Complex classes like FileCache 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 FileCache, and based on these observations, apply Extract Interface, too.
| 1 | <?php |
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| 22 | class FileCache implements CacheInterface, CounterInterface |
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| 23 | { |
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| 24 | // TODO garbage collection |
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| 25 | |||
| 26 | /** |
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| 27 | * @var string control characters for keys, reserved by PSR-16 |
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| 28 | */ |
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| 29 | const PSR16_RESERVED = '/\{|\}|\(|\)|\/|\\\\|\@|\:/u'; |
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| 30 | |||
| 31 | /** |
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| 32 | * @var string |
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| 33 | */ |
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| 34 | private $cache_path; |
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| 35 | |||
| 36 | /** |
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| 37 | * @var int |
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| 38 | */ |
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| 39 | private $default_ttl; |
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| 40 | |||
| 41 | /** |
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| 42 | * @param string $cache_path absolute root path of cache-file folder |
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| 43 | * @param int $default_ttl default time-to-live (in seconds) |
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| 44 | * |
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| 45 | * @throws InvalidArgumentException if the specified cache-path does not exist (or is not writable) |
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| 46 | */ |
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| 47 | 13 | public function __construct($cache_path, $default_ttl) |
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| 66 | |||
| 67 | public function get($key, $default = null) |
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| 101 | |||
| 102 | public function set($key, $value, $ttl = null) |
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| 136 | |||
| 137 | public function delete($key) |
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| 141 | |||
| 142 | public function clear() |
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| 150 | |||
| 151 | public function getMultiple($keys) |
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| 161 | |||
| 162 | public function setMultiple($items, $ttl = null) |
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| 172 | |||
| 173 | public function deleteMultiple($keys) |
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| 179 | |||
| 180 | public function has($key) |
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| 184 | |||
| 185 | public function increment($key, $step = 1) |
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| 209 | |||
| 210 | public function decrement($key, $step = 1) |
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| 214 | |||
| 215 | /** |
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| 216 | * Clean up expired cache-files. |
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| 217 | * |
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| 218 | * This method is outside the scope of the PSR-16 cache concept, and is specific to |
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| 219 | * this implementation, being a file-cache. |
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| 220 | * |
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| 221 | * In scenarios with dynamic keys (such as Session IDs) you should call this method |
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| 222 | * periodically - for example from a scheduled daily cron-job. |
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| 223 | * |
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| 224 | * @return void |
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| 225 | */ |
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| 226 | public function cleanExpired() |
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| 238 | |||
| 239 | /** |
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| 240 | * For a given cache key, obtain the absolute file path |
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| 241 | * |
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| 242 | * @param string $key |
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| 243 | * |
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| 244 | * @return string absolute path to cache-file |
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| 245 | * |
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| 246 | * @throws InvalidArgumentException if the specified key contains a character reserved by PSR-16 |
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| 247 | */ |
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| 248 | protected function getPath($key) |
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| 264 | |||
| 265 | /** |
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| 266 | * @return int current timestamp |
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| 267 | */ |
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| 268 | 13 | protected function getTime() |
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| 272 | |||
| 273 | /** |
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| 274 | * @return Generator|string[] |
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| 275 | */ |
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| 276 | protected function listPaths() |
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| 293 | } |
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| 294 |
If you suppress an error, we recommend checking for the error condition explicitly: