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
@paramannotations 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.