Category

Development Platform
Home > SourceCode/Document > Compiler program > View Code
TokenStreamBasicFilter.java
Package: antlr-2_7_0.zip　[view]
Upload User: afrynkmhm
Upload Date: 2007-01-06
Package Size: 1262k
Code Size: 1k
Category:

Compiler program

Development Platform:

Others

TokenStreamBasicFilter.java：Code Content
  1. package antlr;
  3. /* ANTLR Translator Generator
  4.  * Project led by Terence Parr at http://www.jGuru.com
  5.  * Software rights: http://www.antlr.org/RIGHTS.html
  6.  *
  7.  * $Id: //depot/code/org.antlr/release/antlr-2.7.0/antlr/TokenStreamBasicFilter.java#1 $
  8.  */
  10. import antlr.collections.impl.BitSet;
  12. /** This object is a TokenStream that passes through all
  13.  *  tokens except for those that you tell it to discard.
  14.  *  There is no buffering of the tokens.
  15.  */
  16. public class TokenStreamBasicFilter implements TokenStream {
  17.     /** The set of token types to discard */
  18.     protected BitSet discardMask;
  20.     /** The input stream */
  21.     protected TokenStream input;
  23.     public TokenStreamBasicFilter(TokenStream input) {
  24. this.input = input;
  25. discardMask = new BitSet();
  26.     }
  27.     public void discard(int ttype) {
  28. discardMask.add(ttype);
  29.     }
  30.     public void discard(BitSet mask) {
  31. discardMask = mask;
  32.     }
  33.     public Token nextToken() throws TokenStreamException {
  34. Token tok = input.nextToken();
  35. while ( tok!=null && discardMask.member(tok.getType()) ) {
  36.     tok = input.nextToken();
  37. }
  38. return tok;
  39.     }
  40. }