@Override public void agg(Object newVal){
  valueSet.add(newVal instanceof BigDecimal ? (BigDecimal)newVal : new BigDecimal(newVal.toString()));
  firstTime=false;
}

@ Override public void agg ( Object newVal ) { valueSet . add ( newVal instanceof BigDecimal ? ( BigDecimal ) newVal : new BigDecimal ( newVal . toString ( ) ) ) ; firstTime = false ; }
distinct aggregate function which update the distinct set
