antlr
Class TokenStreamSelector

java.lang.Object
  |
  +--antlr.TokenStreamSelector

All Implemented Interfaces:

TokenStream

public class TokenStreamSelector

extends Object

implements TokenStream

Untamed: A token stream MUX (multiplexor) knows about n token streams and can multiplex them onto the same channel for use by token stream consumer like a parser. This is a way to have multiple lexers break up the same input stream for a single parser. Or, you can have multiple instances of the same lexer handle multiple input streams; this works great for includes.

Field Summary

protected TokenStream	input The currently-selected token stream input
protected Hashtable	inputStreamNames The set of inputs to the MUX
protected Stack	streamStack Used to track stack of input streams

Constructor Summary

TokenStreamSelector()
Enabled:

Method Summary

void	addInputStream(TokenStream stream, String key) Enabled:
TokenStream	getCurrentStream() Enabled: Return the stream from tokens are being pulled at the moment.
TokenStream	getStream(String sname) Enabled:
Token	nextToken() Enabled:
TokenStream	pop() Enabled:
void	push(String sname) Enabled:
void	push(TokenStream stream) Enabled:
void	retry() Enabled: Abort recognition of current Token and try again.
void	select(String sname) Enabled:
void	select(TokenStream stream) Enabled: Set the stream without pushing old stream

Methods inherited from class java.lang.Object

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

Field Detail

inputStreamNames

protected Hashtable inputStreamNames

The set of inputs to the MUX

input

protected TokenStream input

The currently-selected token stream input

streamStack

protected Stack streamStack

Used to track stack of input streams

Constructor Detail

TokenStreamSelector

public TokenStreamSelector()

Enabled:

Method Detail

addInputStream

public void addInputStream(TokenStream stream,
                           String key)

Enabled:

getCurrentStream

public TokenStream getCurrentStream()

Enabled: Return the stream from tokens are being pulled at the moment.

getStream

public TokenStream getStream(String sname)

Enabled:

nextToken

public Token nextToken()
                throws TokenStreamException

Enabled:

Specified by:

nextToken in interface TokenStream

TokenStreamException

pop

public TokenStream pop()

Enabled:

push

public void push(TokenStream stream)

Enabled:

push

public void push(String sname)

Enabled:

retry

public void retry()
           throws TokenStreamRetryException

Enabled: Abort recognition of current Token and try again. A stream can push a new stream (for include files for example, and then retry(), which will cause the current stream to abort back to this.nextToken(). this.nextToken() then asks for a token from the current stream, which is the new "substream."

TokenStreamRetryException

select

public void select(TokenStream stream)

Enabled: Set the stream without pushing old stream

select

public void select(String sname)
            throws IllegalArgumentException

Enabled:

IllegalArgumentException