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icu::SelectFormat Class Reference

#include <selfmt.h>

Inheritance diagram for icu::SelectFormat:
icu::Format icu::UObject icu::UMemory

Public Member Functions

 SelectFormat (const UnicodeString &pattern, UErrorCode &status)
 Creates a new SelectFormat for a given pattern string.
 SelectFormat (const SelectFormat &other)
 copy constructor.
virtual ~SelectFormat ()
 Destructor.
void applyPattern (const UnicodeString &pattern, UErrorCode &status)
 Sets the pattern used by this select format.
UnicodeStringformat (const UnicodeString &keyword, UnicodeString &appendTo, FieldPosition &pos, UErrorCode &status) const
 Selects the phrase for the given keyword.
SelectFormatoperator= (const SelectFormat &other)
 Assignment operator.
virtual UBool operator== (const Format &other) const
 Return true if another object is semantically equal to this one.
virtual UBool operator!= (const Format &other) const
 Return true if another object is semantically unequal to this one.
virtual Formatclone (void) const
 Clones this Format object polymorphically.
UnicodeStringformat (const Formattable &obj, UnicodeString &appendTo, FieldPosition &pos, UErrorCode &status) const
 Format an object to produce a string.
UnicodeStringtoPattern (UnicodeString &appendTo)
 Returns the pattern from applyPattern() or constructor.
virtual void parseObject (const UnicodeString &source, Formattable &result, ParsePosition &parse_pos) const
 This method is not yet supported by SelectFormat.
virtual UClassID getDynamicClassID () const
 ICU "poor man's RTTI", returns a UClassID for the actual class.
- Public Member Functions inherited from icu::Format
virtual ~Format ()
 Destructor.
UnicodeStringformat (const Formattable &obj, UnicodeString &appendTo, UErrorCode &status) const
 Formats an object to produce a string.
virtual UnicodeStringformat (const Formattable &obj, UnicodeString &appendTo, FieldPositionIterator *posIter, UErrorCode &status) const
 Format an object to produce a string.
void parseObject (const UnicodeString &source, Formattable &result, UErrorCode &status) const
 Parses a string to produce an object.
Locale getLocale (ULocDataLocaleType type, UErrorCode &status) const
 Get the locale for this format object.
const char * getLocaleID (ULocDataLocaleType type, UErrorCode &status) const
 Get the locale for this format object.
- Public Member Functions inherited from icu::UObject
virtual ~UObject ()
 Destructor.

Static Public Member Functions

static UClassID getStaticClassID (void)
 ICU "poor man's RTTI", returns a UClassID for this class.

Friends

class MessageFormat

Additional Inherited Members

- Protected Member Functions inherited from icu::Format
void setLocaleIDs (const char *valid, const char *actual)
 Format ()
 Default constructor for subclass use only.
 Format (const Format &)
Formatoperator= (const Format &)
- Static Protected Member Functions inherited from icu::Format
static void syntaxError (const UnicodeString &pattern, int32_t pos, UParseError &parseError)
 Simple function for initializing a UParseError from a UnicodeString.

Detailed Description

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:

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}.

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:
 

UErrorCode status = U_ZERO_ERROR;
MessageFormat *msgFmt = new MessageFormat(UnicodeString("{0} est  {1, select, female {allée} other {allé}} à Paris."), Locale("fr"),  status);
if (U_FAILURE(status)) {
      return;
}
FieldPosition ignore(FieldPosition::DONT_CARE);
UnicodeString result;

char* str1= "Kirti,female";
Formattable args1[] = {"Kirti","female"};
msgFmt->format(args1, 2, result, ignore, status);
cout << "Input is " << str1 << " and result is: " << result << endl;
delete msgFmt;


Produces the output:
Kirti est allée à Paris.

Stable:
ICU 4.4

Definition at line 183 of file selfmt.h.

Constructor & Destructor Documentation

icu::SelectFormat::SelectFormat ( const UnicodeString pattern,
UErrorCode status 
)

Creates a new SelectFormat for a given pattern string.

Parameters
patternthe pattern for this SelectFormat. errors are returned to status if the pattern is invalid.
statusoutput param set to success/failure code on exit, which must not indicate a failure before the function call.
Stable:
ICU 4.4
icu::SelectFormat::SelectFormat ( const SelectFormat other)

copy constructor.

Stable:
ICU 4.4
virtual icu::SelectFormat::~SelectFormat ( )
virtual

Destructor.

Stable:
ICU 4.4

Member Function Documentation

void icu::SelectFormat::applyPattern ( const UnicodeString pattern,
UErrorCode status 
)

Sets the pattern used by this select format.

for the keyword rules. Patterns and their interpretation are specified in the class description.

Parameters
patternthe pattern for this select format errors are returned to status if the pattern is invalid.
statusoutput param set to success/failure code on exit, which must not indicate a failure before the function call.
Stable:
ICU 4.4
virtual Format* icu::SelectFormat::clone ( void  ) const
virtual

Clones this Format object polymorphically.

The caller owns the result and should delete it when done.

Stable:
ICU 4.4

Implements icu::Format.

UnicodeString& icu::SelectFormat::format ( const UnicodeString keyword,
UnicodeString appendTo,
FieldPosition pos,
UErrorCode status 
) const

Selects the phrase for the given keyword.

Parameters
keywordThe keyword that is used to select an alternative.
appendTooutput parameter to receive result. result is appended to existing contents.
posOn input: an alignment field, if desired. On output: the offsets of the alignment field.
statusoutput param set to success/failure code on exit, which must not indicate a failure before the function call.
Returns
Reference to 'appendTo' parameter.
Stable:
ICU 4.4
UnicodeString& icu::SelectFormat::format ( const Formattable obj,
UnicodeString appendTo,
FieldPosition pos,
UErrorCode status 
) const
virtual

Format an object to produce a string.

This method handles keyword strings. If the Formattable object is not a UnicodeString, then it returns a failing UErrorCode.

Parameters
objA keyword string that is used to select an alternative.
appendTooutput parameter to receive result. Result is appended to existing contents.
posOn input: an alignment field, if desired. On output: the offsets of the alignment field.
statusoutput param filled with success/failure status.
Returns
Reference to 'appendTo' parameter.
Stable:
ICU 4.4

Implements icu::Format.

virtual UClassID icu::SelectFormat::getDynamicClassID ( ) const
virtual

ICU "poor man's RTTI", returns a UClassID for the actual class.

Stable:
ICU 4.4

Reimplemented from icu::UObject.

static UClassID icu::SelectFormat::getStaticClassID ( void  )
static

ICU "poor man's RTTI", returns a UClassID for this class.

Stable:
ICU 4.4
virtual UBool icu::SelectFormat::operator!= ( const Format other) const
virtual

Return true if another object is semantically unequal to this one.

Parameters
otherthe SelectFormat object to be compared with.
Returns
true if other is semantically unequal to this.
Stable:
ICU 4.4

Reimplemented from icu::Format.

SelectFormat& icu::SelectFormat::operator= ( const SelectFormat other)

Assignment operator.

Parameters
otherthe SelectFormat object to copy from.
Stable:
ICU 4.4
virtual UBool icu::SelectFormat::operator== ( const Format other) const
virtual

Return true if another object is semantically equal to this one.

Parameters
otherthe SelectFormat object to be compared with.
Returns
true if other is semantically equal to this.
Stable:
ICU 4.4

Implements icu::Format.

virtual void icu::SelectFormat::parseObject ( const UnicodeString source,
Formattable result,
ParsePosition parse_pos 
) const
virtual

This method is not yet supported by SelectFormat.

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.

Parameters
sourceThe string to be parsed into an object.
resultFormattable to be set to the parse result. If parse fails, return contents are undefined.
parse_posThe position to start parsing at. Upon return this param is set to the position after the last character successfully parsed. If the source is not parsed successfully, this param will remain unchanged.
Stable:
ICU 4.4

Implements icu::Format.

UnicodeString& icu::SelectFormat::toPattern ( UnicodeString appendTo)

Returns the pattern from applyPattern() or constructor.

Parameters
appendTooutput parameter to receive result. Result is appended to existing contents.
Returns
the UnicodeString with inserted pattern.
Stable:
ICU 4.4

The documentation for this class was generated from the following file: