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 | trait ModifiesLabels |
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9 | { |
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10 | |||
11 | public function __construct() |
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15 | |||
16 | /** |
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17 | * @param array $labels |
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18 | * |
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19 | * @return Mail|string |
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20 | * @throws \Exception |
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21 | */ |
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22 | View Code Duplication | public function addLabels( array $labels ) |
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31 | |||
32 | /** |
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33 | * @param array $labels |
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34 | * |
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35 | * @return Mail|string |
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36 | * @throws \Exception |
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37 | */ |
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38 | View Code Duplication | public function removeLabels( array $labels ) |
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47 | |||
48 | /** |
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49 | * Adds a single label to the request |
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50 | * |
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51 | * @param $label |
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52 | * |
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53 | * @return Mail |
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54 | */ |
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55 | private function addSingleLabel( $label ) |
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61 | |||
62 | /** |
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63 | * Removes a single label from the request |
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64 | * |
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65 | * @param $label |
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66 | * |
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67 | * @return Mail |
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68 | */ |
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69 | private function removeSingleLabel( $label ) |
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75 | |||
76 | /** |
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77 | * Executes the modification |
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78 | * |
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79 | * @return Mail |
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80 | */ |
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81 | private function modify() |
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85 | } |
In PHP it is possible to write to properties without declaring them. For example, the following is perfectly valid PHP code:
Generally, it is a good practice to explictly declare properties to avoid accidental typos and provide IDE auto-completion: