ICU 60.1  60.1
Data Structures | Public Member Functions | Static Public Member Functions
icu::MessagePattern Class Reference

Parses and represents ICU MessageFormat patterns. More...

#include <messagepattern.h>

Inheritance diagram for icu::MessagePattern:
icu::UObject icu::UMemory

Data Structures

class  Part
 A message pattern "part", representing a pattern parsing event. More...
 

Public Member Functions

 MessagePattern (UErrorCode &errorCode)
 Constructs an empty MessagePattern with default UMessagePatternApostropheMode. More...
 
 MessagePattern (UMessagePatternApostropheMode mode, UErrorCode &errorCode)
 Constructs an empty MessagePattern. More...
 
 MessagePattern (const UnicodeString &pattern, UParseError *parseError, UErrorCode &errorCode)
 Constructs a MessagePattern with default UMessagePatternApostropheMode and parses the MessageFormat pattern string. More...
 
 MessagePattern (const MessagePattern &other)
 Copy constructor. More...
 
MessagePatternoperator= (const MessagePattern &other)
 Assignment operator. More...
 
virtual ~MessagePattern ()
 Destructor. More...
 
MessagePatternparse (const UnicodeString &pattern, UParseError *parseError, UErrorCode &errorCode)
 Parses a MessageFormat pattern string. More...
 
MessagePatternparseChoiceStyle (const UnicodeString &pattern, UParseError *parseError, UErrorCode &errorCode)
 Parses a ChoiceFormat pattern string. More...
 
MessagePatternparsePluralStyle (const UnicodeString &pattern, UParseError *parseError, UErrorCode &errorCode)
 Parses a PluralFormat pattern string. More...
 
MessagePatternparseSelectStyle (const UnicodeString &pattern, UParseError *parseError, UErrorCode &errorCode)
 Parses a SelectFormat pattern string. More...
 
void clear ()
 Clears this MessagePattern. More...
 
void clearPatternAndSetApostropheMode (UMessagePatternApostropheMode mode)
 Clears this MessagePattern and sets the UMessagePatternApostropheMode. More...
 
UBool operator== (const MessagePattern &other) const
 
UBool operator!= (const MessagePattern &other) const
 
int32_t hashCode () const
 
UMessagePatternApostropheMode getApostropheMode () const
 
const UnicodeStringgetPatternString () const
 
UBool hasNamedArguments () const
 Does the parsed pattern have named arguments like {first_name}? More...
 
UBool hasNumberedArguments () const
 Does the parsed pattern have numbered arguments like {2}? More...
 
UnicodeString autoQuoteApostropheDeep () const
 Returns a version of the parsed pattern string where each ASCII apostrophe is doubled (escaped) if it is not already, and if it is not interpreted as quoting syntax. More...
 
int32_t countParts () const
 Returns the number of "parts" created by parsing the pattern string. More...
 
const PartgetPart (int32_t i) const
 Gets the i-th pattern "part". More...
 
UMessagePatternPartType getPartType (int32_t i) const
 Returns the UMessagePatternPartType of the i-th pattern "part". More...
 
int32_t getPatternIndex (int32_t partIndex) const
 Returns the pattern index of the specified pattern "part". More...
 
UnicodeString getSubstring (const Part &part) const
 Returns the substring of the pattern string indicated by the Part. More...
 
UBool partSubstringMatches (const Part &part, const UnicodeString &s) const
 Compares the part's substring with the input string s. More...
 
double getNumericValue (const Part &part) const
 Returns the numeric value associated with an ARG_INT or ARG_DOUBLE. More...
 
double getPluralOffset (int32_t pluralStart) const
 Returns the "offset:" value of a PluralFormat argument, or 0 if none is specified. More...
 
int32_t getLimitPartIndex (int32_t start) const
 Returns the index of the ARG|MSG_LIMIT part corresponding to the ARG|MSG_START at start. More...
 
- Public Member Functions inherited from icu::UObject
virtual ~UObject ()
 Destructor. More...
 
virtual UClassID getDynamicClassID () const
 ICU4C "poor man's RTTI", returns a UClassID for the actual ICU class. More...
 

Static Public Member Functions

static int32_t validateArgumentName (const UnicodeString &name)
 Validates and parses an argument name or argument number string. More...
 

Detailed Description

Parses and represents ICU MessageFormat patterns.

Also handles patterns for ChoiceFormat, PluralFormat and SelectFormat. Used in the implementations of those classes as well as in tools for message validation, translation and format conversion.

The parser handles all syntax relevant for identifying message arguments. This includes "complex" arguments whose style strings contain nested MessageFormat pattern substrings. For "simple" arguments (with no nested MessageFormat pattern substrings), the argument style is not parsed any further.

The parser handles named and numbered message arguments and allows both in one message.

Once a pattern has been parsed successfully, iterate through the parsed data with countParts(), getPart() and related methods.

The data logically represents a parse tree, but is stored and accessed as a list of "parts" for fast and simple parsing and to minimize object allocations. Arguments and nested messages are best handled via recursion. For every _START "part", MessagePattern.getLimitPartIndex() efficiently returns the index of the corresponding _LIMIT "part".

List of "parts":

message = MSG_START (SKIP_SYNTAX | INSERT_CHAR | REPLACE_NUMBER | argument)* MSG_LIMIT
argument = noneArg | simpleArg | complexArg
complexArg = choiceArg | pluralArg | selectArg
noneArg = ARG_START.NONE (ARG_NAME | ARG_NUMBER) ARG_LIMIT.NONE
simpleArg = ARG_START.SIMPLE (ARG_NAME | ARG_NUMBER) ARG_TYPE [ARG_STYLE] ARG_LIMIT.SIMPLE
choiceArg = ARG_START.CHOICE (ARG_NAME | ARG_NUMBER) choiceStyle ARG_LIMIT.CHOICE
pluralArg = ARG_START.PLURAL (ARG_NAME | ARG_NUMBER) pluralStyle ARG_LIMIT.PLURAL
selectArg = ARG_START.SELECT (ARG_NAME | ARG_NUMBER) selectStyle ARG_LIMIT.SELECT
choiceStyle = ((ARG_INT | ARG_DOUBLE) ARG_SELECTOR message)+
pluralStyle = [ARG_INT | ARG_DOUBLE] (ARG_SELECTOR [ARG_INT | ARG_DOUBLE] message)+
selectStyle = (ARG_SELECTOR message)+

This class is not intended for public subclassing.

Stable:
ICU 4.8

Definition at line 360 of file messagepattern.h.

Constructor & Destructor Documentation

◆ MessagePattern() [1/4]

icu::MessagePattern::MessagePattern ( UErrorCode errorCode)

Constructs an empty MessagePattern with default UMessagePatternApostropheMode.

Parameters
errorCodeStandard ICU error code. Its input value must pass the U_SUCCESS() test, or else the function returns immediately. Check for U_FAILURE() on output or use with function chaining. (See User Guide for details.)
Stable:
ICU 4.8

◆ MessagePattern() [2/4]

icu::MessagePattern::MessagePattern ( UMessagePatternApostropheMode  mode,
UErrorCode errorCode 
)

Constructs an empty MessagePattern.

Parameters
modeExplicit UMessagePatternApostropheMode.
errorCodeStandard ICU error code. Its input value must pass the U_SUCCESS() test, or else the function returns immediately. Check for U_FAILURE() on output or use with function chaining. (See User Guide for details.)
Stable:
ICU 4.8

◆ MessagePattern() [3/4]

icu::MessagePattern::MessagePattern ( const UnicodeString pattern,
UParseError parseError,
UErrorCode errorCode 
)

Constructs a MessagePattern with default UMessagePatternApostropheMode and parses the MessageFormat pattern string.

Parameters
patterna MessageFormat pattern string
parseErrorStruct to receive information on the position of an error within the pattern. Can be NULL.
errorCodeStandard ICU error code. Its input value must pass the U_SUCCESS() test, or else the function returns immediately. Check for U_FAILURE() on output or use with function chaining. (See User Guide for details.) TODO: turn
Exceptions
intoUErrorCode specifics?
IllegalArgumentExceptionfor syntax errors in the pattern string
IndexOutOfBoundsExceptionif certain limits are exceeded (e.g., argument number too high, argument name too long, etc.)
NumberFormatExceptionif a number could not be parsed
Stable:
ICU 4.8

◆ MessagePattern() [4/4]

icu::MessagePattern::MessagePattern ( const MessagePattern other)

Copy constructor.

Parameters
otherObject to copy.
Stable:
ICU 4.8

◆ ~MessagePattern()

virtual icu::MessagePattern::~MessagePattern ( )
virtual

Destructor.

Stable:
ICU 4.8

Member Function Documentation

◆ autoQuoteApostropheDeep()

UnicodeString icu::MessagePattern::autoQuoteApostropheDeep ( ) const

Returns a version of the parsed pattern string where each ASCII apostrophe is doubled (escaped) if it is not already, and if it is not interpreted as quoting syntax.

For example, this turns "I don't '{know}' {gender,select,female{h''er}other{h'im}}." into "I don''t '{know}' {gender,select,female{h''er}other{h''im}}."

Returns
the deep-auto-quoted version of the parsed pattern string.
See also
MessageFormat.autoQuoteApostrophe()
Stable:
ICU 4.8

◆ clear()

void icu::MessagePattern::clear ( )

Clears this MessagePattern.

countParts() will return 0.

Stable:
ICU 4.8

◆ clearPatternAndSetApostropheMode()

void icu::MessagePattern::clearPatternAndSetApostropheMode ( UMessagePatternApostropheMode  mode)
inline

Clears this MessagePattern and sets the UMessagePatternApostropheMode.

countParts() will return 0.

Parameters
modeThe new UMessagePatternApostropheMode.
Stable:
ICU 4.8

Definition at line 517 of file messagepattern.h.

References icu::operator==().

◆ countParts()

int32_t icu::MessagePattern::countParts ( ) const
inline

Returns the number of "parts" created by parsing the pattern string.

Returns 0 if no pattern has been parsed or clear() was called.

Returns
the number of pattern parts.
Stable:
ICU 4.8

Definition at line 614 of file messagepattern.h.

◆ getApostropheMode()

UMessagePatternApostropheMode icu::MessagePattern::getApostropheMode ( ) const
inline
Returns
this instance's UMessagePatternApostropheMode.
Stable:
ICU 4.8

Definition at line 548 of file messagepattern.h.

◆ getLimitPartIndex()

int32_t icu::MessagePattern::getLimitPartIndex ( int32_t  start) const
inline

Returns the index of the ARG|MSG_LIMIT part corresponding to the ARG|MSG_START at start.

Parameters
startThe index of some Part data (0..countParts()-1); this Part should be of Type ARG_START or MSG_START.
Returns
The first i>start where getPart(i).getType()==ARG|MSG_LIMIT at the same nesting level, or start itself if getPartType(msgStart)!=ARG|MSG_START.
Stable:
ICU 4.8

Definition at line 696 of file messagepattern.h.

◆ getNumericValue()

double icu::MessagePattern::getNumericValue ( const Part part) const

Returns the numeric value associated with an ARG_INT or ARG_DOUBLE.

Parameters
parta part of this MessagePattern.
Returns
the part's numeric value, or UMSGPAT_NO_NUMERIC_VALUE if this is not a numeric part.
Stable:
ICU 4.8

◆ getPart()

const Part& icu::MessagePattern::getPart ( int32_t  i) const
inline

Gets the i-th pattern "part".

Parameters
iThe index of the Part data. (0..countParts()-1)
Returns
the i-th pattern "part".
Stable:
ICU 4.8

Definition at line 624 of file messagepattern.h.

◆ getPartType()

UMessagePatternPartType icu::MessagePattern::getPartType ( int32_t  i) const
inline

Returns the UMessagePatternPartType of the i-th pattern "part".

Convenience method for getPart(i).getType().

Parameters
iThe index of the Part data. (0..countParts()-1)
Returns
The UMessagePatternPartType of the i-th Part.
Stable:
ICU 4.8

Definition at line 635 of file messagepattern.h.

◆ getPatternIndex()

int32_t icu::MessagePattern::getPatternIndex ( int32_t  partIndex) const
inline

Returns the pattern index of the specified pattern "part".

Convenience method for getPart(partIndex).getIndex().

Parameters
partIndexThe index of the Part data. (0..countParts()-1)
Returns
The pattern index of this Part.
Stable:
ICU 4.8

Definition at line 646 of file messagepattern.h.

◆ getPatternString()

const UnicodeString& icu::MessagePattern::getPatternString ( ) const
inline
Returns
the parsed pattern string (null if none was parsed).
Stable:
ICU 4.8

Definition at line 559 of file messagepattern.h.

◆ getPluralOffset()

double icu::MessagePattern::getPluralOffset ( int32_t  pluralStart) const

Returns the "offset:" value of a PluralFormat argument, or 0 if none is specified.

Parameters
pluralStartthe index of the first PluralFormat argument style part. (0..countParts()-1)
Returns
the "offset:" value.
Stable:
ICU 4.8

◆ getSubstring()

UnicodeString icu::MessagePattern::getSubstring ( const Part part) const
inline

Returns the substring of the pattern string indicated by the Part.

Convenience method for getPatternString().substring(part.getIndex(), part.getLimit()).

Parameters
parta part of this MessagePattern.
Returns
the substring associated with part.
Stable:
ICU 4.8

Definition at line 657 of file messagepattern.h.

References icu::UnicodeString::tempSubString().

◆ hashCode()

int32_t icu::MessagePattern::hashCode ( ) const
Returns
A hash code for this object.
Stable:
ICU 4.8

◆ hasNamedArguments()

UBool icu::MessagePattern::hasNamedArguments ( ) const
inline

Does the parsed pattern have named arguments like {first_name}?

Returns
TRUE if the parsed pattern has at least one named argument.
Stable:
ICU 4.8

Definition at line 568 of file messagepattern.h.

◆ hasNumberedArguments()

UBool icu::MessagePattern::hasNumberedArguments ( ) const
inline

Does the parsed pattern have numbered arguments like {2}?

Returns
TRUE if the parsed pattern has at least one numbered argument.
Stable:
ICU 4.8

Definition at line 577 of file messagepattern.h.

◆ operator!=()

UBool icu::MessagePattern::operator!= ( const MessagePattern other) const
inline
Parameters
otheranother object to compare with.
Returns
FALSE if this object is equivalent to the other one.
Stable:
ICU 4.8

Definition at line 534 of file messagepattern.h.

References icu::operator==().

◆ operator=()

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

Assignment operator.

Parameters
otherObject to copy.
Returns
*this=other
Stable:
ICU 4.8

◆ operator==()

UBool icu::MessagePattern::operator== ( const MessagePattern other) const
Parameters
otheranother object to compare with.
Returns
TRUE if this object is equivalent to the other one.
Stable:
ICU 4.8

◆ parse()

MessagePattern& icu::MessagePattern::parse ( const UnicodeString pattern,
UParseError parseError,
UErrorCode errorCode 
)

Parses a MessageFormat pattern string.

Parameters
patterna MessageFormat pattern string
parseErrorStruct to receive information on the position of an error within the pattern. Can be NULL.
errorCodeStandard ICU error code. Its input value must pass the U_SUCCESS() test, or else the function returns immediately. Check for U_FAILURE() on output or use with function chaining. (See User Guide for details.)
Returns
*this
Exceptions
IllegalArgumentExceptionfor syntax errors in the pattern string
IndexOutOfBoundsExceptionif certain limits are exceeded (e.g., argument number too high, argument name too long, etc.)
NumberFormatExceptionif a number could not be parsed
Stable:
ICU 4.8

◆ parseChoiceStyle()

MessagePattern& icu::MessagePattern::parseChoiceStyle ( const UnicodeString pattern,
UParseError parseError,
UErrorCode errorCode 
)

Parses a ChoiceFormat pattern string.

Parameters
patterna ChoiceFormat pattern string
parseErrorStruct to receive information on the position of an error within the pattern. Can be NULL.
errorCodeStandard ICU error code. Its input value must pass the U_SUCCESS() test, or else the function returns immediately. Check for U_FAILURE() on output or use with function chaining. (See User Guide for details.)
Returns
*this
Exceptions
IllegalArgumentExceptionfor syntax errors in the pattern string
IndexOutOfBoundsExceptionif certain limits are exceeded (e.g., argument number too high, argument name too long, etc.)
NumberFormatExceptionif a number could not be parsed
Stable:
ICU 4.8

◆ parsePluralStyle()

MessagePattern& icu::MessagePattern::parsePluralStyle ( const UnicodeString pattern,
UParseError parseError,
UErrorCode errorCode 
)

Parses a PluralFormat pattern string.

Parameters
patterna PluralFormat pattern string
parseErrorStruct to receive information on the position of an error within the pattern. Can be NULL.
errorCodeStandard ICU error code. Its input value must pass the U_SUCCESS() test, or else the function returns immediately. Check for U_FAILURE() on output or use with function chaining. (See User Guide for details.)
Returns
*this
Exceptions
IllegalArgumentExceptionfor syntax errors in the pattern string
IndexOutOfBoundsExceptionif certain limits are exceeded (e.g., argument number too high, argument name too long, etc.)
NumberFormatExceptionif a number could not be parsed
Stable:
ICU 4.8

◆ parseSelectStyle()

MessagePattern& icu::MessagePattern::parseSelectStyle ( const UnicodeString pattern,
UParseError parseError,
UErrorCode errorCode 
)

Parses a SelectFormat pattern string.

Parameters
patterna SelectFormat pattern string
parseErrorStruct to receive information on the position of an error within the pattern. Can be NULL.
errorCodeStandard ICU error code. Its input value must pass the U_SUCCESS() test, or else the function returns immediately. Check for U_FAILURE() on output or use with function chaining. (See User Guide for details.)
Returns
*this
Exceptions
IllegalArgumentExceptionfor syntax errors in the pattern string
IndexOutOfBoundsExceptionif certain limits are exceeded (e.g., argument number too high, argument name too long, etc.)
NumberFormatExceptionif a number could not be parsed
Stable:
ICU 4.8

◆ partSubstringMatches()

UBool icu::MessagePattern::partSubstringMatches ( const Part part,
const UnicodeString s 
) const
inline

Compares the part's substring with the input string s.

Parameters
parta part of this MessagePattern.
sa string.
Returns
TRUE if getSubstring(part).equals(s).
Stable:
ICU 4.8

Definition at line 668 of file messagepattern.h.

◆ validateArgumentName()

static int32_t icu::MessagePattern::validateArgumentName ( const UnicodeString name)
static

Validates and parses an argument name or argument number string.

An argument name must be a "pattern identifier", that is, it must contain no Unicode Pattern_Syntax or Pattern_White_Space characters. If it only contains ASCII digits, then it must be a small integer with no leading zero.

Parameters
nameInput string.
Returns
>=0 if the name is a valid number, ARG_NAME_NOT_NUMBER (-1) if it is a "pattern identifier" but not all ASCII digits, ARG_NAME_NOT_VALID (-2) if it is neither.
Stable:
ICU 4.8

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