MessagePattern

java.lang.Object
- ohos.global.icu.text.MessagePattern

所有已实现的接口:

Cloneable, Freezable<MessagePattern>
```
public final class MessagePattern
extends Object
implements Cloneable, Freezable<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.

嵌套类概要

嵌套类
限定符和类型	类	说明
`static class`	`MessagePattern.ApostropheMode`	Mode for when an apostrophe starts quoted literal text for MessageFormat output.
`static class`	`MessagePattern.ArgType`	Argument type constants.
`static class`	`MessagePattern.Part`	A message pattern "part", representing a pattern parsing event.

字段概要

字段
限定符和类型	字段	说明
`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.

构造器概要

构造器
构造器	说明
`MessagePattern()`	Constructs an empty MessagePattern with default ApostropheMode.
`MessagePattern(String pattern)`	Constructs a MessagePattern with default ApostropheMode and parses the MessageFormat pattern string.
`MessagePattern(MessagePattern.ApostropheMode mode)`	Constructs an empty MessagePattern.

方法概要

所有方法静态方法实例方法具体方法
限定符和类型	方法	说明
`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.
`void`	`clear()`	Clears this MessagePattern.
`void`	`clearPatternAndSetApostropheMode(MessagePattern.ApostropheMode mode)`	Clears this MessagePattern and sets the ApostropheMode.
`Object`	`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(Object other)`	Indicates whether some other object is "equal to" this one.
`MessagePattern`	`freeze()`	Freezes this object, making it immutable and thread-safe.
`MessagePattern.ApostropheMode`	`getApostropheMode()`
`int`	`getLimitPartIndex(int start)`	Returns the index of the ARG\|MSG_LIMIT part corresponding to the ARG\|MSG_START at start.
`double`	`getNumericValue(MessagePattern.Part part)`	Returns the numeric value associated with an ARG_INT or ARG_DOUBLE.
`MessagePattern.Part`	`getPart(int i)`	Gets the i-th pattern "part".
`MessagePattern.Part.Type`	`getPartType(int i)`	Returns the Part.Type of the i-th pattern "part".
`int`	`getPatternIndex(int partIndex)`	Returns the pattern index of the specified pattern "part".
`String`	`getPatternString()`
`double`	`getPluralOffset(int pluralStart)`	Returns the "offset:" value of a PluralFormat argument, or 0 if none is specified.
`String`	`getSubstring(MessagePattern.Part part)`	Returns the substring of the pattern string indicated by the Part.
`int`	`hashCode()`	Returns a hash code value for the object.
`boolean`	`hasNamedArguments()`	Does the parsed pattern have named arguments like {first_name}?
`boolean`	`hasNumberedArguments()`	Does the parsed pattern have numbered arguments like {2}?
`boolean`	`isFrozen()`	Determines whether this object is frozen (immutable) or not.
`MessagePattern`	`parse(String pattern)`	Parses a MessageFormat pattern string.
`MessagePattern`	`parseChoiceStyle(String pattern)`	Parses a ChoiceFormat pattern string.
`MessagePattern`	`parsePluralStyle(String pattern)`	Parses a PluralFormat pattern string.
`MessagePattern`	`parseSelectStyle(String pattern)`	Parses a SelectFormat pattern string.
`boolean`	`partSubstringMatches(MessagePattern.Part part, String s)`	Compares the part's substring with the input string s.
`String`	`toString()`	Returns a string representation of the object.
`static int`	`validateArgumentName(String name)`	Validates and parses an argument name or argument number string.

从类继承的方法 java.lang.Object
finalize, getClass, notify, notifyAll, wait, wait, wait

- 字段详细资料
  - ARG_NAME_NOT_NUMBER
```
public static final 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.
    
    另请参阅:
    
    常量字段值
  - ARG_NAME_NOT_VALID
```
public static final int ARG_NAME_NOT_VALID
```
    Return value from validateArgumentName(java.lang.String) for when the string is invalid. It might not be a valid "pattern identifier", or it have only ASCII digits but there is a leading zero or the number is too large.
    
    另请参阅:
    
    常量字段值
  - NO_NUMERIC_VALUE
```
public static final double NO_NUMERIC_VALUE
```
    Special value that is returned by getNumericValue(Part) when no numeric value is defined for a part.
    
    另请参阅:
    
    getNumericValue(ohos.global.icu.text.MessagePattern.Part), 常量字段值
- 构造器详细资料
  - MessagePattern
```
public MessagePattern()
```
    Constructs an empty MessagePattern with default ApostropheMode.
  - MessagePattern
```
public MessagePattern(MessagePattern.ApostropheMode mode)
```
    Constructs an empty MessagePattern.
    
    参数:
    
    mode - Explicit ApostropheMode.
  - MessagePattern
```
public MessagePattern(String pattern)
```
    Constructs a MessagePattern with default ApostropheMode and parses the MessageFormat pattern string.
    
    参数:
    
    pattern - a MessageFormat pattern string
    
    抛出:
    
    IllegalArgumentException - for syntax errors in the pattern string
    
    IndexOutOfBoundsException - if certain limits are exceeded (e.g., argument number too high, argument name too long, etc.)
    
    NumberFormatException - if a number could not be parsed
- 方法详细资料
  - parse
```
public MessagePattern parse(String pattern)
```
    Parses a MessageFormat pattern string.
    
    参数:
    
    pattern - a MessageFormat pattern string
    
    返回:
    
    this
    
    抛出:
    
    IllegalArgumentException - for syntax errors in the pattern string
    
    IndexOutOfBoundsException - if certain limits are exceeded (e.g., argument number too high, argument name too long, etc.)
    
    NumberFormatException - if a number could not be parsed
  - parseChoiceStyle
```
public MessagePattern parseChoiceStyle(String pattern)
```
    Parses a ChoiceFormat pattern string.
    
    参数:
    
    pattern - a ChoiceFormat pattern string
    
    返回:
    
    this
    
    抛出:
    
    IllegalArgumentException - for syntax errors in the pattern string
    
    IndexOutOfBoundsException - if certain limits are exceeded (e.g., argument number too high, argument name too long, etc.)
    
    NumberFormatException - if a number could not be parsed
  - parsePluralStyle
```
public MessagePattern parsePluralStyle(String pattern)
```
    Parses a PluralFormat pattern string.
    
    参数:
    
    pattern - a PluralFormat pattern string
    
    返回:
    
    this
    
    抛出:
    
    IllegalArgumentException - for syntax errors in the pattern string
    
    IndexOutOfBoundsException - if certain limits are exceeded (e.g., argument number too high, argument name too long, etc.)
    
    NumberFormatException - if a number could not be parsed
  - parseSelectStyle
```
public MessagePattern parseSelectStyle(String pattern)
```
    Parses a SelectFormat pattern string.
    
    参数:
    
    pattern - a SelectFormat pattern string
    
    返回:
    
    this
    
    抛出:
    
    IllegalArgumentException - for syntax errors in the pattern string
    
    IndexOutOfBoundsException - if certain limits are exceeded (e.g., argument number too high, argument name too long, etc.)
    
    NumberFormatException - if a number could not be parsed
  - clear
```
public void clear()
```
    Clears this MessagePattern. countParts() will return 0.
  - clearPatternAndSetApostropheMode
```
public void clearPatternAndSetApostropheMode(MessagePattern.ApostropheMode mode)
```
    Clears this MessagePattern and sets the ApostropheMode. countParts() will return 0.
    
    参数:
    
    mode - The new ApostropheMode.
  - equals
```
public boolean equals(Object other)
```
    从类复制的说明: Object
    Indicates whether some other object is "equal to" this one.
    The equals method implements an equivalence relation on non-null object references:
    - It is reflexive: for any non-null reference value x, x.equals(x) should return true.
    - It is symmetric: for any non-null reference values x and y, x.equals(y) should return true if and only if y.equals(x) returns true.
    - It is transitive: for any non-null reference values x, y, and z, if x.equals(y) returns true and y.equals(z) returns true, then x.equals(z) should return true.
    - It is consistent: for any non-null reference values 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.
    - For any non-null reference value 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.
    覆盖:
    
    equals 在类中 Object
    
    参数:
    
    other - another object to compare with.
    
    返回:
    
    true if this object is equivalent to the other one.
    
    另请参阅:
    
    Object.hashCode(), HashMap
  - hashCode
```
public 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:
    - Whenever it is invoked on the same object more than once during an execution of a Java application, the 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.
    - If two objects are equal according to the equals(Object) method, then calling the hashCode method on each of the two objects must produce the same integer result.
    - It is not required that if two objects are unequal according to the Object.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 Java™ programming language.)
    覆盖:
    
    hashCode 在类中 Object
    
    返回:
    
    a hash code value for this object.
    
    另请参阅:
    
    Object.equals(java.lang.Object), System.identityHashCode(java.lang.Object)
  - getApostropheMode
```
public MessagePattern.ApostropheMode getApostropheMode()
```
    返回:
    
    this instance's ApostropheMode.
  - getPatternString
```
public String getPatternString()
```
    返回:
    
    the parsed pattern string (null if none was parsed).
  - hasNamedArguments
```
public boolean hasNamedArguments()
```
    Does the parsed pattern have named arguments like {first_name}?
    
    返回:
    
    true if the parsed pattern has at least one named argument.
  - hasNumberedArguments
```
public boolean hasNumberedArguments()
```
    Does the parsed pattern have numbered arguments like {2}?
    
    返回:
    
    true if the parsed pattern has at least one numbered argument.
  - toString
```
public 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())
    覆盖:
    
    toString 在类中 Object
    
    返回:
    
    a string representation of the object.
  - validateArgumentName
```
public static int validateArgumentName(String name)
```
    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.
    
    参数:
    
    name - Input string.
    
    返回:
    
    >=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.
  - autoQuoteApostropheDeep
```
public 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.
    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}}."
    
    返回:
    
    the deep-auto-quoted version of the parsed pattern string.
    
    另请参阅:
    
    MessageFormat.autoQuoteApostrophe(String)
  - countParts
```
public int countParts()
```
    Returns the number of "parts" created by parsing the pattern string. Returns 0 if no pattern has been parsed or clear() was called.
    
    返回:
    
    the number of pattern parts.
  - getPart
```
public MessagePattern.Part getPart(int i)
```
    Gets the i-th pattern "part".
    
    参数:
    
    i - The index of the Part data. (0..countParts()-1)
    
    返回:
    
    the i-th pattern "part".
    
    抛出:
    
    IndexOutOfBoundsException - if i is outside the (0..countParts()-1) range
  - getPartType
```
public MessagePattern.Part.Type getPartType(int i)
```
    Returns the Part.Type of the i-th pattern "part". Convenience method for getPart(i).getType().
    
    参数:
    
    i - The index of the Part data. (0..countParts()-1)
    
    返回:
    
    The Part.Type of the i-th Part.
    
    抛出:
    
    IndexOutOfBoundsException - if i is outside the (0..countParts()-1) range
  - getPatternIndex
```
public int getPatternIndex(int partIndex)
```
    Returns the pattern index of the specified pattern "part". Convenience method for getPart(partIndex).getIndex().
    
    参数:
    
    partIndex - The index of the Part data. (0..countParts()-1)
    
    返回:
    
    The pattern index of this Part.
    
    抛出:
    
    IndexOutOfBoundsException - if partIndex is outside the (0..countParts()-1) range
  - getSubstring
```
public String getSubstring(MessagePattern.Part part)
```
    Returns the substring of the pattern string indicated by the Part. Convenience method for getPatternString().substring(part.getIndex(), part.getLimit()).
    
    参数:
    
    part - a part of this MessagePattern.
    
    返回:
    
    the substring associated with part.
  - partSubstringMatches
```
public boolean partSubstringMatches(MessagePattern.Part part,
                                    String s)
```
    Compares the part's substring with the input string s.
    
    参数:
    
    part - a part of this MessagePattern.
    
    s - a string.
    
    返回:
    
    true if getSubstring(part).equals(s).
  - getNumericValue
```
public double getNumericValue(MessagePattern.Part part)
```
    Returns the numeric value associated with an ARG_INT or ARG_DOUBLE.
    
    参数:
    
    part - a part of this MessagePattern.
    
    返回:
    
    the part's numeric value, or NO_NUMERIC_VALUE if this is not a numeric part.
  - getPluralOffset
```
public double getPluralOffset(int pluralStart)
```
    Returns the "offset:" value of a PluralFormat argument, or 0 if none is specified.
    
    参数:
    
    pluralStart - the index of the first PluralFormat argument style part. (0..countParts()-1)
    
    返回:
    
    the "offset:" value.
    
    抛出:
    
    IndexOutOfBoundsException - if pluralStart is outside the (0..countParts()-1) range
  - getLimitPartIndex
```
public int getLimitPartIndex(int start)
```
    Returns the index of the ARG|MSG_LIMIT part corresponding to the ARG|MSG_START at start.
    
    参数:
    
    start - The index of some Part data (0..countParts()-1); this Part should be of Type ARG_START or MSG_START.
    
    返回:
    
    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.
    
    抛出:
    
    IndexOutOfBoundsException - if start is outside the (0..countParts()-1) range
  - clone
```
public Object clone()
```
    Creates and returns a copy of this object.
    
    覆盖:
    
    clone 在类中 Object
    
    返回:
    
    a copy of this object (or itself if frozen).
    
    另请参阅:
    
    Cloneable
  - cloneAsThawed
```
public MessagePattern cloneAsThawed()
```
    Creates and returns an unfrozen copy of this object.
    
    指定者:
    
    cloneAsThawed 在接口中 Freezable<MessagePattern>
    
    返回:
    
    a copy of this object.
  - freeze
```
public MessagePattern freeze()
```
    Freezes this object, making it immutable and thread-safe.
    
    指定者:
    
    freeze 在接口中 Freezable<MessagePattern>
    
    返回:
    
    this
  - isFrozen
```
public boolean isFrozen()
```
    Determines whether this object is frozen (immutable) or not.
    
    指定者:
    
    isFrozen 在接口中 Freezable<MessagePattern>
    
    返回:
    
    true if this object is frozen.

类 MessagePattern

嵌套类概要

字段概要

构造器概要

方法概要

从类继承的方法 java.lang.Object

字段详细资料

ARG_NAME_NOT_NUMBER

ARG_NAME_NOT_VALID

NO_NUMERIC_VALUE

构造器详细资料

MessagePattern

MessagePattern

MessagePattern

方法详细资料

parse

parseChoiceStyle

parsePluralStyle

parseSelectStyle

clear

clearPatternAndSetApostropheMode

equals

hashCode

getApostropheMode

getPatternString

hasNamedArguments

hasNumberedArguments

toString

validateArgumentName

autoQuoteApostropheDeep

countParts

getPart

getPartType

getPatternIndex

getSubstring

partSubstringMatches

getNumericValue

getPluralOffset

getLimitPartIndex

clone

cloneAsThawed

freeze

isFrozen