public
class
SelectFormat
extends Format
java.lang.Object | ||
↳ | 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.
SelectFormat
for Gender AgreementNote: 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:
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:
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}.
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.
Public constructors | |
---|---|
SelectFormat(String pattern)
Creates a new |
Public methods | |
---|---|
void
|
applyPattern(String pattern)
Sets the pattern used by this select format. |
boolean
|
equals(Object obj)
Indicates whether some other object is "equal to" this one. |
StringBuffer
|
format(Object keyword, StringBuffer toAppendTo, FieldPosition pos)
Selects the phrase for the given keyword. |
final
String
|
format(String keyword)
Selects the phrase for the given keyword. |
int
|
hashCode()
Returns a hash code value for the object. |
Object
|
parseObject(String source, ParsePosition pos)
This method is not supported by |
String
|
toPattern()
Returns the pattern for this |
String
|
toString()
Returns a string representation of the object. |
Inherited methods | |
---|---|
From
class
java.text.Format
| |
From
class
java.lang.Object
|
SelectFormat (String pattern)
Creates a new SelectFormat
for a given pattern string.
Parameters | |
---|---|
pattern |
String :
the pattern for this SelectFormat .
|
void applyPattern (String pattern)
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. |
Throws | |
---|---|
IllegalArgumentException |
when the pattern is not a valid select format pattern. |
boolean equals (Object obj)
Indicates whether some other object is "equal to" this one.
The equals
method implements an equivalence relation
on non-null object references:
x
, x.equals(x)
should return
true
.
x
and y
, x.equals(y)
should return true
if and only if
y.equals(x)
returns true
.
x
, y
, and z
, if
x.equals(y)
returns true
and
y.equals(z)
returns true
, then
x.equals(z)
should return true
.
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.
x
,
x.equals(null)
should return false
.
The equals
method for class Object
implements
the most discriminating possible equivalence relation on objects;
that is, for any non-null reference values x
and
y
, this method returns true
if and only
if x
and y
refer to the same object
(x == y
has the value true
).
Note that it is generally necessary to override the hashCode
method whenever this method is overridden, so as to maintain the
general contract for the hashCode
method, which states
that equal objects must have equal hash codes.
Parameters | |
---|---|
obj |
Object :
the reference object with which to compare. |
Returns | |
---|---|
boolean |
true if this object is the same as the obj
argument; false otherwise. |
StringBuffer format (Object keyword, StringBuffer toAppendTo, FieldPosition pos)
Selects the phrase for the given keyword.
and appends the formatted message to the given StringBuffer
.
Parameters | |
---|---|
keyword |
Object :
a phrase selection keyword. |
toAppendTo |
StringBuffer :
the selected phrase will be appended to this
StringBuffer . |
pos |
FieldPosition :
will be ignored by this method. |
Returns | |
---|---|
StringBuffer |
the string buffer passed in as toAppendTo, with formatted text appended. |
Throws | |
---|---|
IllegalArgumentException |
when the given keyword is not a String or not a "pattern identifier" |
String format (String keyword)
Selects the phrase for the given keyword.
Parameters | |
---|---|
keyword |
String :
a phrase selection keyword. |
Returns | |
---|---|
String |
the string containing the formatted select message. |
Throws | |
---|---|
IllegalArgumentException |
when the given keyword is not a "pattern identifier" |
int hashCode ()
Returns a hash code value for the object. This method is
supported for the benefit of hash tables such as those provided by
HashMap
.
The general contract of hashCode
is:
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.
equals(Object)
method, then calling the hashCode
method on each of
the two objects must produce the same integer result.
equals(java.lang.Object)
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.
As much as is reasonably practical, the hashCode method defined by
class Object
does return distinct integers for distinct
objects. (This is typically implemented by converting the internal
address of the object into an integer, but this implementation
technique is not required by the
JavaTM programming language.)
Returns | |
---|---|
int |
a hash code value for this object. |
Object parseObject (String source, ParsePosition pos)
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. |
Returns | |
---|---|
Object |
nothing because this method is not supported. |
Throws | |
---|---|
UnsupportedOperationException |
thrown always. |
String toPattern ()
Returns the pattern for this SelectFormat
Returns | |
---|---|
String |
the pattern string |
String toString ()
Returns a string representation of the object. In general, the
toString
method returns a string that
"textually represents" this object. The result should
be a concise but informative representation that is easy for a
person to read.
It is recommended that all subclasses override this method.
The toString
method for class Object
returns a string consisting of the name of the class of which the
object is an instance, the at-sign character `@
', and
the unsigned hexadecimal representation of the hash code of the
object. In other words, this method returns a string equal to the
value of:
getClass().getName() + '@' + Integer.toHexString(hashCode())
Returns | |
---|---|
String |
a string representation of the object. |