SelectFormat Class Reference

#include <selfmt.h>

Inheritance diagram for SelectFormat:
Format UObject UMemory

Public Member Functions

 SelectFormat (UErrorCode &status)
 Creates a new SelectFormat .
 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.

Static Public Member Functions

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

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

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.

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}.

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 text defines the phrase output for each user-defined keyword. The pattern is a sequence of keyword{phrase} clauses. Each clause assigns the phrase phrase to the user-defined keyword.

Keywords must match the pattern [a-zA-Z][a-zA-Z0-9_-]*; keywords that don't match this pattern result in the error code U_ILLEGAL_CHARACTER. 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. If a pattern provides more than one phrase for the same keyword, the error U_DUPLICATE_KEYWORD is returned.
Spaces between keyword and {phrase} will be ignored; spaces within {phrase} will be preserved.

The phrase for a particular select case may contain other message format patterns. SelectFormat preserves these so that you can use the strings produced by SelectFormat with other formatters. If you are using SelectFormat inside a MessageFormat pattern, MessageFormat will automatically evaluate the resulting format pattern. Thus, curly braces ({, }) are only allowed in phrases to define a nested format pattern.

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:
Input is Kirti,female and result is: Kirti est allée à Paris.

Draft:
This API may be changed in the future versions and was introduced in ICU 4.4

Definition at line 185 of file selfmt.h.


Constructor & Destructor Documentation

SelectFormat::SelectFormat ( UErrorCode status  ) 

Creates a new SelectFormat .

Parameters:
status output param set to success/failure code on exit, which must not indicate a failure before the function call.
Internal:
Do not use. This API is for internal use only. This function will be removed and will not be API.
SelectFormat::SelectFormat ( const UnicodeString pattern,
UErrorCode status 
)

Creates a new SelectFormat for a given pattern string.

Parameters:
pattern the pattern for this SelectFormat. errors are returned to status if the pattern is invalid.
status output param set to success/failure code on exit, which must not indicate a failure before the function call.
Draft:
This API may be changed in the future versions and was introduced in ICU 4.4
SelectFormat::SelectFormat ( const SelectFormat other  ) 

copy constructor.

Draft:
This API may be changed in the future versions and was introduced in ICU 4.4
virtual SelectFormat::~SelectFormat (  )  [virtual]

Destructor.

Draft:
This API may be changed in the future versions and was introduced in ICU 4.4

Member Function Documentation

void 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:
pattern the pattern for this select format errors are returned to status if the pattern is invalid.
status output param set to success/failure code on exit, which must not indicate a failure before the function call.
Draft:
This API may be changed in the future versions and was introduced in ICU 4.4
virtual Format* SelectFormat::clone ( void   )  const [virtual]

Clones this Format object polymorphically.

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

Draft:
This API may be changed in the future versions and was introduced in ICU 4.4

Implements Format.

UnicodeString& 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:
obj A keyword string that is used to select an alternative.
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.
status output param filled with success/failure status.
Returns:
Reference to 'appendTo' parameter.
Draft:
This API may be changed in the future versions and was introduced in ICU 4.4

Implements Format.

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

Selects the phrase for the given keyword.

Parameters:
keyword The keyword that is used to select an alternative.
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.
status output param set to success/failure code on exit, which must not indicate a failure before the function call.
Returns:
Reference to 'appendTo' parameter.
Draft:
This API may be changed in the future versions and was introduced in ICU 4.4
virtual UClassID SelectFormat::getDynamicClassID (  )  const [virtual]

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

Draft:
This API may be changed in the future versions and was introduced in ICU 4.4

Implements Format.

static UClassID SelectFormat::getStaticClassID ( void   )  [static]

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

Draft:
This API may be changed in the future versions and was introduced in ICU 4.4
virtual UBool SelectFormat::operator!= ( const Format other  )  const [virtual]

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

Parameters:
other the SelectFormat object to be compared with.
Returns:
true if other is semantically unequal to this.
Draft:
This API may be changed in the future versions and was introduced in ICU 4.4
SelectFormat& SelectFormat::operator= ( const SelectFormat other  ) 

Assignment operator.

Parameters:
other the SelectFormat object to copy from.
Draft:
This API may be changed in the future versions and was introduced in ICU 4.4

Reimplemented from Format.

virtual UBool SelectFormat::operator== ( const Format other  )  const [virtual]

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

Parameters:
other the SelectFormat object to be compared with.
Returns:
true if other is semantically equal to this.
Draft:
This API may be changed in the future versions and was introduced in ICU 4.4
virtual void 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:
source The string to be parsed into an object.
result Formattable to be set to the parse result. If parse fails, return contents are undefined.
parse_pos The 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.
Draft:
This API may be changed in the future versions and was introduced in ICU 4.4

Implements Format.

UnicodeString& SelectFormat::toPattern ( UnicodeString appendTo  ) 

Returns the pattern from applyPattern() or constructor.

Parameters:
appendTo output parameter to receive result. Result is appended to existing contents.
Returns:
the UnicodeString with inserted pattern.
Draft:
This API may be changed in the future versions and was introduced in ICU 4.4

The documentation for this class was generated from the following file:
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Generated on Sat Jan 23 15:17:44 2010 for ICU 4.3.4 by  doxygen 1.6.1