com.ibm.icu.text
Class DateIntervalFormat

java.lang.Object
  java.text.Format
      com.ibm.icu.text.UFormat
          com.ibm.icu.text.DateIntervalFormat

All Implemented Interfaces:

Serializable, Cloneable

public class DateIntervalFormat
extends UFormat

DateIntervalFormat is a class for formatting and parsing date intervals in a language-independent manner. Only formatting is supported. Parsing is not supported.

Date interval means from one date to another date, for example, from "Jan 11, 2008" to "Jan 18, 2008". We introduced class DateInterval to represent it. DateInterval is a pair of UDate, which is the standard milliseconds since 24:00 GMT, Jan 1, 1970.

DateIntervalFormat formats a DateInterval into text as compactly as possible. For example, the date interval format from "Jan 11, 2008" to "Jan 18,. 2008" is "Jan 11-18, 2008" for English. And it parses text into DateInterval, although initially, parsing is not supported.

There is no structural information in date time patterns. For any punctuations and string literals inside a date time pattern, we do not know whether it is just a separator, or a prefix, or a suffix. Without such information, so, it is difficult to generate a sub-pattern (or super-pattern) by algorithm. So, formatting a DateInterval is pattern-driven. It is very similar to formatting in SimpleDateFormat. We introduce class DateIntervalInfo to save date interval patterns, similar to date time pattern in SimpleDateFormat.

Logically, the interval patterns are mappings from (skeleton, the_largest_different_calendar_field) to (date_interval_pattern).

A skeleton

1. only keeps the field pattern letter and ignores all other parts in a pattern, such as space, punctuations, and string literals.
2. hides the order of fields.
3. might hide a field's pattern letter length. For those non-digit calendar fields, the pattern letter length is important, such as MMM, MMMM, and MMMMM; EEE and EEEE, and the field's pattern letter length is honored. For the digit calendar fields, such as M or MM, d or dd, yy or yyyy, the field pattern length is ignored and the best match, which is defined in date time patterns, will be returned without honor the field pattern letter length in skeleton.

The calendar fields we support for interval formatting are: year, month, date, day-of-week, am-pm, hour, hour-of-day, and minute. Those calendar fields can be defined in the following order: year > month > date > hour (in day) > minute The largest different calendar fields between 2 calendars is the first different calendar field in above order. For example: the largest different calendar fields between "Jan 10, 2007" and "Feb 20, 2008" is year.

For other calendar fields, the compact interval formatting is not supported. And the interval format will be fall back to fall-back patterns, which is mostly "{date0} - {date1}".

There is a set of pre-defined static skeleton strings in DateFormat, There are pre-defined interval patterns for those pre-defined skeletons in locales' resource files. For example, for a skeleton YEAR_ABBR_MONTH_DAY, which is "yMMMd", in en_US, if the largest different calendar field between date1 and date2 is "year", the date interval pattern is "MMM d, yyyy - MMM d, yyyy", such as "Jan 10, 2007 - Jan 10, 2008". If the largest different calendar field between date1 and date2 is "month", the date interval pattern is "MMM d - MMM d, yyyy", such as "Jan 10 - Feb 10, 2007". If the largest different calendar field between date1 and date2 is "day", the date interval pattern is ""MMM d-d, yyyy", such as "Jan 10-20, 2007". For date skeleton, the interval patterns when year, or month, or date is different are defined in resource files. For time skeleton, the interval patterns when am/pm, or hour, or minute is different are defined in resource files.

If a skeleton is not found in a locale's DateIntervalInfo, which means the interval patterns for the skeleton is not defined in resource file, the interval pattern will falls back to the interval "fallback" pattern defined in resource file. If the interval "fallback" pattern is not defined, the default fall-back is "{date0} - {data1}".

For the combination of date and time, The rule to genearte interval patterns are:

1. when the year, month, or day differs, falls back to fall-back interval pattern, which mostly is the concatenate the two original expressions with a separator between, For example, interval pattern from "Jan 10, 2007 10:10 am" to "Jan 11, 2007 10:10am" is "Jan 10, 2007 10:10 am - Jan 11, 2007 10:10am"
2. otherwise, present the date followed by the range expression for the time. For example, interval pattern from "Jan 10, 2007 10:10 am" to "Jan 10, 2007 11:10am" is "Jan 10, 2007 10:10 am - 11:10am"

If two dates are the same, the interval pattern is the single date pattern. For example, interval pattern from "Jan 10, 2007" to "Jan 10, 2007" is "Jan 10, 2007". Or if the presenting fields between 2 dates have the exact same values, the interval pattern is the single date pattern. For example, if user only requests year and month, the interval pattern from "Jan 10, 2007" to "Jan 20, 2007" is "Jan 2007".

DateIntervalFormat needs the following information for correct formatting: time zone, calendar type, pattern, date format symbols, and date interval patterns. It can be instantiated in several ways:

1. create an instance using default or given locale plus given skeleton. Users are encouraged to created date interval formatter this way and to use the pre-defined skeleton macros, such as YEAR_NUM_MONTH, which consists the calendar fields and the format style.
2. create an instance using default or given locale plus given skeleton plus a given DateIntervalInfo. This factory method is for powerful users who want to provide their own interval patterns. Locale provides the timezone, calendar, and format symbols information. Local plus skeleton provides full pattern information. DateIntervalInfo provides the date interval patterns.

For the calendar field pattern letter, such as G, y, M, d, a, h, H, m, s etc. DateIntervalFormat uses the same syntax as that of DateTime format.

Code Sample: general usage

   // the date interval object which the DateIntervalFormat formats on
   // and parses into
   DateInterval dtInterval = new DateInterval(1000*3600*24L, 1000*3600*24*2L);
   DateIntervalFormat dtIntervalFmt = DateIntervalFormat.getInstance(
                   YEAR_MONTH_DAY, Locale("en", "GB", ""));
   StringBuffer str = new StringBuffer("");
   FieldPosition pos = new FieldPosition(0);
   // formatting
   dtIntervalFmt.format(dtInterval, dateIntervalString, pos);

 

Code Sample: for powerful users who wants to use their own interval pattern

     import com.ibm.icu.text.DateIntervalInfo;
     import com.ibm.icu.text.DateIntervalFormat;
     ....................
     
     // Get DateIntervalFormat instance using default locale
     DateIntervalFormat dtitvfmt = DateIntervalFormat.getInstance(YEAR_MONTH_DAY);
     
     // Create an empty DateIntervalInfo object, which does not have any interval patterns inside.
     dtitvinf = new DateIntervalInfo();
     
     // a series of set interval patterns.
     // Only ERA, YEAR, MONTH, DATE,  DAY_OF_MONTH, DAY_OF_WEEK, AM_PM,  HOUR, HOUR_OF_DAY, and MINUTE  are supported.
     dtitvinf.setIntervalPattern("yMMMd", Calendar.YEAR, "'y ~ y'"); 
     dtitvinf.setIntervalPattern("yMMMd", Calendar.MONTH, "yyyy 'diff' MMM d - MMM d");
     dtitvinf.setIntervalPattern("yMMMd", Calendar.DATE, "yyyy MMM d ~ d");
     dtitvinf.setIntervalPattern("yMMMd", Calendar.HOUR_OF_DAY, "yyyy MMM d HH:mm ~ HH:mm");
     
     // Set fallback interval pattern. Fallback pattern is used when interval pattern is not found.
     // If the fall-back pattern is not set,  falls back to {date0} - {date1} if interval pattern is not found.
     dtitvinf.setFallbackIntervalPattern("{0} - {1}");
     
     // Set above DateIntervalInfo object as the interval patterns of date interval formatter
     dtitvfmt.setDateIntervalInfo(dtitvinf);
     
     // Prepare to format
     pos = new FieldPosition(0);
     str = new StringBuffer("");
     
     // The 2 calendars should be equivalent, otherwise,  IllegalArgumentException will be thrown by format()
     Calendar fromCalendar = (Calendar) dtfmt.getCalendar().clone();
     Calendar toCalendar = (Calendar) dtfmt.getCalendar().clone();
     fromCalendar.setTimeInMillis(....);
     toCalendar.setTimeInMillis(...);
     
     //Formatting given 2 calendars
     dtitvfmt.format(fromCalendar, toCalendar, str, pos);
 

 

See Also:

Serialized Form

Status:

Stable ICU 4.0.

Nested Class Summary

Nested classes/interfaces inherited from class java.text.Format

Format.Field

Method Summary

Object	clone() Clone this Format object polymorphically.
StringBuffer	format(Calendar fromCalendar, Calendar toCalendar, StringBuffer appendTo, FieldPosition pos) Format 2 Calendars to produce a string.
StringBuffer	format(DateInterval dtInterval, StringBuffer appendTo, FieldPosition fieldPosition) Format a DateInterval to produce a string.
StringBuffer	format(Object obj, StringBuffer appendTo, FieldPosition fieldPosition) Format an object to produce a string.
DateFormat	getDateFormat() Gets the date formatter
DateIntervalInfo	getDateIntervalInfo() Gets the date time interval patterns.
static DateIntervalFormat	getInstance(String skeleton) Construct a DateIntervalFormat from skeleton and the default locale.
static DateIntervalFormat	getInstance(String skeleton, DateIntervalInfo dtitvinf) Construct a DateIntervalFormat from skeleton DateIntervalInfo, and default locale.
static DateIntervalFormat	getInstance(String skeleton, Locale locale) Construct a DateIntervalFormat from skeleton and a given locale.
static DateIntervalFormat	getInstance(String skeleton, Locale locale, DateIntervalInfo dtitvinf) Construct a DateIntervalFormat from skeleton a DateIntervalInfo, and the given locale.
static DateIntervalFormat	getInstance(String skeleton, ULocale locale) Construct a DateIntervalFormat from skeleton and a given locale.
static DateIntervalFormat	getInstance(String skeleton, ULocale locale, DateIntervalInfo dtitvinf) Construct a DateIntervalFormat from skeleton a DateIntervalInfo, and the given locale.
Object	parseObject(String source, ParsePosition parse_pos) Deprecated. This API is ICU internal only.
void	setDateIntervalInfo(DateIntervalInfo newItvPattern) Set the date time interval patterns.

Methods inherited from class com.ibm.icu.text.UFormat

getLocale

Methods inherited from class java.text.Format

format, formatToCharacterIterator, parseObject

Methods inherited from class java.lang.Object

equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Detail

getInstance

public static final DateIntervalFormat getInstance(String skeleton)

Construct a DateIntervalFormat from skeleton and the default locale. This is a convenient override of getInstance(String skeleton, ULocale locale) with the value of locale as default locale.

Parameters:

skeleton - the skeleton on which interval format based.

Returns:

a date time interval formatter.

Status:

Stable ICU 4.0.

getInstance

public static final DateIntervalFormat getInstance(String skeleton,
                                                   Locale locale)

Construct a DateIntervalFormat from skeleton and a given locale. This is a convenient override of getInstance(String skeleton, ULocale locale)

Parameters:

skeleton - the skeleton on which interval format based.

locale - the given locale

Returns:

a date time interval formatter.

Status:

Stable ICU 4.0.

getInstance

public static final DateIntervalFormat getInstance(String skeleton,
                                                   ULocale locale)

Construct a DateIntervalFormat from skeleton and a given locale.

In this factory method, the date interval pattern information is load from resource files. Users are encouraged to created date interval formatter this way and to use the pre-defined skeleton macros.

There are pre-defined skeletons in DateFormat, such as MONTH_DAY, YEAR_MONTH_WEEKDAY_DAY etc. Those skeletons have pre-defined interval patterns in resource files. Users are encouraged to use them. For example: DateIntervalFormat.getInstance(DateFormat.MONTH_DAY, false, loc); The given Locale provides the interval patterns. For example, for en_GB, if skeleton is YEAR_ABBR_MONTH_WEEKDAY_DAY, which is "yMMMEEEd", the interval patterns defined in resource file to above skeleton are: "EEE, d MMM, yyyy - EEE, d MMM, yyyy" for year differs, "EEE, d MMM - EEE, d MMM, yyyy" for month differs, "EEE, d - EEE, d MMM, yyyy" for day differs,

Parameters:

skeleton - the skeleton on which interval format based.

locale - the given locale

Returns:

a date time interval formatter.

Status:

Stable ICU 4.0.

getInstance

public static final DateIntervalFormat getInstance(String skeleton,
                                                   DateIntervalInfo dtitvinf)

Construct a DateIntervalFormat from skeleton DateIntervalInfo, and default locale. This is a convenient override of getInstance(String skeleton, ULocale locale, DateIntervalInfo dtitvinf) with the locale value as default locale.

Parameters:

skeleton - the skeleton on which interval format based.

dtitvinf - the DateIntervalInfo object to be adopted.

Returns:

a date time interval formatter.

Status:

Stable ICU 4.0.

getInstance

public static final DateIntervalFormat getInstance(String skeleton,
                                                   Locale locale,
                                                   DateIntervalInfo dtitvinf)

Construct a DateIntervalFormat from skeleton a DateIntervalInfo, and the given locale. This is a convenient override of getInstance(String skeleton, ULocale locale, DateIntervalInfo dtitvinf)

Parameters:

skeleton - the skeleton on which interval format based.

locale - the given locale

dtitvinf - the DateIntervalInfo object to be adopted.

Returns:

a date time interval formatter.

Status:

Stable ICU 4.0.

getInstance

public static final DateIntervalFormat getInstance(String skeleton,
                                                   ULocale locale,
                                                   DateIntervalInfo dtitvinf)

Construct a DateIntervalFormat from skeleton a DateIntervalInfo, and the given locale.

In this factory method, user provides its own date interval pattern information, instead of using those pre-defined data in resource file. This factory method is for powerful users who want to provide their own interval patterns.

There are pre-defined skeleton in DateFormat, such as MONTH_DAY, YEAR_MONTH_WEEKDAY_DAY etc. Those skeletons have pre-defined interval patterns in resource files. Users are encouraged to use them. For example: DateIntervalFormat.getInstance(DateFormat.MONTH_DAY, false, loc,itvinf); the DateIntervalInfo provides the interval patterns. User are encouraged to set default interval pattern in DateIntervalInfo as well, if they want to set other interval patterns ( instead of reading the interval patterns from resource files). When the corresponding interval pattern for a largest calendar different field is not found ( if user not set it ), interval format fallback to the default interval pattern. If user does not provide default interval pattern, it fallback to "{date0} - {date1}"

Parameters:

skeleton - the skeleton on which interval format based.

locale - the given locale

dtitvinf - the DateIntervalInfo object to be adopted.

Returns:

a date time interval formatter.

Status:

Stable ICU 4.0.

clone

public Object clone()

Clone this Format object polymorphically.

Overrides:

clone in class Format

Returns:

A copy of the object.

Status:

Stable ICU 4.0.

format

public final StringBuffer format(Object obj,
                                 StringBuffer appendTo,
                                 FieldPosition fieldPosition)

Format an object to produce a string. This method handles Formattable objects with a DateInterval type. If a the Formattable object type is not a DateInterval, IllegalArgumentException is thrown.

Specified by:

format in class Format

Parameters:

obj - The object to format. Must be a DateInterval.

appendTo - Output parameter to receive result. Result is appended to existing contents.

fieldPosition - On input: an alignment field, if desired. On output: the offsets of the alignment field.

Returns:

Reference to 'appendTo' parameter.

Throws:

IllegalArgumentException - if the formatted object is not DateInterval object

Status:

Stable ICU 4.0.

format

public final StringBuffer format(DateInterval dtInterval,
                                 StringBuffer appendTo,
                                 FieldPosition fieldPosition)

Format a DateInterval to produce a string.

Parameters:

dtInterval - DateInterval to be formatted.

appendTo - Output parameter to receive result. Result is appended to existing contents.

fieldPosition - On input: an alignment field, if desired. On output: the offsets of the alignment field.

Returns:

Reference to 'appendTo' parameter.

Status:

Stable ICU 4.0.

format

public final StringBuffer format(Calendar fromCalendar,
                                 Calendar toCalendar,
                                 StringBuffer appendTo,
                                 FieldPosition pos)

Format 2 Calendars to produce a string.

Parameters:

fromCalendar - calendar set to the from date in date interval to be formatted into date interval string

toCalendar - calendar set to the to date in date interval to be formatted into date interval string

appendTo - Output parameter to receive result. Result is appended to existing contents.

pos - On input: an alignment field, if desired. On output: the offsets of the alignment field.

Returns:

Reference to 'appendTo' parameter.

Throws:

IllegalArgumentException - if the two calendars are not equivalent.

Status:

Stable ICU 4.0.

parseObject

public Object parseObject(String source,
                          ParsePosition parse_pos)

Deprecated. This API is ICU internal only.

Date interval parsing is not supported.

This method should handle parsing of date time interval strings into Formattable objects with DateInterval type, which is a pair of UDate.

Before calling, set parse_pos.index to the offset you want to start parsing at in the source. After calling, parse_pos.index is the end of the text you parsed. If error occurs, index is unchanged.

When parsing, leading whitespace is discarded (with a successful parse), while trailing whitespace is left as is.

See Format.parseObject() for more.

Specified by:

parseObject in class Format

Parameters:

source - The string to be parsed into an object.

parse_pos - The position to start parsing at. Since no parsing is supported, upon return this param is unchanged.

Returns:

A newly created Formattable* object, or NULL on failure.

Status:

Internal. This API is ICU internal only.

getDateIntervalInfo

public DateIntervalInfo getDateIntervalInfo()

Gets the date time interval patterns.

Returns:

a copy of the date time interval patterns associated with this date interval formatter.

Status:

Stable ICU 4.0.

setDateIntervalInfo

public void setDateIntervalInfo(DateIntervalInfo newItvPattern)

Set the date time interval patterns.

Parameters:

newItvPattern - the given interval patterns to copy.

Status:

Stable ICU 4.0.

getDateFormat

public DateFormat getDateFormat()

Gets the date formatter

Returns:

a copy of the date formatter associated with this date interval formatter.

Status:

Stable ICU 4.0.