MessagePattern

Kotlin |Java

class MessagePattern : Cloneable, Freezable<MessagePattern!>

kotlin.Any
↳	android.icu.text.MessagePattern

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", getLimitPartIndex(int) 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)+

Literal output text is not represented directly by "parts" but accessed between parts of a message, from one part's getLimit() to the next part's getIndex().
ARG_START.CHOICE stands for an ARG_START Part with ArgType CHOICE.
In the choiceStyle, the ARG_SELECTOR has the '<', the '#' or the less-than-or-equal-to sign (U+2264).
In the pluralStyle, the first, optional numeric Part has the "offset:" value. The optional numeric Part between each (ARG_SELECTOR, message) pair is the value of an explicit-number selector like "=2", otherwise the selector is a non-numeric identifier.
The REPLACE_NUMBER Part can occur only in an immediate sub-message of the pluralStyle.

This class is not intended for public subclassing.

Summary

Nested classes
	`ApostropheMode` Mode for when an apostrophe starts quoted literal text for MessageFormat output.
	`ArgType` Argument type constants.
	`Part` A message pattern "part", representing a pattern parsing event.

Constants
static Int	`ARG_NAME_NOT_NUMBER` Return value from `validateArgumentName(java.lang.String)` for when the string is a valid "pattern identifier" but not a number.
static Int	`ARG_NAME_NOT_VALID` Return value from `validateArgumentName(java.lang.String)` for when the string is invalid.
static Double	`NO_NUMERIC_VALUE` Special value that is returned by getNumericValue(Part) when no numeric value is defined for a part.

Public constructors
`MessagePattern()` Constructs an empty MessagePattern with default ApostropheMode.
`MessagePattern(mode: MessagePattern.ApostropheMode!)` Constructs an empty MessagePattern.
`MessagePattern(pattern: String!)` Constructs a MessagePattern with default ApostropheMode and parses the MessageFormat pattern string.

Public methods
String!	`autoQuoteApostropheDeep()` 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.
Unit	`clear()` Clears this MessagePattern.
Unit	`clearPatternAndSetApostropheMode(mode: MessagePattern.ApostropheMode!)` Clears this MessagePattern and sets the ApostropheMode.
Any	`clone()` Creates and returns a copy of this object.
MessagePattern!	`cloneAsThawed()` Creates and returns an unfrozen copy of this object.
Int	`countParts()` Returns the number of "parts" created by parsing the pattern string.
Boolean	`equals(other: Any?)`
MessagePattern!	`freeze()` Freezes this object, making it immutable and thread-safe.
MessagePattern.ApostropheMode!	`getApostropheMode()`
Int	`getLimitPartIndex(start: Int)` Returns the index of the ARG\|MSG_LIMIT part corresponding to the ARG\|MSG_START at start.
Double	`getNumericValue(part: MessagePattern.Part!)` Returns the numeric value associated with an ARG_INT or ARG_DOUBLE.
MessagePattern.Part!	`getPart(i: Int)` Gets the i-th pattern "part".
MessagePattern.Part.Type!	`getPartType(i: Int)` Returns the Part.
Int	`getPatternIndex(partIndex: Int)` Returns the pattern index of the specified pattern "part".
String!	`getPatternString()`
Double	`getPluralOffset(pluralStart: Int)` Returns the "offset:" value of a PluralFormat argument, or 0 if none is specified.
String!	`getSubstring(part: MessagePattern.Part!)` Returns the substring of the pattern string indicated by the Part.
Boolean	`hasNamedArguments()` Does the parsed pattern have named arguments like {first_name}?
Boolean	`hasNumberedArguments()` Does the parsed pattern have numbered arguments like {2}?
Int	`hashCode()` Returns a hash code value for the object.
Boolean	`isFrozen()` Determines whether this object is frozen (immutable) or not.
MessagePattern!	`parse(pattern: String!)` Parses a MessageFormat pattern string.
MessagePattern!	`parseChoiceStyle(pattern: String!)` Parses a ChoiceFormat pattern string.
MessagePattern!	`parsePluralStyle(pattern: String!)` Parses a PluralFormat pattern string.
MessagePattern!	`parseSelectStyle(pattern: String!)` Parses a SelectFormat pattern string.
Boolean	`partSubstringMatches(part: MessagePattern.Part!, s: String!)` Compares the part's substring with the input string s.
String	`toString()` Returns a string representation of the object.
static Int	`validateArgumentName(name: String!)` Validates and parses an argument name or argument number string.

Exceptions
`java.lang.IllegalArgumentException`	for syntax errors in the pattern string
`java.lang.IndexOutOfBoundsException`	if certain limits are exceeded (e.g., argument number too high, argument name too long, etc.)
`java.lang.NumberFormatException`	if a number could not be parsed

Parameters
`obj`	the reference object with which to compare.
`other`	Any?: another object to compare with.

Parameters
`part`	MessagePattern.Part!: a part of this MessagePattern.
`s`	String!: a string.

MessagePattern

Summary

Constants

ARG_NAME_NOT_NUMBER

ARG_NAME_NOT_VALID

NO_NUMERIC_VALUE

Public constructors

MessagePattern

MessagePattern

MessagePattern

Public methods

autoQuoteApostropheDeep

clear

clearPatternAndSetApostropheMode

clone

cloneAsThawed

countParts

equals

freeze

getApostropheMode

getLimitPartIndex

getNumericValue

getPart

getPartType

getPatternIndex

getPatternString

getPluralOffset

getSubstring

hasNamedArguments

hasNumberedArguments

hashCode

isFrozen

parse

parseChoiceStyle

parsePluralStyle

parseSelectStyle

partSubstringMatches

toString

validateArgumentName