Package antlr

Class TokenStreamHiddenTokenFilter

java.lang.Object

antlr.TokenStreamBasicFilter

antlr.TokenStreamHiddenTokenFilter

All Implemented Interfaces:

IASDebugStream, TokenStream

public class TokenStreamHiddenTokenFilter
extends TokenStreamBasicFilter
implements TokenStream

This object filters a token stream coming from a lexer or another TokenStream so that only certain token channels get transmitted to the parser. Any of the channels can be filtered off as "hidden" channels whose tokens can be accessed from the parser.

Field Summary

Fields

Modifier and Type	Field	Description
protected CommonHiddenStreamToken	firstHidden
protected BitSet	hideMask
protected CommonHiddenStreamToken	lastHiddenToken	track tail of hidden list emanating from previous monitored token
protected CommonHiddenStreamToken	nextMonitoredToken

Fields inherited from class antlr.TokenStreamBasicFilter

discardMask, input

Constructor Summary

Constructors

Constructor	Description
TokenStreamHiddenTokenFilter(TokenStream input)

Method Summary

Modifier and Type	Method	Description
protected void	consume()
BitSet	getDiscardMask()
CommonHiddenStreamToken	getHiddenAfter(CommonHiddenStreamToken t)	Return a ptr to the hidden token appearing immediately after token t in the input stream.
CommonHiddenStreamToken	getHiddenBefore(CommonHiddenStreamToken t)	Return a ptr to the hidden token appearing immediately before token t in the input stream.
BitSet	getHideMask()
CommonHiddenStreamToken	getInitialHiddenToken()	Return the first hidden token if one appears before any monitored token.
void	hide(int m)
void	hide(BitSet mask)
protected CommonHiddenStreamToken	LA(int i)
Token	nextToken()	Return the next monitored token.

Methods inherited from class antlr.TokenStreamBasicFilter

discard, discard, getEntireText, getOffsetInfo

Methods inherited from class java.lang.Object

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

Field Details

hideMask

protected BitSet hideMask

nextMonitoredToken

protected CommonHiddenStreamToken nextMonitoredToken

lastHiddenToken

protected CommonHiddenStreamToken lastHiddenToken

track tail of hidden list emanating from previous monitored token

firstHidden

protected CommonHiddenStreamToken firstHidden

Constructor Details

TokenStreamHiddenTokenFilter

public TokenStreamHiddenTokenFilter(TokenStream input)

Method Details

consume

protected void consume()
                throws TokenStreamException

Throws:

TokenStreamException

getDiscardMask

public BitSet getDiscardMask()

getHiddenAfter

public CommonHiddenStreamToken getHiddenAfter(CommonHiddenStreamToken t)

Return a ptr to the hidden token appearing immediately after token t in the input stream.

getHiddenBefore

public CommonHiddenStreamToken getHiddenBefore(CommonHiddenStreamToken t)

Return a ptr to the hidden token appearing immediately before token t in the input stream.

getHideMask

public BitSet getHideMask()

getInitialHiddenToken

public CommonHiddenStreamToken getInitialHiddenToken()

Return the first hidden token if one appears before any monitored token.

hide

public void hide(int m)

hide

public void hide(BitSet mask)

LA

protected CommonHiddenStreamToken LA(int i)

nextToken

public Token nextToken()
                throws TokenStreamException

Return the next monitored token. Test the token following the monitored token. If following is another monitored token, save it for the next invocation of nextToken (like a single lookahead token) and return it then. If following is unmonitored, nondiscarded (hidden) channel token, add it to the monitored token. Note: EOF must be a monitored Token.

Specified by:

nextToken in interface TokenStream

Overrides:

nextToken in class TokenStreamBasicFilter

Throws:

TokenStreamException