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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| 9 | trait UserAndPermission |
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| 10 | { |
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| 11 | /** |
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| 12 | * USER & PERMISSION |
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| 13 | * A model belongs to a Level |
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| 14 | * |
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| 15 | * @return mixed |
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| 16 | */ |
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| 17 | 15 | public function level() |
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| 21 | |||
| 22 | /** |
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| 23 | * USER & PERMISSION |
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| 24 | * Assign a model to a level |
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| 25 | * |
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| 26 | * @param $level |
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| 27 | * @return mixed |
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| 28 | */ |
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| 29 | 19 | public function assignLevel($level) |
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| 35 | |||
| 36 | /** |
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| 37 | * USER & PERMISSION |
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| 38 | * Clear a model's level |
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| 39 | * |
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| 40 | * @return mixed |
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| 41 | */ |
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| 42 | 2 | public function clearLevel() |
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| 46 | |||
| 47 | /** |
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| 48 | * USER & PERMISSION |
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| 49 | * First try the cache to return the collection, |
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| 50 | * then fetch it from the database. |
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| 51 | * |
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| 52 | * See @cacheGetLevel() |
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| 53 | * |
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| 54 | * @return mixed |
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| 55 | */ |
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| 56 | 3 | public function getLevel() |
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| 68 | |||
| 69 | |||
| 70 | /* ------------------------------------------------------------------------------------------------ |
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| 71 | | Other Functions |
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| 72 | | ------------------------------------------------------------------------------------------------ |
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| 73 | */ |
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| 74 | /** |
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| 75 | * USER & PERMISSION |
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| 76 | * Return a relationship of the level on a user/permission |
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| 77 | * associated to a user by direct or inheritance |
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| 78 | * |
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| 79 | * @return mixed |
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| 80 | */ |
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| 81 | 3 | protected function cacheGetLevel() |
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| 85 | |||
| 86 | /** |
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| 87 | * USER & PERMISSION |
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| 88 | * Helper function to get the level whether it is the ID |
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| 89 | * or the name of the level, or the level object itself. |
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| 90 | * |
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| 91 | * @param $level |
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| 92 | * @return mixed |
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| 93 | * @throws LevelNotFoundException |
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| 94 | */ |
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| 95 | 19 | View Code Duplication | protected function getALevel($level) |
| 108 | } |
This check looks for methods that are used by a trait but not required by it.
To illustrate, let’s look at the following code example
The trait
Idableprovides a methodequalsIdthat in turn relies on the methodgetId(). If this method does not exist on a class mixing in this trait, the method will fail.Adding the
getId()as an abstract method to the trait will make sure it is available.