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: