* DateFormat provides many class methods for obtaining default date/time * formatters based on the default or a given locale and a number of formatting * styles. The formatting styles include FULL, LONG, MEDIUM, and SHORT. More * details and examples for using these styles are provided in the method * descriptions. *
* {@code DateFormat} helps you to format and parse dates for any locale. Your * code can be completely independent of the locale conventions for months, days * of the week, or even the calendar format: lunar vs. solar. *
* To format a date for the current Locale, use one of the static factory * methods: *
* *** myString = DateFormat.getDateInstance().format(myDate); ** *
* If you are formatting multiple dates, it is more efficient to get the format * and use it multiple times so that the system doesn't have to fetch the * information about the local language and country conventions multiple times. *
*
*
* DateFormat df = DateFormat.getDateInstance();
* for (int i = 0; i < a.length; ++i) {
* output.println(df.format(myDate[i]) + "; ");
* }
*
*
*
* * To format a number for a different locale, specify it in the call to * {@code getDateInstance}: *
* *** DateFormat df = DateFormat.getDateInstance(DateFormat.LONG, Locale.FRANCE); ** *
* {@code DateFormat} can also be used to parse strings: *
* *** myDate = df.parse(myString); ** *
* Use {@code getDateInstance} to get the normal date format for a country. * Other static factory methods are available: Use {@code getTimeInstance} to * get the time format for a country. Use {@code getDateTimeInstance} to get the * date and time format. You can pass in different options to these factory * methods to control the length of the result; from SHORT to MEDIUM to LONG to * FULL. The exact result depends on the locale, but generally: *
* If needed, the time zone can be set on the format. For even greater control * over the formatting or parsing, try casting the {@code DateFormat} you get * from the factory methods to a {@code SimpleDateFormat}. This will work for * the majority of countries; just remember to put it in a try block in case you * encounter an unusual one. *
* There are versions of the parse and format methods which use * {@code ParsePosition} and {@code FieldPosition} to allow you to *
* Date formats are not synchronized. It is recommended to create separate * format instances for each thread. If multiple threads access a format * concurrently, it must be synchronized externally. * * @see NumberFormat * @see SimpleDateFormat * @see Calendar * @see TimeZone */ public abstract class DateFormat extends Format { private static final long serialVersionUID = 7218322306649953788L; /** * The calendar that this {@code DateFormat} uses to format a number * representing a date. */ protected Calendar calendar; /** * The number format used to format a number. */ protected NumberFormat numberFormat; /** * The format style constant defining the default format style. The default * is MEDIUM. */ public static final int DEFAULT = 2; /** * The format style constant defining the full style. */ public static final int FULL = 0; /** * The format style constant defining the long style. */ public static final int LONG = 1; /** * The format style constant defining the medium style. */ public static final int MEDIUM = 2; /** * The format style constant defining the short style. */ public static final int SHORT = 3; /** * The {@code FieldPosition} selector for 'G' field alignment, corresponds * to the {@link Calendar#ERA} field. */ public static final int ERA_FIELD = 0; /** * The {@code FieldPosition} selector for 'y' field alignment, corresponds * to the {@link Calendar#YEAR} field. */ public static final int YEAR_FIELD = 1; /** * The {@code FieldPosition} selector for 'M' field alignment, corresponds * to the {@link Calendar#MONTH} field. */ public static final int MONTH_FIELD = 2; /** * The {@code FieldPosition} selector for 'd' field alignment, corresponds * to the {@link Calendar#DATE} field. */ public static final int DATE_FIELD = 3; /** * The {@code FieldPosition} selector for 'k' field alignment, corresponds * to the {@link Calendar#HOUR_OF_DAY} field. {@code HOUR_OF_DAY1_FIELD} is * used for the one-based 24-hour clock. For example, 23:59 + 01:00 results * in 24:59. */ public static final int HOUR_OF_DAY1_FIELD = 4; /** * The {@code FieldPosition} selector for 'H' field alignment, corresponds * to the {@link Calendar#HOUR_OF_DAY} field. {@code HOUR_OF_DAY0_FIELD} is * used for the zero-based 24-hour clock. For example, 23:59 + 01:00 results * in 00:59. */ public static final int HOUR_OF_DAY0_FIELD = 5; /** * FieldPosition selector for 'm' field alignment, corresponds to the * {@link Calendar#MINUTE} field. */ public static final int MINUTE_FIELD = 6; /** * FieldPosition selector for 's' field alignment, corresponds to the * {@link Calendar#SECOND} field. */ public static final int SECOND_FIELD = 7; /** * FieldPosition selector for 'S' field alignment, corresponds to the * {@link Calendar#MILLISECOND} field. */ public static final int MILLISECOND_FIELD = 8; /** * FieldPosition selector for 'E' field alignment, corresponds to the * {@link Calendar#DAY_OF_WEEK} field. */ public static final int DAY_OF_WEEK_FIELD = 9; /** * FieldPosition selector for 'D' field alignment, corresponds to the * {@link Calendar#DAY_OF_YEAR} field. */ public static final int DAY_OF_YEAR_FIELD = 10; /** * FieldPosition selector for 'F' field alignment, corresponds to the * {@link Calendar#DAY_OF_WEEK_IN_MONTH} field. */ public static final int DAY_OF_WEEK_IN_MONTH_FIELD = 11; /** * FieldPosition selector for 'w' field alignment, corresponds to the * {@link Calendar#WEEK_OF_YEAR} field. */ public static final int WEEK_OF_YEAR_FIELD = 12; /** * FieldPosition selector for 'W' field alignment, corresponds to the * {@link Calendar#WEEK_OF_MONTH} field. */ public static final int WEEK_OF_MONTH_FIELD = 13; /** * FieldPosition selector for 'a' field alignment, corresponds to the * {@link Calendar#AM_PM} field. */ public static final int AM_PM_FIELD = 14; /** * FieldPosition selector for 'h' field alignment, corresponding to the * {@link Calendar#HOUR} field. */ public static final int HOUR1_FIELD = 15; /** * The {@code FieldPosition} selector for 'K' field alignment, corresponding to the * {@link Calendar#HOUR} field. */ public static final int HOUR0_FIELD = 16; /** * The {@code FieldPosition} selector for 'z' field alignment, corresponds * to the {@link Calendar#ZONE_OFFSET} and {@link Calendar#DST_OFFSET} * fields. */ public static final int TIMEZONE_FIELD = 17; /** * Constructs a new instance of {@code DateFormat}. */ protected DateFormat() { } /** * Returns a new instance of {@code DateFormat} with the same properties. */ @Override public Object clone() { DateFormat clone = (DateFormat) super.clone(); clone.calendar = (Calendar) calendar.clone(); clone.numberFormat = (NumberFormat) numberFormat.clone(); return clone; } /** * Compares this date format with the specified object and indicates if they * are equal. * * @param object * the object to compare with this date format. * @return {@code true} if {@code object} is a {@code DateFormat} object and * it has the same properties as this date format; {@code false} * otherwise. * @see #hashCode */ @Override public boolean equals(Object object) { if (this == object) { return true; } if (!(object instanceof DateFormat)) { return false; } DateFormat dateFormat = (DateFormat) object; return numberFormat.equals(dateFormat.numberFormat) && calendar.getTimeZone().equals( dateFormat.calendar.getTimeZone()) && calendar.getFirstDayOfWeek() == dateFormat.calendar .getFirstDayOfWeek() && calendar.getMinimalDaysInFirstWeek() == dateFormat.calendar .getMinimalDaysInFirstWeek() && calendar.isLenient() == dateFormat.calendar.isLenient(); } /** * Formats the specified object as a string using the pattern of this date * format and appends the string to the specified string buffer. *
* If the {@code field} member of {@code field} contains a value specifying * a format field, then its {@code beginIndex} and {@code endIndex} members * will be updated with the position of the first occurrence of this field * in the formatted text. * * @param object * the source object to format, must be a {@code Date} or a * {@code Number}. If {@code object} is a number then a date is * constructed using the {@code longValue()} of the number. * @param buffer * the target string buffer to append the formatted date/time to. * @param field * on input: an optional alignment field; on output: the offsets * of the alignment field in the formatted text. * @return the string buffer. * @throws IllegalArgumentException * if {@code object} is neither a {@code Date} nor a * {@code Number} instance. */ @Override public final StringBuffer format(Object object, StringBuffer buffer, FieldPosition field) { if (object instanceof Date) { return format((Date) object, buffer, field); } if (object instanceof Number) { return format(new Date(((Number) object).longValue()), buffer, field); } throw new IllegalArgumentException(); } /** * Formats the specified date using the rules of this date format. * * @param date * the date to format. * @return the formatted string. */ public final String format(Date date) { return format(date, new StringBuffer(), new FieldPosition(0)) .toString(); } /** * Formats the specified date as a string using the pattern of this date * format and appends the string to the specified string buffer. *
* If the {@code field} member of {@code field} contains a value specifying * a format field, then its {@code beginIndex} and {@code endIndex} members * will be updated with the position of the first occurrence of this field * in the formatted text. * * @param date * the date to format. * @param buffer * the target string buffer to append the formatted date/time to. * @param field * on input: an optional alignment field; on output: the offsets * of the alignment field in the formatted text. * @return the string buffer. */ public abstract StringBuffer format(Date date, StringBuffer buffer, FieldPosition field); /** * Returns an array of locales for which custom {@code DateFormat} instances * are available. *
Note that Android does not support user-supplied locale service providers. */ public static Locale[] getAvailableLocales() { return ICU.getAvailableDateFormatLocales(); } /** * Returns the calendar used by this {@code DateFormat}. * * @return the calendar used by this date format. */ public Calendar getCalendar() { return calendar; } /** * Returns a {@code DateFormat} instance for formatting and parsing dates in * the DEFAULT style for the default locale. * * @return the {@code DateFormat} instance for the default style and locale. */ public static final DateFormat getDateInstance() { return getDateInstance(DEFAULT); } /** * Returns a {@code DateFormat} instance for formatting and parsing dates in * the specified style for the user's default locale. * See "Be wary of the default locale". * @param style * one of SHORT, MEDIUM, LONG, FULL, or DEFAULT. * @return the {@code DateFormat} instance for {@code style} and the default * locale. * @throws IllegalArgumentException * if {@code style} is not one of SHORT, MEDIUM, LONG, FULL, or * DEFAULT. */ public static final DateFormat getDateInstance(int style) { checkDateStyle(style); return getDateInstance(style, Locale.getDefault()); } /** * Returns a {@code DateFormat} instance for formatting and parsing dates in * the specified style for the specified locale. * * @param style * one of SHORT, MEDIUM, LONG, FULL, or DEFAULT. * @param locale * the locale. * @throws IllegalArgumentException * if {@code style} is not one of SHORT, MEDIUM, LONG, FULL, or * DEFAULT. * @return the {@code DateFormat} instance for {@code style} and * {@code locale}. */ public static final DateFormat getDateInstance(int style, Locale locale) { checkDateStyle(style); return new SimpleDateFormat(LocaleData.get(locale).getDateFormat(style), locale); } /** * Returns a {@code DateFormat} instance for formatting and parsing dates * and time values in the DEFAULT style for the default locale. * * @return the {@code DateFormat} instance for the default style and locale. */ public static final DateFormat getDateTimeInstance() { return getDateTimeInstance(DEFAULT, DEFAULT); } /** * Returns a {@code DateFormat} instance for formatting and parsing of both * dates and time values in the manner appropriate for the user's default locale. * See "Be wary of the default locale". * @param dateStyle * one of SHORT, MEDIUM, LONG, FULL, or DEFAULT. * @param timeStyle * one of SHORT, MEDIUM, LONG, FULL, or DEFAULT. * @return the {@code DateFormat} instance for {@code dateStyle}, * {@code timeStyle} and the default locale. * @throws IllegalArgumentException * if {@code dateStyle} or {@code timeStyle} is not one of * SHORT, MEDIUM, LONG, FULL, or DEFAULT. */ public static final DateFormat getDateTimeInstance(int dateStyle, int timeStyle) { checkTimeStyle(timeStyle); checkDateStyle(dateStyle); return getDateTimeInstance(dateStyle, timeStyle, Locale.getDefault()); } /** * Returns a {@code DateFormat} instance for formatting and parsing dates * and time values in the specified styles for the specified locale. * * @param dateStyle * one of SHORT, MEDIUM, LONG, FULL, or DEFAULT. * @param timeStyle * one of SHORT, MEDIUM, LONG, FULL, or DEFAULT. * @param locale * the locale. * @return the {@code DateFormat} instance for {@code dateStyle}, * {@code timeStyle} and {@code locale}. * @throws IllegalArgumentException * if {@code dateStyle} or {@code timeStyle} is not one of * SHORT, MEDIUM, LONG, FULL, or DEFAULT. */ public static final DateFormat getDateTimeInstance(int dateStyle, int timeStyle, Locale locale) { checkTimeStyle(timeStyle); checkDateStyle(dateStyle); LocaleData localeData = LocaleData.get(locale); String pattern = localeData.getDateFormat(dateStyle) + " " + localeData.getTimeFormat(timeStyle); return new SimpleDateFormat(pattern, locale); } /** * Returns a {@code DateFormat} instance for formatting and parsing dates * and times in the SHORT style for the default locale. * * @return the {@code DateFormat} instance for the SHORT style and default * locale. */ public static final DateFormat getInstance() { return getDateTimeInstance(SHORT, SHORT); } /** * Returns the {@code NumberFormat} used by this {@code DateFormat}. * * @return the {@code NumberFormat} used by this date format. */ public NumberFormat getNumberFormat() { return numberFormat; } /** * Returns a {@code DateFormat} instance for formatting and parsing time * values in the DEFAULT style for the default locale. * * @return the {@code DateFormat} instance for the default style and locale. */ public static final DateFormat getTimeInstance() { return getTimeInstance(DEFAULT); } /** * Returns a {@code DateFormat} instance for formatting and parsing time * values in the specified style for the user's default locale. * See "Be wary of the default locale". * @param style * one of SHORT, MEDIUM, LONG, FULL, or DEFAULT. * @return the {@code DateFormat} instance for {@code style} and the default * locale. * @throws IllegalArgumentException * if {@code style} is not one of SHORT, MEDIUM, LONG, FULL, or * DEFAULT. */ public static final DateFormat getTimeInstance(int style) { checkTimeStyle(style); return getTimeInstance(style, Locale.getDefault()); } /** * Returns a {@code DateFormat} instance for formatting and parsing time * values in the specified style for the specified locale. * * @param style * one of SHORT, MEDIUM, LONG, FULL, or DEFAULT. * @param locale * the locale. * @throws IllegalArgumentException * if {@code style} is not one of SHORT, MEDIUM, LONG, FULL, or * DEFAULT. * @return the {@code DateFormat} instance for {@code style} and * {@code locale}. */ public static final DateFormat getTimeInstance(int style, Locale locale) { checkTimeStyle(style); return new SimpleDateFormat(LocaleData.get(locale).getTimeFormat(style), locale); } /** * Returns the time zone of this date format's calendar. * * @return the time zone of the calendar used by this date format. */ public TimeZone getTimeZone() { return calendar.getTimeZone(); } @Override public int hashCode() { return calendar.getFirstDayOfWeek() + calendar.getMinimalDaysInFirstWeek() + calendar.getTimeZone().hashCode() + (calendar.isLenient() ? 1231 : 1237) + numberFormat.hashCode(); } /** * Indicates whether the calendar used by this date format is lenient. * * @return {@code true} if the calendar is lenient; {@code false} otherwise. */ public boolean isLenient() { return calendar.isLenient(); } /** * Parses a date from the specified string using the rules of this date * format. * * @param string * the string to parse. * @return the {@code Date} resulting from the parsing. * @throws ParseException * if an error occurs during parsing. */ public Date parse(String string) throws ParseException { ParsePosition position = new ParsePosition(0); Date date = parse(string, position); if (position.getIndex() == 0) { throw new ParseException("Unparseable date: \"" + string + "\"", position.getErrorIndex()); } return date; } /** * Parses a date from the specified string starting at the index specified * by {@code position}. If the string is successfully parsed then the index * of the {@code ParsePosition} is updated to the index following the parsed * text. On error, the index is unchanged and the error index of {@code * ParsePosition} is set to the index where the error occurred. *
* By default, parsing is lenient: If the input is not in the form used by * this object's format method but can still be parsed as a date, then the * parse succeeds. Clients may insist on strict adherence to the format by * calling {@code setLenient(false)}. * * @param string * the string to parse. * @param position * input/output parameter, specifies the start index in {@code * string} from where to start parsing. If parsing is successful, * it is updated with the index following the parsed text; on * error, the index is unchanged and the error index is set to * the index where the error occurred. * @return the date resulting from the parse, or {@code null} if there is an * error. */ public abstract Date parse(String string, ParsePosition position); /** * Parses a date from the specified string starting at the index specified * by {@code position}. If the string is successfully parsed then the index * of the {@code ParsePosition} is updated to the index following the parsed * text. On error, the index is unchanged and the error index of * {@code ParsePosition} is set to the index where the error occurred. *
* By default, parsing is lenient: If the input is not in the form used by * this object's format method but can still be parsed as a date, then the * parse succeeds. Clients may insist on strict adherence to the format by * calling {@code setLenient(false)}. * * @param string * the string to parse. * @param position * input/output parameter, specifies the start index in * {@code string} from where to start parsing. If parsing is * successful, it is updated with the index following the parsed * text; on error, the index is unchanged and the error index * is set to the index where the error occurred. * @return the date resulting from the parsing, or {@code null} if there is * an error. */ @Override public Object parseObject(String string, ParsePosition position) { return parse(string, position); } /** * Sets the calendar used by this date format. * * @param cal * the new calendar. */ public void setCalendar(Calendar cal) { calendar = cal; } /** * Specifies whether or not date/time parsing shall be lenient. With lenient * parsing, the parser may use heuristics to interpret inputs that do not * precisely match this object's format. With strict parsing, inputs must * match this object's format. * * @param value * {@code true} to set the calendar to be lenient, {@code false} * otherwise. */ public void setLenient(boolean value) { calendar.setLenient(value); } /** * Sets the {@code NumberFormat} used by this date format. * * @param format * the new number format. */ public void setNumberFormat(NumberFormat format) { numberFormat = format; } /** * Sets the time zone of the calendar used by this date format. * * @param timezone * the new time zone. */ public void setTimeZone(TimeZone timezone) { calendar.setTimeZone(timezone); } /** * The instances of this inner class are used as attribute keys and values * in {@code AttributedCharacterIterator} that the * {@link SimpleDateFormat#formatToCharacterIterator(Object)} method returns. *
* There is no public constructor in this class, the only instances are the
* constants defined here.
*/
public static class Field extends Format.Field {
private static final long serialVersionUID = 7441350119349544720L;
private static Hashtable