org.codehaus.groovy.syntax
Class AbstractTokenStream

java.lang.Object
  org.codehaus.groovy.syntax.AbstractTokenStream

All Implemented Interfaces:

TokenStream

Direct Known Subclasses:

LexerTokenStream

public abstract class AbstractTokenStream

extends java.lang.Object

implements TokenStream

Provides the common code for TokenStream implementations.

Field Summary

private int	avail
private Token[]	buf
private int	checkpoint_avail
private int	checkpoint_first
private int	first
private java.lang.String	sourceLocator

Constructor Summary

AbstractTokenStream()
Default constructor.

AbstractTokenStream(java.lang.String sourceLocator)
Initializes the stream with information about the source.

Method Summary

boolean	atEnd() A synonym for atEnd(true).
boolean	atEnd(boolean ignoringWhitespace) Returns true if the stream is out of tokens.
void	checkpoint() Saves the look-ahead state for restore()ing later.
Token	consume() Removes and returns the first token in the stream, provided it isn't the EOF.
Token	consume(int type) Removes and returns the first token in the stream, provided it matches the specified type.
java.lang.String	getSourceLocator() Returns a description of the source (typically a file name).
Token	la() Returns the next token in the stream without consuming it.
Token	la(int k) Returns the kth token in the stream without consuming it (or any other unconsumed tokens).
protected abstract Token	nextToken() Implemented by concrete subtypes, provides access to the next token in the underlying stream.
void	restore() Restores the look-ahead state saved by checkpoint().

Methods inherited from class java.lang.Object

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

Field Detail

buf

private Token[] buf

first

private int first

avail

private int avail

checkpoint_first

private int checkpoint_first

checkpoint_avail

private int checkpoint_avail

sourceLocator

private java.lang.String sourceLocator

Constructor Detail

AbstractTokenStream

public AbstractTokenStream()

Default constructor.

AbstractTokenStream

public AbstractTokenStream(java.lang.String sourceLocator)

Initializes the stream with information about the source.

Method Detail

getSourceLocator

public java.lang.String getSourceLocator()

Returns a description of the source (typically a file name).

Specified by:

getSourceLocator in interface TokenStream

nextToken

protected abstract Token nextToken()
                            throws ReadException,
                                   SyntaxException

Implemented by concrete subtypes, provides access to the next token in the underlying stream.

Throws:

ReadException

SyntaxException

la

public Token la()
         throws ReadException,
                SyntaxException

Returns the next token in the stream without consuming it.

Specified by:

la in interface TokenStream

Returns:

The next token or null if no more tokens available.

Throws:

ReadException - If an error occurs attempting to lookahead a token.

SyntaxException

See Also:

TokenStream.la(int)

la

public Token la(int k)
         throws ReadException,
                SyntaxException

Returns the kth token in the stream without consuming it (or any other unconsumed tokens).

Specified by:

la in interface TokenStream

Parameters:

k - Number of token to look ahead.

Returns:

the kth token or null if no more tokens available.

Throws:

ReadException - If an error occurs attempting to lookahead a token.

SyntaxException

consume

public Token consume(int type)
              throws ReadException,
                     SyntaxException

Removes and returns the first token in the stream, provided it matches the specified type.

Specified by:

consume in interface TokenStream

Parameters:

type - The token type.

Returns:

The consumed token or null if no more tokens available.

Throws:

ReadException - If an error occurs attempting to consume a token.

SyntaxException

consume

public Token consume()
              throws ReadException,
                     SyntaxException

Removes and returns the first token in the stream, provided it isn't the EOF.

Throws:

ReadException

SyntaxException

checkpoint

public void checkpoint()

Saves the look-ahead state for restore()ing later.

Specified by:

checkpoint in interface TokenStream

restore

public void restore()

Restores the look-ahead state saved by checkpoint().

Specified by:

restore in interface TokenStream

atEnd

public boolean atEnd(boolean ignoringWhitespace)

Returns true if the stream is out of tokens.

Specified by:

atEnd in interface TokenStream

atEnd

public boolean atEnd()

A synonym for atEnd(true).

Specified by:

atEnd in interface TokenStream