org.antlr.v4.runtime

Class VocabularyImpl

java.lang.Object

org.antlr.v4.runtime.VocabularyImpl

All Implemented Interfaces:

Vocabulary

public class VocabularyImpl
extends Object
implements Vocabulary

This class provides a default implementation of the Vocabulary interface.

Author:

Sam Harwell

Field Summary

Fields

Modifier and Type	Field and Description
static VocabularyImpl	EMPTY_VOCABULARY Gets an empty Vocabulary instance.

Constructor Summary

Constructors

Constructor and Description
VocabularyImpl(String[] literalNames, String[] symbolicNames) Constructs a new instance of VocabularyImpl from the specified literal and symbolic token names.
VocabularyImpl(String[] literalNames, String[] symbolicNames, String[] displayNames) Constructs a new instance of VocabularyImpl from the specified literal, symbolic, and display token names.

Method Summary

Methods

Modifier and Type	Method and Description
static Vocabulary	fromTokenNames(String[] tokenNames) Returns a VocabularyImpl instance from the specified set of token names.
String	getDisplayName(int tokenType) Gets the display name of a token type.
String	getLiteralName(int tokenType) Gets the string literal associated with a token type.
int	getMaxTokenType() Returns the highest token type value.
String	getSymbolicName(int tokenType) Gets the symbolic name associated with a token type.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

EMPTY_VOCABULARY

public static final VocabularyImpl EMPTY_VOCABULARY

Gets an empty Vocabulary instance.

No literal or symbol names are assigned to token types, so getDisplayName(int) returns the numeric value for all tokens except Token.EOF.

Constructor Detail

VocabularyImpl

public VocabularyImpl(String[] literalNames,
              String[] symbolicNames)

Constructs a new instance of VocabularyImpl from the specified literal and symbolic token names.

Parameters:

literalNames - The literal names assigned to tokens, or null if no literal names are assigned.

symbolicNames - The symbolic names assigned to tokens, or null if no symbolic names are assigned.

See Also:

getLiteralName(int), getSymbolicName(int)

VocabularyImpl

public VocabularyImpl(String[] literalNames,
              String[] symbolicNames,
              String[] displayNames)

Constructs a new instance of VocabularyImpl from the specified literal, symbolic, and display token names.

Parameters:

literalNames - The literal names assigned to tokens, or null if no literal names are assigned.

symbolicNames - The symbolic names assigned to tokens, or null if no symbolic names are assigned.

displayNames - The display names assigned to tokens, or null to use the values in literalNames and symbolicNames as the source of display names, as described in getDisplayName(int).

See Also:

getLiteralName(int), getSymbolicName(int), getDisplayName(int)

Method Detail

fromTokenNames

public static Vocabulary fromTokenNames(String[] tokenNames)

Returns a VocabularyImpl instance from the specified set of token names. This method acts as a compatibility layer for the single tokenNames array generated by previous releases of ANTLR.

The resulting vocabulary instance returns null for getLiteralName(int) and getSymbolicName(int), and the value from tokenNames for the display names.

Parameters:

tokenNames - The token names, or null if no token names are available.

Returns:

A Vocabulary instance which uses tokenNames for the display names of tokens.

getMaxTokenType

public int getMaxTokenType()

Description copied from interface: Vocabulary

Returns the highest token type value. It can be used to iterate from zero to that number, inclusively, thus querying all stored entries.

Specified by:

getMaxTokenType in interface Vocabulary

Returns:

the highest token type value

getLiteralName

public String getLiteralName(int tokenType)

Description copied from interface: Vocabulary

Gets the string literal associated with a token type. The string returned by this method, when not null, can be used unaltered in a parser grammar to represent this token type.

The following table shows examples of lexer rules and the literal names assigned to the corresponding token types.

Rule	Literal Name	Java String Literal
THIS : 'this';	'this'	"'this'"
SQUOTE : '\'';	'\''	"'\\''"
ID : [A-Z]+;	n/a	null

Specified by:

getLiteralName in interface Vocabulary

Parameters:

tokenType - The token type.

Returns:

The string literal associated with the specified token type, or null if no string literal is associated with the type.

getSymbolicName

public String getSymbolicName(int tokenType)

Description copied from interface: Vocabulary

Gets the symbolic name associated with a token type. The string returned by this method, when not null, can be used unaltered in a parser grammar to represent this token type.

This method supports token types defined by any of the following methods:

• Tokens created by lexer rules.
• Tokens defined in a tokens{} block in a lexer or parser grammar.
• The implicitly defined EOF token, which has the token type Token.EOF.

The following table shows examples of lexer rules and the literal names assigned to the corresponding token types.

Rule	Symbolic Name
THIS : 'this';	THIS
SQUOTE : '\'';	SQUOTE
ID : [A-Z]+;	ID

Specified by:

getSymbolicName in interface Vocabulary

Parameters:

tokenType - The token type.

Returns:

The symbolic name associated with the specified token type, or null if no symbolic name is associated with the type.

getDisplayName

public String getDisplayName(int tokenType)

Description copied from interface: Vocabulary

Gets the display name of a token type.

ANTLR provides a default implementation of this method, but applications are free to override the behavior in any manner which makes sense for the application. The default implementation returns the first result from the following list which produces a non-null result.

1. The result of Vocabulary.getLiteralName(int)
2. The result of Vocabulary.getSymbolicName(int)
3. The result of Integer.toString(int, int)

Specified by:

getDisplayName in interface Vocabulary

Parameters:

tokenType - The token type.

Returns:

The display name of the token type, for use in error reporting or other user-visible messages which reference specific token types.