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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| 21 | class Track implements IMusicServiceEndpoint |
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| 22 | { |
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| 23 | const DATA_SOURCE = 'spotify'; |
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| 24 | |||
| 25 | protected $parent; |
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| 26 | |||
| 27 | 39 | public function __construct(SpotifyService $apiService, CacheItemPoolInterface $cache) |
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| 32 | |||
| 33 | /** |
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| 34 | * @param $apiService |
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| 35 | * |
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| 36 | * @return $this |
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| 37 | */ |
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| 38 | 39 | public function setParent($apiService) |
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| 44 | |||
| 45 | /** |
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| 46 | * @param CacheItemPoolInterface $cacheItemPool |
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| 47 | * @return $this |
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| 48 | */ |
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| 49 | 39 | public function setCache(CacheItemPoolInterface $cacheItemPool) |
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| 55 | |||
| 56 | /** |
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| 57 | * Transform single item to model |
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| 58 | * |
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| 59 | * @param $raw |
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| 60 | * |
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| 61 | * @return TrackModel |
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| 62 | */ |
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| 63 | 2 | public function transformSingle($raw) |
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| 77 | |||
| 78 | /** |
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| 79 | * @param $raw |
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| 80 | * |
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| 81 | * @return ArrayCollection |
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| 82 | * @throws \Exception |
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| 83 | */ |
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| 84 | 2 | View Code Duplication | public function transformCollection($raw) |
| 97 | |||
| 98 | /** |
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| 99 | * @param $raw |
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| 100 | * |
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| 101 | * @return ArrayCollection |
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| 102 | * @throws \Exception |
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| 103 | */ |
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| 104 | 2 | public function transform($raw) |
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| 108 | |||
| 109 | /** |
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| 110 | * @return SpotifyService |
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| 111 | */ |
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| 112 | 2 | public function getParent() |
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| 116 | |||
| 117 | /** |
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| 118 | * @param $arguments |
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| 119 | * |
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| 120 | * @return mixed |
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| 121 | */ |
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| 122 | public function get($arguments) |
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| 127 | |||
| 128 | /** |
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| 129 | * @param $arguments |
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| 130 | * |
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| 131 | * @return void |
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| 132 | * |
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| 133 | * @throws MethodNotImplementedException |
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| 134 | */ |
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| 135 | public function getComplete($arguments) |
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| 140 | |||
| 141 | /** |
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| 142 | * @param $id |
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| 143 | * |
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| 144 | * @return mixed |
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| 145 | */ |
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| 146 | public function getById($id) |
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| 150 | |||
| 151 | /** |
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| 152 | * @param $name |
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| 153 | * |
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| 154 | * @return mixed |
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| 155 | */ |
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| 156 | 2 | public function getByName($name) |
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| 160 | |||
| 161 | /** |
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| 162 | * @param $guid |
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| 163 | * |
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| 164 | * @return mixed |
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| 165 | */ |
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| 166 | public function getByGuid($guid) |
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| 170 | } |
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| 171 |
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: