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:
| 1 | <?php | ||
| 28 | class HistorySubscriber extends AbstractTimerSubscriber | ||
| 29 | { | ||
| 30 | /** | ||
| 31 | * @var JournalInterface | ||
| 32 | */ | ||
| 33 | private $journal; | ||
| 34 | |||
| 35 | /** | ||
| 36 | * @param JournalInterface|null $journal | ||
| 37 | * @param TimerInterface|null $timer | ||
| 38 | */ | ||
| 39 | 45 | public function __construct(JournalInterface $journal = null, TimerInterface $timer = null) | |
| 45 | |||
| 46 | /** | ||
| 47 | * @return JournalInterface | ||
| 48 | */ | ||
| 49 | 18 | public function getJournal() | |
| 53 | |||
| 54 | /** | ||
| 55 | * @param RequestCreatedEvent $event | ||
| 56 | */ | ||
| 57 | 9 | public function onRequestCreated(RequestCreatedEvent $event) | |
| 61 | |||
| 62 | /** | ||
| 63 | * @param RequestSentEvent $event | ||
| 64 | */ | ||
| 65 | 9 | public function onRequestSent(RequestSentEvent $event) | |
| 69 | |||
| 70 | /** | ||
| 71 | * @param MultiRequestCreatedEvent $event | ||
| 72 | */ | ||
| 73 | 9 | public function onMultiRequestCreated(MultiRequestCreatedEvent $event) | |
| 80 | |||
| 81 | /** | ||
| 82 | * @param MultiRequestSentEvent $event | ||
| 83 | */ | ||
| 84 | 9 | View Code Duplication | public function onMultiRequestSent(MultiRequestSentEvent $event) | 
| 93 | |||
| 94 | /** | ||
| 95 |      * {@inheritdoc} | ||
| 96 | */ | ||
| 97 | 9 | public static function getSubscribedEvents() | |
| 106 | |||
| 107 | /** | ||
| 108 | * @param InternalRequestInterface $internalRequest | ||
| 109 | * @param ResponseInterface $response | ||
| 110 | * | ||
| 111 | * @return InternalRequestInterface | ||
| 112 | */ | ||
| 113 | 18 | private function record(InternalRequestInterface $internalRequest, ResponseInterface $response) | |
| 120 | } | ||
| 121 | 
Unless you are absolutely sure that the expression can never be null because of other conditions, we strongly recommend to add an additional type check to your code: