants.JANUARY, this.year + 1);
269 }
270 else {
271 result = null;
272 }
273 }
274 return result;
275 }
276
277 /**
278 * Returns a serial index number for the month.
279 *
280 * @return The serial index number.
281 */
282 public long getSerialIndex() {
283 return this.year * 12L + this.month;
284 }
285
286 /**
287 * Returns a string representing the month (e.g. "January 2002").
288 * <P>
289 * To do: look at internationalisation.
290 *
291 * @return A string representing the month.
292 */
293 public String toString() {
294 return SerialDate.monthCodeToString(this.month) + " " + this.year;
295 }
296
297 /**
298 * Tests the equality of this Month object to an arbitrary object.
299 * Returns true if the target is a Month instance representing the same
300 * month as this object. In all other cases, returns false.
301 *
302 * @param obj the object (<code>null</code> permitted).
303 *
304 * @return <code>true</code> if month and year of this and object are the
305 * same.
306 */
307 public boolean equals(Object obj) {
308
309 if (obj != null) {
310 if (obj instanceof Month) {
311 Month target = (Month) obj;
312 return (this.month == target.getMonth()
313 && (this.year == target.getYearValue()));
314 }
315 else {
316 return false;
317 }
318 }
319 else {
320 return false;
321 }
322
323 }
324
325 /**
326 * Returns a hash code for this object instance. The approach described by
327 * Joshua Bloch in "Effective Java" has been used here:
328 * <p>
329 * <code>http://developer.java.sun.com/developer/Books/effectivejava
330 * /Chapter3.pdf</code>
331 *
332 * @return A hash code.
333 */
334 public int hashCode() {
335 int result = 17;
336 result = 37 * result + this.month;
337 result = 37 * result + this.year;
338 return result;
339 }
340
341 /**
342 * Returns an integer indicating the order of this Month object relative to
343 * the specified
344 * object: negative == before, zero == same, positive == after.
345 *
346 * @param o1 the object to compare.
347 *
348 * @return negative == before, zero == same, positive == after.
349 */
350 public int compareTo(Object o1) {
351
352 int result;
353
354 // CASE 1 : Comparing to another Month object
355 // --------------------------------------------
356 if (o1 instanceof Month) {
357 Month m = (Month) o1;
358 result = this.year - m.getYearValue();
359 if (result == 0) {
360 result = this.month - m.getMonth();
361 }
362 }
363
364 // CASE 2 : Comparing to another TimePeriod object
365 // -----------------------------------------------
366 else if (o1 instanceof RegularTimePeriod) {
367 // more difficult case - evaluate later...
368 result = 0;
369 }
370
371 // CASE 3 : Comparing to a non-TimePeriod object
372 // ---------------------------------------------
373 else {
374 // consider time periods to be ordered after general objects
375 result = 1;
376 }
377
378 return result;
379
380 }
381
382 /**
383 * Returns the first millisecond of the month, evaluated using the supplied
384 * calendar (which determines the time zone).
385 *
386 * @param calendar the calendar (<code>null</code> not permitted).
387 *
388 * @return The first millisecond of the month.
389 *
390 * @throws NullPointerException if <code>calendar</code> is
391 * <code>null</code>.
392 */
393 public long getFirstMillisecond(Calendar calendar) {
394 calendar.set(this.year, this.month - 1, 1, 0, 0, 0);
395 calendar.set(Calendar.MILLISECOND, 0);
396 // in the following line, we'd rather call calendar.getTimeInMillis()
397 // to avoid object creation, but that isn't supported in Java 1.3.1
398 return calendar.getTime().getTime();
399 }
400
401 /**
402 * Returns the last millisecond of the month, evaluated using the supplied
403 * calendar (which determines the time zone).
404 *
405 * @param calendar the calendar (<code>null</code> not permitted).
406 *
407 * @return The last millisecond of the month.
408 *
409 * @throws NullPointerException if <code>calendar</code> is
410 * <code>null</code>.
411 */
412 public long getLastMillisecond(Calendar calendar) {
413 int eom = SerialDate.lastDayOfMonth(this.month, this.year);
414 calendar.set(this.year, this.month - 1, eom, 23, 59, 59);
415 calendar.set(Calendar.MILLISECOND, 999);
416 // in the following line, we'd rather call calendar.getTimeInMillis()
417 // to avoid object creation, but that isn't supported in Java 1.3.1
418 return calendar.getTime().getTime();
419 }
420
421 /**
422 * Parses the string argument as a month. This method is required to
423 * accept the format "YYYY-MM". It will also accept "MM-YYYY". Anything
424 * else, at the moment, is a bonus.
425 *
426 * @param s the string to parse (<code>null</code> permitted).
427 *
428 * @return <code>null</code> if the string is not parseable, the month
429 * otherwise.
430 */
431 public static Month parseMonth(String s) {
432 Month result = null;
433 if (s == null) {
434 return result;
435 }
436 // trim whitespace from either end of the string
437 s = s.trim();
438 int i = Month.findSeparator(s);
439 String s1, s2;
440 boolean yearIsFirst;
441 // if there is no separator, we assume the first four characters
442 // are YYYY
443 if (i == -1) {
444 yearIsFirst = true;
445 s1 = s.substring(0, 5);
446 s2 = s.substring(5);
447 }
448 else {
449 s1 = s.substring(0, i).trim();
450 s2 = s.substring(i + 1, s.length()).trim();
451 // now it is trickier to determine if the month or year is first
452 Year y1 = Month.evaluateAsYear(s1);
453 if (y1 == null) {
454 yearIsFirst = false;
455 }
456 else {
457 Year y2 = Month.evaluateAsYear(s2);
458 if (y2 == null) {
459 yearIsFirst = true;
460 }
461 else {
462 yearIsFirst = (s1.length() > s2.length());
463 }
464 }
465 }
466 Year year;
467 int month;
468 if (yearIsFirst) {
469 year = Month.evaluateAsYear(s1);
470 month = SerialDate.stringToMonthCode(s2);
471 }
472 else {
473 year = Month.evaluateAsYear(s2);
474 month = SerialDate.stringToMonthCode(s1);
475 }
476 if (month == -1) {
477 throw new TimePeriodFormatException("Can't evaluate the month.");
478 }
479 if (year == null) {
480 throw new TimePeriodFormatException("Can't evaluate the year.");
481 }
482 result = new Month(month, year);
483 return result;
484 }
485
486 /**
487 * Finds the first occurrence of '-', or if that character is not found,
488 * the first occurrence of ',', or the first occurrence of ' ' or '.'
489 *
490 * @param s the string to parse.
491 *
492 * @return The position of the separator character, or <code>-1</code> if
493 * none of the characters were found.
494 */
495 private static int findSeparator(String s) {
496 int result = s.indexOf('-');
497 if (result == -1) {
498 result = s.indexOf(',');
499 }
500 if (result == -1) {
501 result = s.indexOf(' ');
502 }
503 if (result == -1) {
504 result = s.indexOf('.');
505 }
506 return result;
507 }
508
509 /**
510 * Creates a year from a string, or returns <code>null</code> (format
511 * exceptions suppressed).
512 *
513 * @param s the string to parse.
514 *
515 * @return <code>null</code> if the string is not parseable, the year
516 * otherwise.
517 */
518 private static Year evaluateAsYear(String s) {
519 Year result = null;
520 try {
521 result = Year.parseYear(s);
522 }
523 catch (TimePeriodFormatException e) {
524 // suppress
525 }
526 return result;
527 }
528
529 }