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 enumerator |
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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 enumerator 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 | 28 | $ambiguous = array(); |
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300 | |||
301 | 28 | if (PHP_VERSION_ID >= 70100) { |
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302 | // Since PHP-7.1 visibility modifiers are allowed for class constants |
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303 | // but for enumerations only public once makes sense. |
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304 | $constants = array(); |
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305 | foreach ($reflection->getReflectionConstants() as $reflConstant) { |
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306 | // We are interested in public constants only |
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307 | if ($reflConstant->isPublic()) { |
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308 | $value = $reflConstant->getValue(); |
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309 | |||
310 | // Detect ambiguous values (and memory const names) |
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311 | $names = array_keys($constants, $value, true); |
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312 | if (count($names) > 1) { |
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313 | $ambiguous[var_export($value, true)] = $names; |
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314 | } |
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315 | |||
316 | // Memory NAME => VALUE pairs |
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317 | $constants[ $reflConstant->getName() ] = $value; |
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318 | } |
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319 | } |
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320 | } else { |
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321 | // In PHP < 7.1 all class constants were public by definition |
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322 | 28 | $constants = $reflection->getConstants(); |
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323 | |||
324 | // Detect ambiguous values (and memory const names) |
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325 | 28 | $ambiguous = array(); |
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326 | 28 | foreach ($constants as $value) { |
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327 | 28 | $names = array_keys($constants, $value, true); |
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328 | 28 | if (count($names) > 1) { |
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329 | 28 | $ambiguous[var_export($value, true)] = $names; |
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330 | } |
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331 | } |
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332 | } |
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333 | |||
334 | // Error on ambiguous values |
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335 | 28 | if (!empty($ambiguous)) { |
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336 | 2 | throw new LogicException( |
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337 | 'All possible values needs to be unique. The following are ambiguous: ' |
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338 | 2 | . implode(', ', array_map(function ($names) use ($constants) { |
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339 | 2 | return implode('/', $names) . '=' . var_export($constants[$names[0]], true); |
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340 | 2 | }, $ambiguous)) |
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341 | ); |
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342 | } |
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343 | |||
344 | // This is required to make sure that constants of base classes will be the first |
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345 | 26 | while (($reflection = $reflection->getParentClass()) && $reflection->name !== __CLASS__) { |
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346 | 8 | $constants = $reflection->getConstants() + $constants; |
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347 | } |
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348 | |||
349 | 26 | self::$constants[$class] = $constants; |
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350 | } |
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351 | |||
352 | 43 | return self::$constants[$class]; |
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353 | } |
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354 | |||
355 | /** |
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356 | * Get an enumerator instance by the given name. |
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357 | * |
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358 | * This will be called automatically on calling a method |
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359 | * with the same name of a defined enumerator. |
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360 | * |
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361 | * @param string $method The name of the enumeraotr (called as method) |
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362 | * @param array $args There should be no arguments |
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363 | * @return static |
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364 | * @throws InvalidArgumentException On an invalid or unknown name |
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365 | * @throws LogicException On ambiguous constant values |
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366 | */ |
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367 | 21 | final public static function __callStatic($method, array $args) |
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371 | } |
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372 |