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 |
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8 | class StringLiteral implements ValueObjectInterface |
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9 | { |
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10 | protected $value; |
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11 | |||
12 | /** |
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13 | * Returns a StringLiteral object given a PHP native string as parameter. |
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14 | * |
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15 | * @param string $value |
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16 | * @return StringLiteral |
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17 | */ |
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18 | 1 | public static function fromNative() |
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24 | |||
25 | /** |
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26 | * Returns a StringLiteral object given a PHP native string as parameter. |
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27 | * |
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28 | * @param string $value |
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29 | */ |
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30 | 6 | public function __construct($value) |
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38 | |||
39 | /** |
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40 | * Returns the value of the string |
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41 | * |
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42 | * @return string |
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43 | */ |
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44 | 32 | public function toNative() |
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48 | |||
49 | /** |
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50 | * Tells whether two string literals are equal by comparing their values |
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51 | * |
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52 | * @param ValueObjectInterface $stringLiteral |
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53 | * @return bool |
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54 | */ |
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55 | 2 | View Code Duplication | public function sameValueAs(ValueObjectInterface $stringLiteral) |
63 | |||
64 | /** |
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65 | * Tells whether the StringLiteral is empty |
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66 | * |
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67 | * @return bool |
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68 | */ |
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69 | 1 | public function isEmpty() |
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73 | |||
74 | /** |
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75 | * Returns the string value itself |
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76 | * |
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77 | * @return string |
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78 | */ |
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79 | 1 | public function __toString() |
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83 | } |
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84 |
This check looks for PHPDoc comments describing methods or function parameters that do not exist on the corresponding method or function.
Consider the following example. The parameter
$italy
is not defined by the methodfinale(...)
.The most likely cause is that the parameter was removed, but the annotation was not.