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 Cache 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 Cache, and based on these observations, apply Extract Interface, too.
| 1 | <?php |
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| 17 | class Cache implements iCache |
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| 18 | { |
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| 19 | |||
| 20 | /** |
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| 21 | * @var iAdapter |
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| 22 | */ |
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| 23 | private $adapter; |
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| 24 | |||
| 25 | /** |
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| 26 | * @var iSerializer |
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| 27 | */ |
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| 28 | private $serializer; |
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| 29 | |||
| 30 | /** |
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| 31 | * @var string |
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| 32 | */ |
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| 33 | private $prefix = ''; |
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| 34 | |||
| 35 | /** |
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| 36 | * @var bool |
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| 37 | */ |
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| 38 | private $isReady = false; |
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| 39 | |||
| 40 | /** |
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| 41 | * @var bool |
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| 42 | */ |
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| 43 | private $isActive = true; |
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| 44 | |||
| 45 | /** |
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| 46 | * @var mixed no cache, if admin-session is set |
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| 47 | */ |
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| 48 | private $isAdminSession = false; |
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| 49 | |||
| 50 | /** |
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| 51 | * __construct |
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| 52 | * |
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| 53 | * @param null|iAdapter $adapter |
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| 54 | * @param null|iSerializer $serializer |
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| 55 | * @param boolean $checkForUser check for dev-ip or if cms-user is logged-in |
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| 56 | * @param boolean $cacheEnabled false will disable the cache (use it e.g. for global settings) |
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| 57 | * @param string|boolean $isAdminSession set a user-id, if the user is a admin (so we can disable cache for this |
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| 58 | * user) |
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| 59 | */ |
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| 60 | 39 | public function __construct($adapter = null, $serializer = null, $checkForUser = true, $cacheEnabled = true, $isAdminSession = false) |
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| 102 | |||
| 103 | /** |
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| 104 | * enable / disable the cache |
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| 105 | * |
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| 106 | * @param boolean $isActive |
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| 107 | */ |
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| 108 | 39 | public function setActive($isActive) |
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| 112 | |||
| 113 | /** |
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| 114 | * check if the current use is a admin || dev || server == client |
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| 115 | * |
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| 116 | * @return bool |
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| 117 | */ |
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| 118 | public function isCacheActiveForTheCurrentUser() |
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| 146 | |||
| 147 | /** |
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| 148 | * returns the IP address of the client |
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| 149 | * |
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| 150 | * @param bool $trust_proxy_headers Whether or not to trust the |
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| 151 | * proxy headers HTTP_CLIENT_IP |
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| 152 | * and HTTP_X_FORWARDED_FOR. ONLY |
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| 153 | * use if your $_SERVER is behind a |
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| 154 | * proxy that sets these values |
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| 155 | * |
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| 156 | * @return string |
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| 157 | */ |
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| 158 | private function getClientIp($trust_proxy_headers = false) |
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| 176 | |||
| 177 | /** |
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| 178 | * check for developer |
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| 179 | * |
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| 180 | * @return bool |
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| 181 | */ |
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| 182 | private function checkForDev() |
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| 211 | |||
| 212 | /** |
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| 213 | * set the default-prefix via "SERVER"-var + "SESSION"-language |
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| 214 | */ |
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| 215 | 39 | protected function getTheDefaultPrefix() |
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| 223 | |||
| 224 | /** |
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| 225 | * auto-connect to the available cache-system on the server |
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| 226 | * |
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| 227 | * @return iAdapter |
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| 228 | */ |
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| 229 | protected function autoConnectToAvailableCacheSystem() |
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| 348 | |||
| 349 | /** |
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| 350 | * set cacheIsReady state |
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| 351 | * |
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| 352 | * @param boolean $isReady |
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| 353 | */ |
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| 354 | 39 | private function setCacheIsReady($isReady) |
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| 358 | |||
| 359 | /** |
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| 360 | * get the cacheIsReady state |
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| 361 | * |
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| 362 | * @return boolean |
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| 363 | */ |
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| 364 | 5 | public function getCacheIsReady() |
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| 368 | |||
| 369 | /** |
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| 370 | * get cached-item by key |
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| 371 | * |
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| 372 | * @param string $key |
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| 373 | * |
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| 374 | * @return mixed |
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| 375 | */ |
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| 376 | 18 | public function getItem($key) |
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| 388 | |||
| 389 | /** |
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| 390 | * calculate store-key (prefix + $rawKey) |
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| 391 | * |
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| 392 | * @param String $rawKey |
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| 393 | * |
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| 394 | * @return string |
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| 395 | */ |
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| 396 | 33 | private function calculateStoreKey($rawKey) |
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| 406 | |||
| 407 | /** |
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| 408 | * @param $str |
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| 409 | * |
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| 410 | * @return string |
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| 411 | */ |
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| 412 | 5 | private function cleanStoreKey($str) |
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| 438 | |||
| 439 | /** |
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| 440 | * @return mixed |
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| 441 | */ |
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| 442 | 33 | public function getPrefix() |
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| 446 | |||
| 447 | /** |
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| 448 | * set prefix [WARNING: do not use if you don't know what you do] |
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| 449 | * |
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| 450 | * @param string $prefix |
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| 451 | */ |
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| 452 | 39 | public function setPrefix($prefix) |
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| 456 | |||
| 457 | /** |
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| 458 | * set cache-item by key => value + date |
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| 459 | * |
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| 460 | * @param string $key |
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| 461 | * @param mixed $value |
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| 462 | * @param \DateTime $date |
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| 463 | * |
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| 464 | * @return mixed|void |
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| 465 | * @throws \Exception |
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| 466 | */ |
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| 467 | 7 | public function setItemToDate($key, $value, \DateTime $date) |
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| 479 | |||
| 480 | /** |
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| 481 | * set cache-item by key => value + ttl |
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| 482 | * |
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| 483 | * @param string $key |
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| 484 | * @param mixed $value |
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| 485 | * @param int $ttl |
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| 486 | * |
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| 487 | * @return bool |
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| 488 | */ |
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| 489 | 18 | public function setItem($key, $value, $ttl = 0) |
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| 508 | |||
| 509 | /** |
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| 510 | * remove cached-item |
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| 511 | * |
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| 512 | * @param string $key |
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| 513 | * |
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| 514 | * @return bool |
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| 515 | */ |
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| 516 | 1 | View Code Duplication | public function removeItem($key) |
| 526 | |||
| 527 | /** |
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| 528 | * check if cached-item exists |
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| 529 | * |
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| 530 | * @param string $key |
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| 531 | * |
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| 532 | * @return boolean |
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| 533 | */ |
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| 534 | 6 | View Code Duplication | public function existsItem($key) |
| 544 | |||
| 545 | } |
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| 546 |
Instead of super-globals, we recommend to explicitly inject the dependencies of your class. This makes your code less dependent on global state and it becomes generally more testable: