Class CommonTokenStream

java.lang.Object
org.antlr.runtime.BufferedTokenStream
org.antlr.runtime.CommonTokenStream
All Implemented Interfaces:
IntStream, TokenStream
Direct Known Subclasses:
TokenRewriteStream
public class CommonTokenStream extends BufferedTokenStream
The most common stream of tokens where every token is buffered up and tokens are filtered for a certain channel (the parser will only see these tokens). Even though it buffers all of the tokens, this token stream pulls tokens from the tokens source on demand. In other words, until you ask for a token using consume(), LT(), etc. the stream does not pull from the lexer. The only difference between this stream and BufferedTokenStream superclass is that this stream knows how to ignore off channel tokens. There may be a performance advantage to using the superclass if you don't pass whitespace and comments etc. to the parser on a hidden channel (i.e., you set $channel instead of calling skip() in lexer rules.)
See Also:

  • Field Details

    • channel

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

  • Constructor Details

    • CommonTokenStream

      public CommonTokenStream()

    • CommonTokenStream

      public CommonTokenStream(TokenSource tokenSource)

    • CommonTokenStream

      public CommonTokenStream(TokenSource tokenSource, int channel)

  • Method Details

    • consume

      public void consume()
      Always leave p on an on-channel token.
      Specified by:
      consume in interface IntStream
      Overrides:
      consume in class BufferedTokenStream

    • LB

      protected Token LB(int k)
      Overrides:
      LB in class BufferedTokenStream

    • LT

      public Token LT(int k)
      Description copied from interface: TokenStream
      Get Token at current input pointer + i ahead where i=1 is next Token. i<0 indicates tokens in the past. So -1 is previous token and -2 is two tokens ago. LT(0) is undefined. For i>=n, return Token.EOFToken. Return null for LT(0) and any index that results in an absolute address that is negative.
      Specified by:
      LT in interface TokenStream
      Overrides:
      LT in class BufferedTokenStream

    • skipOffTokenChannels

      protected int skipOffTokenChannels(int i)
      Given a starting index, return the index of the first on-channel token.

    • skipOffTokenChannelsReverse

      protected int skipOffTokenChannelsReverse(int i)

    • reset

      public void reset()
      Overrides:
      reset in class BufferedTokenStream

    • setup

      protected void setup()
      Overrides:
      setup in class BufferedTokenStream

    • getNumberOfOnChannelTokens

      public int getNumberOfOnChannelTokens()
      Count EOF just once.

    • setTokenSource

      public void setTokenSource(TokenSource tokenSource)
      Reset this token stream by setting its token source.
      Overrides:
      setTokenSource in class BufferedTokenStream