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:
Complex classes like Enum often do a lot of different things. To break such a class down, we need to identify a cohesive component within that class. A common approach to find such a component is to look for fields/methods that share the same prefixes, or suffixes. You can also have a look at the cohesion graph to spot any un-connected, or weakly-connected components.
Once you have determined the fields that belong together, you can apply the Extract Class refactoring. If the component makes sense as a sub-class, Extract Subclass is also a candidate, and is often faster.
While breaking up the class, it is a good idea to analyze how other classes use Enum, and based on these observations, apply Extract Interface, too.
| 1 | <?php |
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| 16 | abstract class Enum |
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| 17 | { |
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| 18 | /** |
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| 19 | * The selected enumerator value |
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| 20 | * |
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| 21 | * @var null|bool|int|float|string |
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| 22 | */ |
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| 23 | private $value; |
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| 24 | |||
| 25 | /** |
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| 26 | * The ordinal number of the enumerator |
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| 27 | * |
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| 28 | * @var null|int |
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| 29 | */ |
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| 30 | private $ordinal; |
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| 31 | |||
| 32 | /** |
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| 33 | * A map of enumerator names and values by enumeration class |
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| 34 | * |
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| 35 | * @var array ["$class" => ["$name" => $value, ...], ...] |
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| 36 | */ |
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| 37 | private static $constants = array(); |
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| 38 | |||
| 39 | /** |
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| 40 | * A List of of available enumerator names by enumeration class |
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| 41 | * |
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| 42 | * @var array ["$class" => ["$name0", ...], ...] |
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| 43 | */ |
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| 44 | private static $names = array(); |
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| 45 | |||
| 46 | /** |
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| 47 | * Already instantiated enumerators |
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| 48 | * |
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| 49 | * @var array ["$class" => ["$name" => $instance, ...], ...] |
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| 50 | */ |
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| 51 | private static $instances = array(); |
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| 52 | |||
| 53 | /** |
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| 54 | * Constructor |
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| 55 | * |
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| 56 | * @param null|bool|int|float|string $value The value of the enumerator |
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| 57 | * @param int|null $ordinal The ordinal number of the enumerator |
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| 58 | */ |
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| 59 | 66 | final private function __construct($value, $ordinal = null) |
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| 64 | |||
| 65 | /** |
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| 66 | * Get the name of the enumerator |
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| 67 | * |
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| 68 | * @return string |
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| 69 | * @see getName() |
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| 70 | */ |
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| 71 | 2 | public function __toString() |
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| 75 | |||
| 76 | /** |
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| 77 | * @throws LogicException Enums are not cloneable |
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| 78 | * because instances are implemented as singletons |
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| 79 | */ |
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| 80 | 2 | final private function __clone() |
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| 84 | |||
| 85 | /** |
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| 86 | * @throws LogicException Enums are not serializable |
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| 87 | * because instances are implemented as singletons |
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| 88 | */ |
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| 89 | 2 | final public function __sleep() |
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| 93 | |||
| 94 | /** |
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| 95 | * @throws LogicException Enums are not serializable |
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| 96 | * because instances are implemented as singletons |
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| 97 | */ |
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| 98 | 2 | final public function __wakeup() |
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| 102 | |||
| 103 | /** |
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| 104 | * Get the value of the enumerator |
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| 105 | * |
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| 106 | * @return null|bool|int|float|string |
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| 107 | */ |
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| 108 | 44 | final public function getValue() |
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| 112 | |||
| 113 | /** |
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| 114 | * Get the name of the enumerator |
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| 115 | * |
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| 116 | * @return string |
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| 117 | */ |
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| 118 | 16 | final public function getName() |
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| 119 | { |
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| 120 | 16 | if ($this->ordinal !== null) { |
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| 121 | 6 | return self::$names[static::class][$this->ordinal]; |
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| 122 | } |
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| 123 | 10 | return array_search($this->value, self::detectConstants(static::class), true); |
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| 124 | } |
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| 125 | |||
| 126 | /** |
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| 127 | * Get the ordinal number of the enumerator |
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| 128 | * |
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| 129 | * @return int |
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| 130 | */ |
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| 131 | 80 | final public function getOrdinal() |
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| 150 | |||
| 151 | /** |
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| 152 | * Compare this enumerator against another and check if it's the same. |
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| 153 | * |
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| 154 | * @param mixed $enumerator |
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| 155 | * @return bool |
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| 156 | */ |
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| 157 | 4 | final public function is($enumerator) |
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| 167 | |||
| 168 | /** |
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| 169 | * Get an enumerator instance of the given value or instance |
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| 170 | * |
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| 171 | * @param static|null|bool|int|float|string $value |
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| 172 | * @return static |
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| 173 | * @throws InvalidArgumentException On an unknwon or invalid value |
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| 174 | * @throws LogicException On ambiguous constant values |
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| 175 | */ |
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| 176 | 122 | final public static function get($value) |
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| 184 | |||
| 185 | /** |
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| 186 | * Get an enumerator instance by the given value |
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| 187 | * |
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| 188 | * @param mixed $value |
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| 189 | * @return static |
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| 190 | * @throws InvalidArgumentException On an unknwon or invalid value |
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| 191 | * @throws LogicException On ambiguous constant values |
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| 192 | */ |
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| 193 | 92 | final public static function byValue($value) |
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| 211 | |||
| 212 | /** |
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| 213 | * Get an enumerator instance by the given name |
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| 214 | * |
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| 215 | * @param string $name The name of the enumerator |
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| 216 | * @return static |
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| 217 | * @throws InvalidArgumentException On an invalid or unknown name |
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| 218 | * @throws LogicException On ambiguous values |
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| 219 | */ |
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| 220 | 66 | final public static function byName($name) |
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| 235 | |||
| 236 | /** |
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| 237 | * Get an enumeration instance by the given ordinal number |
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| 238 | * |
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| 239 | * @param int $ordinal The ordinal number or the enumerator |
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| 240 | * @return static |
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| 241 | * @throws InvalidArgumentException On an invalid ordinal number |
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| 242 | * @throws LogicException On ambiguous values |
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| 243 | */ |
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| 244 | 38 | final public static function byOrdinal($ordinal) |
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| 245 | { |
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| 246 | 38 | $ordinal = (int) $ordinal; |
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| 247 | 38 | $class = static::class; |
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| 248 | |||
| 249 | 38 | if (!isset(self::$names[$class])) { |
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| 250 | 4 | self::detectConstants($class); |
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| 251 | 2 | } |
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| 252 | |||
| 253 | 38 | if (!isset(self::$names[$class][$ordinal])) { |
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| 254 | 2 | throw new InvalidArgumentException(sprintf( |
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| 255 | 2 | 'Invalid ordinal number, must between 0 and %s', |
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| 256 | 2 | count(self::$names[$class]) - 1 |
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| 257 | 1 | )); |
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| 258 | } |
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| 259 | |||
| 260 | 36 | $name = self::$names[$class][$ordinal]; |
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| 261 | 36 | if (isset(self::$instances[$class][$name])) { |
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| 262 | 32 | return self::$instances[$class][$name]; |
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| 263 | } |
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| 264 | |||
| 265 | 6 | $const = $class . '::' . $name; |
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| 266 | 6 | return self::$instances[$class][$name] = new $class(constant($const)); |
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| 267 | } |
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| 268 | |||
| 269 | /** |
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| 270 | * Get a list of enumerator instances ordered by ordinal number |
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| 271 | * |
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| 272 | * @return static[] |
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| 273 | */ |
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| 274 | 26 | final public static function getEnumerators() |
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| 275 | { |
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| 276 | 26 | if (!isset(self::$names[static::class])) { |
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| 277 | 2 | self::detectConstants(static::class); |
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| 278 | 1 | } |
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| 279 | 26 | return array_map([static::class, 'byName'], self::$names[static::class]); |
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| 280 | } |
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| 281 | |||
| 282 | /** |
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| 283 | * Get a list of enumerator values ordered by ordinal number |
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| 284 | * |
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| 285 | * @return mixed[] |
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| 286 | */ |
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| 287 | 2 | final public static function getValues() |
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| 291 | |||
| 292 | /** |
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| 293 | * Get a list of enumerator names ordered by ordinal number |
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| 294 | * |
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| 295 | * @return string[] |
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| 296 | */ |
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| 297 | 4 | final public static function getNames() |
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| 298 | { |
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| 299 | 4 | if (!isset(self::$names[static::class])) { |
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| 300 | 2 | self::detectConstants(static::class); |
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| 301 | 1 | } |
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| 302 | 4 | return self::$names[static::class]; |
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| 303 | } |
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| 304 | /* |
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| 305 | * Get a list of enumerator ordinal numbers |
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| 306 | * |
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| 307 | * @return int[] |
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| 308 | */ |
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| 309 | 2 | final public static function getOrdinals() |
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| 314 | |||
| 315 | /** |
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| 316 | * Get all available constants of the called class |
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| 317 | * |
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| 318 | * @return array |
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| 319 | * @throws LogicException On ambiguous constant values |
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| 320 | */ |
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| 321 | 128 | final public static function getConstants() |
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| 325 | |||
| 326 | /** |
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| 327 | * Is the given enumerator part of this enumeration |
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| 328 | * |
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| 329 | * @param static|null|bool|int|float|string $value |
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| 330 | * @return bool |
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| 331 | */ |
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| 332 | 2 | final public static function has($value) |
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| 341 | |||
| 342 | /** |
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| 343 | * Detect all public available constants of given enumeration class |
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| 344 | * |
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| 345 | * @param string $class |
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| 346 | * @return array |
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| 347 | * @throws LogicException On ambiguous constant values |
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| 348 | */ |
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| 349 | 166 | private static function detectConstants($class) |
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| 350 | { |
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| 351 | 166 | if (!isset(self::$constants[$class])) { |
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| 352 | 68 | $reflection = new ReflectionClass($class); |
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| 353 | 68 | $constants = array(); |
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| 354 | |||
| 355 | do { |
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| 356 | 68 | $scopeConstants = array(); |
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| 357 | 68 | if (PHP_VERSION_ID >= 70100) { |
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| 358 | // Since PHP-7.1 visibility modifiers are allowed for class constants |
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| 359 | // for enumerations we are only interested in public once. |
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| 360 | 35 | foreach ($reflection->getReflectionConstants() as $reflConstant) { |
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| 361 | 34 | if ($reflConstant->isPublic()) { |
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| 362 | 35 | $scopeConstants[ $reflConstant->getName() ] = $reflConstant->getValue(); |
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| 363 | } |
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| 364 | } |
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| 365 | } else { |
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| 366 | // In PHP < 7.1 all class constants were public by definition |
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| 367 | 33 | $scopeConstants = $reflection->getConstants(); |
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| 368 | } |
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| 369 | |||
| 370 | 68 | $constants = $scopeConstants + $constants; |
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| 371 | 68 | } while (($reflection = $reflection->getParentClass()) && $reflection->name !== __CLASS__); |
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| 372 | |||
| 373 | // Detect ambiguous values and report names |
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| 374 | 68 | $ambiguous = array(); |
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| 375 | 68 | foreach ($constants as $value) { |
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| 376 | 66 | $names = array_keys($constants, $value, true); |
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| 377 | 66 | if (count($names) > 1) { |
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| 378 | 36 | $ambiguous[var_export($value, true)] = $names; |
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| 379 | 2 | } |
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| 380 | 33 | } |
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| 381 | 68 | if (!empty($ambiguous)) { |
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| 382 | 4 | throw new LogicException( |
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| 383 | 'All possible values needs to be unique. The following are ambiguous: ' |
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| 384 | 4 | . implode(', ', array_map(function ($names) use ($constants) { |
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| 385 | 4 | return implode('/', $names) . '=' . var_export($constants[$names[0]], true); |
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| 386 | 4 | }, $ambiguous)) |
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| 387 | 2 | ); |
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| 388 | } |
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| 389 | |||
| 390 | 64 | self::$constants[$class] = $constants; |
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| 391 | 64 | self::$names[$class] = array_keys($constants); |
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| 392 | 31 | } |
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| 393 | |||
| 394 | 162 | return self::$constants[$class]; |
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| 395 | } |
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| 396 | |||
| 397 | /** |
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| 398 | * Get an enumerator instance by the given name. |
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| 399 | * |
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| 400 | * This will be called automatically on calling a method |
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| 401 | * with the same name of a defined enumerator. |
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| 402 | * |
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| 403 | * @param string $method The name of the enumeraotr (called as method) |
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| 404 | * @param array $args There should be no arguments |
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| 405 | * @return static |
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| 406 | * @throws InvalidArgumentException On an invalid or unknown name |
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| 407 | * @throws LogicException On ambiguous constant values |
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| 408 | */ |
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| 409 | 36 | final public static function __callStatic($method, array $args) |
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| 413 | } |
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| 414 |