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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| 18 | abstract class Model |
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| 19 | { |
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| 20 | protected $mappingClasses = []; |
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| 21 | |||
| 22 | /** |
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| 23 | * Contains property name mappings. |
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| 24 | * |
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| 25 | * [ |
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| 26 | * 'data_array_property1' => 'objectProperty1', |
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| 27 | * 'data_array_property2' => 'objectProperty2', |
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| 28 | * ] |
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| 29 | * |
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| 30 | * Data array property uses as keys |
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| 31 | * because there is can be more then one rule per object property |
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| 32 | * |
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| 33 | * f.g. $data['nmodels'] and ['modelsnum'] should map in modelsCount property. |
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| 34 | * Otherwise not unique array keys cause remapping of properties. |
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| 35 | * |
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| 36 | * @var array |
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| 37 | */ |
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| 38 | protected $propNameMap = []; |
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| 39 | |||
| 40 | /** |
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| 41 | * Constructor |
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| 42 | * |
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| 43 | * @param array $data |
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| 44 | */ |
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| 45 | 71 | public function __construct($data = []) |
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| 49 | |||
| 50 | /** |
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| 51 | * Set from array |
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| 52 | * |
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| 53 | * @param array $data |
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| 54 | * @return $this |
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| 55 | */ |
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| 56 | 71 | public function fromArray($data) |
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| 88 | |||
| 89 | /** |
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| 90 | * Set from json |
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| 91 | * |
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| 92 | * @param string $json |
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| 93 | * @return $this |
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| 94 | */ |
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| 95 | public function fromJson($json) |
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| 100 | |||
| 101 | /** |
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| 102 | * Get array from object |
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| 103 | * |
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| 104 | * @return array |
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| 105 | */ |
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| 106 | 8 | public function toArray() |
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| 110 | |||
| 111 | /** |
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| 112 | * Get array from object |
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| 113 | * |
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| 114 | * @return string |
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| 115 | */ |
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| 116 | public function toJson() |
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| 120 | |||
| 121 | /** |
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| 122 | * Get array from object |
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| 123 | * |
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| 124 | * @param array|object $data |
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| 125 | * @return array |
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| 126 | */ |
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| 127 | 8 | protected function toArrayRecursive($data) |
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| 156 | } |
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| 157 |
Let’s take a look at an example:
In the above example, the authenticate() method works fine as long as you just pass instances of MyUser. However, if you now also want to pass a different sub-classes of User which does not have a getDisplayName() method, the code will break.
Available Fixes
Change the type-hint for the parameter:
Add an additional type-check:
Add the method to the parent class: