SelectFormat

Kotlin |Java

open class SelectFormat : Format

kotlin.Any
↳	java.text.Format
	↳	android.icu.text.SelectFormat

SelectFormat supports the creation of internationalized messages by selecting phrases based on keywords. The pattern specifies how to map keywords to phrases and provides a default phrase. The object provided to the format method is a string that's matched against the keywords. If there is a match, the corresponding phrase is selected; otherwise, the default phrase is used.

Using `SelectFormat` for Gender Agreement

Note: Typically, select formatting is done via MessageFormat with a select argument type, rather than using a stand-alone SelectFormat.

The main use case for the select format is gender based inflection. When names or nouns are inserted into sentences, their gender can affect pronouns, verb forms, articles, and adjectives. Special care needs to be taken for the case where the gender cannot be determined. The impact varies between languages:

English has three genders, and unknown gender is handled as a special case. Names use the gender of the named person (if known), nouns referring to people use natural gender, and inanimate objects are usually neutral. The gender only affects pronouns: "he", "she", "it", "they".
German differs from English in that the gender of nouns is rather arbitrary, even for nouns referring to people ("Mädchen", girl, is neutral). The gender affects pronouns ("er", "sie", "es"), articles ("der", "die", "das"), and adjective forms ("guter Mann", "gute Frau", "gutes Mädchen").
French has only two genders; as in German the gender of nouns is rather arbitrary - for sun and moon, the genders are the opposite of those in German. The gender affects pronouns ("il", "elle"), articles ("le", "la"), adjective forms ("bon", "bonne"), and sometimes verb forms ("allé", "allée").
Polish distinguishes five genders (or noun classes), human masculine, animate non-human masculine, inanimate masculine, feminine, and neuter.

Some other languages have noun classes that are not related to gender, but similar in grammatical use. Some African languages have around 20 noun classes.

Note:For the gender of a person in a given sentence, we usually need to distinguish only between female, male and other/unknown.

To enable localizers to create sentence patterns that take their language's gender dependencies into consideration, software has to provide information about the gender associated with a noun or name to MessageFormat. Two main cases can be distinguished:

For people, natural gender information should be maintained for each person. Keywords like "male", "female", "mixed" (for groups of people) and "unknown" could be used.
For nouns, grammatical gender information should be maintained for each noun and per language, e.g., in resource bundles. The keywords "masculine", "feminine", and "neuter" are commonly used, but some languages may require other keywords.

The resulting keyword is provided to MessageFormat as a parameter separate from the name or noun it's associated with. For example, to generate a message such as "Jean went to Paris", three separate arguments would be provided: The name of the person as argument 0, the gender of the person as argument 1, and the name of the city as argument 2. The sentence pattern for English, where the gender of the person has no impact on this simple sentence, would not refer to argument 1 at all:

{0} went to {2}.

Note: The entire sentence should be included (and partially repeated) inside each phrase. Otherwise translators would have to be trained on how to move bits of the sentence in and out of the select argument of a message. (The examples below do not follow this recommendation!)

The sentence pattern for French, where the gender of the person affects the form of the participle, uses a select format based on argument 1:

{0} est {1, select, female {allée} other {allé}} à {2}.

Patterns can be nested, so that it's possible to handle interactions of number and gender where necessary. For example, if the above sentence should allow for the names of several people to be inserted, the following sentence pattern can be used (with argument 0 the list of people's names, argument 1 the number of people, argument 2 their combined gender, and argument 3 the city name):

{0} {1, plural,
  one {est {2, select, female {allée} other  {allé}}}
  other {sont {2, select, female {allées} other {allés}}}
  }à {3}.

Patterns and Their Interpretation

The SelectFormat pattern string defines the phrase output for each user-defined keyword. The pattern is a sequence of (keyword, message) pairs. A keyword is a "pattern identifier": [^[[:Pattern_Syntax:][:Pattern_White_Space:]]]+

Each message is a MessageFormat pattern string enclosed in {curly braces}.

You always have to define a phrase for the default keyword other; this phrase is returned when the keyword provided to the format method matches no other keyword. If a pattern does not provide a phrase for other, the method it's provided to returns the error U_DEFAULT_KEYWORD_MISSING.
Pattern_White_Space between keywords and messages is ignored. Pattern_White_Space within a message is preserved and output.

Example:
  MessageFormat msgFmt = new MessageFormat("{0} est " +
      "{1, select, female {allée} other {allé}} à Paris.",
      new ULocale("fr"));
  Object args[] = {"Kirti","female"};
  System.out.println(msgFmt.format(args));

Produces the output:
Kirti est allée à Paris.

Summary

Public constructors
`SelectFormat(pattern: String!)` Creates a new `SelectFormat` for a given pattern string.

Public methods
open Unit	`applyPattern(pattern: String!)` Sets the pattern used by this select format.
open Boolean	`equals(other: Any?)` Indicates whether some other object is "equal to" this one.
String!	`format(keyword: String!)` Selects the phrase for the given keyword.
open StringBuffer!	`format(keyword: Any!, toAppendTo: StringBuffer!, pos: FieldPosition!)` Selects the phrase for the given keyword.
open Int	`hashCode()` Returns a hash code value for the object.
open Any!	`parseObject(source: String!, pos: ParsePosition!)` This method is not supported by `SelectFormat`.
open String!	`toPattern()` Returns the pattern for this `SelectFormat`
open String	`toString()` Returns a string representation of the object.

Inherited functions

From class Format

`Any`	`clone()` Creates and returns a copy of this object.
`String!`	`format(obj: Any!)` Formats an object to produce a string. This is equivalent to `format(obj, new StringBuffer(), new FieldPosition(0)).toString();`
`AttributedCharacterIterator!`	`formatToCharacterIterator(obj: Any!)` Formats an Object producing an `AttributedCharacterIterator`. You can use the returned `AttributedCharacterIterator` to build the resulting String, as well as to determine information about the resulting String. Each attribute key of the AttributedCharacterIterator will be of type `Field`. It is up to each `Format` implementation to define what the legal values are for each attribute in the `AttributedCharacterIterator`, but typically the attribute key is also used as the attribute value. The default implementation creates an `AttributedCharacterIterator` with no attributes. Subclasses that support fields should override this and create an `AttributedCharacterIterator` with meaningful attributes.
`Any!`	`parseObject(source: String!)` Parses text from the beginning of the given string to produce an object. The method may not use the entire text of the given string.

Public constructors

SelectFormat

Added in API level 24

SelectFormat(pattern: String!)

Creates a new SelectFormat for a given pattern string.

Parameters
`pattern`	String!: the pattern for this `SelectFormat`.

Public methods

applyPattern

Added in API level 24

open fun applyPattern(pattern: String!): Unit

Sets the pattern used by this select format. Patterns and their interpretation are specified in the class description.

Parameters
`pattern`	String!: the pattern for this select format.

Exceptions
`java.lang.IllegalArgumentException`	when the pattern is not a valid select format pattern.

equals

Added in API level 24

open fun equals(other: Any?): Boolean

Indicates whether some other object is "equal to" this one.

The equals method implements an equivalence relation on non-null object references:

It is reflexive: for any non-null reference value x, x.equals(x) should return true.
It is symmetric: for any non-null reference values x and y, x.equals(y) should return true if and only if y.equals(x) returns true.
It is transitive: for any non-null reference values x, y, and z, if x.equals(y) returns true and y.equals(z) returns true, then x.equals(z) should return true.
It is consistent: for any non-null reference values x and y, multiple invocations of x.equals(y) consistently return true or consistently return false, provided no information used in equals comparisons on the objects is modified.
For any non-null reference value x, x.equals(null) should return false.

An equivalence relation partitions the elements it operates on into equivalence classes; all the members of an equivalence class are equal to each other. Members of an equivalence class are substitutable for each other, at least for some purposes.

Parameters
`obj`	the reference object with which to compare.

Return
`Boolean`	`true` if this object is the same as the obj argument; `false` otherwise.

format

Added in API level 24

fun format(keyword: String!): String!

Selects the phrase for the given keyword.

Parameters
`keyword`	String!: a phrase selection keyword.

Return
`String!`	the string containing the formatted select message.

Exceptions
`java.lang.IllegalArgumentException`	when the given keyword is not a "pattern identifier"

format

Added in API level 24

open fun format(
    keyword: Any!, 
    toAppendTo: StringBuffer!, 
    pos: FieldPosition!
): StringBuffer!

Selects the phrase for the given keyword. and appends the formatted message to the given StringBuffer.

Parameters
`obj`	The object to format
`toAppendTo`	StringBuffer!: the selected phrase will be appended to this `StringBuffer`.
`pos`	FieldPosition!: will be ignored by this method.
`keyword`	Any!: a phrase selection keyword.

Return
`StringBuffer!`	the string buffer passed in as toAppendTo, with formatted text appended.

Exceptions
`java.lang.NullPointerException`	if `toAppendTo` or `pos` is null
`java.lang.IllegalArgumentException`	when the given keyword is not a String or not a "pattern identifier"

hashCode

Added in API level 24

open fun hashCode(): Int

Returns a hash code value for the object. This method is supported for the benefit of hash tables such as those provided by java.util.HashMap.

The general contract of hashCode is:

Whenever it is invoked on the same object more than once during an execution of a Java application, the hashCode method must consistently return the same integer, provided no information used in equals comparisons on the object is modified. This integer need not remain consistent from one execution of an application to another execution of the same application.
If two objects are equal according to the equals method, then calling the hashCode method on each of the two objects must produce the same integer result.
It is not required that if two objects are unequal according to the equals method, then calling the hashCode method on each of the two objects must produce distinct integer results. However, the programmer should be aware that producing distinct integer results for unequal objects may improve the performance of hash tables.

Return
`Int`	a hash code value for this object.

parseObject

Added in API level 24

open fun parseObject(
    source: String!, 
    pos: ParsePosition!
): Any!

This method is not supported by SelectFormat.

Parameters
`source`	String!: the string to be parsed.
`pos`	ParsePosition!: defines the position where parsing is to begin, and upon return, the position where parsing left off. If the position has not changed upon return, then parsing failed.

Return
`Any!`	nothing because this method is not supported.

Exceptions
`java.lang.NullPointerException`	if `source` or `pos` is null.
`java.lang.UnsupportedOperationException`	thrown always.

toPattern

Added in API level 24

open fun toPattern(): String!

Returns the pattern for this SelectFormat

Return
`String!`	the pattern string

toString

Added in API level 24

open fun toString(): String

Returns a string representation of the object.

Return
`String`	a string representation of the object.

SelectFormat

Using SelectFormat for Gender Agreement

Patterns and Their Interpretation

Summary

Public constructors

SelectFormat

Public methods

applyPattern

equals

format

format

hashCode

parseObject

toPattern

toString

Using `SelectFormat` for Gender Agreement