10th Day of Refactoring: extracting Methods (Extract method)

understand : Often write code, there are some computational logic more complex methods, write down a very long and long method, we can put this method, according to the function, decomposition into a few small methods alone. This will not only increase the maintainability of the code, but also increase legibility.

Detailed :

Refactoring Pre-code:

1  Public classReceipt2     {3         Privateilist<decimal> Discounts {Get;Set; }4         Privateilist<decimal> itemtotals {Get;Set; }5 6          Public decimalcalculategrandtotal ()7         {8             decimalSubTotal =0m;9             foreach(decimalItemtotalinchitemtotals)TenSubTotal + =itemtotal; One  A             if(Discounts.count >0) -             { -                 foreach(decimalDiscountinchdiscounts) theSubTotal-=discount; -             } -  -             decimalTax = SubTotal *0.065m; +  -SubTotal + =Tax ; +  A             returnsubTotal; at         } -}

We see the Calculategrandtotal method, which uses 2 foreach loops, to see, it is really inappropriate to understand, do not know what each foreach mainly do.

Look at the refactoring code:

1  Public classReceipt2     {3         Privateilist<decimal> Discounts {Get;Set; }4         Privateilist<decimal> itemtotals {Get;Set; }5 6          Public decimalcalculategrandtotal ()7         {8             decimalSubTotal =calculatesubtotal ();9 TenSubTotal =calculatediscounts (subTotal); One  ASubTotal =Calculatetax (subTotal); -  -             returnsubTotal; the         } -  -         Private decimalCalculatetax (decimalsubTotal) -         { +             decimalTax = SubTotal *0.065m; -  +SubTotal + =Tax ; A             returnsubTotal; at         } -  -         Private decimalCalculatediscounts (decimalsubTotal) -         { -             if(Discounts.count >0) -             { in                 foreach(decimalDiscountinchdiscounts) -SubTotal-=discount; to             } +             returnsubTotal; -         } the  *         Private decimalcalculatesubtotal () $         {Panax Notoginseng             decimalSubTotal =0m; -             foreach(decimalItemtotalinchitemtotals) theSubTotal + =itemtotal; +             returnsubTotal; A         } the}

After refactoring, we decompose the Calculategrandtotal method into 3 small methods, each named according to its function. Calculatetax as the name implies, is to calculate tax, calculatediscounts is calculate discount amount.

This makes it clear that the logic is stripped away.

10th Day of Refactoring: extracting Methods (Extract method)