public RuleCharacterIterator(String text,SymbolTable sym,ParsePosition pos){
  if (text == null || pos.getIndex() > text.length()) {
    throw new IllegalArgumentException();
  }
  this.text=text;
  this.sym=sym;
  this.pos=pos;
  buf=null;
}

public RuleCharacterIterator ( String text , SymbolTable sym , ParsePosition pos ) { if ( text == null || pos . getIndex ( ) > text . length ( ) ) { throw new IllegalArgumentException ( ) ; } this . text = text ; this . sym = sym ; this . pos = pos ; buf = null ; }
constructs an iterator over the given text , starting at the given position .
