Duplicate code is one of the most pungent code smells. A rule that is often used is to re-structure code once it is duplicated in three or more places.
Common duplication problems, and corresponding solutions are:
1 | <?php |
||
7 | class Accountant |
||
8 | { |
||
9 | /** |
||
10 | * @param Money $money1 |
||
11 | * @param Money $money2 |
||
12 | * @throws InvalidArgumentException |
||
13 | */ |
||
14 | 4 | protected function checkCurrenciesMatch(Money $money1, Money $money2) |
|
24 | |||
25 | /** |
||
26 | * $money1 + $money2 |
||
27 | * |
||
28 | * @param Money $money1 |
||
29 | * @param Money $money2 |
||
30 | * @return Money |
||
31 | */ |
||
32 | 3 | View Code Duplication | public function add(Money $money1, Money $money2) |
41 | |||
42 | /** |
||
43 | * $money1 - $money2 |
||
44 | * |
||
45 | * @param Money $money1 |
||
46 | * @param Money $money2 |
||
47 | * @return Money |
||
48 | */ |
||
49 | 1 | View Code Duplication | public function subtract(Money $money1, Money $money2) |
58 | |||
59 | /** |
||
60 | * $money * $fraction |
||
61 | * |
||
62 | * @param Money $money |
||
63 | * @param float|integer $fraction |
||
64 | * @return Money |
||
65 | */ |
||
66 | 1 | public function multiply(Money $money, $fraction) |
|
73 | |||
74 | /** |
||
75 | * $money / $fraction |
||
76 | * |
||
77 | * @param Money $money |
||
78 | * @param float|integer $fraction |
||
79 | * @return Money |
||
80 | */ |
||
81 | 1 | public function divide(Money $money, $fraction) |
|
88 | |||
89 | /** |
||
90 | * @param Money[] $monies |
||
91 | * @return Money|null |
||
92 | */ |
||
93 | 2 | public function sum(array $monies) |
|
113 | } |
||
114 |
Duplicated code is one of the most pungent code smells. If you need to duplicate the same code in three or more different places, we strongly encourage you to look into extracting the code into a single class or operation.
You can also find more detailed suggestions in the “Code” section of your repository.