Duplicate code is one of the most pungent code smells. A rule that is often used is to re-structure code once it is duplicated in three or more places.
Common duplication problems, and corresponding solutions are:
Complex classes like DisplayTab 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 DisplayTab, and based on these observations, apply Extract Interface, too.
| 1 | <?php |
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| 28 | class DisplayTab implements TabInterface, DisplayInterface, FormInterface |
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| 29 | { |
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| 30 | use VisibleCondition, \SleepingOwl\Admin\Traits\Renderable; |
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| 31 | |||
| 32 | /** |
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| 33 | * @var string |
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| 34 | */ |
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| 35 | protected $label; |
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| 36 | |||
| 37 | /** |
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| 38 | * @var bool |
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| 39 | */ |
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| 40 | protected $active = false; |
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| 41 | |||
| 42 | /** |
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| 43 | * @var string |
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| 44 | */ |
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| 45 | protected $name; |
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| 46 | |||
| 47 | /** |
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| 48 | * @var string |
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| 49 | */ |
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| 50 | protected $icon; |
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| 51 | |||
| 52 | /** |
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| 53 | * @var Renderable |
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| 54 | */ |
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| 55 | protected $content; |
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| 56 | |||
| 57 | /** |
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| 58 | * @var |
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| 59 | */ |
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| 60 | protected $badge; |
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| 61 | |||
| 62 | /** |
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| 63 | * @var string |
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| 64 | */ |
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| 65 | protected $view = 'display.tab'; |
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| 66 | |||
| 67 | /** |
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| 68 | * @param Renderable $content |
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| 69 | * @param string|null $label |
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| 70 | * @param string|null $icon |
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| 71 | * @param Badge|string|\Closure|null $badge |
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| 72 | */ |
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| 73 | 27 | public function __construct(Renderable $content, $label = null, $icon = null, $badge = null) |
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| 89 | |||
| 90 | /** |
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| 91 | * @param Badge|string|\Closure|null $badge |
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| 92 | * @return $this |
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| 93 | */ |
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| 94 | public function setBadge($badge) |
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| 108 | |||
| 109 | /** |
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| 110 | * @return mixed |
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| 111 | */ |
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| 112 | 1 | public function getBadge() |
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| 116 | |||
| 117 | /** |
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| 118 | * @return string |
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| 119 | */ |
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| 120 | 4 | public function getLabel() |
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| 124 | |||
| 125 | /** |
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| 126 | * @param string $label |
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| 127 | * |
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| 128 | * @return $this |
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| 129 | */ |
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| 130 | 3 | public function setLabel($label) |
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| 136 | |||
| 137 | /** |
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| 138 | * @return bool |
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| 139 | */ |
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| 140 | 2 | public function isActive() |
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| 144 | |||
| 145 | /** |
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| 146 | * @param bool $active |
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| 147 | * |
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| 148 | * @return $this |
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| 149 | */ |
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| 150 | 1 | public function setActive($active = true) |
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| 156 | |||
| 157 | /** |
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| 158 | * @return $this |
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| 159 | */ |
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| 160 | public function addTabElement() |
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| 212 | |||
| 213 | /** |
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| 214 | * @return string |
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| 215 | * @throws DisplayTabException |
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| 216 | */ |
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| 217 | 3 | public function getName() |
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| 227 | |||
| 228 | /** |
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| 229 | * @param string $name |
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| 230 | * |
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| 231 | * @return $this |
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| 232 | */ |
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| 233 | 1 | public function setName($name) |
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| 239 | |||
| 240 | /** |
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| 241 | * @return string |
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| 242 | */ |
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| 243 | 2 | public function getIcon() |
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| 247 | |||
| 248 | /** |
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| 249 | * @param string $icon |
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| 250 | * |
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| 251 | * @return $this |
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| 252 | */ |
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| 253 | 1 | public function setIcon($icon) |
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| 259 | |||
| 260 | /** |
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| 261 | * @return Renderable |
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| 262 | */ |
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| 263 | 19 | public function getContent() |
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| 267 | |||
| 268 | /** |
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| 269 | * @param string $class |
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| 270 | * |
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| 271 | * @return $this |
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| 272 | */ |
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| 273 | 2 | public function setModelClass($class) |
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| 281 | |||
| 282 | /** |
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| 283 | * Initialize tab. |
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| 284 | * |
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| 285 | * @return $this |
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| 286 | */ |
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| 287 | 2 | public function initialize() |
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| 295 | |||
| 296 | /** |
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| 297 | * @param string $action |
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| 298 | * |
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| 299 | * @return $this |
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| 300 | */ |
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| 301 | 2 | public function setAction($action) |
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| 309 | |||
| 310 | /** |
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| 311 | * @param int $id |
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| 312 | * |
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| 313 | * @return $this |
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| 314 | */ |
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| 315 | 2 | public function setId($id) |
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| 323 | |||
| 324 | /** |
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| 325 | * @param \Illuminate\Http\Request $request |
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| 326 | * @param ModelConfigurationInterface $model |
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| 327 | * |
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| 328 | * @throws ValidationException |
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| 329 | */ |
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| 330 | 2 | public function validateForm(\Illuminate\Http\Request $request, ModelConfigurationInterface $model = null) |
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| 336 | |||
| 337 | /** |
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| 338 | * Save model. |
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| 339 | * |
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| 340 | * @param \Illuminate\Http\Request $request |
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| 341 | * @param ModelConfigurationInterface $model |
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| 342 | * |
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| 343 | * @return void |
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| 344 | */ |
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| 345 | 2 | public function saveForm(\Illuminate\Http\Request $request, ModelConfigurationInterface $model = null) |
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| 351 | |||
| 352 | /** |
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| 353 | * Set currently rendered instance. |
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| 354 | * |
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| 355 | * @param Model $model |
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| 356 | * |
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| 357 | * @return $this |
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| 358 | */ |
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| 359 | 2 | public function setModel(Model $model) |
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| 367 | |||
| 368 | /** |
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| 369 | * @return Model $model |
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| 370 | */ |
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| 371 | 2 | public function getModel() |
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| 377 | |||
| 378 | /** |
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| 379 | * Get form item validation rules. |
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| 380 | * @return array |
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| 381 | */ |
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| 382 | 2 | public function getValidationRules() |
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| 390 | |||
| 391 | /** |
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| 392 | * @return array |
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| 393 | */ |
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| 394 | 2 | public function getValidationMessages() |
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| 402 | |||
| 403 | /** |
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| 404 | * @return array |
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| 405 | */ |
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| 406 | 2 | public function getValidationLabels() |
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| 414 | |||
| 415 | /** |
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| 416 | * @param \Illuminate\Http\Request $request |
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| 417 | * |
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| 418 | * @return void |
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| 419 | */ |
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| 420 | 2 | public function save(\Illuminate\Http\Request $request) |
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| 426 | |||
| 427 | /** |
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| 428 | * @param \Illuminate\Http\Request $request |
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| 429 | * |
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| 430 | * @return void |
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| 431 | */ |
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| 432 | 2 | public function afterSave(\Illuminate\Http\Request $request) |
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| 438 | |||
| 439 | /** |
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| 440 | * @return mixed |
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| 441 | */ |
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| 442 | 2 | public function getValue() |
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| 448 | |||
| 449 | /** |
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| 450 | * @return bool |
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| 451 | */ |
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| 452 | 2 | public function isReadonly() |
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| 460 | |||
| 461 | /** |
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| 462 | * @return bool |
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| 463 | */ |
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| 464 | public function isValueSkipped() |
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| 472 | |||
| 473 | /** |
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| 474 | * @param string $path |
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| 475 | * |
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| 476 | * @return FormElementInterface|null |
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| 477 | */ |
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| 478 | 2 | public function getElement($path) |
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| 484 | |||
| 485 | /** |
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| 486 | * @return FormElementsCollection |
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| 487 | */ |
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| 488 | 2 | public function getElements() |
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| 496 | |||
| 497 | /** |
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| 498 | * @param array $elements |
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| 499 | * |
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| 500 | * @return $this |
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| 501 | */ |
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| 502 | 2 | public function setElements(array $elements) |
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| 510 | |||
| 511 | /** |
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| 512 | * @return array |
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| 513 | */ |
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| 514 | 1 | public function toArray() |
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| 524 | } |
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| 525 |
Let’s take a look at an example:
In the above example, the authenticate() method works fine as long as you just pass instances of MyUser. However, if you now also want to pass a different implementation of User which does not have a getDisplayName() method, the code will break.
Available Fixes
Change the type-hint for the parameter:
Add an additional type-check:
Add the method to the interface: