Complex classes like Container 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 Container, and based on these observations, apply Extract Interface, too.
1 | <?php |
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15 | class Container implements ContainerInterface { |
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16 | private $currentRule; |
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17 | private $currentRuleName; |
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18 | private $instances; |
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19 | private $rules; |
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20 | private $factories; |
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21 | |||
22 | /** |
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23 | * Construct a new instance of the {@link Container} class. |
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24 | */ |
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25 | 93 | public function __construct() { |
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32 | |||
33 | /** |
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34 | * Deep clone rules. |
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35 | */ |
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36 | 1 | public function __clone() { |
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40 | |||
41 | /** |
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42 | * Clear all instances |
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43 | * |
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44 | */ |
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45 | 1 | public function clearInstances() { |
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48 | |||
49 | /** |
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50 | * Deep clone an array. |
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51 | * |
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52 | * @param array $array The array to clone. |
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53 | * @return array Returns the cloned array. |
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54 | * @see http://stackoverflow.com/a/17729234 |
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55 | */ |
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56 | 1 | private function arrayClone(array $array) { |
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57 | return array_map(function ($element) { |
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58 | 1 | return ((is_array($element)) |
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59 | 1 | ? $this->arrayClone($element) |
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60 | 1 | : ((is_object($element)) |
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61 | ? clone $element |
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62 | 1 | : $element |
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63 | ) |
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64 | ); |
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65 | 1 | }, $array); |
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66 | } |
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67 | |||
68 | /** |
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69 | * Normalize a container entry ID. |
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70 | * |
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71 | * @param string $id The ID to normalize. |
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72 | * @return string Returns a normalized ID as a string. |
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73 | */ |
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74 | 94 | private function normalizeID($id) { |
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77 | |||
78 | /** |
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79 | * Set the current rule to the default rule. |
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80 | * |
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81 | * @return $this |
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82 | */ |
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83 | 1 | public function defaultRule() { |
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86 | |||
87 | /** |
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88 | * Set the current rule. |
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89 | * |
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90 | * @param string $id The ID of the rule. |
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91 | * @return $this |
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92 | */ |
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93 | 93 | public function rule($id) { |
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104 | |||
105 | /** |
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106 | * Get the class name of the current rule. |
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107 | * |
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108 | * @return string Returns a class name. |
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109 | */ |
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110 | 2 | public function getClass() { |
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113 | |||
114 | /** |
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115 | * Set the name of the class for the current rule. |
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116 | * |
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117 | * @param string $className A valid class name. |
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118 | * @return $this |
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119 | */ |
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120 | 8 | public function setClass($className) { |
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124 | |||
125 | /** |
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126 | * Get the rule that the current rule references. |
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127 | * |
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128 | * @return string Returns a reference name or an empty string if there is no reference. |
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129 | */ |
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130 | 3 | public function getAliasOf() { |
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133 | |||
134 | /** |
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135 | * Set the rule that the current rule is an alias of. |
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136 | * |
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137 | * @param string $alias The name of an entry in the container to point to. |
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138 | * @return $this |
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139 | */ |
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140 | 4 | public function setAliasOf($alias) { |
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150 | |||
151 | /** |
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152 | * Add an alias of the current rule. |
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153 | * |
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154 | * Setting an alias to the current rule means that getting an item with the alias' name will be like getting the item |
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155 | * with the current rule. If the current rule is shared then the same shared instance will be returned. You can add |
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156 | * multiple aliases by passing additional arguments to this method. |
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157 | * |
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158 | * If {@link Container::addAlias()} is called with an alias that is the same as the current rule then an **E_USER_NOTICE** |
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159 | * level error is raised and the alias is not added. |
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160 | * |
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161 | * @param string ...$alias The alias to set. |
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162 | * @return $this |
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163 | * @since 1.4 Added the ability to pass multiple aliases. |
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164 | */ |
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165 | 8 | public function addAlias(...$alias) { |
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177 | |||
178 | /** |
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179 | * Remove an alias of the current rule. |
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180 | * |
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181 | * If {@link Container::removeAlias()} is called with an alias that references a different rule then an **E_USER_NOTICE** |
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182 | * level error is raised, but the alias is still removed. |
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183 | * |
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184 | * @param string $alias The alias to remove. |
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185 | * @return $this |
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186 | */ |
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187 | 2 | public function removeAlias($alias) { |
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197 | |||
198 | /** |
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199 | * Get all of the aliases of the current rule. |
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200 | * |
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201 | * This method is intended to aid in debugging and should not be used in production as it walks the entire rule array. |
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202 | * |
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203 | * @return array Returns an array of strings representing aliases. |
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204 | */ |
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205 | 6 | public function getAliases() { |
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216 | |||
217 | /** |
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218 | * Get the factory callback for the current rule. |
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219 | * |
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220 | * @return callable|null Returns the rule's factory or **null** if it has none. |
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221 | */ |
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222 | 2 | public function getFactory() { |
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225 | |||
226 | /** |
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227 | * Set the factory that will be used to create the instance for the current rule. |
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228 | * |
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229 | * @param callable|null $factory This callback will be called to create the instance for the rule. |
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230 | * @return $this |
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231 | */ |
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232 | 10 | public function setFactory(callable $factory = null) { |
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236 | |||
237 | /** |
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238 | * Whether or not the current rule is shared. |
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239 | * |
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240 | * @return bool Returns **true** if the rule is shared or **false** otherwise. |
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241 | */ |
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242 | 2 | public function isShared() { |
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245 | |||
246 | /** |
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247 | * Set whether or not the current rule is shared. |
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248 | * |
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249 | * @param bool $shared Whether or not the current rule is shared. |
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250 | * @return $this |
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251 | */ |
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252 | 42 | public function setShared($shared) { |
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256 | |||
257 | /** |
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258 | * Whether or not the current rule will inherit to subclasses. |
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259 | * |
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260 | * @return bool Returns **true** if the current rule inherits or **false** otherwise. |
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261 | */ |
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262 | 2 | public function getInherit() { |
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265 | |||
266 | /** |
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267 | * Set whether or not the current rule extends to subclasses. |
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268 | * |
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269 | * @param bool $inherit Pass **true** to have subclasses inherit this rule or **false** otherwise. |
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270 | * @return $this |
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271 | */ |
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272 | 3 | public function setInherit($inherit) { |
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276 | |||
277 | /** |
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278 | * Get the constructor arguments for the current rule. |
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279 | * |
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280 | * @return array Returns the constructor arguments for the current rule. |
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281 | */ |
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282 | 2 | public function getConstructorArgs() { |
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285 | |||
286 | /** |
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287 | * Set the constructor arguments for the current rule. |
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288 | * |
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289 | * @param array $args An array of constructor arguments. |
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290 | * @return $this |
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291 | */ |
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292 | 25 | public function setConstructorArgs(array $args) { |
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296 | |||
297 | /** |
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298 | * Set a specific shared instance into the container. |
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299 | * |
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300 | * When you set an instance into the container then it will always be returned by subsequent retrievals, even if a |
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301 | * rule is configured that says that instances should not be shared. |
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302 | * |
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303 | * @param string $name The name of the container entry. |
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304 | * @param mixed $instance This instance. |
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305 | * @return $this |
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306 | */ |
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307 | 9 | public function setInstance($name, $instance) { |
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311 | |||
312 | /** |
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313 | * Add a method call to a rule. |
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314 | * |
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315 | * @param string $method The name of the method to call. |
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316 | * @param array $args The arguments to pass to the method. |
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317 | * @return $this |
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318 | */ |
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319 | 8 | public function addCall($method, array $args = []) { |
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324 | |||
325 | /** |
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326 | * Finds an entry of the container by its identifier and returns it. |
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327 | * |
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328 | * @param string $id Identifier of the entry to look for. |
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329 | * @param array $args Additional arguments to pass to the constructor. |
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330 | * |
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331 | * @throws NotFoundException No entry was found for this identifier. |
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332 | * @throws ContainerException Error while retrieving the entry. |
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333 | * |
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334 | * @return mixed Entry. |
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335 | */ |
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336 | 74 | public function getArgs($id, array $args = []) { |
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358 | |||
359 | /** |
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360 | * Make a rule based on an ID. |
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361 | * |
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362 | * @param string $nid A normalized ID. |
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363 | * @return array Returns an array representing a rule. |
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364 | */ |
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365 | 70 | private function makeRule($nid) { |
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415 | |||
416 | /** |
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417 | * Make a function that creates objects from a rule. |
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418 | * |
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419 | * @param string $nid The normalized ID of the container item. |
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420 | * @param array $rule The resolved rule for the ID. |
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421 | * @return \Closure Returns a function that when called will create a new instance of the class. |
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422 | * @throws NotFoundException No entry was found for this identifier. |
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423 | */ |
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424 | 46 | private function makeFactory($nid, array $rule) { |
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494 | |||
495 | /** |
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496 | * Create a shared instance of a class from a rule. |
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497 | * |
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498 | * This method has the side effect of adding the new instance to the internal instances array of this object. |
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499 | * |
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500 | * @param string $nid The normalized ID of the container item. |
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501 | * @param array $rule The resolved rule for the ID. |
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502 | * @param array $args Additional arguments passed during creation. |
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503 | * @return object Returns the the new instance. |
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504 | * @throws NotFoundException Throws an exception if the class does not exist. |
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505 | */ |
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506 | 26 | private function createSharedInstance($nid, array $rule, array $args) { |
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507 | 26 | if (!empty($rule['factory'])) { |
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508 | // The instance is created with a user-supplied factory function. |
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509 | 3 | $callback = $rule['factory']; |
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510 | 3 | $function = $this->reflectCallback($callback); |
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511 | |||
512 | 3 | if ($function->getNumberOfParameters() > 0) { |
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513 | 1 | $callbackArgs = $this->resolveArgs( |
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514 | 1 | $this->makeDefaultArgs($function, (array)$rule['constructorArgs']), |
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515 | 1 | $args |
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516 | ); |
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517 | |||
518 | 1 | $this->instances[$nid] = null; // prevent cyclic dependency from infinite loop. |
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519 | 1 | $this->instances[$nid] = $instance = call_user_func_array($callback, $callbackArgs); |
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520 | } else { |
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521 | 2 | $this->instances[$nid] = $instance = $callback(); |
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522 | } |
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523 | |||
524 | // Reflect on the instance so that calls can be made against it. |
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525 | 3 | if (is_object($instance)) { |
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526 | 3 | $class = new \ReflectionClass(get_class($instance)); |
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527 | } |
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528 | } else { |
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529 | 23 | $className = empty($rule['class']) ? $nid : $rule['class']; |
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530 | 23 | if (!class_exists($className)) { |
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531 | 1 | throw new NotFoundException("Class $className does not exist.", 404); |
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532 | } |
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533 | 22 | $class = new \ReflectionClass($className); |
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534 | 22 | $constructor = $class->getConstructor(); |
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535 | |||
536 | 22 | if ($constructor && $constructor->getNumberOfParameters() > 0) { |
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537 | // Instantiate the object first so that this instance can be used for cyclic dependencies. |
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538 | 21 | $this->instances[$nid] = $instance = $class->newInstanceWithoutConstructor(); |
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539 | |||
540 | 21 | $constructorArgs = $this->resolveArgs( |
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541 | 21 | $this->makeDefaultArgs($constructor, (array)$rule['constructorArgs'], $rule), |
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542 | 20 | $args |
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543 | ); |
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544 | 19 | $constructor->invokeArgs($instance, $constructorArgs); |
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545 | } else { |
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546 | 2 | $this->instances[$nid] = $instance = new $class->name; |
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547 | } |
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548 | } |
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549 | |||
550 | // Call subsequent calls on the new object. |
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551 | 23 | if (isset($class) && !empty($rule['calls'])) { |
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552 | 2 | foreach ($rule['calls'] as $call) { |
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553 | 2 | list($methodName, $args) = $call; |
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554 | 2 | $method = $class->getMethod($methodName); |
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555 | |||
556 | 2 | $args = $this->resolveArgs( |
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557 | 2 | $this->makeDefaultArgs($method, $args, $rule), |
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558 | 2 | [], |
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559 | 2 | $instance |
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560 | ); |
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561 | |||
562 | 2 | $method->invokeArgs($instance, $args); |
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563 | } |
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564 | } |
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565 | |||
566 | 23 | return $instance; |
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567 | } |
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568 | |||
569 | |||
570 | /** |
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571 | * Find the class implemented by an ID. |
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572 | * |
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573 | * This tries to see if a rule exists for a normalized ID and what class it evaluates to. |
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574 | * |
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575 | * @param string $nid The normalized ID to look up. |
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576 | * @return string|null Returns the name of the class associated with the rule or **null** if one could not be found. |
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577 | */ |
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578 | 6 | private function findRuleClass($nid) { |
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589 | |||
590 | /** |
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591 | * Make an array of default arguments for a given function. |
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592 | * |
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593 | * @param \ReflectionFunctionAbstract $function The function to make the arguments for. |
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594 | * @param array $ruleArgs An array of default arguments specifically for the function. |
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595 | * @return array Returns an array in the form `name => defaultValue`. |
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596 | * @throws NotFoundException If a non-optional class param is reflected and does not exist. |
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597 | */ |
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598 | 63 | private function makeDefaultArgs(\ReflectionFunctionAbstract $function, array $ruleArgs) { |
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651 | |||
652 | /** |
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653 | * Replace an array of default args with called args. |
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654 | * |
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655 | * @param array $defaultArgs The default arguments from {@link Container::makeDefaultArgs()}. |
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656 | * @param array $args The arguments passed into a creation. |
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657 | * @param mixed $instance An object instance if the arguments are being resolved on an already constructed object. |
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658 | * @return array Returns an array suitable to be applied to a function call. |
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659 | * @throws MissingArgumentException Throws an exception when a required parameter is missing. |
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660 | */ |
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661 | 61 | private function resolveArgs(array $defaultArgs, array $args, $instance = null) { |
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693 | |||
694 | /** |
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695 | * Create an instance of a container item. |
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696 | * |
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697 | * This method either creates a new instance or returns an already created shared instance. |
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698 | * |
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699 | * @param string $nid The normalized ID of the container item. |
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700 | * @param array $args Additional arguments to pass to the constructor. |
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701 | * @return object Returns an object instance. |
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702 | */ |
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703 | 70 | private function createInstance($nid, array $args) { |
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716 | |||
717 | /** |
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718 | * Call a callback with argument injection. |
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719 | * |
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720 | * @param callable $callback The callback to call. |
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721 | * @param array $args Additional arguments to pass to the callback. |
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722 | * @return mixed Returns the result of the callback. |
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723 | * @throws ContainerException Throws an exception if the callback cannot be understood. |
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724 | */ |
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725 | 4 | public function call(callable $callback, array $args = []) { |
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742 | |||
743 | /** |
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744 | * Returns true if the container can return an entry for the given identifier. Returns false otherwise. |
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745 | * |
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746 | * @param string $id Identifier of the entry to look for. |
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747 | * |
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748 | * @return boolean |
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749 | */ |
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750 | 5 | public function has($id) { |
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755 | |||
756 | /** |
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757 | * Determines whether a rule has been defined at a given ID. |
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758 | * |
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759 | * @param string $id Identifier of the entry to look for. |
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760 | * @return bool Returns **true** if a rule has been defined or **false** otherwise. |
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761 | */ |
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762 | 4 | public function hasRule($id) { |
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766 | |||
767 | /** |
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768 | * Returns true if the container already has an instance for the given identifier. Returns false otherwise. |
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769 | * |
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770 | * @param string $id Identifier of the entry to look for. |
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771 | * |
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772 | * @return bool |
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773 | */ |
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774 | 1 | public function hasInstance($id) { |
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779 | |||
780 | /** |
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781 | * Finds an entry of the container by its identifier and returns it. |
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782 | * |
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783 | * @param string $id Identifier of the entry to look for. |
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784 | * |
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785 | * @throws NotFoundException No entry was found for this identifier. |
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786 | * @throws ContainerException Error while retrieving the entry. |
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787 | * |
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788 | * @return mixed Entry. |
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789 | */ |
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790 | 62 | public function get($id) { |
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793 | |||
794 | /** |
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795 | * Determine the reflection information for a callback. |
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796 | * |
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797 | * @param callable $callback The callback to reflect. |
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798 | * @return \ReflectionFunctionAbstract Returns the reflection function for the callback. |
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799 | */ |
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800 | 9 | private function reflectCallback(callable $callback) { |
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807 | } |
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808 |
This check looks for
@param
annotations where the type inferred by our type inference engine differs from the declared type.It makes a suggestion as to what type it considers more descriptive.
Most often this is a case of a parameter that can be null in addition to its declared types.