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
SomeClassto useselfinstead: