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 User 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 User, and based on these observations, apply Extract Interface, too.
| 1 | <?php | ||
| 50 | class User implements IUser { | ||
| 51 | use EventEmitterTrait, EmptyStringTrait; | ||
| 52 | |||
| 53 | /** @var Account */ | ||
| 54 | private $account; | ||
| 55 | |||
| 56 | /** @var Emitter|Manager $emitter */ | ||
| 57 | private $emitter; | ||
| 58 | |||
| 59 | /** @var \OCP\IConfig $config */ | ||
| 60 | private $config; | ||
| 61 | |||
| 62 | /** @var IAvatarManager */ | ||
| 63 | private $avatarManager; | ||
| 64 | |||
| 65 | /** @var IURLGenerator */ | ||
| 66 | private $urlGenerator; | ||
| 67 | |||
| 68 | /** @var EventDispatcher */ | ||
| 69 | private $eventDispatcher; | ||
| 70 | |||
| 71 | /** @var AccountMapper */ | ||
| 72 | private $mapper; | ||
| 73 | |||
| 74 | /** @var \OC\Group\Manager */ | ||
| 75 | private $groupManager; | ||
| 76 | |||
| 77 | /** @var Session */ | ||
| 78 | private $userSession; | ||
| 79 | |||
| 80 | /** | ||
| 81 | * User constructor. | ||
| 82 | * | ||
| 83 | * @param Account $account | ||
| 84 | * @param AccountMapper $mapper | ||
| 85 | * @param null $emitter | ||
| 86 | * @param IConfig|null $config | ||
| 87 | * @param null $urlGenerator | ||
| 88 | * @param EventDispatcher|null $eventDispatcher | ||
| 89 | * @param \OC\Group\Manager|null $groupManager | ||
| 90 | * @param Session|null $userSession | ||
| 91 | */ | ||
| 92 | public function __construct(Account $account, AccountMapper $mapper, $emitter = null, IConfig $config = null, | ||
| 117 | |||
| 118 | /** | ||
| 119 | * get the user id | ||
| 120 | * | ||
| 121 | * @return string | ||
| 122 | */ | ||
| 123 | 	public function getUID() { | ||
| 126 | |||
| 127 | /** | ||
| 128 | * get the display name for the user, if no specific display name is set it will fallback to the user id | ||
| 129 | * | ||
| 130 | * @return string | ||
| 131 | */ | ||
| 132 | 	public function getDisplayName() { | ||
| 139 | |||
| 140 | /** | ||
| 141 | * set the displayname for the user | ||
| 142 | * | ||
| 143 | * @param string $displayName | ||
| 144 | * @return bool | ||
| 145 | */ | ||
| 146 | 	public function setDisplayName($displayName) { | ||
| 166 | |||
| 167 | /** | ||
| 168 | * set the email address of the user | ||
| 169 | * | ||
| 170 | * @param string|null $mailAddress | ||
| 171 | * @return void | ||
| 172 | * @since 9.0.0 | ||
| 173 | */ | ||
| 174 | 	public function setEMailAddress($mailAddress) { | ||
| 183 | |||
| 184 | /** | ||
| 185 | * returns the timestamp of the user's last login or 0 if the user did never | ||
| 186 | * login | ||
| 187 | * | ||
| 188 | * @return int | ||
| 189 | */ | ||
| 190 | 	public function getLastLogin() { | ||
| 193 | |||
| 194 | /** | ||
| 195 | * updates the timestamp of the most recent login of this user | ||
| 196 | */ | ||
| 197 | 	public function updateLastLoginTimestamp() { | ||
| 203 | |||
| 204 | /** | ||
| 205 | * Delete the user | ||
| 206 | * | ||
| 207 | * @return bool | ||
| 208 | */ | ||
| 209 | 	public function delete() { | ||
| 254 | |||
| 255 | /** | ||
| 256 | * Set the user's password | ||
| 257 | * | ||
| 258 | * @param string $password | ||
| 259 | * @param string $recoveryPassword for the encryption app to reset encryption keys | ||
| 260 | * @return bool | ||
| 261 | * @throws ArgumentNotSetException | ||
| 262 | */ | ||
| 263 | 	public function setPassword($password, $recoveryPassword = null) { | ||
| 295 | |||
| 296 | /** | ||
| 297 | * get the users home folder to mount | ||
| 298 | * | ||
| 299 | * @return string | ||
| 300 | */ | ||
| 301 | 	public function getHome() { | ||
| 304 | |||
| 305 | /** | ||
| 306 | * Get the name of the backend class the user is connected with | ||
| 307 | * | ||
| 308 | * @return string | ||
| 309 | */ | ||
| 310 | 	public function getBackendClassName() { | ||
| 317 | |||
| 318 | /** | ||
| 319 | * check if the backend allows the user to change his avatar on Personal page | ||
| 320 | * | ||
| 321 | * @return bool | ||
| 322 | */ | ||
| 323 | 	public function canChangeAvatar() { | ||
| 333 | |||
| 334 | /** | ||
| 335 | * check if the backend supports changing passwords | ||
| 336 | * | ||
| 337 | * @return bool | ||
| 338 | */ | ||
| 339 | 	public function canChangePassword() { | ||
| 346 | |||
| 347 | /** | ||
| 348 | * check if the backend supports changing display names | ||
| 349 | * | ||
| 350 | * @return bool | ||
| 351 | */ | ||
| 352 | 	public function canChangeDisplayName() { | ||
| 370 | |||
| 371 | /** | ||
| 372 | * check if the user is enabled | ||
| 373 | * | ||
| 374 | * @return bool | ||
| 375 | */ | ||
| 376 | 	public function isEnabled() { | ||
| 379 | |||
| 380 | /** | ||
| 381 | * set the enabled status for the user | ||
| 382 | * | ||
| 383 | * @param bool $enabled | ||
| 384 | */ | ||
| 385 | 	public function setEnabled($enabled) { | ||
| 397 | |||
| 398 | /** | ||
| 399 | * get the users email address | ||
| 400 | * | ||
| 401 | * @return string|null | ||
| 402 | * @since 9.0.0 | ||
| 403 | */ | ||
| 404 | 	public function getEMailAddress() { | ||
| 407 | |||
| 408 | /** | ||
| 409 | * get the users' quota | ||
| 410 | * | ||
| 411 | * @return string | ||
| 412 | * @since 9.0.0 | ||
| 413 | */ | ||
| 414 | 	public function getQuota() { | ||
| 421 | |||
| 422 | /** | ||
| 423 | * set the users' quota | ||
| 424 | * | ||
| 425 | * @param string $quota | ||
| 426 | * @return void | ||
| 427 | * @since 9.0.0 | ||
| 428 | */ | ||
| 429 | 	public function setQuota($quota) { | ||
| 438 | |||
| 439 | /** | ||
| 440 | * get the avatar image if it exists | ||
| 441 | * | ||
| 442 | * @param int $size | ||
| 443 | * @return IImage|null | ||
| 444 | * @since 9.0.0 | ||
| 445 | */ | ||
| 446 | 	public function getAvatarImage($size) { | ||
| 460 | |||
| 461 | /** | ||
| 462 | * get the federation cloud id | ||
| 463 | * | ||
| 464 | * @return string | ||
| 465 | * @since 9.0.0 | ||
| 466 | */ | ||
| 467 | 	public function getCloudId() { | ||
| 472 | |||
| 473 | /** | ||
| 474 | * @param string $url | ||
| 475 | * @return string | ||
| 476 | */ | ||
| 477 | View Code Duplication | 	private function removeProtocolFromUrl($url) { | |
| 486 | |||
| 487 | 	public function triggerChange($feature, $value = null) { | ||
| 492 | |||
| 493 | /** | ||
| 494 | * @return string[] | ||
| 495 | * @since 10.0.1 | ||
| 496 | */ | ||
| 497 | 	public function getSearchTerms() { | ||
| 504 | |||
| 505 | /** | ||
| 506 | * @param string[] $terms | ||
| 507 | * @since 10.0.1 | ||
| 508 | */ | ||
| 509 | 	public function setSearchTerms(array $terms) { | ||
| 516 | } | ||
| 517 | 
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: