com.ibm.icu.text

Class RelativeDateTimeFormatter

java.lang.Object

com.ibm.icu.text.RelativeDateTimeFormatter

public final class RelativeDateTimeFormatter
extends Object

Formats simple relative dates. There are two types of relative dates that it handles:

• relative dates with a quantity e.g "in 5 days"
• relative dates without a quantity e.g "next Tuesday"

This API is very basic and is intended to be a building block for more fancy APIs. The caller tells it exactly what to display in a locale independent way. While this class automatically provides the correct plural forms, the grammatical form is otherwise as neutral as possible. It is the caller's responsibility to handle cut-off logic such as deciding between displaying "in 7 days" or "in 1 week." This API supports relative dates involving one single unit. This API does not support relative dates involving compound units. e.g "in 5 days and 4 hours" nor does it support parsing. This class is both immutable and thread-safe.

Here are some examples of use:

 RelativeDateTimeFormatter fmt = RelativeDateTimeFormatter.getInstance();
 fmt.format(1, Direction.NEXT, RelativeUnit.DAYS); // "in 1 day"
 fmt.format(3, Direction.NEXT, RelativeUnit.DAYS); // "in 3 days"
 fmt.format(3.2, Direction.LAST, RelativeUnit.YEARS); // "3.2 years ago"

 fmt.format(Direction.LAST, AbsoluteUnit.SUNDAY); // "last Sunday"
 fmt.format(Direction.THIS, AbsoluteUnit.SUNDAY); // "this Sunday"
 fmt.format(Direction.NEXT, AbsoluteUnit.SUNDAY); // "next Sunday"
 fmt.format(Direction.PLAIN, AbsoluteUnit.SUNDAY); // "Sunday"

 fmt.format(Direction.LAST, AbsoluteUnit.DAY); // "yesterday"
 fmt.format(Direction.THIS, AbsoluteUnit.DAY); // "today"
 fmt.format(Direction.NEXT, AbsoluteUnit.DAY); // "tomorrow"

 fmt.format(Direction.PLAIN, AbsoluteUnit.NOW); // "now"
 

The Style parameter allows selection of different length styles: LONG ("3 seconds ago"), SHORT ("3 sec. ago"), NARROW ("3s ago"). In the future, we may add more forms, such as relative day periods ("yesterday afternoon"), etc.

Status:

Stable ICU 53.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	RelativeDateTimeFormatter.AbsoluteUnit Represents an absolute unit.
static class	RelativeDateTimeFormatter.Direction Represents a direction for an absolute unit e.g "Next Tuesday" or "Last Tuesday"
static class	RelativeDateTimeFormatter.Field Field constants used when accessing field information for relative datetime strings in FormattedValue.
static class	RelativeDateTimeFormatter.FormattedRelativeDateTime Represents the result of a formatting operation of a relative datetime.
static class	RelativeDateTimeFormatter.RelativeDateTimeUnit Represents the unit for formatting a relative date. e.g "in 5 days" or "next year"
static class	RelativeDateTimeFormatter.RelativeUnit Represents the unit for formatting a relative date. e.g "in 5 days" or "in 3 months"
static class	RelativeDateTimeFormatter.Style The formatting style

Method Summary

Modifier and Type	Method and Description
String	combineDateAndTime(String relativeDateString, String timeString) Combines a relative date string and a time string in this object's locale.
String	format(double quantity, RelativeDateTimeFormatter.Direction direction, RelativeDateTimeFormatter.RelativeUnit unit) Formats a relative date with a quantity such as "in 5 days" or "3 months ago".
String	format(double offset, RelativeDateTimeFormatter.RelativeDateTimeUnit unit) Format a combination of RelativeDateTimeUnit and numeric offset using a text style if possible, e.g.
String	format(RelativeDateTimeFormatter.Direction direction, RelativeDateTimeFormatter.AbsoluteUnit unit) Formats a relative date without a quantity.
String	formatNumeric(double offset, RelativeDateTimeFormatter.RelativeDateTimeUnit unit) Format a combination of RelativeDateTimeUnit and numeric offset using a numeric style, e.g. "1 week ago", "in 1 week", "5 weeks ago", "in 5 weeks".
RelativeDateTimeFormatter.FormattedRelativeDateTime	formatNumericToValue(double offset, RelativeDateTimeFormatter.RelativeDateTimeUnit unit) Format a combination of RelativeDateTimeUnit and numeric offset using a numeric style, e.g. "1 week ago", "in 1 week", "5 weeks ago", "in 5 weeks".
RelativeDateTimeFormatter.FormattedRelativeDateTime	formatToValue(double quantity, RelativeDateTimeFormatter.Direction direction, RelativeDateTimeFormatter.RelativeUnit unit) Formats a relative date with a quantity such as "in 5 days" or "3 months ago".
RelativeDateTimeFormatter.FormattedRelativeDateTime	formatToValue(double offset, RelativeDateTimeFormatter.RelativeDateTimeUnit unit) Format a combination of RelativeDateTimeUnit and numeric offset using a text style if possible, e.g.
RelativeDateTimeFormatter.FormattedRelativeDateTime	formatToValue(RelativeDateTimeFormatter.Direction direction, RelativeDateTimeFormatter.AbsoluteUnit unit) Formats a relative date without a quantity.
DisplayContext	getCapitalizationContext() Return capitalization context.
RelativeDateTimeFormatter.Style	getFormatStyle() Return style
static RelativeDateTimeFormatter	getInstance() Returns a RelativeDateTimeFormatter for the default locale.
static RelativeDateTimeFormatter	getInstance(Locale locale) Returns a RelativeDateTimeFormatter for a particular Locale.
static RelativeDateTimeFormatter	getInstance(Locale locale, NumberFormat nf) Returns a RelativeDateTimeFormatter for a particular Locale that uses a particular NumberFormat object.
static RelativeDateTimeFormatter	getInstance(ULocale locale) Returns a RelativeDateTimeFormatter for a particular locale.
static RelativeDateTimeFormatter	getInstance(ULocale locale, NumberFormat nf) Returns a RelativeDateTimeFormatter for a particular locale that uses a particular NumberFormat object.
static RelativeDateTimeFormatter	getInstance(ULocale locale, NumberFormat nf, RelativeDateTimeFormatter.Style style, DisplayContext capitalizationContext) Returns a RelativeDateTimeFormatter for a particular locale that uses a particular NumberFormat object, style, and capitalization context
NumberFormat	getNumberFormat() Returns a copy of the NumberFormat this object is using.

Methods inherited from class java.lang.Object

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

Method Detail

getInstance

public static RelativeDateTimeFormatter getInstance()

Returns a RelativeDateTimeFormatter for the default locale.

Status:

Stable ICU 53.

getInstance

public static RelativeDateTimeFormatter getInstance(ULocale locale)

Returns a RelativeDateTimeFormatter for a particular locale.

Parameters:

locale - the locale.

Returns:

An instance of RelativeDateTimeFormatter.

Status:

Stable ICU 53.

getInstance

public static RelativeDateTimeFormatter getInstance(Locale locale)

Returns a RelativeDateTimeFormatter for a particular Locale.

Parameters:

locale - the Locale.

Returns:

An instance of RelativeDateTimeFormatter.

Status:

Stable ICU 54.

getInstance

public static RelativeDateTimeFormatter getInstance(ULocale locale,
                                                    NumberFormat nf)

Returns a RelativeDateTimeFormatter for a particular locale that uses a particular NumberFormat object.

Parameters:

locale - the locale

nf - the number format object. It is defensively copied to ensure thread-safety and immutability of this class.

Returns:

An instance of RelativeDateTimeFormatter.

Status:

Stable ICU 53.

getInstance

public static RelativeDateTimeFormatter getInstance(ULocale locale,
                                                    NumberFormat nf,
                                                    RelativeDateTimeFormatter.Style style,
                                                    DisplayContext capitalizationContext)

Returns a RelativeDateTimeFormatter for a particular locale that uses a particular NumberFormat object, style, and capitalization context

Parameters:

locale - the locale

nf - the number format object. It is defensively copied to ensure thread-safety and immutability of this class. May be null.

style - the style.

capitalizationContext - the capitalization context.

Status:

Stable ICU 54.

getInstance

public static RelativeDateTimeFormatter getInstance(Locale locale,
                                                    NumberFormat nf)

Returns a RelativeDateTimeFormatter for a particular Locale that uses a particular NumberFormat object.

Parameters:

locale - the Locale

nf - the number format object. It is defensively copied to ensure thread-safety and immutability of this class.

Returns:

An instance of RelativeDateTimeFormatter.

Status:

Stable ICU 54.

format

public String format(double quantity,
                     RelativeDateTimeFormatter.Direction direction,
                     RelativeDateTimeFormatter.RelativeUnit unit)

Formats a relative date with a quantity such as "in 5 days" or "3 months ago". This method returns a String. To get more information about the formatting result, use formatToValue().

Parameters:

quantity - The numerical amount e.g 5. This value is formatted according to this object's NumberFormat object.

direction - NEXT means a future relative date; LAST means a past relative date.

unit - the unit e.g day? month? year?

Returns:

the formatted string

Throws:

IllegalArgumentException - if direction is something other than NEXT or LAST.

Status:

Stable ICU 53.

formatToValue

public RelativeDateTimeFormatter.FormattedRelativeDateTime formatToValue(double quantity,
                                                                         RelativeDateTimeFormatter.Direction direction,
                                                                         RelativeDateTimeFormatter.RelativeUnit unit)

Formats a relative date with a quantity such as "in 5 days" or "3 months ago". This method returns a FormattedRelativeDateTime, which exposes more information than the String returned by format().

Parameters:

quantity - The numerical amount e.g 5. This value is formatted according to this object's NumberFormat object.

direction - NEXT means a future relative date; LAST means a past relative date.

unit - the unit e.g day? month? year?

Returns:

the formatted relative datetime

Throws:

IllegalArgumentException - if direction is something other than NEXT or LAST.

Status:

Stable ICU 64.

formatNumeric

public String formatNumeric(double offset,
                            RelativeDateTimeFormatter.RelativeDateTimeUnit unit)

Format a combination of RelativeDateTimeUnit and numeric offset using a numeric style, e.g. "1 week ago", "in 1 week", "5 weeks ago", "in 5 weeks". This method returns a String. To get more information about the formatting result, use formatNumericToValue().

Parameters:

offset - The signed offset for the specified unit. This will be formatted according to this object's NumberFormat object.

unit - The unit to use when formatting the relative date, e.g. RelativeDateTimeUnit.WEEK, RelativeDateTimeUnit.FRIDAY.

Returns:

The formatted string (may be empty in case of error)

Status:

Stable ICU 57.

formatNumericToValue

public RelativeDateTimeFormatter.FormattedRelativeDateTime formatNumericToValue(double offset,
                                                                                RelativeDateTimeFormatter.RelativeDateTimeUnit unit)

Format a combination of RelativeDateTimeUnit and numeric offset using a numeric style, e.g. "1 week ago", "in 1 week", "5 weeks ago", "in 5 weeks". This method returns a FormattedRelativeDateTime, which exposes more information than the String returned by formatNumeric().

Parameters:

offset - The signed offset for the specified unit. This will be formatted according to this object's NumberFormat object.

unit - The unit to use when formatting the relative date, e.g. RelativeDateTimeUnit.WEEK, RelativeDateTimeUnit.FRIDAY.

Returns:

The formatted string (may be empty in case of error)

Status:

Stable ICU 64.

format

public String format(RelativeDateTimeFormatter.Direction direction,
                     RelativeDateTimeFormatter.AbsoluteUnit unit)

Formats a relative date without a quantity. This method returns a String. To get more information about the formatting result, use formatToValue().

Parameters:

direction - NEXT, LAST, THIS, etc.

unit - e.g SATURDAY, DAY, MONTH

Returns:

the formatted string. If direction has a value that is documented as not being fully supported in every locale (for example NEXT_2 or LAST_2) then this function may return null to signal that no formatted string is available.

Throws:

IllegalArgumentException - if the direction is incompatible with unit this can occur with NOW which can only take PLAIN.

Status:

Stable ICU 53.

formatToValue

public RelativeDateTimeFormatter.FormattedRelativeDateTime formatToValue(RelativeDateTimeFormatter.Direction direction,
                                                                         RelativeDateTimeFormatter.AbsoluteUnit unit)

Formats a relative date without a quantity. This method returns a FormattedRelativeDateTime, which exposes more information than the String returned by format().

Parameters:

direction - NEXT, LAST, THIS, etc.

unit - e.g SATURDAY, DAY, MONTH

Returns:

the formatted string. If direction has a value that is documented as not being fully supported in every locale (for example NEXT_2 or LAST_2) then this function may return null to signal that no formatted string is available.

Throws:

IllegalArgumentException - if the direction is incompatible with unit this can occur with NOW which can only take PLAIN.

Status:

Stable ICU 64.

format

public String format(double offset,
                     RelativeDateTimeFormatter.RelativeDateTimeUnit unit)

Format a combination of RelativeDateTimeUnit and numeric offset using a text style if possible, e.g. "last week", "this week", "next week", "yesterday", "tomorrow". Falls back to numeric style if no appropriate text term is available for the specified offset in the object’s locale. This method returns a String. To get more information about the formatting result, use formatToValue().

Parameters:

offset - The signed offset for the specified field.

unit - The unit to use when formatting the relative date, e.g. RelativeDateTimeUnit.WEEK, RelativeDateTimeUnit.FRIDAY.

Returns:

The formatted string (may be empty in case of error)

Status:

Stable ICU 57.

formatToValue

public RelativeDateTimeFormatter.FormattedRelativeDateTime formatToValue(double offset,
                                                                         RelativeDateTimeFormatter.RelativeDateTimeUnit unit)

Format a combination of RelativeDateTimeUnit and numeric offset using a text style if possible, e.g. "last week", "this week", "next week", "yesterday", "tomorrow". Falls back to numeric style if no appropriate text term is available for the specified offset in the object’s locale. This method returns a FormattedRelativeDateTime, which exposes more information than the String returned by format().

Parameters:

offset - The signed offset for the specified field.

unit - The unit to use when formatting the relative date, e.g. RelativeDateTimeUnit.WEEK, RelativeDateTimeUnit.FRIDAY.

Returns:

The formatted string (may be empty in case of error)

Status:

Stable ICU 64.

combineDateAndTime

public String combineDateAndTime(String relativeDateString,
                                 String timeString)

Combines a relative date string and a time string in this object's locale. This is done with the same date-time separator used for the default calendar in this locale.

Parameters:

relativeDateString - the relative date e.g 'yesterday'

timeString - the time e.g '3:45'

Returns:

the date and time concatenated according to the default calendar in this locale e.g 'yesterday, 3:45'

Status:

Stable ICU 53.

getNumberFormat

public NumberFormat getNumberFormat()

Returns a copy of the NumberFormat this object is using.

Returns:

A copy of the NumberFormat.

Status:

Stable ICU 53.

getCapitalizationContext

public DisplayContext getCapitalizationContext()

Return capitalization context.

Returns:

The capitalization context.

Status:

Stable ICU 54.

getFormatStyle

public RelativeDateTimeFormatter.Style getFormatStyle()

Return style

Returns:

The formatting style.

Status:

Stable ICU 54.