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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22 | { |
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23 | 3 | $this->name = $name; |
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24 | 3 | } |
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25 | |||
26 | /** |
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27 | * Creates enum instance with short static constructor |
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28 | * |
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29 | * @param string $name |
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30 | * @param array $arguments |
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31 | * |
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32 | * @return static |
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33 | * |
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34 | * @throws EnumException |
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35 | */ |
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36 | 6 | final public static function __callStatic(string $name, array $arguments) |
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37 | { |
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38 | 6 | $const = static::getConstList(); |
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39 | |||
40 | 6 | if (!\in_array($name, $const, true)) { |
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41 | 1 | throw EnumException::becauseUnknownMember(static::class, $name); |
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42 | } |
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43 | |||
44 | 5 | return static::createNamedInstance($name); |
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45 | } |
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46 | |||
47 | 7 | public static function getConstList(): array |
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48 | { |
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49 | 7 | return array_keys(self::getEnumReflection(static::class)->getConstants()); |
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50 | } |
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51 | |||
52 | 5 | View Code Duplication | private static function getConstantReflection(string $class, string $name): \ReflectionClassConstant |
63 | |||
64 | 5 | private static function getConstKey(string $class, string $name): string |
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68 | |||
69 | 5 | private static function findParentClassForConst(string $name): string |
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73 | |||
74 | 7 | private static function getEnumReflection(string $class): \ReflectionClass |
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75 | { |
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76 | 7 | if (!array_key_exists($class, self::$reflections)) { |
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82 | |||
83 | /** |
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84 | * Create named enum instance |
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85 | * |
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86 | * @param string $name |
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87 | * |
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88 | * @return static |
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89 | */ |
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90 | 5 | View Code Duplication | private static function createNamedInstance(string $name) |
102 | |||
103 | 1 | final public function getName(): string |
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107 | |||
108 | /** |
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109 | * {@inheritdoc} |
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110 | */ |
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111 | 1 | final public function __toString(): string |
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115 | } |
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116 |
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: