code: private static List<String> expandRange(String expression) throws IllegalArgumentException {
  		int first = 0;
  		int last = 0;
  		try {
  			String[] range = expression.split("-");
  			first = Integer.parseInt(range[0]);
  			last = Integer.parseInt(range[1]);
  		} catch (Exception e) {
  			throw new IllegalArgumentException("Invalid range specification in oper_expression: " + expression);
  		}
  
  		List<String> expandedExpression = new ArrayList<String>(last-first+1);
  		for (int i = first; i <= last; i++) {
  			expandedExpression.add(String.valueOf(i));
  		}
  		return expandedExpression;
  	}
docs: Expands a range expression, i.e. (1-6) to a list 1,2,3,4,5,6
  @param expression the expression to be expanded
  @return list of items in range
  @throws IllegalArgumentException