private void verifyRowsAndColumns(String rows, String columns)throws DimensionException {
        String[] valuesEntered = new String [2];
      
           valuesEntered[0] = rows;
           valuesEntered[1] = columns;
            

           // user java regular expression to check for valid integer number 
           // for both numbers
           String regExpressionPattern = ".*\\d.*";
           try{
                if (!valuesEntered[0].matches(regExpressionPattern) ||
                    !valuesEntered[1].matches(regExpressionPattern)) {
                    throw new DimensionException(ErrorType.ERROR102.getMessage());
                }

           int rowsEntered = Integer.parseInt(valuesEntered[0]);
           int columnsEntered = Integer.parseInt(valuesEntered[1]);
           
           if (rowsEntered < 6 || rowsEntered > 15) {
           throw new DimensionException(ErrorType.ERROR207.getMessage());
           }

           if (columnsEntered < 6 || columnsEntered > 15) {
               throw new DimensionException(ErrorType.ERROR207.getMessage());
           }
           }catch(DimensionException ex) {
               throw ex;
           }


    
    }