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 $ordinal; |
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| 31 | |||
| 32 | /** |
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| 33 | * An array of available constants by class |
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| 34 | * |
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| 35 | * @var array ["$class" => ["$name" => $value, ...], ...] |
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| 36 | */ |
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| 37 | private static $constants = array(); |
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| 38 | |||
| 39 | /** |
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| 40 | * Already instantiated enumerators |
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| 41 | * |
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| 42 | * @var array ["$class" => ["$name" => $instance, ...], ...] |
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| 43 | */ |
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| 44 | private static $instances = array(); |
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| 45 | |||
| 46 | /** |
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| 47 | * Constructor |
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| 48 | * |
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| 49 | * @param null|bool|int|float|string $value The value of the enumerator |
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| 50 | * @param int|null $ordinal The ordinal number of the enumerator |
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| 51 | */ |
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| 52 | 29 | final private function __construct($value, $ordinal = null) |
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| 53 | { |
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| 54 | 29 | $this->value = $value; |
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| 55 | 29 | $this->ordinal = $ordinal; |
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| 56 | 29 | } |
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| 57 | |||
| 58 | /** |
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| 59 | * Get the name of the enumerator |
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| 60 | * |
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| 61 | * @return string |
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| 62 | * @see getName() |
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| 63 | */ |
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| 64 | 1 | public function __toString() |
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| 68 | |||
| 69 | /** |
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| 70 | * @throws LogicException Enums are not cloneable |
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| 71 | * because instances are implemented as singletons |
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| 72 | */ |
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| 73 | 1 | final private function __clone() |
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| 77 | |||
| 78 | /** |
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| 79 | * @throws LogicException Enums are not serializable |
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| 80 | * because instances are implemented as singletons |
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| 81 | */ |
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| 82 | 1 | final public function __sleep() |
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| 86 | |||
| 87 | /** |
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| 88 | * @throws LogicException Enums are not serializable |
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| 89 | * because instances are implemented as singletons |
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| 90 | */ |
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| 91 | 1 | final public function __wakeup() |
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| 95 | |||
| 96 | /** |
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| 97 | * Get the value of the enumerator |
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| 98 | * |
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| 99 | * @return null|bool|int|float|string |
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| 100 | */ |
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| 101 | 9 | final public function getValue() |
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| 105 | |||
| 106 | /** |
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| 107 | * Get the name of the enumarator |
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| 108 | * |
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| 109 | * @return string |
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| 110 | */ |
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| 111 | 6 | final public function getName() |
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| 115 | |||
| 116 | /** |
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| 117 | * Get the ordinal number of the enumerator |
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| 118 | * |
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| 119 | * @return int |
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| 120 | */ |
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| 121 | 17 | final public function getOrdinal() |
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| 122 | { |
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| 123 | 17 | if ($this->ordinal !== null) { |
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| 124 | 15 | return $this->ordinal; |
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| 125 | } |
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| 126 | |||
| 127 | // detect ordinal |
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| 128 | 8 | $ordinal = 0; |
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| 129 | 8 | $value = $this->value; |
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| 130 | 8 | foreach (self::detectConstants(get_called_class()) as $constValue) { |
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| 131 | 8 | if ($value === $constValue) { |
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| 132 | 8 | break; |
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| 133 | } |
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| 134 | 7 | ++$ordinal; |
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| 135 | } |
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| 136 | |||
| 137 | 8 | $this->ordinal = $ordinal; |
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| 138 | 8 | return $ordinal; |
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| 139 | } |
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| 140 | |||
| 141 | /** |
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| 142 | * Compare this enumerator against another and check if it's the same. |
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| 143 | * |
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| 144 | * @param mixed $enumerator |
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| 145 | * @return bool |
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| 146 | */ |
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| 147 | 1 | final public function is($enumerator) |
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| 151 | |||
| 152 | /** |
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| 153 | * Get an enumerator instance of the given value or instance |
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| 154 | * |
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| 155 | * @param static|null|bool|int|float|string $value |
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| 156 | * @return static |
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| 157 | * @throws InvalidArgumentException On an unknwon or invalid value |
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| 158 | * @throws LogicException On ambiguous constant values |
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| 159 | */ |
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| 160 | 40 | final public static function get($value) |
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| 161 | { |
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| 162 | 40 | if ($value instanceof static && get_class($value) === get_called_class()) { |
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| 163 | 15 | return $value; |
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| 164 | } |
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| 165 | |||
| 166 | 29 | $class = get_called_class(); |
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| 167 | 29 | $constants = self::detectConstants($class); |
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| 168 | 27 | $name = array_search($value, $constants, true); |
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| 169 | 27 | View Code Duplication | if ($name === false) { |
| 170 | 7 | $message = is_scalar($value) |
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| 171 | 3 | ? 'Unknown value ' . var_export($value, true) |
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| 172 | 7 | : 'Invalid value of type ' . (is_object($value) ? get_class($value) : gettype($value)); |
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| 173 | 7 | throw new InvalidArgumentException($message); |
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| 174 | } |
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| 175 | |||
| 176 | 21 | if (!isset(self::$instances[$class][$name])) { |
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| 177 | 15 | self::$instances[$class][$name] = new $class($constants[$name]); |
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| 178 | } |
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| 179 | |||
| 180 | 21 | return self::$instances[$class][$name]; |
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| 181 | } |
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| 182 | |||
| 183 | /** |
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| 184 | * Get an enumarator instance by the given name |
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| 185 | * |
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| 186 | * @param string $name The name of the enumerator |
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| 187 | * @return static |
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| 188 | * @throws InvalidArgumentException On an invalid or unknown name |
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| 189 | * @throws LogicException On ambiguous values |
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| 190 | */ |
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| 191 | 24 | final public static function getByName($name) |
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| 192 | { |
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| 193 | 24 | $name = (string) $name; |
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| 194 | 24 | $class = get_called_class(); |
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| 195 | 24 | if (isset(self::$instances[$class][$name])) { |
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| 196 | 16 | return self::$instances[$class][$name]; |
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| 197 | } |
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| 198 | |||
| 199 | 12 | $const = $class . '::' . $name; |
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| 200 | 12 | if (!defined($const)) { |
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| 201 | 1 | throw new InvalidArgumentException($const . ' not defined'); |
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| 202 | } |
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| 203 | |||
| 204 | 11 | return self::$instances[$class][$name] = new $class(constant($const)); |
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| 205 | } |
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| 206 | |||
| 207 | /** |
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| 208 | * Get an enumeration instance by the given ordinal number |
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| 209 | * |
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| 210 | * @param int $ordinal The ordinal number or the enumerator |
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| 211 | * @return static |
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| 212 | * @throws InvalidArgumentException On an invalid ordinal number |
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| 213 | * @throws LogicException On ambiguous values |
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| 214 | */ |
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| 215 | 8 | final public static function getByOrdinal($ordinal) |
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| 216 | { |
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| 217 | 8 | $ordinal = (int) $ordinal; |
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| 218 | 8 | $class = get_called_class(); |
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| 219 | 8 | $constants = self::detectConstants($class); |
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| 220 | 8 | $item = array_slice($constants, $ordinal, 1, true); |
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| 221 | 8 | if (empty($item)) { |
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| 222 | 1 | throw new InvalidArgumentException(sprintf( |
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| 223 | 1 | 'Invalid ordinal number, must between 0 and %s', |
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| 224 | 1 | count($constants) - 1 |
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| 225 | )); |
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| 226 | } |
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| 227 | |||
| 228 | 7 | $name = key($item); |
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| 229 | 7 | if (isset(self::$instances[$class][$name])) { |
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| 230 | 5 | return self::$instances[$class][$name]; |
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| 231 | } |
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| 232 | |||
| 233 | 3 | return self::$instances[$class][$name] = new $class(current($item), $ordinal); |
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| 234 | } |
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| 235 | |||
| 236 | /** |
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| 237 | * Clear all instantiated enumerators of the called class |
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| 238 | * |
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| 239 | * NOTE: This can break singleton behavior ... use it with caution! |
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| 240 | * |
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| 241 | * @return void |
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| 242 | */ |
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| 243 | 31 | final public static function clear() |
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| 244 | { |
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| 245 | 31 | $class = get_called_class(); |
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| 246 | 31 | unset(self::$instances[$class], self::$constants[$class]); |
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| 247 | 31 | } |
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| 248 | |||
| 249 | /** |
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| 250 | * Get a list of enumerator instances ordered by ordinal number |
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| 251 | * |
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| 252 | * @return static[] |
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| 253 | */ |
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| 254 | 1 | final public static function getEnumerators() |
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| 258 | |||
| 259 | /** |
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| 260 | * Get all available constants of the called class |
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| 261 | * |
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| 262 | * @return array |
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| 263 | * @throws LogicException On ambiguous constant values |
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| 264 | */ |
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| 265 | 25 | final public static function getConstants() |
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| 269 | |||
| 270 | /** |
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| 271 | * Is the given enumerator part of this enumeration |
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| 272 | * |
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| 273 | * @param static|null|bool|int|float|string $value |
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| 274 | * @return bool |
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| 275 | */ |
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| 276 | 1 | final public static function has($value) |
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| 287 | |||
| 288 | /** |
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| 289 | * Detect all available constants by the given class |
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| 290 | * |
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| 291 | * @param string $class |
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| 292 | * @return array |
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| 293 | * @throws LogicException On ambiguous constant values |
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| 294 | */ |
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| 295 | 45 | private static function detectConstants($class) |
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| 296 | { |
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| 297 | 45 | if (!isset(self::$constants[$class])) { |
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| 298 | 28 | $reflection = new ReflectionClass($class); |
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| 299 | |||
| 300 | 28 | if (PHP_VERSION_ID >= 70100) { |
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| 301 | $constants = array_filter($reflection->getReflectionConstants(), function ($const) { |
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| 302 | return $const->isPublic(); |
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| 303 | }); |
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| 304 | } else { |
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| 305 | 28 | $constants = $reflection->getConstants(); |
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| 306 | } |
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| 307 | |||
| 308 | // values needs to be unique |
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| 309 | 28 | $ambiguous = array(); |
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| 310 | 28 | foreach ($constants as $value) { |
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| 311 | 28 | $names = array_keys($constants, $value, true); |
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| 312 | 28 | if (count($names) > 1) { |
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| 313 | 28 | $ambiguous[var_export($value, true)] = $names; |
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| 314 | } |
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| 315 | } |
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| 316 | 28 | if (!empty($ambiguous)) { |
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| 317 | 2 | throw new LogicException( |
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| 318 | 'All possible values needs to be unique. The following are ambiguous: ' |
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| 319 | 2 | . implode(', ', array_map(function ($names) use ($constants) { |
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| 320 | 2 | return implode('/', $names) . '=' . var_export($constants[$names[0]], true); |
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| 321 | 2 | }, $ambiguous)) |
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| 322 | ); |
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| 323 | } |
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| 324 | |||
| 325 | // This is required to make sure that constants of base classes will be the first |
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| 326 | 26 | while (($reflection = $reflection->getParentClass()) && $reflection->name !== __CLASS__) { |
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| 327 | 8 | $constants = $reflection->getConstants() + $constants; |
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| 328 | } |
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| 329 | |||
| 330 | 26 | self::$constants[$class] = $constants; |
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| 331 | } |
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| 332 | |||
| 333 | 43 | return self::$constants[$class]; |
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| 334 | } |
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| 335 | |||
| 336 | /** |
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| 337 | * Get an enumarator instance by the given name. |
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| 338 | * |
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| 339 | * This will be called automatically on calling a method |
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| 340 | * with the same name of a defined enumerator. |
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| 341 | * |
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| 342 | * @param string $method The name of the enumeraotr (called as method) |
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| 343 | * @param array $args There should be no arguments |
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| 344 | * @return static |
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| 345 | * @throws InvalidArgumentException On an invalid or unknown name |
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| 346 | * @throws LogicException On ambiguous constant values |
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| 347 | */ |
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| 348 | 21 | final public static function __callStatic($method, array $args) |
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| 352 | } |
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| 353 |