001 /*
002 * Copyright 1996-2005 Sun Microsystems, Inc. All Rights Reserved.
003 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
004 *
005 * This code is free software; you can redistribute it and/or modify it
006 * under the terms of the GNU General Public License version 2 only, as
007 * published by the Free Software Foundation. Sun designates this
008 * particular file as subject to the "Classpath" exception as provided
009 * by Sun in the LICENSE file that accompanied this code.
010 *
011 * This code is distributed in the hope that it will be useful, but WITHOUT
012 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
013 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
014 * version 2 for more details (a copy is included in the LICENSE file that
015 * accompanied this code).
016 *
017 * You should have received a copy of the GNU General Public License version
018 * 2 along with this work; if not, write to the Free Software Foundation,
019 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
020 *
021 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
022 * CA 95054 USA or visit www.sun.com if you need additional information or
023 * have any questions.
024 */
025
026 /*
027 * (C) Copyright Taligent, Inc. 1996 - All Rights Reserved
028 * (C) Copyright IBM Corp. 1996 - All Rights Reserved
029 *
030 * The original version of this source code and documentation is copyrighted
031 * and owned by Taligent, Inc., a wholly-owned subsidiary of IBM. These
032 * materials are provided under terms of a License Agreement between Taligent
033 * and Sun. This technology is protected by multiple US and International
034 * patents. This notice and attribution to Taligent may not be removed.
035 * Taligent is a registered trademark of Taligent, Inc.
036 *
037 */
038
039 package java.text;
040
041 import java.io.InvalidObjectException;
042 import java.text.spi.DateFormatProvider;
043 import java.util.Calendar;
044 import java.util.Date;
045 import java.util.GregorianCalendar;
046 import java.util.HashMap;
047 import java.util.Locale;
048 import java.util.Map;
049 import java.util.MissingResourceException;
050 import java.util.ResourceBundle;
051 import java.util.TimeZone;
052 import java.util.spi.LocaleServiceProvider;
053 import sun.util.LocaleServiceProviderPool;
054
055 /**
056 * DateFormat is an abstract class for date/time formatting subclasses which
057 * formats and parses dates or time in a language-independent manner.
058 * The date/time formatting subclass, such as SimpleDateFormat, allows for
059 * formatting (i.e., date -> text), parsing (text -> date), and
060 * normalization. The date is represented as a <code>Date</code> object or
061 * as the milliseconds since January 1, 1970, 00:00:00 GMT.
062 *
063 * <p>DateFormat provides many class methods for obtaining default date/time
064 * formatters based on the default or a given locale and a number of formatting
065 * styles. The formatting styles include FULL, LONG, MEDIUM, and SHORT. More
066 * detail and examples of using these styles are provided in the method
067 * descriptions.
068 *
069 * <p>DateFormat helps you to format and parse dates for any locale.
070 * Your code can be completely independent of the locale conventions for
071 * months, days of the week, or even the calendar format: lunar vs. solar.
072 *
073 * <p>To format a date for the current Locale, use one of the
074 * static factory methods:
075 * <pre>
076 * myString = DateFormat.getDateInstance().format(myDate);
077 * </pre>
078 * <p>If you are formatting multiple dates, it is
079 * more efficient to get the format and use it multiple times so that
080 * the system doesn't have to fetch the information about the local
081 * language and country conventions multiple times.
082 * <pre>
083 * DateFormat df = DateFormat.getDateInstance();
084 * for (int i = 0; i < myDate.length; ++i) {
085 * output.println(df.format(myDate[i]) + "; ");
086 * }
087 * </pre>
088 * <p>To format a date for a different Locale, specify it in the
089 * call to getDateInstance().
090 * <pre>
091 * DateFormat df = DateFormat.getDateInstance(DateFormat.LONG, Locale.FRANCE);
092 * </pre>
093 * <p>You can use a DateFormat to parse also.
094 * <pre>
095 * myDate = df.parse(myString);
096 * </pre>
097 * <p>Use getDateInstance to get the normal date format for that country.
098 * There are other static factory methods available.
099 * Use getTimeInstance to get the time format for that country.
100 * Use getDateTimeInstance to get a date and time format. You can pass in
101 * different options to these factory methods to control the length of the
102 * result; from SHORT to MEDIUM to LONG to FULL. The exact result depends
103 * on the locale, but generally:
104 * <ul><li>SHORT is completely numeric, such as 12.13.52 or 3:30pm
105 * <li>MEDIUM is longer, such as Jan 12, 1952
106 * <li>LONG is longer, such as January 12, 1952 or 3:30:32pm
107 * <li>FULL is pretty completely specified, such as
108 * Tuesday, April 12, 1952 AD or 3:30:42pm PST.
109 * </ul>
110 *
111 * <p>You can also set the time zone on the format if you wish.
112 * If you want even more control over the format or parsing,
113 * (or want to give your users more control),
114 * you can try casting the DateFormat you get from the factory methods
115 * to a SimpleDateFormat. This will work for the majority
116 * of countries; just remember to put it in a try block in case you
117 * encounter an unusual one.
118 *
119 * <p>You can also use forms of the parse and format methods with
120 * ParsePosition and FieldPosition to
121 * allow you to
122 * <ul><li>progressively parse through pieces of a string.
123 * <li>align any particular field, or find out where it is for selection
124 * on the screen.
125 * </ul>
126 *
127 * <h4><a name="synchronization">Synchronization</a></h4>
128 *
129 * <p>
130 * Date formats are not synchronized.
131 * It is recommended to create separate format instances for each thread.
132 * If multiple threads access a format concurrently, it must be synchronized
133 * externally.
134 *
135 * @see Format
136 * @see NumberFormat
137 * @see SimpleDateFormat
138 * @see java.util.Calendar
139 * @see java.util.GregorianCalendar
140 * @see java.util.TimeZone
141 * @version 1.63 05/05/07
142 * @author Mark Davis, Chen-Lieh Huang, Alan Liu
143 */
144 public abstract class DateFormat extends Format {
145
146 /**
147 * The calendar that <code>DateFormat</code> uses to produce the time field
148 * values needed to implement date and time formatting. Subclasses should
149 * initialize this to a calendar appropriate for the locale associated with
150 * this <code>DateFormat</code>.
151 * @serial
152 */
153 protected Calendar calendar;
154
155 /**
156 * The number formatter that <code>DateFormat</code> uses to format numbers
157 * in dates and times. Subclasses should initialize this to a number format
158 * appropriate for the locale associated with this <code>DateFormat</code>.
159 * @serial
160 */
161 protected NumberFormat numberFormat;
162
163 /**
164 * Useful constant for ERA field alignment.
165 * Used in FieldPosition of date/time formatting.
166 */
167 public final static int ERA_FIELD = 0;
168 /**
169 * Useful constant for YEAR field alignment.
170 * Used in FieldPosition of date/time formatting.
171 */
172 public final static int YEAR_FIELD = 1;
173 /**
174 * Useful constant for MONTH field alignment.
175 * Used in FieldPosition of date/time formatting.
176 */
177 public final static int MONTH_FIELD = 2;
178 /**
179 * Useful constant for DATE field alignment.
180 * Used in FieldPosition of date/time formatting.
181 */
182 public final static int DATE_FIELD = 3;
183 /**
184 * Useful constant for one-based HOUR_OF_DAY field alignment.
185 * Used in FieldPosition of date/time formatting.
186 * HOUR_OF_DAY1_FIELD is used for the one-based 24-hour clock.
187 * For example, 23:59 + 01:00 results in 24:59.
188 */
189 public final static int HOUR_OF_DAY1_FIELD = 4;
190 /**
191 * Useful constant for zero-based HOUR_OF_DAY field alignment.
192 * Used in FieldPosition of date/time formatting.
193 * HOUR_OF_DAY0_FIELD is used for the zero-based 24-hour clock.
194 * For example, 23:59 + 01:00 results in 00:59.
195 */
196 public final static int HOUR_OF_DAY0_FIELD = 5;
197 /**
198 * Useful constant for MINUTE field alignment.
199 * Used in FieldPosition of date/time formatting.
200 */
201 public final static int MINUTE_FIELD = 6;
202 /**
203 * Useful constant for SECOND field alignment.
204 * Used in FieldPosition of date/time formatting.
205 */
206 public final static int SECOND_FIELD = 7;
207 /**
208 * Useful constant for MILLISECOND field alignment.
209 * Used in FieldPosition of date/time formatting.
210 */
211 public final static int MILLISECOND_FIELD = 8;
212 /**
213 * Useful constant for DAY_OF_WEEK field alignment.
214 * Used in FieldPosition of date/time formatting.
215 */
216 public final static int DAY_OF_WEEK_FIELD = 9;
217 /**
218 * Useful constant for DAY_OF_YEAR field alignment.
219 * Used in FieldPosition of date/time formatting.
220 */
221 public final static int DAY_OF_YEAR_FIELD = 10;
222 /**
223 * Useful constant for DAY_OF_WEEK_IN_MONTH field alignment.
224 * Used in FieldPosition of date/time formatting.
225 */
226 public final static int DAY_OF_WEEK_IN_MONTH_FIELD = 11;
227 /**
228 * Useful constant for WEEK_OF_YEAR field alignment.
229 * Used in FieldPosition of date/time formatting.
230 */
231 public final static int WEEK_OF_YEAR_FIELD = 12;
232 /**
233 * Useful constant for WEEK_OF_MONTH field alignment.
234 * Used in FieldPosition of date/time formatting.
235 */
236 public final static int WEEK_OF_MONTH_FIELD = 13;
237 /**
238 * Useful constant for AM_PM field alignment.
239 * Used in FieldPosition of date/time formatting.
240 */
241 public final static int AM_PM_FIELD = 14;
242 /**
243 * Useful constant for one-based HOUR field alignment.
244 * Used in FieldPosition of date/time formatting.
245 * HOUR1_FIELD is used for the one-based 12-hour clock.
246 * For example, 11:30 PM + 1 hour results in 12:30 AM.
247 */
248 public final static int HOUR1_FIELD = 15;
249 /**
250 * Useful constant for zero-based HOUR field alignment.
251 * Used in FieldPosition of date/time formatting.
252 * HOUR0_FIELD is used for the zero-based 12-hour clock.
253 * For example, 11:30 PM + 1 hour results in 00:30 AM.
254 */
255 public final static int HOUR0_FIELD = 16;
256 /**
257 * Useful constant for TIMEZONE field alignment.
258 * Used in FieldPosition of date/time formatting.
259 */
260 public final static int TIMEZONE_FIELD = 17;
261
262 // Proclaim serial compatibility with 1.1 FCS
263 private static final long serialVersionUID = 7218322306649953788L;
264
265 /**
266 * Overrides Format.
267 * Formats a time object into a time string. Examples of time objects
268 * are a time value expressed in milliseconds and a Date object.
269 * @param obj must be a Number or a Date.
270 * @param toAppendTo the string buffer for the returning time string.
271 * @return the string buffer passed in as toAppendTo, with formatted text appended.
272 * @param fieldPosition keeps track of the position of the field
273 * within the returned string.
274 * On input: an alignment field,
275 * if desired. On output: the offsets of the alignment field. For
276 * example, given a time text "1996.07.10 AD at 15:08:56 PDT",
277 * if the given fieldPosition is DateFormat.YEAR_FIELD, the
278 * begin index and end index of fieldPosition will be set to
279 * 0 and 4, respectively.
280 * Notice that if the same time field appears
281 * more than once in a pattern, the fieldPosition will be set for the first
282 * occurrence of that time field. For instance, formatting a Date to
283 * the time string "1 PM PDT (Pacific Daylight Time)" using the pattern
284 * "h a z (zzzz)" and the alignment field DateFormat.TIMEZONE_FIELD,
285 * the begin index and end index of fieldPosition will be set to
286 * 5 and 8, respectively, for the first occurrence of the timezone
287 * pattern character 'z'.
288 * @see java.text.Format
289 */
290 public final StringBuffer format(Object obj,
291 StringBuffer toAppendTo, FieldPosition fieldPosition) {
292 if (obj instanceof Date)
293 return format((Date) obj, toAppendTo, fieldPosition);
294 else if (obj instanceof Number)
295 return format(new Date(((Number) obj).longValue()),
296 toAppendTo, fieldPosition);
297 else
298 throw new IllegalArgumentException(
299 "Cannot format given Object as a Date");
300 }
301
302 /**
303 * Formats a Date into a date/time string.
304 * @param date a Date to be formatted into a date/time string.
305 * @param toAppendTo the string buffer for the returning date/time string.
306 * @param fieldPosition keeps track of the position of the field
307 * within the returned string.
308 * On input: an alignment field,
309 * if desired. On output: the offsets of the alignment field. For
310 * example, given a time text "1996.07.10 AD at 15:08:56 PDT",
311 * if the given fieldPosition is DateFormat.YEAR_FIELD, the
312 * begin index and end index of fieldPosition will be set to
313 * 0 and 4, respectively.
314 * Notice that if the same time field appears
315 * more than once in a pattern, the fieldPosition will be set for the first
316 * occurrence of that time field. For instance, formatting a Date to
317 * the time string "1 PM PDT (Pacific Daylight Time)" using the pattern
318 * "h a z (zzzz)" and the alignment field DateFormat.TIMEZONE_FIELD,
319 * the begin index and end index of fieldPosition will be set to
320 * 5 and 8, respectively, for the first occurrence of the timezone
321 * pattern character 'z'.
322 * @return the string buffer passed in as toAppendTo, with formatted text appended.
323 */
324 public abstract StringBuffer format(Date date,
325 StringBuffer toAppendTo, FieldPosition fieldPosition);
326
327 /**
328 * Formats a Date into a date/time string.
329 * @param date the time value to be formatted into a time string.
330 * @return the formatted time string.
331 */
332 public final String format(Date date) {
333 return format(date, new StringBuffer(),
334 DontCareFieldPosition.INSTANCE).toString();
335 }
336
337 /**
338 * Parses text from the beginning of the given string to produce a date.
339 * The method may not use the entire text of the given string.
340 * <p>
341 * See the {@link #parse(String, ParsePosition)} method for more information
342 * on date parsing.
343 *
344 * @param source A <code>String</code> whose beginning should be parsed.
345 * @return A <code>Date</code> parsed from the string.
346 * @exception ParseException if the beginning of the specified string
347 * cannot be parsed.
348 */
349 public Date parse(String source) throws ParseException {
350 ParsePosition pos = new ParsePosition(0);
351 Date result = parse(source, pos);
352 if (pos.index == 0)
353 throw new ParseException("Unparseable date: \"" + source
354 + "\"", pos.errorIndex);
355 return result;
356 }
357
358 /**
359 * Parse a date/time string according to the given parse position. For
360 * example, a time text "07/10/96 4:5 PM, PDT" will be parsed into a Date
361 * that is equivalent to Date(837039928046).
362 *
363 * <p> By default, parsing is lenient: If the input is not in the form used
364 * by this object's format method but can still be parsed as a date, then
365 * the parse succeeds. Clients may insist on strict adherence to the
366 * format by calling setLenient(false).
367 *
368 * @see java.text.DateFormat#setLenient(boolean)
369 *
370 * @param source The date/time string to be parsed
371 *
372 * @param pos On input, the position at which to start parsing; on
373 * output, the position at which parsing terminated, or the
374 * start position if the parse failed.
375 *
376 * @return A Date, or null if the input could not be parsed
377 */
378 public abstract Date parse(String source, ParsePosition pos);
379
380 /**
381 * Parses text from a string to produce a <code>Date</code>.
382 * <p>
383 * The method attempts to parse text starting at the index given by
384 * <code>pos</code>.
385 * If parsing succeeds, then the index of <code>pos</code> is updated
386 * to the index after the last character used (parsing does not necessarily
387 * use all characters up to the end of the string), and the parsed
388 * date is returned. The updated <code>pos</code> can be used to
389 * indicate the starting point for the next call to this method.
390 * If an error occurs, then the index of <code>pos</code> is not
391 * changed, the error index of <code>pos</code> is set to the index of
392 * the character where the error occurred, and null is returned.
393 * <p>
394 * See the {@link #parse(String, ParsePosition)} method for more information
395 * on date parsing.
396 *
397 * @param source A <code>String</code>, part of which should be parsed.
398 * @param pos A <code>ParsePosition</code> object with index and error
399 * index information as described above.
400 * @return A <code>Date</code> parsed from the string. In case of
401 * error, returns null.
402 * @exception NullPointerException if <code>pos</code> is null.
403 */
404 public Object parseObject(String source, ParsePosition pos) {
405 return parse(source, pos);
406 }
407
408 /**
409 * Constant for full style pattern.
410 */
411 public static final int FULL = 0;
412 /**
413 * Constant for long style pattern.
414 */
415 public static final int LONG = 1;
416 /**
417 * Constant for medium style pattern.
418 */
419 public static final int MEDIUM = 2;
420 /**
421 * Constant for short style pattern.
422 */
423 public static final int SHORT = 3;
424 /**
425 * Constant for default style pattern. Its value is MEDIUM.
426 */
427 public static final int DEFAULT = MEDIUM;
428
429 /**
430 * Gets the time formatter with the default formatting style
431 * for the default locale.
432 * @return a time formatter.
433 */
434 public final static DateFormat getTimeInstance() {
435 return get(DEFAULT, 0, 1, Locale.getDefault());
436 }
437
438 /**
439 * Gets the time formatter with the given formatting style
440 * for the default locale.
441 * @param style the given formatting style. For example,
442 * SHORT for "h:mm a" in the US locale.
443 * @return a time formatter.
444 */
445 public final static DateFormat getTimeInstance(int style) {
446 return get(style, 0, 1, Locale.getDefault());
447 }
448
449 /**
450 * Gets the time formatter with the given formatting style
451 * for the given locale.
452 * @param style the given formatting style. For example,
453 * SHORT for "h:mm a" in the US locale.
454 * @param aLocale the given locale.
455 * @return a time formatter.
456 */
457 public final static DateFormat getTimeInstance(int style,
458 Locale aLocale) {
459 return get(style, 0, 1, aLocale);
460 }
461
462 /**
463 * Gets the date formatter with the default formatting style
464 * for the default locale.
465 * @return a date formatter.
466 */
467 public final static DateFormat getDateInstance() {
468 return get(0, DEFAULT, 2, Locale.getDefault());
469 }
470
471 /**
472 * Gets the date formatter with the given formatting style
473 * for the default locale.
474 * @param style the given formatting style. For example,
475 * SHORT for "M/d/yy" in the US locale.
476 * @return a date formatter.
477 */
478 public final static DateFormat getDateInstance(int style) {
479 return get(0, style, 2, Locale.getDefault());
480 }
481
482 /**
483 * Gets the date formatter with the given formatting style
484 * for the given locale.
485 * @param style the given formatting style. For example,
486 * SHORT for "M/d/yy" in the US locale.
487 * @param aLocale the given locale.
488 * @return a date formatter.
489 */
490 public final static DateFormat getDateInstance(int style,
491 Locale aLocale) {
492 return get(0, style, 2, aLocale);
493 }
494
495 /**
496 * Gets the date/time formatter with the default formatting style
497 * for the default locale.
498 * @return a date/time formatter.
499 */
500 public final static DateFormat getDateTimeInstance() {
501 return get(DEFAULT, DEFAULT, 3, Locale.getDefault());
502 }
503
504 /**
505 * Gets the date/time formatter with the given date and time
506 * formatting styles for the default locale.
507 * @param dateStyle the given date formatting style. For example,
508 * SHORT for "M/d/yy" in the US locale.
509 * @param timeStyle the given time formatting style. For example,
510 * SHORT for "h:mm a" in the US locale.
511 * @return a date/time formatter.
512 */
513 public final static DateFormat getDateTimeInstance(int dateStyle,
514 int timeStyle) {
515 return get(timeStyle, dateStyle, 3, Locale.getDefault());
516 }
517
518 /**
519 * Gets the date/time formatter with the given formatting styles
520 * for the given locale.
521 * @param dateStyle the given date formatting style.
522 * @param timeStyle the given time formatting style.
523 * @param aLocale the given locale.
524 * @return a date/time formatter.
525 */
526 public final static DateFormat getDateTimeInstance(int dateStyle,
527 int timeStyle, Locale aLocale) {
528 return get(timeStyle, dateStyle, 3, aLocale);
529 }
530
531 /**
532 * Get a default date/time formatter that uses the SHORT style for both the
533 * date and the time.
534 */
535 public final static DateFormat getInstance() {
536 return getDateTimeInstance(SHORT, SHORT);
537 }
538
539 /**
540 * Returns an array of all locales for which the
541 * <code>get*Instance</code> methods of this class can return
542 * localized instances.
543 * The returned array represents the union of locales supported by the Java
544 * runtime and by installed
545 * {@link java.text.spi.DateFormatProvider DateFormatProvider} implementations.
546 * It must contain at least a <code>Locale</code> instance equal to
547 * {@link java.util.Locale#US Locale.US}.
548 *
549 * @return An array of locales for which localized
550 * <code>DateFormat</code> instances are available.
551 */
552 public static Locale[] getAvailableLocales() {
553 LocaleServiceProviderPool pool = LocaleServiceProviderPool
554 .getPool(DateFormatProvider.class);
555 return pool.getAvailableLocales();
556 }
557
558 /**
559 * Set the calendar to be used by this date format. Initially, the default
560 * calendar for the specified or default locale is used.
561 * @param newCalendar the new Calendar to be used by the date format
562 */
563 public void setCalendar(Calendar newCalendar) {
564 this .calendar = newCalendar;
565 }
566
567 /**
568 * Gets the calendar associated with this date/time formatter.
569 * @return the calendar associated with this date/time formatter.
570 */
571 public Calendar getCalendar() {
572 return calendar;
573 }
574
575 /**
576 * Allows you to set the number formatter.
577 * @param newNumberFormat the given new NumberFormat.
578 */
579 public void setNumberFormat(NumberFormat newNumberFormat) {
580 this .numberFormat = newNumberFormat;
581 }
582
583 /**
584 * Gets the number formatter which this date/time formatter uses to
585 * format and parse a time.
586 * @return the number formatter which this date/time formatter uses.
587 */
588 public NumberFormat getNumberFormat() {
589 return numberFormat;
590 }
591
592 /**
593 * Sets the time zone for the calendar of this DateFormat object.
594 * @param zone the given new time zone.
595 */
596 public void setTimeZone(TimeZone zone) {
597 calendar.setTimeZone(zone);
598 }
599
600 /**
601 * Gets the time zone.
602 * @return the time zone associated with the calendar of DateFormat.
603 */
604 public TimeZone getTimeZone() {
605 return calendar.getTimeZone();
606 }
607
608 /**
609 * Specify whether or not date/time parsing is to be lenient. With
610 * lenient parsing, the parser may use heuristics to interpret inputs that
611 * do not precisely match this object's format. With strict parsing,
612 * inputs must match this object's format.
613 * @param lenient when true, parsing is lenient
614 * @see java.util.Calendar#setLenient
615 */
616 public void setLenient(boolean lenient) {
617 calendar.setLenient(lenient);
618 }
619
620 /**
621 * Tell whether date/time parsing is to be lenient.
622 */
623 public boolean isLenient() {
624 return calendar.isLenient();
625 }
626
627 /**
628 * Overrides hashCode
629 */
630 public int hashCode() {
631 return numberFormat.hashCode();
632 // just enough fields for a reasonable distribution
633 }
634
635 /**
636 * Overrides equals
637 */
638 public boolean equals(Object obj) {
639 if (this == obj)
640 return true;
641 if (obj == null || getClass() != obj.getClass())
642 return false;
643 DateFormat other = (DateFormat) obj;
644 return (// calendar.equivalentTo(other.calendar) // THIS API DOESN'T EXIST YET!
645 calendar.getFirstDayOfWeek() == other.calendar
646 .getFirstDayOfWeek()
647 && calendar.getMinimalDaysInFirstWeek() == other.calendar
648 .getMinimalDaysInFirstWeek()
649 && calendar.isLenient() == other.calendar.isLenient()
650 && calendar.getTimeZone().equals(
651 other.calendar.getTimeZone()) && numberFormat
652 .equals(other.numberFormat));
653 }
654
655 /**
656 * Overrides Cloneable
657 */
658 public Object clone() {
659 DateFormat other = (DateFormat) super .clone();
660 other.calendar = (Calendar) calendar.clone();
661 other.numberFormat = (NumberFormat) numberFormat.clone();
662 return other;
663 }
664
665 /**
666 * Creates a DateFormat with the given time and/or date style in the given
667 * locale.
668 * @param timeStyle a value from 0 to 3 indicating the time format,
669 * ignored if flags is 2
670 * @param dateStyle a value from 0 to 3 indicating the time format,
671 * ignored if flags is 1
672 * @param flags either 1 for a time format, 2 for a date format,
673 * or 3 for a date/time format
674 * @param loc the locale for the format
675 */
676 private static DateFormat get(int timeStyle, int dateStyle,
677 int flags, Locale loc) {
678 if ((flags & 1) != 0) {
679 if (timeStyle < 0 || timeStyle > 3) {
680 throw new IllegalArgumentException(
681 "Illegal time style " + timeStyle);
682 }
683 } else {
684 timeStyle = -1;
685 }
686 if ((flags & 2) != 0) {
687 if (dateStyle < 0 || dateStyle > 3) {
688 throw new IllegalArgumentException(
689 "Illegal date style " + dateStyle);
690 }
691 } else {
692 dateStyle = -1;
693 }
694 try {
695 // Check whether a provider can provide an implementation that's closer
696 // to the requested locale than what the Java runtime itself can provide.
697 LocaleServiceProviderPool pool = LocaleServiceProviderPool
698 .getPool(DateFormatProvider.class);
699 if (pool.hasProviders()) {
700 DateFormat providersInstance = pool.getLocalizedObject(
701 DateFormatGetter.INSTANCE, loc, timeStyle,
702 dateStyle, flags);
703 if (providersInstance != null) {
704 return providersInstance;
705 }
706 }
707
708 return new SimpleDateFormat(timeStyle, dateStyle, loc);
709 } catch (MissingResourceException e) {
710 return new SimpleDateFormat("M/d/yy h:mm a");
711 }
712 }
713
714 /**
715 * Create a new date format.
716 */
717 protected DateFormat() {
718 }
719
720 /**
721 * Defines constants that are used as attribute keys in the
722 * <code>AttributedCharacterIterator</code> returned
723 * from <code>DateFormat.formatToCharacterIterator</code> and as
724 * field identifiers in <code>FieldPosition</code>.
725 * <p>
726 * The class also provides two methods to map
727 * between its constants and the corresponding Calendar constants.
728 *
729 * @since 1.4
730 * @see java.util.Calendar
731 */
732 public static class Field extends Format.Field {
733
734 // Proclaim serial compatibility with 1.4 FCS
735 private static final long serialVersionUID = 7441350119349544720L;
736
737 // table of all instances in this class, used by readResolve
738 private static final Map instanceMap = new HashMap(18);
739 // Maps from Calendar constant (such as Calendar.ERA) to Field
740 // constant (such as Field.ERA).
741 private static final Field[] calendarToFieldMapping = new Field[Calendar.FIELD_COUNT];
742
743 /** Calendar field. */
744 private int calendarField;
745
746 /**
747 * Returns the <code>Field</code> constant that corresponds to
748 * the <code>Calendar</code> constant <code>calendarField</code>.
749 * If there is no direct mapping between the <code>Calendar</code>
750 * constant and a <code>Field</code>, null is returned.
751 *
752 * @throws IllegalArgumentException if <code>calendarField</code> is
753 * not the value of a <code>Calendar</code> field constant.
754 * @param calendarField Calendar field constant
755 * @return Field instance representing calendarField.
756 * @see java.util.Calendar
757 */
758 public static Field ofCalendarField(int calendarField) {
759 if (calendarField < 0
760 || calendarField >= calendarToFieldMapping.length) {
761 throw new IllegalArgumentException(
762 "Unknown Calendar constant " + calendarField);
763 }
764 return calendarToFieldMapping[calendarField];
765 }
766
767 /**
768 * Creates a <code>Field</code>.
769 *
770 * @param name the name of the <code>Field</code>
771 * @param calendarField the <code>Calendar</code> constant this
772 * <code>Field</code> corresponds to; any value, even one
773 * outside the range of legal <code>Calendar</code> values may
774 * be used, but <code>-1</code> should be used for values
775 * that don't correspond to legal <code>Calendar</code> values
776 */
777 protected Field(String name, int calendarField) {
778 super (name);
779 this .calendarField = calendarField;
780 if (this .getClass() == DateFormat.Field.class) {
781 instanceMap.put(name, this );
782 if (calendarField >= 0) {
783 // assert(calendarField < Calendar.FIELD_COUNT);
784 calendarToFieldMapping[calendarField] = this ;
785 }
786 }
787 }
788
789 /**
790 * Returns the <code>Calendar</code> field associated with this
791 * attribute. For example, if this represents the hours field of
792 * a <code>Calendar</code>, this would return
793 * <code>Calendar.HOUR</code>. If there is no corresponding
794 * <code>Calendar</code> constant, this will return -1.
795 *
796 * @return Calendar constant for this field
797 * @see java.util.Calendar
798 */
799 public int getCalendarField() {
800 return calendarField;
801 }
802
803 /**
804 * Resolves instances being deserialized to the predefined constants.
805 *
806 * @throws InvalidObjectException if the constant could not be
807 * resolved.
808 * @return resolved DateFormat.Field constant
809 */
810 protected Object readResolve() throws InvalidObjectException {
811 if (this .getClass() != DateFormat.Field.class) {
812 throw new InvalidObjectException(
813 "subclass didn't correctly implement readResolve");
814 }
815
816 Object instance = instanceMap.get(getName());
817 if (instance != null) {
818 return instance;
819 } else {
820 throw new InvalidObjectException(
821 "unknown attribute name");
822 }
823 }
824
825 //
826 // The constants
827 //
828
829 /**
830 * Constant identifying the era field.
831 */
832 public final static Field ERA = new Field("era", Calendar.ERA);
833
834 /**
835 * Constant identifying the year field.
836 */
837 public final static Field YEAR = new Field("year",
838 Calendar.YEAR);
839
840 /**
841 * Constant identifying the month field.
842 */
843 public final static Field MONTH = new Field("month",
844 Calendar.MONTH);
845
846 /**
847 * Constant identifying the day of month field.
848 */
849 public final static Field DAY_OF_MONTH = new Field(
850 "day of month", Calendar.DAY_OF_MONTH);
851
852 /**
853 * Constant identifying the hour of day field, where the legal values
854 * are 1 to 24.
855 */
856 public final static Field HOUR_OF_DAY1 = new Field(
857 "hour of day 1", -1);
858
859 /**
860 * Constant identifying the hour of day field, where the legal values
861 * are 0 to 23.
862 */
863 public final static Field HOUR_OF_DAY0 = new Field(
864 "hour of day", Calendar.HOUR_OF_DAY);
865
866 /**
867 * Constant identifying the minute field.
868 */
869 public final static Field MINUTE = new Field("minute",
870 Calendar.MINUTE);
871
872 /**
873 * Constant identifying the second field.
874 */
875 public final static Field SECOND = new Field("second",
876 Calendar.SECOND);
877
878 /**
879 * Constant identifying the millisecond field.
880 */
881 public final static Field MILLISECOND = new Field(
882 "millisecond", Calendar.MILLISECOND);
883
884 /**
885 * Constant identifying the day of week field.
886 */
887 public final static Field DAY_OF_WEEK = new Field(
888 "day of week", Calendar.DAY_OF_WEEK);
889
890 /**
891 * Constant identifying the day of year field.
892 */
893 public final static Field DAY_OF_YEAR = new Field(
894 "day of year", Calendar.DAY_OF_YEAR);
895
896 /**
897 * Constant identifying the day of week field.
898 */
899 public final static Field DAY_OF_WEEK_IN_MONTH = new Field(
900 "day of week in month", Calendar.DAY_OF_WEEK_IN_MONTH);
901
902 /**
903 * Constant identifying the week of year field.
904 */
905 public final static Field WEEK_OF_YEAR = new Field(
906 "week of year", Calendar.WEEK_OF_YEAR);
907
908 /**
909 * Constant identifying the week of month field.
910 */
911 public final static Field WEEK_OF_MONTH = new Field(
912 "week of month", Calendar.WEEK_OF_MONTH);
913
914 /**
915 * Constant identifying the time of day indicator
916 * (e.g. "a.m." or "p.m.") field.
917 */
918 public final static Field AM_PM = new Field("am pm",
919 Calendar.AM_PM);
920
921 /**
922 * Constant identifying the hour field, where the legal values are
923 * 1 to 12.
924 */
925 public final static Field HOUR1 = new Field("hour 1", -1);
926
927 /**
928 * Constant identifying the hour field, where the legal values are
929 * 0 to 11.
930 */
931 public final static Field HOUR0 = new Field("hour",
932 Calendar.HOUR);
933
934 /**
935 * Constant identifying the time zone field.
936 */
937 public final static Field TIME_ZONE = new Field("time zone", -1);
938 }
939
940 /**
941 * Obtains a DateFormat instance from a DateFormatProvider
942 * implementation.
943 */
944 private static class DateFormatGetter
945 implements
946 LocaleServiceProviderPool.LocalizedObjectGetter<DateFormatProvider, DateFormat> {
947 private static final DateFormatGetter INSTANCE = new DateFormatGetter();
948
949 public DateFormat getObject(
950 DateFormatProvider dateFormatProvider, Locale locale,
951 String key, Object... params) {
952 assert params.length == 3;
953
954 int timeStyle = (Integer) params[0];
955 int dateStyle = (Integer) params[1];
956 int flags = (Integer) params[2];
957
958 switch (flags) {
959 case 1:
960 return dateFormatProvider.getTimeInstance(timeStyle,
961 locale);
962 case 2:
963 return dateFormatProvider.getDateInstance(dateStyle,
964 locale);
965 case 3:
966 return dateFormatProvider.getDateTimeInstance(
967 dateStyle, timeStyle, locale);
968 default:
969 assert false : "should not happen";
970 }
971
972 return null;
973 }
974 }
975 }
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