Class UnbufferedTokenStream

All Implemented Interfaces:
IntStream, TokenStream

public class UnbufferedTokenStream extends LookaheadStream<Token> implements TokenStream
A token stream that pulls tokens from the code source on-demand and without tracking a complete buffer of the tokens. This stream buffers the minimum number of tokens possible. It's the same as OnDemandTokenStream except that OnDemandTokenStream buffers all tokens. You can't use this stream if you pass whitespace or other off-channel tokens to the parser. The stream can't ignore off-channel tokens. You can only look backwards 1 token: LT(-1). Use this when you need to read from a socket or other infinite stream.
See Also:
  • Field Details

    • tokenSource

      protected TokenSource tokenSource
    • tokenIndex

      protected int tokenIndex
    • channel

      protected int channel
      Skip tokens on any channel but this one; this is how we skip whitespace...
  • Constructor Details

    • UnbufferedTokenStream

      public UnbufferedTokenStream(TokenSource tokenSource)
  • Method Details

    • nextElement

      public Token nextElement()
      Description copied from class: LookaheadStream
      Implement nextElement to supply a stream of elements to this lookahead buffer. Return EOF upon end of the stream we're pulling from.
      Specified by:
      nextElement in class LookaheadStream<Token>
      See Also:
    • isEOF

      public boolean isEOF(Token o)
      Specified by:
      isEOF in class LookaheadStream<Token>
    • getTokenSource

      public TokenSource getTokenSource()
      Description copied from interface: TokenStream
      Where is this stream pulling tokens from? This is not the name, but the object that provides Token objects.
      Specified by:
      getTokenSource in interface TokenStream
    • toString

      public String toString(int start, int stop)
      Description copied from interface: TokenStream
      Return the text of all tokens from start to stop, inclusive. If the stream does not buffer all the tokens then it can just return "" or null; Users should not access $ruleLabel.text in an action of course in that case.
      Specified by:
      toString in interface TokenStream
    • toString

      public String toString(Token start, Token stop)
      Description copied from interface: TokenStream
      Because the user is not required to use a token with an index stored in it, we must provide a means for two token objects themselves to indicate the start/end location. Most often this will just delegate to the other toString(int,int). This is also parallel with the TreeNodeStream.toString(Object,Object).
      Specified by:
      toString in interface TokenStream
    • LA

      public int LA(int i)
      Description copied from interface: IntStream
      Get int at current input pointer + i ahead where i=1 is next int. Negative indexes are allowed. LA(-1) is previous token (token just matched). LA(-i) where i is before first token should yield -1, invalid char / EOF.
      Specified by:
      LA in interface IntStream
    • get

      public Token get(int i)
      Description copied from interface: TokenStream
      Get a token at an absolute index i; 0..n-1. This is really only needed for profiling and debugging and token stream rewriting. If you don't want to buffer up tokens, then this method makes no sense for you. Naturally you can't use the rewrite stream feature. I believe DebugTokenStream can easily be altered to not use this method, removing the dependency.
      Specified by:
      get in interface TokenStream
    • getSourceName

      public String getSourceName()
      Description copied from interface: IntStream
      Where are you getting symbols from? Normally, implementations will pass the buck all the way to the lexer who can ask its input stream for the file name or whatever.
      Specified by:
      getSourceName in interface IntStream