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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7 | abstract class Enum |
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8 | { |
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9 | /** @var Enum[] */ |
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10 | private static $instances = []; |
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11 | /** @var \ReflectionClassConstant[] */ |
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12 | private static $constReflections = []; |
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13 | /** @var \ReflectionClass[] */ |
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14 | private static $reflections = []; |
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15 | /** @var string */ |
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16 | private $name; |
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17 | |||
18 | /** |
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19 | * @param string $name |
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20 | */ |
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21 | 3 | final private function __construct(string $name) |
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25 | |||
26 | /** |
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27 | * Creates enum instance by name |
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28 | * |
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29 | * @param string $name |
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30 | * |
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31 | * @return static |
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32 | * |
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33 | * @throws EnumException |
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34 | */ |
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35 | 8 | final public static function createByName(string $name) |
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51 | |||
52 | /** |
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53 | * Creates enum instance with short static constructor |
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54 | * |
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55 | * @param string $name |
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56 | * @param array $arguments |
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57 | * |
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58 | * @return static |
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59 | * |
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60 | * @throws EnumException |
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61 | */ |
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62 | 7 | final public static function __callStatic(string $name, array $arguments) |
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66 | |||
67 | 8 | public static function getConstList(): array |
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71 | |||
72 | 6 | View Code Duplication | private static function getConstantReflection(string $class, string $name): \ReflectionClassConstant |
83 | |||
84 | 6 | private static function getConstKey(string $class, string $name): string |
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88 | |||
89 | 6 | private static function findParentClassForConst(string $name): string |
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93 | |||
94 | 8 | private static function getEnumReflection(string $class): \ReflectionClass |
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108 | |||
109 | /** |
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110 | * Create named enum instance |
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111 | * |
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112 | * @param string $name |
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113 | * |
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114 | * @return static |
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115 | */ |
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116 | 6 | View Code Duplication | private static function createNamedInstance(string $name) |
128 | |||
129 | 1 | final public function getName(): string |
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133 | |||
134 | /** |
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135 | * {@inheritdoc} |
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136 | */ |
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137 | 1 | final public function __toString(): string |
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141 | } |
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142 |
Let’s assume you have a class which uses late-static binding:
}
The code above will run fine in your PHP runtime. However, if you now create a sub-class and call the
getSomeVariable()
on that sub-class, you will receive a runtime error:In the case above, it makes sense to update
SomeClass
to useself
instead: