001    /* ===========================================================
002     * JFreeChart : a free chart library for the Java(tm) platform
003     * ===========================================================
004     *
005     * (C) Copyright 2000-2007, 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     * Week.java
029     * ---------
030     * (C) Copyright 2001-2007, by Object Refinery Limited and Contributors.
031     *
032     * Original Author:  David Gilbert (for Object Refinery Limited);
033     * Contributor(s):   Aimin Han;
034     *
035     * $Id: Week.java,v 1.7.2.5 2007/01/10 11:43:46 mungady Exp $
036     *
037     * Changes
038     * -------
039     * 11-Oct-2001 : Version 1 (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 parseWeek() method (DG);
043     * 13-Feb-2002 : Fixed bug in Week(Date) constructor (DG);
044     * 26-Feb-2002 : Changed getStart(), getMiddle() and getEnd() methods to 
045     *               evaluate with reference to a particular time zone (DG);
046     * 05-Apr-2002 : Reinstated this class to the JCommon library (DG);
047     * 24-Jun-2002 : Removed unnecessary main method (DG);
048     * 10-Sep-2002 : Added getSerialIndex() method (DG);
049     * 06-Oct-2002 : Fixed errors reported by Checkstyle (DG);
050     * 18-Oct-2002 : Changed to observe 52 or 53 weeks per year, consistent with 
051     *               GregorianCalendar. Thanks to Aimin Han for the code (DG);
052     * 02-Jan-2003 : Removed debug code (DG);
053     * 13-Mar-2003 : Moved to com.jrefinery.data.time package, and implemented 
054     *               Serializable (DG);
055     * 21-Oct-2003 : Added hashCode() method (DG);
056     * 24-May-2004 : Modified getFirstMillisecond() and getLastMillisecond() to 
057     *               take account of firstDayOfWeek setting in Java's Calendar 
058     *               class (DG);
059     * 30-Sep-2004 : Replaced getTime().getTime() with getTimeInMillis() (DG);
060     * 04-Nov-2004 : Reverted change of 30-Sep-2004, because it won't work for 
061     *               JDK 1.3 (DG);
062     * ------------- JFREECHART 1.0.x ---------------------------------------------
063     * 06-Mar-2006 : Fix for bug 1448828, incorrect calculation of week and year
064     *               for the first few days of some years (DG);
065     * 05-Oct-2006 : Updated API docs (DG);
066     * 06-Oct-2006 : Refactored to cache first and last millisecond values (DG);
067     * 09-Jan-2007 : Fixed bug in next() (DG);
068     *
069     */
070    
071    package org.jfree.data.time;
072    
073    import java.io.Serializable;
074    import java.util.Calendar;
075    import java.util.Date;
076    import java.util.TimeZone;
077    
078    /**
079     * A calendar week.  All years are considered to have 53 weeks, numbered from 1 
080     * to 53, although in many cases the 53rd week is empty.  Most of the time, the
081     * 1st week of the year *begins* in the previous calendar year, but it always 
082     * finishes in the current year (this behaviour matches the workings of the 
083     * <code>GregorianCalendar</code> class).
084     * <P>
085     * This class is immutable, which is a requirement for all 
086     * {@link RegularTimePeriod} subclasses.
087     */
088    public class Week extends RegularTimePeriod implements Serializable {
089    
090        /** For serialization. */
091        private static final long serialVersionUID = 1856387786939865061L;
092        
093        /** Constant for the first week in the year. */
094        public static final int FIRST_WEEK_IN_YEAR = 1;
095    
096        /** Constant for the last week in the year. */
097        public static final int LAST_WEEK_IN_YEAR = 53;
098    
099        /** The year in which the week falls. */
100        private short year;
101    
102        /** The week (1-53). */
103        private byte week;
104    
105        /** The first millisecond. */
106        private long firstMillisecond;
107        
108        /** The last millisecond. */
109        private long lastMillisecond;
110    
111        /**
112         * Creates a new time period for the week in which the current system 
113         * date/time falls.
114         */
115        public Week() {
116            this(new Date());
117        }
118    
119        /**
120         * Creates a time period representing the week in the specified year.
121         *
122         * @param week  the week (1 to 53).
123         * @param year  the year (1900 to 9999).
124         */
125        public Week(int week, int year) {
126            if ((week < FIRST_WEEK_IN_YEAR) && (week > LAST_WEEK_IN_YEAR)) {
127                throw new IllegalArgumentException(
128                        "The 'week' argument must be in the range 1 - 53.");
129            }
130            this.week = (byte) week;
131            this.year = (short) year;
132            peg(Calendar.getInstance());
133        }
134    
135        /**
136         * Creates a time period representing the week in the specified year.
137         *
138         * @param week  the week (1 to 53).
139         * @param year  the year (1900 to 9999).
140         */
141        public Week(int week, Year year) {
142            if ((week < FIRST_WEEK_IN_YEAR) && (week > LAST_WEEK_IN_YEAR)) {
143                throw new IllegalArgumentException(
144                        "The 'week' argument must be in the range 1 - 53.");
145            }
146            this.week = (byte) week;
147            this.year = (short) year.getYear();
148            peg(Calendar.getInstance());
149       }
150    
151        /**
152         * Creates a time period for the week in which the specified date/time 
153         * falls.
154         *
155         * @param time  the time (<code>null</code> not permitted).
156         */
157        public Week(Date time) {
158            // defer argument checking...
159            this(time, RegularTimePeriod.DEFAULT_TIME_ZONE);
160        }
161    
162        /**
163         * Creates a time period for the week in which the specified date/time 
164         * falls, calculated relative to the specified time zone.
165         *
166         * @param time  the date/time (<code>null</code> not permitted).
167         * @param zone  the time zone (<code>null</code> not permitted).
168         */
169        public Week(Date time, TimeZone zone) {
170            if (time == null) {
171                throw new IllegalArgumentException("Null 'time' argument.");   
172            }
173            if (zone == null) {
174                throw new IllegalArgumentException("Null 'zone' argument.");   
175            }
176            Calendar calendar = Calendar.getInstance(zone);
177            calendar.setTime(time);
178    
179            // sometimes the last few days of the year are considered to fall in 
180            // the *first* week of the following year.  Refer to the Javadocs for 
181            // GregorianCalendar.
182            int tempWeek = calendar.get(Calendar.WEEK_OF_YEAR);
183            if (tempWeek == 1 
184                    && calendar.get(Calendar.MONTH) == Calendar.DECEMBER) {
185                this.week = 1;
186                this.year = (short) (calendar.get(Calendar.YEAR) + 1);
187            }
188            else {
189                this.week = (byte) Math.min(tempWeek, LAST_WEEK_IN_YEAR);
190                int yyyy = calendar.get(Calendar.YEAR);
191                // alternatively, sometimes the first few days of the year are
192                // considered to fall in the *last* week of the previous year...
193                if (calendar.get(Calendar.MONTH) == Calendar.JANUARY 
194                        && this.week >= 52) {
195                    yyyy--; 
196                }
197                this.year = (short) yyyy;
198            }
199            peg(calendar);
200    
201        }
202    
203        /**
204         * Returns the year in which the week falls.
205         *
206         * @return The year (never <code>null</code>).
207         */
208        public Year getYear() {
209            return new Year(this.year);
210        }
211    
212        /**
213         * Returns the year in which the week falls, as an integer value.
214         *
215         * @return The year.
216         */
217        public int getYearValue() {
218            return this.year;
219        }
220    
221        /**
222         * Returns the week.
223         *
224         * @return The week.
225         */
226        public int getWeek() {
227            return this.week;
228        }
229    
230        /**
231         * Returns the first millisecond of the week.  This will be determined 
232         * relative to the time zone specified in the constructor, or in the 
233         * calendar instance passed in the most recent call to the 
234         * {@link #peg(Calendar)} method.
235         *
236         * @return The first millisecond of the week.
237         * 
238         * @see #getLastMillisecond()
239         */
240        public long getFirstMillisecond() {
241            return this.firstMillisecond;
242        }
243    
244        /**
245         * Returns the last millisecond of the week.  This will be 
246         * determined relative to the time zone specified in the constructor, or
247         * in the calendar instance passed in the most recent call to the 
248         * {@link #peg(Calendar)} method.
249         *
250         * @return The last millisecond of the week.
251         * 
252         * @see #getFirstMillisecond()
253         */
254        public long getLastMillisecond() {
255            return this.lastMillisecond;
256        }
257        
258        /** 
259         * Recalculates the start date/time and end date/time for this time period 
260         * relative to the supplied calendar (which incorporates a time zone).
261         * 
262         * @param calendar  the calendar (<code>null</code> not permitted).
263         * 
264         * @since 1.0.3
265         */
266        public void peg(Calendar calendar) {
267            this.firstMillisecond = getFirstMillisecond(calendar);
268            this.lastMillisecond = getLastMillisecond(calendar);
269        }
270    
271        /**
272         * Returns the week preceding this one.  This method will return 
273         * <code>null</code> for some lower limit on the range of weeks (currently 
274         * week 1, 1900).  For week 1 of any year, the previous week is always week 
275         * 53, but week 53 may not contain any days (you should check for this).
276         *
277         * @return The preceding week (possibly <code>null</code>).
278         */
279        public RegularTimePeriod previous() {
280    
281            Week result;
282            if (this.week != FIRST_WEEK_IN_YEAR) {
283                result = new Week(this.week - 1, this.year);
284            }
285            else {
286                // we need to work out if the previous year has 52 or 53 weeks...
287                if (this.year > 1900) {
288                    int yy = this.year - 1;
289                    Calendar prevYearCalendar = Calendar.getInstance();
290                    prevYearCalendar.set(yy, Calendar.DECEMBER, 31);
291                    result = new Week(prevYearCalendar.getActualMaximum(
292                            Calendar.WEEK_OF_YEAR), yy);
293                }
294                else {
295                    result = null;
296                }
297            }
298            return result;
299    
300        }
301    
302        /**
303         * Returns the week following this one.  This method will return 
304         * <code>null</code> for some upper limit on the range of weeks (currently 
305         * week 53, 9999).  For week 52 of any year, the following week is always 
306         * week 53, but week 53 may not contain any days (you should check for 
307         * this).
308         *
309         * @return The following week (possibly <code>null</code>).
310         */
311        public RegularTimePeriod next() {
312    
313            Week result;
314            if (this.week < 52) {
315                result = new Week(this.week + 1, this.year);
316            }
317            else {
318                Calendar calendar = Calendar.getInstance();
319                calendar.set(this.year, Calendar.DECEMBER, 31);
320                int actualMaxWeek 
321                    = calendar.getActualMaximum(Calendar.WEEK_OF_YEAR);
322                if (this.week < actualMaxWeek) {
323                    result = new Week(this.week + 1, this.year);
324                }
325                else {
326                    if (this.year < 9999) {
327                        result = new Week(FIRST_WEEK_IN_YEAR, this.year + 1);
328                    }
329                    else {
330                        result = null;
331                    }
332                }
333            }
334            return result;
335    
336        }
337    
338        /**
339         * Returns a serial index number for the week.
340         *
341         * @return The serial index number.
342         */
343        public long getSerialIndex() {
344            return this.year * 53L + this.week;
345        }
346    
347        /**
348         * Returns the first millisecond of the week, evaluated using the supplied
349         * calendar (which determines the time zone).
350         *
351         * @param calendar  the calendar (<code>null</code> not permitted).
352         *
353         * @return The first millisecond of the week.
354         *
355         * @throws NullPointerException if <code>calendar</code> is 
356         *     <code>null</code>.
357         */
358        public long getFirstMillisecond(Calendar calendar) {
359            Calendar c = (Calendar) calendar.clone();
360            c.clear();
361            c.set(Calendar.YEAR, this.year);
362            c.set(Calendar.WEEK_OF_YEAR, this.week);
363            c.set(Calendar.DAY_OF_WEEK, c.getFirstDayOfWeek());
364            c.set(Calendar.HOUR, 0);
365            c.set(Calendar.MINUTE, 0);
366            c.set(Calendar.SECOND, 0);
367            c.set(Calendar.MILLISECOND, 0);
368            //return c.getTimeInMillis();  // this won't work for JDK 1.3
369            return c.getTime().getTime();
370        }
371    
372        /**
373         * Returns the last millisecond of the week, evaluated using the supplied
374         * calendar (which determines the time zone).
375         *
376         * @param calendar  the calendar (<code>null</code> not permitted).
377         *
378         * @return The last millisecond of the week.
379         *
380         * @throws NullPointerException if <code>calendar</code> is 
381         *     <code>null</code>.
382         */
383        public long getLastMillisecond(Calendar calendar) {
384            Calendar c = (Calendar) calendar.clone();
385            c.clear();
386            c.set(Calendar.YEAR, this.year);
387            c.set(Calendar.WEEK_OF_YEAR, this.week + 1);
388            c.set(Calendar.DAY_OF_WEEK, c.getFirstDayOfWeek());
389            c.set(Calendar.HOUR, 0);
390            c.set(Calendar.MINUTE, 0);
391            c.set(Calendar.SECOND, 0);
392            c.set(Calendar.MILLISECOND, 0);
393            //return c.getTimeInMillis();  // this won't work for JDK 1.3
394            return c.getTime().getTime() - 1;
395        }
396    
397        /**
398         * Returns a string representing the week (e.g. "Week 9, 2002").
399         *
400         * TODO: look at internationalisation.
401         *
402         * @return A string representing the week.
403         */
404        public String toString() {
405            return "Week " + this.week + ", " + this.year;
406        }
407    
408        /**
409         * Tests the equality of this Week object to an arbitrary object.  Returns
410         * true if the target is a Week instance representing the same week as this
411         * object.  In all other cases, returns false.
412         *
413         * @param obj  the object (<code>null</code> permitted).
414         *
415         * @return <code>true</code> if week and year of this and object are the 
416         *         same.
417         */
418        public boolean equals(Object obj) {
419    
420            if (obj == this) {
421                return true;
422            }
423            if (!(obj instanceof Week)) {
424                return false;
425            }
426            Week that = (Week) obj;
427            if (this.week != that.week) {
428                return false;
429            }
430            if (this.year != that.year) {
431                return false;
432            }
433            return true;
434    
435        }
436    
437        /**
438         * Returns a hash code for this object instance.  The approach described by
439         * Joshua Bloch in "Effective Java" has been used here:
440         * <p>
441         * <code>http://developer.java.sun.com/developer/Books/effectivejava
442         * /Chapter3.pdf</code>
443         * 
444         * @return A hash code.
445         */
446        public int hashCode() {
447            int result = 17;
448            result = 37 * result + this.week;
449            result = 37 * result + this.year;
450            return result;
451        }
452    
453        /**
454         * Returns an integer indicating the order of this Week object relative to
455         * the specified object:
456         *
457         * negative == before, zero == same, positive == after.
458         *
459         * @param o1  the object to compare.
460         *
461         * @return negative == before, zero == same, positive == after.
462         */
463        public int compareTo(Object o1) {
464    
465            int result;
466    
467            // CASE 1 : Comparing to another Week object
468            // --------------------------------------------
469            if (o1 instanceof Week) {
470                Week w = (Week) o1;
471                result = this.year - w.getYear().getYear();
472                if (result == 0) {
473                    result = this.week - w.getWeek();
474                }
475            }
476    
477            // CASE 2 : Comparing to another TimePeriod object
478            // -----------------------------------------------
479            else if (o1 instanceof RegularTimePeriod) {
480                // more difficult case - evaluate later...
481                result = 0;
482            }
483    
484            // CASE 3 : Comparing to a non-TimePeriod object
485            // ---------------------------------------------
486            else {
487                // consider time periods to be ordered after general objects
488                result = 1;
489            }
490    
491            return result;
492    
493        }
494    
495        /**
496         * Parses the string argument as a week.
497         * <P>
498         * This method is required to accept the format "YYYY-Wnn".  It will also
499         * accept "Wnn-YYYY". Anything else, at the moment, is a bonus.
500         *
501         * @param s  string to parse.
502         *
503         * @return <code>null</code> if the string is not parseable, the week 
504         *         otherwise.
505         */
506        public static Week parseWeek(String s) {
507    
508            Week result = null;
509            if (s != null) {
510    
511                // trim whitespace from either end of the string
512                s = s.trim();
513    
514                int i = Week.findSeparator(s);
515                if (i != -1) {
516                    String s1 = s.substring(0, i).trim();
517                    String s2 = s.substring(i + 1, s.length()).trim();
518    
519                    Year y = Week.evaluateAsYear(s1);
520                    int w;
521                    if (y != null) {
522                        w = Week.stringToWeek(s2);
523                        if (w == -1) {
524                            throw new TimePeriodFormatException(
525                                "Can't evaluate the week."
526                            );
527                        }
528                        result = new Week(w, y);
529                    }
530                    else {
531                        y = Week.evaluateAsYear(s2);
532                        if (y != null) {
533                            w = Week.stringToWeek(s1);
534                            if (w == -1) {
535                                throw new TimePeriodFormatException(
536                                    "Can't evaluate the week."
537                                );
538                            }
539                            result = new Week(w, y);
540                        }
541                        else {
542                            throw new TimePeriodFormatException(
543                                "Can't evaluate the year."
544                            );
545                        }
546                    }
547    
548                }
549                else {
550                    throw new TimePeriodFormatException(
551                        "Could not find separator."
552                    );
553                }
554    
555            }
556            return result;
557    
558        }
559    
560        /**
561         * Finds the first occurrence of ' ', '-', ',' or '.'
562         *
563         * @param s  the string to parse.
564         *
565         * @return <code>-1</code> if none of the characters was found, the
566         *      index of the first occurrence otherwise.
567         */
568        private static int findSeparator(String s) {
569    
570            int result = s.indexOf('-');
571            if (result == -1) {
572                result = s.indexOf(',');
573            }
574            if (result == -1) {
575                result = s.indexOf(' ');
576            }
577            if (result == -1) {
578                result = s.indexOf('.');
579            }
580            return result;
581        }
582    
583        /**
584         * Creates a year from a string, or returns null (format exceptions
585         * suppressed).
586         *
587         * @param s  string to parse.
588         *
589         * @return <code>null</code> if the string is not parseable, the year 
590         *         otherwise.
591         */
592        private static Year evaluateAsYear(String s) {
593    
594            Year result = null;
595            try {
596                result = Year.parseYear(s);
597            }
598            catch (TimePeriodFormatException e) {
599                // suppress
600            }
601            return result;
602    
603        }
604    
605        /**
606         * Converts a string to a week.
607         *
608         * @param s  the string to parse.
609         * @return <code>-1</code> if the string does not contain a week number,
610         *         the number of the week otherwise.
611         */
612        private static int stringToWeek(String s) {
613    
614            int result = -1;
615            s = s.replace('W', ' ');
616            s = s.trim();
617            try {
618                result = Integer.parseInt(s);
619                if ((result < 1) || (result > LAST_WEEK_IN_YEAR)) {
620                    result = -1;
621                }
622            }
623            catch (NumberFormatException e) {
624                // suppress
625            }
626            return result;
627    
628        }
629        
630    }