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 $constants = array(); |
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38 | |||
39 | /** |
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40 | * A List of available enumerator names by enumeration class |
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41 | * |
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42 | * @var array ["$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 $ordinal The ordinal number of the enumerator |
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58 | */ |
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59 | 72 | final private function __construct($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 | 46 | 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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123 | |||
124 | /** |
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125 | * Get the ordinal number of the enumerator |
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126 | * |
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127 | * @return int |
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128 | */ |
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129 | 124 | final public function getOrdinal() |
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130 | { |
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131 | 124 | if ($this->ordinal === null) { |
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132 | 38 | $ordinal = 0; |
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133 | 38 | $value = $this->value; |
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134 | 38 | foreach (self::detectConstants(static::class) as $constValue) { |
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135 | 38 | if ($value === $constValue) { |
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136 | 38 | break; |
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137 | } |
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138 | 32 | ++$ordinal; |
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139 | } |
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140 | |||
141 | 38 | $this->ordinal = $ordinal; |
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142 | } |
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143 | |||
144 | 124 | return $this->ordinal; |
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145 | } |
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146 | |||
147 | /** |
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148 | * Compare this enumerator against another and check if it's the same. |
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149 | * |
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150 | * @param mixed $enumerator |
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151 | * @return bool |
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152 | */ |
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153 | 4 | final public function is($enumerator) |
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154 | { |
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155 | 4 | return $this === $enumerator || $this->value === $enumerator |
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156 | |||
157 | // The following additional conditions are required only because of the issue of serializable singletons |
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158 | 4 | || ($enumerator instanceof static |
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159 | 4 | && \get_class($enumerator) === static::class |
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160 | 4 | && $enumerator->value === $this->value |
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161 | ); |
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162 | } |
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163 | |||
164 | /** |
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165 | * Get an enumerator instance of the given value or instance |
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166 | * |
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167 | * @param static|null|bool|int|float|string $value |
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168 | * @return static |
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169 | * @throws InvalidArgumentException On an unknwon or invalid value |
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170 | * @throws LogicException On ambiguous constant values |
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171 | */ |
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172 | 144 | final public static function get($value) |
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180 | |||
181 | /** |
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182 | * Get an enumerator instance by the given value |
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183 | * |
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184 | * @param mixed $value |
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185 | * @return static |
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186 | * @throws InvalidArgumentException On an unknwon or invalid value |
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187 | * @throws LogicException On ambiguous constant values |
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188 | */ |
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189 | 102 | final public static function byValue($value) |
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190 | { |
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191 | 102 | $class = static::class; |
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192 | 102 | $constants = self::detectConstants($class); |
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193 | 98 | $name = \array_search($value, $constants, true); |
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194 | 98 | View Code Duplication | if ($name === false) { |
195 | 14 | $message = \is_scalar($value) |
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196 | 6 | ? 'Unknown value ' . \var_export($value, true) |
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197 | 14 | : 'Invalid value of type ' . (\is_object($value) ? \get_class($value) : \gettype($value)); |
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198 | 14 | throw new InvalidArgumentException($message); |
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199 | } |
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200 | |||
201 | 86 | if (!isset(self::$instances[$class][$name])) { |
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202 | 34 | self::$instances[$class][$name] = new $class($constants[$name]); |
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203 | } |
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204 | |||
205 | 86 | return self::$instances[$class][$name]; |
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206 | } |
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207 | |||
208 | /** |
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209 | * Get an enumerator instance by the given name |
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210 | * |
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211 | * @param string $name The name of the enumerator |
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212 | * @return static |
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213 | * @throws InvalidArgumentException On an invalid or unknown name |
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214 | * @throws LogicException On ambiguous values |
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215 | */ |
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216 | 88 | final public static function byName($name) |
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231 | |||
232 | /** |
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233 | * Get an enumeration instance by the given ordinal number |
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234 | * |
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235 | * @param int $ordinal The ordinal number or the enumerator |
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236 | * @return static |
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237 | * @throws InvalidArgumentException On an invalid ordinal number |
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238 | * @throws LogicException On ambiguous values |
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239 | */ |
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240 | 60 | final public static function byOrdinal($ordinal) |
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241 | { |
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242 | 60 | $ordinal = (int) $ordinal; |
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243 | 60 | $class = static::class; |
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244 | |||
245 | 60 | if (!isset(self::$names[$class])) { |
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246 | 4 | self::detectConstants($class); |
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247 | } |
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248 | |||
249 | 60 | if (!isset(self::$names[$class][$ordinal])) { |
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250 | 2 | throw new InvalidArgumentException(\sprintf( |
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251 | 2 | 'Invalid ordinal number, must between 0 and %s', |
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252 | 2 | \count(self::$names[$class]) - 1 |
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253 | )); |
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254 | } |
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255 | |||
256 | 58 | $name = self::$names[$class][$ordinal]; |
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257 | 58 | if (isset(self::$instances[$class][$name])) { |
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258 | 54 | return self::$instances[$class][$name]; |
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259 | } |
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260 | |||
261 | 6 | $const = $class . '::' . $name; |
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262 | 6 | return self::$instances[$class][$name] = new $class(\constant($const), $ordinal); |
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263 | } |
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264 | |||
265 | /** |
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266 | * Get a list of enumerator instances ordered by ordinal number |
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267 | * |
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268 | * @return static[] |
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269 | */ |
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270 | 32 | final public static function getEnumerators() |
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271 | { |
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272 | 32 | if (!isset(self::$names[static::class])) { |
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273 | 2 | self::detectConstants(static::class); |
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274 | } |
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275 | 32 | return \array_map([static::class, 'byName'], self::$names[static::class]); |
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276 | } |
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277 | |||
278 | /** |
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279 | * Get a list of enumerator values ordered by ordinal number |
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280 | * |
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281 | * @return mixed[] |
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282 | */ |
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283 | 2 | final public static function getValues() |
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287 | |||
288 | /** |
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289 | * Get a list of enumerator names ordered by ordinal number |
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290 | * |
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291 | * @return string[] |
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292 | */ |
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293 | 4 | final public static function getNames() |
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294 | { |
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295 | 4 | if (!isset(self::$names[static::class])) { |
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296 | 2 | self::detectConstants(static::class); |
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297 | } |
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298 | 4 | return self::$names[static::class]; |
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299 | } |
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300 | /* |
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301 | * Get a list of enumerator ordinal numbers |
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302 | * |
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303 | * @return int[] |
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304 | */ |
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305 | 2 | final public static function getOrdinals() |
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310 | |||
311 | /** |
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312 | * Get all available constants of the called class |
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313 | * |
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314 | * @return array |
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315 | * @throws LogicException On ambiguous constant values |
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316 | */ |
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317 | 158 | final public static function getConstants() |
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321 | |||
322 | /** |
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323 | * Is the given enumerator part of this enumeration |
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324 | * |
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325 | * @param static|null|bool|int|float|string $value |
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326 | * @return bool |
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327 | */ |
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328 | 2 | final public static function has($value) |
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337 | |||
338 | /** |
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339 | * Detect all public available constants of given enumeration class |
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340 | * |
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341 | * @param string $class |
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342 | * @return array |
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343 | * @throws LogicException On ambiguous constant values |
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344 | */ |
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345 | 204 | private static function detectConstants($class) |
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346 | { |
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347 | 204 | if (!isset(self::$constants[$class])) { |
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348 | 72 | $reflection = new ReflectionClass($class); |
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349 | 72 | $constants = array(); |
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350 | |||
351 | do { |
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352 | 72 | $scopeConstants = array(); |
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353 | 72 | if (PHP_VERSION_ID >= 70100) { |
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354 | // Since PHP-7.1 visibility modifiers are allowed for class constants |
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355 | // for enumerations we are only interested in public once. |
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356 | 37 | foreach ($reflection->getReflectionConstants() as $reflConstant) { |
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357 | 36 | if ($reflConstant->isPublic()) { |
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358 | 37 | $scopeConstants[ $reflConstant->getName() ] = $reflConstant->getValue(); |
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359 | } |
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360 | } |
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361 | } else { |
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362 | // In PHP < 7.1 all class constants were public by definition |
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363 | 35 | $scopeConstants = $reflection->getConstants(); |
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364 | } |
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365 | |||
366 | 72 | $constants = $scopeConstants + $constants; |
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367 | 72 | } while (($reflection = $reflection->getParentClass()) && $reflection->name !== __CLASS__); |
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368 | |||
369 | // Detect ambiguous values and report names |
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370 | 72 | $ambiguous = array(); |
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371 | 72 | foreach ($constants as $value) { |
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372 | 70 | $names = \array_keys($constants, $value, true); |
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373 | 70 | if (\count($names) > 1) { |
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374 | 70 | $ambiguous[\var_export($value, true)] = $names; |
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375 | } |
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376 | } |
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377 | 72 | if (!empty($ambiguous)) { |
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378 | 4 | throw new LogicException( |
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379 | 'All possible values needs to be unique. The following are ambiguous: ' |
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380 | 4 | . \implode(', ', \array_map(function ($names) use ($constants) { |
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381 | 4 | return \implode('/', $names) . '=' . \var_export($constants[$names[0]], true); |
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382 | 4 | }, $ambiguous)) |
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383 | ); |
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384 | } |
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385 | |||
386 | 68 | self::$constants[$class] = $constants; |
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387 | 68 | self::$names[$class] = \array_keys($constants); |
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388 | } |
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389 | |||
390 | 200 | return self::$constants[$class]; |
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391 | } |
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392 | |||
393 | /** |
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394 | * Get an enumerator instance by the given name. |
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395 | * |
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396 | * This will be called automatically on calling a method |
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397 | * with the same name of a defined enumerator. |
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398 | * |
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399 | * @param string $method The name of the enumeraotr (called as method) |
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400 | * @param array $args There should be no arguments |
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401 | * @return static |
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402 | * @throws InvalidArgumentException On an invalid or unknown name |
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403 | * @throws LogicException On ambiguous constant values |
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404 | */ |
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405 | 52 | final public static function __callStatic($method, array $args) |
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409 | } |
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410 |