code: public void setDriverKeyInfo(FieldList keys, boolean[] sortOrder, int id) {
  		if(id < 0 || id >= driverKeys.length) {
  			throw new CompilerException("Invalid id for driver key information. DriverStrategy requires only "
  											+super.getDriverStrategy().getNumRequiredComparators()+" comparators.");
  		}
  		this.driverKeys[id] = keys;
  		this.driverSortOrders[id] = sortOrder;
  	}
docs: Sets the key field information for the specified driver comparator.
  
  @param keys The key field indexes for the specified driver comparator.
  @param sortOrder The key sort order for the specified driver comparator.
  @param id The ID of the driver comparator.