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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| 11 | class Container implements \ArrayAccess |
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| 12 | { |
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| 13 | /** |
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| 14 | * @var array |
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| 15 | */ |
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| 16 | private $bindings = []; |
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| 17 | |||
| 18 | /** |
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| 19 | * @var array |
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| 20 | */ |
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| 21 | private $resolved = []; |
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| 22 | |||
| 23 | /** |
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| 24 | * @var array |
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| 25 | */ |
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| 26 | private $aliases = []; |
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| 27 | |||
| 28 | /** |
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| 29 | * Resolving all dependencies in the supplied class or object instance constructor. |
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| 30 | * |
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| 31 | * @param string $instance The class name. |
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| 32 | * @param array $parameters List of needed class dependency. |
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| 33 | * @return object |
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| 34 | */ |
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| 35 | public function make($instance, $parameters = []) |
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| 44 | |||
| 45 | /** |
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| 46 | * Register a service alias. |
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| 47 | * |
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| 48 | * @param string $alias The alias name. |
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| 49 | * @param string $abstract The class name. |
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| 50 | */ |
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| 51 | public function register($alias, $abstract) |
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| 65 | |||
| 66 | /** |
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| 67 | * Determine if registered alias were exists. |
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| 68 | * |
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| 69 | * @param string $alias The alias name. |
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| 70 | */ |
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| 71 | public function isAliasExists($alias) |
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| 75 | |||
| 76 | /** |
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| 77 | * Get concrete implementation from supplied alias name. |
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| 78 | * |
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| 79 | * @param string $alias The alias name. |
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| 80 | */ |
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| 81 | public function get($alias) |
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| 91 | |||
| 92 | /** |
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| 93 | * {@inheritdoc} |
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| 94 | */ |
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| 95 | public function offsetExists($offset) |
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| 99 | |||
| 100 | /** |
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| 101 | * {@inheritdoc} |
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| 102 | */ |
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| 103 | public function offsetGet($offset) |
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| 107 | |||
| 108 | /** |
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| 109 | * {@inheritdoc} |
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| 110 | */ |
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| 111 | public function offsetSet($offset, $value) |
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| 115 | |||
| 116 | /** |
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| 117 | * {@inheritdoc} |
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| 118 | */ |
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| 119 | public function offsetUnset($offset) |
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| 123 | |||
| 124 | /** |
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| 125 | * Get list of unresolved class name from class binding stack. |
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| 126 | * |
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| 127 | * @return string |
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| 128 | */ |
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| 129 | protected function getAbstracts() |
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| 133 | |||
| 134 | /** |
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| 135 | * Determine if unresolved class name is exists. |
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| 136 | * |
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| 137 | * @param string $abstract The unresolved class name. |
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| 138 | * @return bool |
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| 139 | */ |
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| 140 | public function isAbstractExists($abstract) |
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| 144 | |||
| 145 | /** |
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| 146 | * Determine if concrete dependency is exists. |
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| 147 | * |
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| 148 | * @param mixed $concrete The concrete dependency. |
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| 149 | * @return bool |
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| 150 | */ |
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| 151 | public function isConcreteExists($concrete) |
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| 163 | |||
| 164 | public function isInterface($abstract) |
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| 170 | |||
| 171 | /** |
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| 172 | * Get concrete list of dependencies based on supplied class name. |
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| 173 | * |
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| 174 | * @param string $abstract The unresolved class name. |
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| 175 | * @return array |
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| 176 | */ |
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| 177 | public function getConcrete($abstract) |
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| 181 | |||
| 182 | /** |
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| 183 | * Resolve class dependencies in the supplied class name. |
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| 184 | * |
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| 185 | * @param string $instance The class name. |
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| 186 | * @param array $parameters The needed class dependency. |
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| 187 | * @return object |
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| 188 | */ |
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| 189 | protected function resolve($instance, $parameters = []) |
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| 213 | |||
| 214 | /** |
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| 215 | * Resolve method parameters. |
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| 216 | * |
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| 217 | * @param array $params The unresolvable method. |
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| 218 | * @return array |
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| 219 | */ |
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| 220 | protected function resolveMethodParameters($params = []) |
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| 257 | |||
| 258 | /** |
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| 259 | * Recursively resolving class dependency. |
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| 260 | * |
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| 261 | * @param string $class The valid class name. |
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| 262 | * @return object |
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| 263 | */ |
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| 264 | protected function circularDependencyResolver($class) |
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| 300 | |||
| 301 | /** |
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| 302 | * Get concrete implementation from abstract. |
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| 303 | * |
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| 304 | * @param string $interface The interface name. |
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| 305 | * @return object |
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| 306 | */ |
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| 307 | protected function getConcreteFromInterface($interface) |
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| 327 | |||
| 328 | /** |
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| 329 | * Determine if current reflection object has constructor. |
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| 330 | * |
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| 331 | * @param \ReflectionClass $refl The current reflection class object. |
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| 332 | * @return boolean |
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| 333 | */ |
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| 334 | protected function hasConstructor(Internal\ReflectionClassFactory $refl) |
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| 338 | |||
| 339 | /** |
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| 340 | * Determine if unresolvable class name has cloneable. |
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| 341 | * |
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| 342 | * @param \ReflectionClass $refl The current reflection class object. |
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| 343 | * @return boolean |
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| 344 | */ |
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| 345 | protected function isCloneable(Internal\ReflectionClassFactory $refl) |
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| 349 | |||
| 350 | /** |
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| 351 | * Determine if unresolvable class name has serializable. |
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| 352 | * |
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| 353 | * @param \ReflectionClass $refl The current reflection class object. |
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| 354 | * @return boolean |
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| 355 | */ |
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| 356 | protected function isSerializable(Internal\ReflectionClassFactory $refl) |
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| 360 | |||
| 361 | /** |
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| 362 | * Resolving class name without constructor. |
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| 363 | * |
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| 364 | * @param \ReflectionClass $refl An instance of \ReflectionClass |
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| 365 | */ |
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| 366 | protected function resolveInstanceWithoutConstructor(Internal\ReflectionClassFactory $refl) |
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| 370 | |||
| 371 | /** |
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| 372 | * Get method parameters. |
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| 373 | * |
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| 374 | * @param \ReflectionClass $refl An reflection class instance. |
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| 375 | * @param string $method The method name. |
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| 376 | * @return array |
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| 377 | */ |
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| 378 | protected function getMethodParameters(Internal\ReflectionClassFactory $refl, $method) |
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| 382 | |||
| 383 | /** |
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| 384 | * Mark resolved class name to true. |
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| 385 | * |
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| 386 | * @param string $abstract The resolved class name. |
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| 387 | * @return void |
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| 388 | */ |
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| 389 | protected function markAsResolved($abstract) |
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| 397 | |||
| 398 | /** |
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| 399 | * Bind service into binding container stack. |
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| 400 | * |
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| 401 | * @param string $abstract The unresolvable class name. |
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| 402 | * @param \Closure|string $concrete Closure or class name being bound to the class name. |
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| 403 | */ |
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| 404 | public function bind($abstract, $concrete = null) |
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| 420 | |||
| 421 | /** |
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| 422 | * Bind service into binding container stack if supplied class name |
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| 423 | * not being bound. |
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| 424 | * |
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| 425 | * @param string $abstract The unresolvable class name. |
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| 426 | * @param \Closure|string $concrete Closure or class name begin bound to the class name. |
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| 427 | */ |
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| 428 | public function bindIf($abstract, $concrete) |
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| 434 | |||
| 435 | /** |
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| 436 | * Call defined instance. |
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| 437 | * |
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| 438 | * @param string $instance The class name to invoke/call. |
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| 439 | * @param array $args The class name __invoke method argument. |
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| 440 | * @return mixed|void |
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| 441 | */ |
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| 442 | public function callInstance($instance, $args = []) |
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| 452 | |||
| 453 | /** |
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| 454 | * Determine if class name has been bound or not. |
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| 455 | * |
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| 456 | * @param string $abstract The unresolvable class name. |
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| 457 | * @return bool |
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| 458 | */ |
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| 459 | public function isBound($abstract) |
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| 463 | |||
| 464 | /** |
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| 465 | * Turn class name into resolvable closure. |
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| 466 | * |
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| 467 | * @param string $abstract The class name |
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| 468 | * @param \Closure|string $concrete Can be instance of \Closure or class name. |
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| 469 | * @return \Closure |
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| 470 | */ |
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| 471 | protected function turnIntoResolvableClosure($abstract, $concrete) |
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| 478 | } |
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| 479 |
If you define a variable conditionally, it can happen that it is not defined for all execution paths.
Let’s take a look at an example:
In the above example, the variable $x is defined if you pass “foo” or “bar” as argument for $a. However, since the switch statement has no default case statement, if you pass any other value, the variable $x would be undefined.
Available Fixes
Check for existence of the variable explicitly:
Define a default value for the variable:
Add a value for the missing path: